fall 2000 vol. 43, no. 4

Louisiana Agriculture, Fall 2000 1

Fall 2000Vol. 43, No. 4Fall 2000Vol. 43, No. 4

Beef IssueBeef Issue

2 Louisiana Agriculture, Fall 2000

EDITORIAL BOARD:David J. Boethel (Chairman)Linda Foster BenedictPat BollichJames ChambersBarbara Groves CornsJane HoneycuttJeffrey W. HoyRichard F. Kazmierczak Jr.James A. OtteaDavid Sanson

Published quarterly by the LouisianaAgricultural Experiment Station,Louisiana State University AgriculturalCenter, Baton Rouge, Louisiana.Subscriptions are free. Send requestsand any comments or questions to:

Linda Foster Benedict, EditorLouisiana AgricultureP.O. Box 25100Baton Rouge, LA 70894-5100

phone (225) 388-2263fax (225) 388-4524e-mail [email protected].

www.lsuagcenter.com

EDITOR: Linda Foster Benedict

COPY EDITOR: Jane Honeycutt

PHOTO EDITOR: John Wozniak

DESIGNER: Barbara Groves Corns

The mention of a pesticide or use of a tradename for any product is intended only as areport of research and does not constitute anendorsement or recommendation by the Loui-siana Agricultural Experiment Station, nor doesit imply that a mentioned product is superiorto other products of a similar nature notmentioned. Uses of pesticides discussed herehave not necessarily been approved by govern-mental regulatory agencies. Information onapproved uses normally appears on the manu-facturer’s label.

Material herein may be used by the press, radioand other media provided the meaning is notchanged. Please give credit to the author and tothe publication for any material used.

Louisiana State University AgriculturalCenter, William B. Richardson, Chancellor

Louisiana Agricultural ExperimentStation, R. Larry Rogers, Director

The Louisiana Agricultural ExperimentStation provides equal opportunities

in programs and employment.

On the cover: One day a year beef producers throughout the state who havesigned up for the Louisiana Calf-to-Carcass program bring their calves in forpreconditioning at one of three sites. These are the calves brought to the LSUAgCenter’s Idlewild Research Station near Clinton on Sept. 7, 2000. See the articlebeginning on page 16. Photo by John Wozniak

Belgian Blue breed bringsmore ‘lean’ into beef

LSU AgCenter scientists are completing their fifth year of a five-year project to testthe introduction of Belgian Blue breeding into Louisiana cattle. Belgian Blue is a breedproduced in Europe, including Belgium, known for its dense muscle.

“We in the United States tend to like our steaks a little more marbled thanEuropeans,” said Paul Humes, head of the LSU AgCenter’s Animal Science Department.“Europeans like to buy very lean meat.”

Leaner beef means less fat and cholesterol, which is becoming a more desired qualityby American consumers. LSU AgCenter research indicates that Belgian Blue combinedwith Louisiana breeds yields leaner beef. Because the beef has less fat and marbling, itgrades lower, which means less money for the producer. Louisiana producers who wantto incorporate Belgian Blue into their breeding programs will have to aim for a specialtymarket who desire this trait.

Members of the LSU AgCenter’s AgLeadership Program saw Belgian Bluesfirst-hand in Belgium during a Europeantour. Belgian Blues can range in colorfrom pure white to pure black. When theblack and white furs are mingled, theygive off a bluish hue, which is where thename came from. At left, Greg Daigle,research farm specialist at the IberiaResearch Station, overlooks three heifersin the Belgian Blue research project.

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Volume 43, Number 4, Fall 2000

Page 9

Page16

Page 29SCIENCE NOTES

4 Overview - A Diversified Industry Leader in Louisiana Agriculture Wayne E. Wyatt and Paul E. Humes

6 Perspective - Bullish on BeefDavid G. Morrison

7 Crossbreeding Research Meets Needs of Louisiana Beef IndustrySidney M. DeRouen, Donald E. Franke, Paul E. Humes and Wayne E. Wyatt

12 Improving Consumer Acceptance of Beef from Brahman CrossbredCattleThomas D. Bidner

14 Structural Change in the Beef IndustryJeffrey M. Gillespie and Alvin Schupp

16 Information-based Programs Prove Valuable to Beef Producers’FutureRonald P. Del Vecchio, Glen T. Gentry Jr., Danny F. Coombs and Darin A. Hylan

21 Controlling Horn FliesLane Foil, Montgomery Alison, Sidney M. DeRouen, Millard Kimball, David G. Morrison,David W. Sanson and Wayne E. Wyatt

24 Internal Parasites of Cattle:Seasonal Patterns of Infection and ControlJames C. Williams, Alvin F. Loyacano, Andy A. DeRosa and Jeffrey A. Gurie

26 New Assisted Reproductive Technologies for Use in the Cattle IndustryJoel Carter, Oscar Perez, Richard Denniston and Robert A. Godke

29 Synchronizing Beef Females for Artificial InseminationGlen T. Gentry Jr., Joe Lamb, Ronald P. Del Vecchio, Bruce M. Olcott and Robert A. Godke

32 Beef Cattle Nutrition Research Aims to Lower Costs,Improve ProductionDavid W. Sanson and Danny F. Coombs

34 Processing, Products and PackagingKenneth W. McMillin and J. Samuel Godber


9 Feedlot and Carcass Traits of Crossbred SteersSidney M. DeRouen, Wayne E. Wyatt, Thomas D. Bidner and Manuel A. Persica III

10 Predicted Calf Birth and Weaning Weights from RotationalCrossbreeding DataDonald E. Franke

13 Scientists Battle Cattle DiseasesSteven S. Nicholson

25 Comparing Beef Breeds by Birth, Weaning and Feedlot Performance Wayne E. Wyatt, Thomas D. Bidner, Paul E. Humes and Donald E. Franke

28 Effect of Synchronization on Beef Cattle EstrusGlen T. Gentry Jr., Ronald P. Del Vecchio and Robert A. Godke

31 Maintaining Adequate Body Condition Improves the Productivityof Young Beef CowsWayne E. Wyatt, Danny F. Coombs, Sidney M. DeRouen, Donald E. Franke, Jeffrey M. Gillespie,Paul E. Humes, David G. Morrison and T.W. White

35 Reduction of E. coli in Ground Beef with Gaseous OzoneKenneth W. McMillin and Michael E. Michel

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BeefA Diversified Industry Leaderin Louisiana in Louisiana in Louisiana in Louisiana in Louisiana AgriculturAgriculturAgriculturAgriculturAgricultureeeeeWayne E. Wyatt and Paul E. Humes

he Louisiana beef industry is asdiverse and complex as it is economi-cally important to the state. The beefindustry ranks within the top 10 Louisi-ana commodities in gross farm income(No. 6 at $237 million) and total value(No. 8 at $263 million) and is secondonly to poultry as the largest animalproduction enterprise in the state. The13,000 beef producers are in everyparish but Orleans.

Louisiana beef producers are adiverse group. Only about 40 percentconsider farming as their principaloccupation, and nearly 60 percent haveother jobs. Also, more than 65 percent ofthose producers who considered farmingas their principal occupation are retire-ment age (56 years or older); only 40percent of producers with other occupa-tions are retirement age. Of Louisiana’scattle producers, about 5.5 percent areminorities and 0.7 percent are women.

The Louisiana beef industry isdiverse in farm and herd size.Pastureland, rangeland and pasturedcropland account for 23.5 percent of thestate’s 7.9 million agricultural acres. Ofthose farms with cattle, 52 percent are onfewer than 100 acres. Similarly, 80percent of the farms have fewer than 50beef cows. About 37 percent of the totalrevenue generated by the sale of cattleand calves is from beef herds with fewerthan 50 head of cattle.

Consequently, a large and economi-cally important segment of the beefproducers in the state are part-time, andtheir cow-calf enterprise competes withthe demands of full-time employmentand family life. Producers with largeherds may benefit from economies ofscale, but most beef producers in thestate will not. Also, investments intechnology, management or productshaving marginal net returns mustcompete with the other commitments ofthe part-time beef producer. In thesesituations, the research “payoff” must besignificant if it is to be adopted oradapted by the producers.

The strength of the Louisiana beefindustry is an abundant forage supplyavailable most of the year. Reliance onforages introduces complexity, however,because forage resources (bermudagrass,dallisgrass, bahiagrass, fescue, ryegrass)and management of these resources varyconsiderably among our diverse soil

types and climates. The many forageresources available to Louisiana beefproducers are almost exclusively usedfor their nutritive value when harvestedby grazing. Managerial inputs signifi-cantly influence the feeding value ofthese resources. They are marketed noother way. Research conducted at theLSU AgCenter provides direction andinsight into the proper management ofthese forage resources across a widearray of environments.

The Louisiana beef industry isgenerally not vertically integrated, andproducers employ diverse productionsystems. Of the farms that have beefcattle, 87 percent maintain beef cows.Those cows account for 56 percent of thetotal beef cattle inventory. The predomi-nant production system is the cow-calfsystem, which is divided into commer-cial and purebred segments, and produc-ers’ goals differ for each segment. Theabundant forage base also allows for a“stocker” industry, in which calves afterweaning (6 to 9 months) are put onpasture to promote growth rather thanfattening. The producer then sells thesecalves at about 14 months of age tofeedlots. Similar to a stocker program,some producers participate in a replace-ment female (heifer) developmentprogram in which they market breedinganimals.

Producers in each of these produc-tion programs face numerous managerialchoices. Often it is difficult to knowwhat long-range effect a managementdecision may have. For instance, achoice made by the cow-calf producer,while benefiting his or her productionsystem, may not be the best choice forthe stocker program to which weanedcalves are marketed. LSU AgCenterscientists have the training and resourcesavailable to compare and evaluate manyof the managerial choices beef producersface. Information derived from their

Overview

Wayne E. Wyatt, Associate Professor, IberiaResearch Station, Jeanerette, La., and Paul E.Humes, Professor, Department of AnimalScience, LSU AgCenter, Baton Rouge, La.

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research helps producers make informeddecisions and provides insight forsubsequent production and marketingsystems.

The Louisiana beef producer hasavailable a wide selection of breedresources, many of which are relativelynew and must be evaluated in the contextof a subtropical environment. Certainlybreeds expressing adaptability to thesubtropical heat and humidity and theattendant pest challenges have playedand continued to play an important rolein Louisiana beef production. Whilethere is not a significant finishing orfeedlot system in Louisiana, producersare becoming more aware that theyparticipate in a national and global agri-food system to produce meat productsthat ultimately must meet with consumeracceptance. Consumer preferences aremany and varied, but most important isthe production of consistently safe, highquality beef products.

The diversity of herd and farm size,producers, soil and climate environ-

ments, production system goals andbreed resources provides a complexchallenge to beef scientists at the LSUAgCenter. Research relating to the beefindustry is conducted by seven campusdepartments (Agronomy, AgriculturalEconomics and Agribusiness, AnimalScience, Dairy Science, Entomology,Food Science and Veterinary Science)and nine research stations (Dean Lee,Hill Farm, Iberia, Idlewild, Northeast-Macon Ridge, Red River, Rosepine,Southeast and St. Gabriel). Academicbackgrounds of the scientists participat-ing in beef research include animalbreeders and geneticists, economists,entomologists, food scientists, forageagronomists, beef management special-ists, meat scientists, plant breeders,reproductive physiologists, ruminantnutritionists and veterinarians. LSUAgCenter scientists are involved in 36beef research projects, the duration ofwhich varies from three to six years.This research is divided into the follow-ing categories:

Breeding and genetics, 5Nutrition, forages and grazing, 17Management, 3Animal health, 6Reproduction and physiology, 5Marketing, economics andbusiness management, 3Meats and consumer acceptabilityof meat products, 6

We hope you enjoy this LouisianaAgriculture issue dedicated to beef. Themix of articles provides insight into theresearch conducted in support of the beefindustry. A goal of the LSU AgCenter isto provide access to research andextension programs and personnel. Tothat end, we encourage you to visit theLSU AgCenter beef web page atwww.agctr.lsu.edu/wwwac/beef/index.htm for a look at beef extensionprograms and ongoing and completedbeef research.

Wayne Wyatt uses a rising plate meter to estimate the amount of forage available for grazing on a pasture. This is part of a researchproject at the LSU AgCenter’s Iberia Research Station near Jeanerette to examine the net returns of grazing systems that either rotategrazing cattle among several smaller pastures or allow them to continuously graze on one larger pasture. Shown is a group of about 18cow-calf pairs that rotationally graze eight 2-acre paddocks throughout the year.

Photo by Mark Claesgens


Beef nimal agriculture is an integral

part of food-producing systems and hasbeen a significant contributor to farmprofitability, consumer health andnutrition, and economic development forhundreds of years. Today, beef cattleproduction is the largest segment of allof American agriculture, generatingmore than $40 billion annually. InLouisiana, beef cattle production affectsthe economy in 63 of the state’s 64

coupled with a rapidly increasingdemand by people to eat more protein.Statistics show that as personal incomesgo up in developing countries, so doesthe demand for meat, milk and eggs.

Total meat consumption is expectedto double in developing countries by theyear 2020 and will increase by 25percent in developed countries. Overall,global demand for meat is projected toincrease more than 60 percent of currentconsumption during the next twodecades. Breaking this down by animalspecies, demand for beef is expected toincrease by 50 percent; for pork, 45percent; and for poultry, 85 percent. Netmeat imports by developing countrieswill increase eightfold during this periodto 6.6 million tons.

Another reason for optimism in thebeef industry is increased per capitademand among U.S. citizens. In 1999,for the first time in 20 years, domesticconsumers increased their demand forbeef. Consumer spending for beef in1999 was up about $2.5 billion from1998. Per capita demand increased by4.5 percent to more than $180, nearly an$8 gain and the largest increase since1988. Consumer spending for beefincreased despite slightly higher prices.Per capita consumption of beef jumpedby 1.6 percent to 69.2 pounds perperson, and beef’s market share isexpected to hold steady in the nearfuture.

A third reason to be “bullish onbeef” is the positive change in consumerperception and attitudes about beef. Thisshift has been slow in coming, but moreand more research shows that beefshould be a major component of a heart-healthy diet. At least three differentstudies provide direct evidence that leanred meat can be included regularly aspart of a diet that reduces the risk ofheart disease. The lead researcher in themost recent study stated, “The caseagainst lean red meat has been misrepre-sented.”

No doubt the increased globaldemand for meat and the increaseddomestic demand for beef will stretchthe capacity of existing production anddistribution systems and may exacerbate

environmental concerns. But what anopportunity for LSU AgCenter animal,veterinary and food scientists! The“Livestock Revolution” points stronglyto the need for new investment in animalresearch to develop new technologiesand to apply known technologies toimprove production efficiency, nutri-tional quality and safety of beef and beefproducts.

Louisiana Agricultural ExperimentStation scientists are up to this challenge,as you will see as you read this publica-tion. Animal scientists are working toimprove beef tenderness through geneticselection, by taking advantage of breedcomplementarity and by applyingvarious post-harvest practices. They aredeveloping new assisted reproductiontechniques to increase fertility anddecrease embryonic death of livestockspecies. Nutritionists seek improvementsto cow-calf and stocker cattle productionefficiency through the judicious use ofgrain and byproduct feeds and throughalternative grazing strategies, which mayinclude new forage varieties and species.Veterinary scientists are discovering newand better disease detection, preventionand treatment methods for such diseasesas bovine respiratory disease, brucellosisand anaplasmosis. Additionally, as thebiology of external and internal parasitesis better understood, treatment regimesaimed at effective control while mini-mizing the progression of resistance arebeing developed. Food scientists areworking to develop new products withenhanced nutritional values while alsoresearching and identifying effectivemechanisms to ensure food safety.

Technological advances during thenext two decades will find solutions andcreate opportunities to facilitate theincreased need for beef and other meatproducts, both domestically and glo-bally. But this will not occur withoutcontinued investment in animal agricul-tural research and in the extension ofnew technologies to appropriate users.The challenges are clear: increaseproductive output and do it moreefficiently, and balance profits withstewardship and short-term productivitywith long-term sustainability.

Bullish on BeefBullish on BeefBullish on BeefBullish on BeefBullish on BeefDavid G. Morrison

Perspective

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David G. Morrison, Assistant Director forAnimal Sciences, Louisiana AgriculturalExperiment Station, LSU AgCenter, BatonRouge, La.

parishes and is among the top threeagricultural commodities in 35 parishes.Despite the current positive position beefoccupies, it and the rest of animalagriculture are on the brink of tremen-dous growth.

According to the International FoodPolicy Research Institute, a “demand-driven” livestock revolution is underway in the developing world. This willhave profound implications for globalagriculture, health, livelihoods and theenvironment. During the next 20 years,world population will increase by 32percent, and much of this increase willoccur in the cities of developing coun-tries. Per capita incomes are expected toincrease in all major developing regionsduring this period. This increase inaffluence and urbanization will be

David G. Morrison

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rossbreeding is a highly produc-tive, yet challenging, beef practice thatcan make a tremendous difference indetermining the economic success of abeef enterprise. Crossbreeding is themating of unrelated animals, such asdifferent breeds or species of beef cattle,to produce an animal geneticallysuperior to both its parents. This is calledheterosis or, more commonly, hybridvigor. Heterosis is the superiorityexhibited by the crossbred individual fora particular trait relative to the averageof the purebred parent breeds.

Levels of heterosis depend on thegenetic differences of the parents.Crosses among British or Europeancattle (Bos taurus) are expected toexpress some heterosis, whereas crossesamong Brahman (Bos indicus) and Bostaurus cattle are expected to expressmore heterosis because of greater geneticdiversity among these breeds. LSUAgCenter researchers were among thefirst to document the greater levelsof heterosis expressed by Brahmanwith British and European crosses.

Crossbreeding allows forbreed complementarity. Thismeans that desirable traits fromone breed such as heat tolerance,which is important in Louisiana,are combined with desirable traitsfrom another breed such asfertility, growth and carcassquality.

Another benefit of crossbreed-ing is that the effects of cross-breeding affect several traitspositively and can thus result in

Crossbreeding Research MeetsNeeds of Louisiana Beef IndustrySidney M. DeRouen, Donald E. Franke,Paul E. Humes and Wayne E. Wyatt

Sidney M. DeRouen, Associate Professor,Hill Farm Research Station, Homer, La.;Donald E. Franke, Professor, and Paul E.Humes, Professor and Head, Departmentof Animal Science, LSU AgCenter, BatonRouge, La.; Wayne E. Wyatt, AssociateProfessor, Iberia Research Station,Jeanerette, La.

First-cross Brahman crossbred cows aregenerally recognized as the more productivebrood cow for Louisiana. Top left is a first-crossBrahman x Hereford cow with an Angus-siredcalf. Above is a pair of first-cross Brahman xHereford cows with Angus-sired calves. At left isa first-cross Brahman x Hereford cow with aSimmental-sired calf.

large increases in overall productivity.Research has demonstrated that withplanned crossbreeding, pounds of calfweaned per cow exposed can be in-creased by as much as 25 percent.

For these reasons, crossbreedingplays a vital role in serving the commer-cial beef cattle industry in Louisiana andthroughout the United States.

Crossbreeding ValueRecognized Early

The value of crossbreeding beefcattle, in terms of adaptation to specificenvironments and the vigor associatedwith hybrid animals, was recognizedearly by Gulf Coast beef producers.Subsequently, crossbreeding research inthe southern United States was initiatedin Louisiana in 1916, and in Texas in1920. This pioneering research estab-lished a leadership role in beef cattlecrossbreeding research for these two

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Photos by Sidney M. DeRouen

states. Findings from these early studiesdocumented the beneficial effects ofcrossbreeding, particularly with Brah-man cattle.

Evaluation of specific breeds incrossbreeding systems with beef cattlewas initiated in the 1940s by the LSUAgCenter’s Department of AnimalScience at the Crossbreeding Unit, BenHur Farm. Mating systems involvingAngus, Brahman, Brangus, Hereford andShorthorn breeds were evaluated. TheCharolais breed also was evaluated laterin this study in the 1950s. Researchfindings from this project documentedthe superior performance of first-crosscalves compared to purebred calves.Furthermore, Brahman first-cross calveswere superior to Bos taurus first-crosses.These findings led into the next phase ofcrossbreeding research that was designedto evaluate the first-cross females.Brahman first-cross cows were found


superior in fertility and maternal traitscompared with Bos taurus first-crossfemales.

The potential for beneficial effectswith crossbreeding, particularly withBrahman breeding, led to furtherinvestigations at research stations innorth Louisiana. Crossbreeding researchwas conducted in the 1970s at the HillFarm and Red River research stations.These two separate research projectsinvestigated performance of purebredand crossbred cow-calf herds. Similarresults were reported from each of theseprojects demonstrating improvedproductivity through crossbreeding. Thegreatest advantage came with theBrahman crosses. Not long after theresults of these studies were published,Brahman cross cow-calf herds becamethe predominate breed type in northLouisiana.

Rotational CrossbreedingResearch

Development of planned cross-breeding mating systems becameincreasingly important for maintainingacceptable levels of heterosis from onegeneration to the next. In the early1970s, research was initiated to evaluaterotational crossbreeding systems for beefproduction at the Crossbreeding Unit,Ben Hur Farm. A major objective was todetermine the ability of this matingsystem to produce replacement females.At that time Brahman first-cross femaleswere difficult to obtain.

This long-term study evaluatedpurebred and two-, three- and four-breedrotational crossbred cattle. This researchinvolved five generations of rotationalcrossbreeding over a 23-year period.This study has progressed through moregenerations of matings than has anyother rotational crossbreeding study withbeef cattle in the United States.

The research found that rotationalcrossbred cattle do perform at theoreticalexpectations and that rotational cross-breeding can serve the industry needs.Today, primarily as a result of findingsfrom this project, several large U.S.ranches use rotational crossbreeding intheir breeding plans.

Continental and BrahmanComposite Breeds inCrossbreeding

Crossing Brahman cattle withBritish breeds (Angus, Hereford,Shorthorn) was a common practice forbeef production before the 1970s. In thelate 1960s, however, many Continentalbreeds (originating from continentalEurope) were introduced into the UnitedStates even though little was knownabout their productivity under southernU.S. environments. A crossbreedingproject was initiated in the mid-1970s atthe St. Gabriel Research Station toevaluate Brahman and Continental(Chianina, Maine Anjou and Simmental)crossbred females. Findings providedadditional evidence of the superiority ofthe Brahman crossbred female for cow-calf production.

In the 1980s, Brahman crossbredcattle were recognized as the mostadaptive and productive type of cattle inthe southern United States. This led tothe expansion of Brahman compositebeef breeds (Beefmaster, Brangus,Gelbray and Simbrah), which allowedproducers to have more simplifiedmating designs (mating like to like) thattook advantage of heterosis withBrahman breeding. Some of the Brah-man composite breeds had been devel-oped recently at this time, and little wasknown about their potential underLouisiana’s subtropical conditions. Inthe late 1980s, a crossbreeding projectwas initiated to evaluate Brahman-British and Brahman-Continentalcomposite breeds. This project wasconducted jointly at the Iberia, Idlewildand St. Gabriel research stations.Findings were some of the first compara-tive results among these compositebreeds, particularly for the Brahman-Continental composites.

Current CrossbreedingResearch

Even though Brahman crossbredcattle are the predominant type of cattlein Louisiana, they are discriminatedagainst because of the perception thatbeef from cattle with Brahman inherit-

ance is less tender and of lower carcassor eating quality. Two research projectsare evaluating beef tenderness andquality involving Brahman inheritance.Research at the Crossbreeding Unit isevaluating Brahman half-sib progenygroups (progeny produced from thesame sire) to identify specific Brahmansires that transmit genes for improvedmeat tenderness and carcass quality.Research at the Hill Farm ResearchStation is determining the most desirablecombination and proportion of Brahmanbreeding to use in crossbreeding sys-tems. Female productivity also is beingevaluated in this study. Findings willhelp producers identify and use Brahmansires with desirable genes for meattenderness and eating quality as well asto identify certain breed combinationsinvolving Brahman, British and Conti-nental breeds with desirable carcass andpalatability traits.

A new breed also is being evaluated.LSU AgCenter scientists are conductinga study at the Idlewild Research Stationevaluating a heavily muscled Continentalbreed called Belgian Blue to determinethis breed’s potential in a crossbreedingsystem under Louisiana’s environmentalconditions.

Cooperative beef crossbreedingresearch is conducted at the LSUAgCenter. Scientists with the Depart-ment of Animal Science, Hill Farm andIberia research stations work with otherscientists across the southern UnitedStates in pooling their resources tocollectively address research projectobjectives. Selection for milk yield andcalf weaning weight are being evaluatedto determine the effect these selectionpressures may have on cow fertility aswell as overall cow productivity.

Beef cattle crossbreeding researchfrom the LSU AgCenter is rich with pastaccomplishments and continues to servethe needs of the industry. LSU AgCenterscientists look forward to providingresearch that enhances the competitive-ness and profitability of the state’s beefcattle producers and ultimately providesthe consumer a safe, abundant and highquality supply of beef.


The future success of the beef industry depends on its abilityto produce cattle desired by the feeder and packer and ultimatelybeef products by the consumer. Therefore, emphasis on feedlotand carcass characteristics is becoming increasingly important indesigning and evaluating breeding systems. The objective of thisstudy was to compare straightbred- and composite-sired prog-eny that varied in percentage of Brahman inheritance for feedlotand carcass performance. British (Angus) and Continental(Gelbvieh) sire breeds were evaluated along with their Brahmanderivative counterparts (Brangus and Gelbray).

Feedlot and carcass data from 231 steers were evaluatedover a four-year period. All steers were produced by first-crossBrahman-Hereford cows at the LSU AgCenter’s Hill Farm Re-search Station. Angus- and Gelbvieh-sired steers had 25 percentBrahman inheritance, whereas Brangus- and Gelbray-sired steershad 44 percent Brahman inheritance. After weaning, all were fedon grass before being transferred to the feedlot. The 114 steersborn in 1993 and 1994 were shipped to feedlot facilities at theIberia Research Station. The 117 steers born in 1995 and 1996were shipped to a commercial feedlot in Guymon, Okla.

For steers fed in Louisiana, Angus- and Gelbvieh-sired steerswere 64 pounds heavier entering the feedlot than Brangus- andGelbray-sired steers. Likewise, Angus- and Gelbvieh-sired steerswere 112 pounds heavier at the end of the feeding period.Gelbray-sired steers had the lowest feedlot gain compared withthe other sire breeds when fed in Louisiana. Feedlot gain, initialand final feedlot weights were similar among sire breeds for steersfed in Oklahoma. Overall, feedlot gains were 50 percent higher inOklahoma than in Louisiana.

Feedlot and Carcass Traits of Crossbred SteersAngus- and Gelbvieh-sired steers fed in Louisiana were 62

pounds heavier for carcass weight than Brangus- and Gelbray-sired steers. Ribeye area for Gelbvieh-sired steers was largercompared to the other sire breeds at both locations. Yield gradeswere considerably lower (leaner carcasses) at both feedlotlocations for Continental-influenced steers (Gelbvieh- and Gelbray-sired). A higher proportion of Angus-sired steers graded Choice,whereas most Brangus-, Gelbvieh- and Gelbray-sired steersgraded Select when fed at both feedlot locations.

Steaks from Angus-sired steers fed in Louisiana had lowershear force values (more tender) than steaks from Gelbvieh-siredsteers. Brangus-sired steers had numerically lower shear forcevalues than Gelbray-sired steers at both feedlot locations. Resultsfrom this study indicate that British-Brahman breed combinationshad more tender meat than Continental-British-Brahman breedcombinations, regardless of level of Brahman breeding.

In conclusion, findings from this study indicate that the use ofAngus sires resulted in improved carcass quality compared withGelbvieh sires when mated to first-cross Brahman-Herefordcows. Improved carcass cutability resulted from the use ofGelbvieh sires. Tenderness was similar among steers with either25 percent or 44 percent Brahman inheritance. There was atendency for improved carcass quality and tenderness with theuse of Angus and Brangus sires compared with Gelbvieh andGelbray sires. These combining abilities for feedlot and carcasstraits among these sire breeds should be considered whendesigning mating systems for crossbreeding.

Sidney M. DeRouen, Associate Professor, Hill Farm Research Station, Homer, La.; Wayne E. Wyatt, Associate Professor, Iberia Research Station,Jeanerette, La.; Thomas D. Bidner, Professor, and Manuel A. Persica III, Research Associate, Department of Animal Science, LSU AgCenter,Baton Rouge, La.

Louisiana Agriculture, Fall 2000 9Photo by John Wozniak

This is one of the Brahman bulls at the LSUAgCenter’s Idlewild Research Station near Clinton.


Among the 80 or more breeds of beef cattle in Northand South America, only 10 to 15 are used routinely byLouisiana cattle producers. Breeds evaluated in cross-breeding systems are often those produced as purebredsin the area where the research takes place. Some breedsnot common to the area may be evaluated if they offerpotential for improved production in local herds. A rota-tional crossbreeding study was initiated at the LSUAgCenter’s Ben Hur Research Farm in 1969 with Angus(A), Brahman (B), Charolais (C) and Hereford (H) breeds,the more popular breeds in Louisiana at the time.

Rotational crossbreeding is a mating system in whichpurebred sires are mated to crossbred females producedby sires of another breed. For example, an Angus xBrahman two-breed rotation mating system uses twobreeds of sires, Angus and Brahman. Angus sires are matedto daughters produced by Brahman sires, and Brahmansires are mated to daughters produced by Angus sires. Themating of sires of one breed to daughters of another sirebreed can continue for many generations. A two-breedrotation mating system maintains about two-thirds of thehybrid vigor possible in first crosses between the twobreeds. The primary advantage of a rotational crossbreed-ing system is that the replacements are produced withinthe system, instead of outside the system.

Predicted Calf Birth and Weaning Weightsfrom Rotational Crossbreeding Data

Figure 1. Predicted birth and weaning weights for Angus xBrahman two-breed rotation mating system.Brahman-sired calves were heavier at birth than Angus-sired calves, butweighed less at weaning.

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BirthWeight

WeaningWeight

Overall Angus-sired Calves

Brahman-sired Calves

6473

446407


Where’s the Beef Grade?Beef sold in the United States is inspected for wholesomeness through the U.S.

Department of Agriculture. Apart from wholesomeness, the beef you buy is usually gradedfor quality. Quality refers to palatability characteristics such as tenderness, juiciness andflavor. Beef grading is performed by USDA graders and is based on the amount of marbling (flecksof fat within the lean) and the age of the animal. Beef grading is optional and is paid for by the beefprocessors. The cost is reflected in the price of meat. Only the top three grades are identified and soldat retail. These grades are USDA Prime, Choice and Select.

The highest grade, USDA Prime, is used mostly by hotels andrestaurants, but a small amount is sold at retail and in specialty markets. The grade most widelysold at retail is USDA Choice. However, consumer preference for leaner beef has increasedthe popularity of the USDA Select grade of beef. The label on fresh meat packages will tellconsumers the cut and grade of beef.

The “select” grade of beef has led to some confusion particularly in seafood-selling statessuch as Louisiana, says Donna Montgomery, consumer food and nutrition specialist with theLSU AgCenter.

“Select is the highest grade for crabs,” she said. “Some consumers don’t understand thatselect is not the highest grade with beef.”

Since the USDA grading program is voluntary, some retailers sell beef that is not graded.In this case, it is usually select quality, Montgomery says. Beef that is graded lower than selectquality is used to make ground beef and manufactured meat items such as frankfurters, coldcuts, canned chili and soups.

The consumer is not likely to see these labels as shown on the cut of meat purchasedat the grocery story, since these labels are placed on the larger cuts of meat.

Six two-breed rotational mating combinations and four three-breed rotational mating combinations are possible with the fourbreeds. Because of the limited size of the research station, all breed


Donald E. Franke, Professor,Department of Animal Science, LSUAgCenter, Baton Rouge, La.

In the late 1960s and 1970s, considerable research in theUnited States and abroad was directed to partitioning into geneticcomponents variation in performance among and within breedsand various breed combinations. This resulted in procedures topartition the variation into that which was due to the cumulativeeffects of genes from breeds in individuals (direct effects) and indams (maternal effects) and to the level of heterosis (hybrid vigor)expressed among breed combinations in individuals and in dams

for specific traits. Using combinations ofthese direct and maternal breed additiveand breed combination heterotic geneticeffects, one can predict with a high de-gree of accuracy the performance of anymating system and breed combinationfor any trait.

Breed direct and maternal additivegenetic effects and breed combinationdirect and maternal heterotic geneticeffects were estimated from data ob-tained in the rotational crossbreedingstudy described above.

The three figures show the predictedbirth weight and predicted weaning weightfor the Angus x Brahman two-breed ro-tation system, the Angus x Brahman xCharolais three-breed rotation systemand the Angus x Charolais x Herefordthree-breed rotation system. Note thatweaning weights of calves in the three-breed rotation systems are larger than inthe two-breed rotation system. This isdue mostly to a larger breed, the Charo-lais, being involved. Also, birth weights ofBrahman-sired calves tend to be largerthan birth weights of calves from othersire breeds, independent of the matingsystem. This is due to a larger heterosiseffect in the Brahman-sired calf for growthrate during gestation than in calves byother sire breeds. A concern in somerotational crossbreeding systems is thevariation among calves from different sirebreeds. Note the larger amount of varia-tion among weaning weights of Angus-,Brahman- and Charolais-sired calves inFigure 2 than the variation among calvesfrom Angus, Charolais and Hereford siresin Figure 3. Larger weaning weights aredesirable but so is uniformity. One canpredict birth and weaning weights forvarious breed combinations and matingsystems to determine which mating sys-tems and breed combinations are moredesirable for a given objective.

Figure 2. Predicted means for overall and for Angus-, Brahman- andCharolais-sired calves in the Angus x Charolais x Brahman three-breedrotation system.In this mating system, Brahman-sired calves were 22 pounds heavier than Angus-siredcalves, but only slightly heavier than Charolais-sired calves. Weaning weights were similar forAngus- and Charolais-sired calves and lower than for Brahman-sired calves.

500

400

300

200

100

0

75

493

BirthWeight

WeaningWeight

Overall Angus-sired Calves

Brahman-sired Calves

6475

479 485

Charolais-sired Calves

514

86

Figure 3. Predicted birth and weaning weights for Angus-, Charolais- andHereford-sired calves in an Angus x Charolais x Hereford three-breedrotation mating system.The Angus-Charolais-Hereford three-breed rotation system was not evaluated in researcheffort, but means for this system were predicted with the genetic effects for these breeds.The birth weight and weaning weight means are more similar across sire breeds than in theAngus-Brahman-Charolais three-breed rotation system, and are more desirable becausevariability is reduced.

combinations could not be evaluated at the same time. Breedcombinations that included Brahman were evaluated, those beingA-B, C-B, H-B, A-C-B, A-H-B, C-H-B and A-B-C-H.

These breed combinations were evaluated through fourgenerations, and reproductive, birth, weaning, feedlot and carcassinformation was obtained. Nevertheless, questions still remainedabout the relative performance of breed combinations notevaluated.



arly research at the LSUAgCenter indicated that althoughBrahman crossbred cattle were superiorin many ways to other breeds for theclimate and conditions of Louisiana, thesteaks from these cattle were not astender as steaks from other breeds. Thisfact led scientists to initiate severalresearch projects on beef tenderness.

Tenderness is the most importantfactor affecting the eating quality ofmeat. Even though flavorful and juicy, abeef steak is considered unacceptable ifit is too tough. Data from severalbreeding projects indicated that tender-ness is directly related to the proportionof Brahman inheritance represented.Since feeder calves with a higherpercentage of Brahman influence receive

lower prices, the Department of AnimalScience is conducting research to studythe growth and carcass characteristics ofsteers with Brahman sires. Preliminarydata indicate that significant geneticvariation exists for tenderness amongBrahman sires so that selection toimprove tenderness will be effective.Sires with unacceptable tenderness canbe culled.

Other research projects haveexamined the influence of length offeeding time on a grain ration, degree offatness, growth rate and amount ofmarbling on tenderness. Since theexternal fat cover acts as an insulatorduring chilling of beef carcasses, lack ofexternal fat can affect beef tendernessnegatively. To study this relationship, aproject was initiated to remove theexternal fat from the shortloins of 20beef carcasses and compare them tointact shortloins. Fat removal increasedthe drip loss and made the steaks toughercompared to steaks from intact beefsides.

Additional studies have looked atthe influence of stress before slaughteron tenderness. Conclusions show the lessstress, the more tender the meat.

Because of social and economicchanges during the early 1970s, therewas renewed interest in producingslaughter beef from forage or limitedamounts of grain. A cooperative researchproject with the Rosepine ResearchStation, School of Human Ecology, andthe departments of Agricultural Econom-ics and Agribusiness, ExperimentalStatistics and Animal Science wasinitiated to determine the feasibility ofmarketing beef finished on forage orgrain-on-grass.

Beef produced from Angus orHereford-Angus cross steers wasevaluated by trained sensory panel andtwo types of consumer panels. Selectedcuts were marketed through a cooperat-ing regional retail food chain. Beeffinished on these feeding treatments hadreduced dressing percentages and lowermarbling scores compared to feedlot

Thomas D. Bidner, Professor, Department ofAnimal Science, LSU AgCenter, Baton Rouge,La.

E

Improving Consumer Acceptanceof Beef from Brahman Crossbred Cattle

Thomas D. Bidner

Photo by John Wozniak


beef. The consumer panels could notdistinguish between feeding treatmentsin evaluating the tenderness, flavor,juiciness and overall acceptability, buttrained sensory profile panels detecteddifferences between forage- and grain-finished beef.

Encouraged by the results of thiscooperative project on forage beef andother forage-fed beef research projects inthe Southern Region, scientists met inAtlanta, Ga., in 1979, to discuss thepossibility of producing slaughter weightbeef using forages throughout the year.The stipulations were that the beefcarcasses should weigh 500 pounds ormore, and the age of the slaughter cattlewould be less than 24 months. Acomprehensive research project withthese objectives was initiated thatincluded the Dean Lee, Iberia, Hill Farm,Northeast, Red River and Rosepineresearch stations and the departments ofAgricultural Economics andAgribusiness, Animal Science andExperimental Statistics. This studyshowed that, in the South, lean beef canbe produced throughout the year fromcattle finished on forages.

Research findings with Brahmangenetics and year-round forage-fed beefhave indicated a need to control factorsthat ultimately affect the consumeracceptance and market value of beef.This stimulated research projects thatcould improve the acceptability of beef.Experiments that used high and lowvoltage electricity to stimulate beefcarcasses postmortem were investigated.These experiments indicated thatelectrical stimulation of beef carcassesimproved tenderness. When electricalstimulation was combined with a hightemperature aging of beef carcasses,tenderness improved further. Anotherexperiment was initiated that combinedelectrical stimulation of beef carcasses,blade tenderization and vacuum aging ofsteaks. Again, electrical stimulationimproved beef tenderness and eitherblade tenderization or vacuum aging – incombination with electrical stimulation –created additional improvements intenderness.

The LSU AgCenter is committed towork on behalf of the Louisiana beefindustry. Scientists in the LSU AgCenterhave conducted numerous researchprojects concerned with quality andacceptability of beef with the goal ofincreased acceptability of beef producedby Brahman-influenced cattle producedin Louisiana and the Gulf Coast.

Scientists Battle Cattle DiseasesCattle in all beef herds are subjected to common diseases that may cause acute or

chronic illness, interfere with pregnancy, cause abortion, and cause intestinal infectionand systemic illnesses in newborn calves. Older calves, yearlings and mature cattle maydevelop warts, foot rot, cancer, chronic diarrhea and wasting, respiratory diseases,mastitis, lumpy jaw and eye and brain infections, among other conditions.

In addition to diseases already in the herd, infections may be introduced bypurchased herd replacements, by show cattle returning to the herd and even acrossfences from herds in adjacent pastures.

Despite the numerous infectious diseases, most beef herds have a low incidence ofmorbidity and mortality. The economic impact of certain infectious diseases can besubtle and often not realized. Vaccines can give some degree of protection against severalof the major diseases of cattle. Pastured cattle whose diets do not contain adequatelevels of biologically available copper, zinc and selenium may not have optimum diseaseresistance. Secondary copper deficiency is a significant problem in cattle pastured onsoils high in organic matter (peat) in coastal parishes.

The LSU AgCenter’s Department of Veterinary Science has provided researchsupport in response to the needs of livestock producers. Here are some of the areasin which research has been conducted.

Anaplasmosis This disease is an important cause of mortality in Louisiana cattle.It was studied for years by LSU AgCenter veterinarians and research entomologists.Mosquitoes and horseflies were identified as the primary transmitters of anaplasmosisin Louisiana cattle. Other biting flies, ticks, needles and surgical instruments also maytransmit infected red blood cells from a carrier or from an acute case to susceptiblecattle. Continuous feeding of chlortetracycline and preventive treatment with injectableoxytetracycline were often impractical measures. A vaccine was developed by LSUAgCenter researchers in the 1980s. Research trials were conducted in commercial beefand dairy herds, and the vaccine proved to be safe and effective. A commercial vaccinemanufacturer introduced and marketed the product in 1994. Business mergers oc-curred, and the product was no longer offered. Today, a commercial vaccine is still notavailable. The Veterinary Science Department now prepares and provides a vaccine fordistribution to Louisiana cattle owners. Vaccination of herd bulls, because of their value,is a standard recommendation. Some beef and dairy producers immunize cow herds also.

Brucellosis This bacterial infection is transmitted cow-to-cow by oral exposureto uterine discharges from infected cows at time of calving or abortion. People assistingcows at calving or drinking unpasteurized milk from infected cows are at risk, also.Sometimes known as Bang’s disease, this costly infection has almost been eliminated inLouisiana through the cooperation of the cattle industry and state-federal animal healthofficials. Immunization of female cattle was an important facet in the effort. A majorresearch effort helped establish the safety and efficacy of a vaccine that providesprotection but does not interfere with blood tests. LSU AgCenter researchers helpeddevelop the official brucellosis vaccine not only for Louisiana but for the United States.

Leptospirosis The role of skunks in transmitting leptospira bacteria to Louisianabeef and dairy cattle was established through research in the 1960s. Leptospirosis is animportant abortion disease of cattle and a lethal disease of young calves. Skunks, cattleand other animals may shed the organism in their urine.

Bovine Leukosis The bovine leukemia virus induces formation of lymphoidtumors in some infected cattle. Infected cattle respond to the virus with increased levelsof lymphocytes, but less than 10 percent eventually develop tumors. Tumors developin the heart, abomasum and various lymph glands. An LSU AgCenter pathologist studiedthe disease in Louisiana commercial beef and dairy herds as well as research stationcattle. Data were shared with a team at the National Veterinary Services Laboratory atAmes, Iowa.

Other Diseases LSU AgCenter research has led to a better understanding of theincidence of the bovine reproductive diseases trichomoniasis and vibriosis, respiratoryvirus infections and diseases of newborn calves.

Steven Nicholson, Veterinary Specialist, LSU AgCenter, Baton Rouge, La.



BeefBeef n recent years, the structure of the

U.S. beef industry has undergonesignificant change, though not to theextent of its competitor industries, porkand poultry. While cow-calf and stockerfarms have become fewer and larger, therate of change has been slow relative toits competitors. Along with the slowchange, few efforts to coordinate thesegments of the industry, from breedingto the consumer, have evolved.

The slower rate of change of thebeef industry is a two-edged sword. Onthe positive side, small, family-run,independent beef operations continue tobe the norm. Thus, cow-calf and stockerproduction, which constitutes almost allLouisiana production, remains a viableopportunity for those who desire tooperate small, family operations. On theother hand, the slower rate of technologi-cal development and relative lack ofcoordination between segments haveresulted in relatively higher costs ofproduction, hence, higher beef prices atthe supermarket, and less consistency inproduct quality than competitor meats.This has contributed to the nationalreduction in per capita consumption ofbeef for a number of years. Qualityinconsistency in Louisiana and nationalbeef industries is due to the many breedsof cattle being raised in vastly differentenvironments, as well as the inefficientpricing system in the industry.

Beef Industry PricingCow-calf producers are paid based

on the weight of calf produced. Stockerproducers are more concerned with calfweight than characteristics of the mothercow. Cattle feeders are concerned withsex, health and feed conversion. Packerstypically buy cattle in pen lots; thus, fatcattle are sold on an average price basis.Further clouding of these price signalsresults from competing preferences of

consumers, resulting in confusing pricesignals at each segment. The currentindustry structure is highly unlikely toachieve product quality consistencywhile simultaneously reducing produc-tion cost.

Supply Chain StructureIn a supply chain, formal organiza-

tional mechanisms direct the flow ofproduct from input to consumption. Forexample, in the integrated broilerindustry, if a fast-food restaurant chaindemands larger chicken parts, it commu-nicates the demand directly to a verti-cally integrated broiler producing andprocessing firm that owns all inputs andfacilities from feed mill and hatchery to

retained ownership, the industry relies onthe open market to direct the flow ofproducts and inputs among the variousproduction segments.

The U.S. and Louisiana beefindustries have not evolved to a supplychain structure for several reasons. First,economies of size have not developed incattle production to the extent of itscompetitor industries; a cow-calfoperation does not have to be large to beeconomically efficient. In the competitorindustries, a significant capital outlay isrequired for production, includinghousing and feed, watering, heating andcooling equipment. To be economicallyefficient, this capital must be spread overa large number of animals, contributingto economies of size. Technologicaladvances in both the poultry and porkindustries continue to increase theeconomically efficient size of operation.This is not true in cattle production,however, where technological changeshave not been capital intensive. Smallereconomies of size mean smaller opera-tions with relatively low capital invest-ment. How is this related to supply chainstructure?

Producers must have incentives tovertically coordinate or integrate withanother segment, such as a packer.Broiler and hog producers have hadmany of these incentives. The increasedmonetary risk associated with a large,highly specialized operation with returnsthat swing with price fluctuations is thefirst incentive. Even under low outputprices, the note on facilities and equip-ment must be paid. The producer rarelyhas another enterprise to diversify theoperation to offset the low price.Discontinuance of production is not anoption, because it leaves empty facilitiesuseful for no other purpose. Thus,producers have the incentive to acceptcontracts that either guarantee a price or,at least, reduce price variability relativeto the market. Beef cattle operations aremore likely to be diversified since theydo not have to be large. While low cattleprices present difficulties for cow-calfproducers, they are less likely to lead toforeclosure, given that most cattle

Structural Changein the Beef IndustryJeffrey M. Gillespie and Alvin Schupp

Jeffrey M. Gillespie, Associate Professor, andAlvin Schupp, Martin D. Woodin EndowedProfessor, Department of Agricultural Econom-ics and Agribusiness, LSU AgCenter, BatonRouge, La.

I

The slow rate oftechnological developmentand relative lack ofcoordination betweensegments have resulted inrelatively higher costs ofproduction, hence, higherbeef prices at thesupermarket, and lessconsistency in productquality than competitormeats.

processing, with the exception ofcontracted broiler growout. The broilersraised are owned by the integrated firm,which directs the flow of inputs from thehatchery to processing. The hog industryis moving toward such a structure, withincreased vertical integration frombreeding to slaughter. The beef industry,however, has shown little evidence ofcoordination through a supply chainstructure. While limited vertical integra-tion between packer and feedlot hasoccurred through the use of captivesupplies and while there is some coordi-nation between other segments using


producers hold less debt than do theircompetitor livestock producers and canpostpone some costs, such as soilfertilization for forage production.

Related to the economies of sizeargument is that transaction costs (costsassociated with doing business, orconducting the transaction, not includingthe actual cost of the product purchasedor sold) are not as high for most cow-calfand stocker producers as with hog andbroiler production. In both of thesecompetitor industries, feed must beregularly acquired. A broiler producerhas birds ready for slaughter six times ayear, and a large hog producer maymove hogs weekly. Thus, significantincentive exists for pre-arranging inputpurchases and selling agreements toreduce these costs. Many cattle produc-ers sell calves and stockers once or twiceper year. Feed is not purchased asregularly as with the competitor indus-tries since cattle rely heavily on farm-grown forages. This reduces theirincentive to coordinate with sellers ofinputs and calf and stocker buyers.

Packers have less incentive to enterinto a supply chain relationship withcattle producers than with hog andbroiler producers. In the competitorindustries, a few breeds have been highlydeveloped such that, under prescribedconfinement housing conditions, animalperformance is relatively predictable.Since the integrator provides most of theinputs and specifies the facilities,performance can be associated withproducer management. The large numberof breeds of cattle raised under vastlydifferent and uncontrollable environmen-tal conditions across the United Stateswould lead to problems in setting up afair contract in which cattle producers

would be paid based on performance.The inability of the integrator to controlthe conditions of production precludesthe development of such contracts.Packer or feedlot integration throughownership of the cow-calf and stockersegments is hindered by the large

chase of cattle in pen lots. With specificquality animals receiving premiumprices, feedlots will, in turn, pay pre-mium prices for top quality feedercalves.

To help instigate this process,packers need to communicate to thebreeding segment the types and combi-nations of breeds desired. At least 15major breeds of cattle are raised inLouisiana today, with many morethroughout the United States. If thenumber of breeds used could be reducedand research devoted exclusively to thedifferent blood lines in the remainingbreeds, more consistency in animal traitsfrom generation to generation could beobtained. Concentration on specificblood lines within a breed could improveboth animal performance and end-product consistency. This would lead toimproved product quality and reducedproduction costs, allowing for a reduc-tion in beef prices at the retail meatcounter. In the interim, cow-calf andstocker producers can form strategicalliances with other producers (such aswith the certified Angus program) toraise similar high quality animals thatcan be marketed to packers throughretained ownership arrangements.

Overall, while the beef industry hasremained viable, its loss of market shareto poultry and pork in recent yearsprovides a challenge. The choice iseither to become more efficient andattuned to the consumer, as have thecompetitor industries, or to continue tolose market share. While we don’tadvocate that a supply chain structureshould evolve in the beef industry, bettercoordination among market segments,including cow-calf operations, will helpbuild a more efficient industry.

investment in land resources required forthese segments. Ownership or leasing ofthe land adds another element of risk forthe integrator.

More Coordination,Efficiency

A supply chain structure similar tothat of the hog and broiler industries isunlikely to evolve in the U.S. andLouisiana beef industries. But, for beefto become more cost competitive with itscompetitors, more industry coordinationneeds to occur. We believe this coordi-nation should originate at the packersegment, which is closest to the con-sumer. For packers to provide consumerswith consistent products, they need toobtain consistent quality raw products.The packer must efficiently communi-cate to the feedlot the type of fed animalneeded and pay prices based on thesespecifications, discontinuing the pur-

Packers have lessincentive to enter into asupply chain relationshipwith cattle producersthan with hog and broilerproducers.

Understanding EPDs (#2692). Fact sheet about expectedprogeny difference, an estimate of an animal’s genetic potential.

Selecting and Developing Replacement Heifers (#2739).Raising heifers for replacements in your own herd or for saleto others requires attention to detail. 12 pages.

Crossbreeding for Beef Production (#2319). Explains thevarious methods of crossbreeding with detailed charts, refer-ences and vocabulary list. 16 pages.

LSU AgCenter Beef Reproduction PublicationsFactors Affecting Reproduction in Beef Cattle (#2308).Biology information and question-answer format on reproduc-tion. 12 pages.

Louisiana residents may obtain up to five free copies of any onepublication by visiting their local parish extension office orclicking on publications at the LSUAgCenter’s website atwww.lsuagcenter. com.


BeefInformation-based ProgramsProve Valuable

to Beef Producers’ FutureRonald P. Del Vecchio, Glen T. Gentry Jr., Danny F. Coombs and Darin A. Hylan

roducers serious about their cattlebusiness routinely try to find ways tomake more money and ensure a betterfuture for themselves and their families.For a long time, the beef industry hasbeen steeped in the tradition that cattleare all pretty much alike and should sellon averages. That mentality has made ithard to find adequate compensation forcattle with superior growth and carcasscharacteristics. But, the beef industry ischanging. Between 35 percent to 45percent of all fed cattle are now sold onsome kind of value-based system, whichaffects the price paid for calves.

To adjust to these changing markettrends, producers, buyers and feedlotoperators point to the merit of providingcritical information on calves at the timeof sale. This information includes:

Health Information. For years,members of the cow-calf industry haveknown the health-related benefits ofproperly preconditioned calves. Produc-ers found no buyers willing to share theexpense, however. Today that is chang-ing as significant premiums are beingpaid for properly vaccinated and weaned(preconditioned) calves.

Post-weaning Performance Data.This includes documentation of a low,moderate or high incidence of health-related problems and average daily gainof those calves while on feed. If health-related problems are numerous, then achange in the health program may beconsidered. Likewise, if average dailygain (ADG) is low, then a change inanimal selection within breed or a breedchange may be in order.

Genetic Information. Feedlots arerapidly becoming aware of the effect ofgenetics on feedlot performance. Pro-

ducers providing genetic information atthe time of sale will find that it can makea difference on calf price. For example,steer and heifer calves from a qualityterminal breeding program may demandhigher prices.

Carcass Information. This infor-mation is valuable because premiums forcattle of superior carcass characteristicscontinue to increase.

Following are several programsdesigned to help Louisiana cattleproducers get the information they need.

Louisiana Calf-to-CarcassProgram

This educational program providesproducers with valuable health, post-weaning performance and carcassinformation about their cattle. Theobjective is to create an opportunity forLouisiana beef cattle producers toevaluate feedlot and carcass performanceof their cattle. The results can guideproducers in evaluating their currentbreeding programs so they can make anynecessary adjustments that will allowthem to remain in the mainstream of thebeef industry as that industry movesmore into a value-based marketingsystem.

This program is not designed topromote one type of marketing, such asretained ownership, or to single outspecific cattle breeds. In Louisiana, thetypical cow-calf producer sells calves atweaning. The calf-to-carcass programallows the cow-calf producer to see whathappens to calves after they are weaned.Data received by each producer addressissues such as herd health, trucking fees,calf shrink, feedlot performance,marketing alternatives and carcassquality. Since 1992, more than 65producers from more than 30 parisheshave participated. They have consigneda total of 2,397 steers and heifers to theprogram.

Beginning with the 1998-1999feedout year, a mandatory 45-daypreconditioning plan was added to theLouisiana Calf-to-Carcass Program. Thisdemonstrates the importance of a quality

health program and helps producersevaluate cattle, make changes forimprovement and meet industry specifi-cations.

Most of the calves are precondi-tioned at one of the three designatedsites: LSU AgCenter’s Idlewild ResearchStation, McNeese State University andLouisiana Tech University. A fewproducers choose to precondition theircalves on their farms. The precondition-ing program includes vaccinations,supplemental copper injection andinternal-external parasite controltreatment.

The calves are fed a medicatedconcentrate ration at about 1 percentbody weight and have good quality hayand clean water available free choice.

Ronald P. Del Vecchio, Associate Professor andBeef Specialist, LSU AgCenter, Baton Rouge,La.; Glen T. Gentry Jr., Research Associate,Idlewild Research Station, Clinton, La.; DannyF. Coombs, Professor, and Darin A. Hylan,Research Associate, Dean Lee Research Station,Alexandria, La.

P



Preconditioning feeder calves not onlybenefits their health, but the cattle alsobecome accustomed to people, becomecalmer, learn to eat from feed bunks anddrink from automatic waterers. Once thecattle arrive at the feedlot, they aresorted into pens based upon weight, size,projected finish date and sex.

The average percent shrink (loss ofbody weight during transportation) forthe cattle during the 1998-1999 and1999-2000 years, calculated as thepercent difference in the final weight inLouisiana and the starting weight inOklahoma, was 3.31 percent. This is amarked improvement over the 1992 to1997 period, when preconditioning wasnot mandatory and when the percentshrink averaged 5.38 percent.

The death loss of steers and heifersduring the past two years was 1.1percent. This is well below the averageof 2.4 percent for steers sent to thefeedlot through this program in the sixyears before preconditioning. Most ofthe losses were caused by enterotoxemiaand pneumonia.

The average number of days on feedfor the steers during the 1998-1999 and1999-2000 feed-out years was fewer

than the average from the previous sixyears (204 days vs. 216 days, respec-tively). The average daily gain for thepast two years was 3.05 pounds, amarked increase from the 1992 to 1997increase of 2.81 pounds per day.

Medical costs averaged $2.97 perhead ($17.67 for every sick animal)during 1998-2000. This value is similarto the average for the previous six years($2.94). During the two-year period(1998-2000), a total of 15.5 percent ofthe cattle became sick at the feedlot,which is lower than the previous sixyears (22.1 percent). When examiningthe profit/loss margin of the cattle thatbecame sick vs. the cattle that remainedhealthy, we found that over the last twoyears, the cattle that became sick had aprofit margin of $41.13 per head, whilethe cattle remaining healthy had a profitmargin of $119.43 per head. These dataindicate that healthy cattle will generateabout three times as much profit as thosethat become sick.

The average number of sick penhead days (total number of days cattlewere in the sick pen) was 143 for 1998-2000. This is a marked reduction in theaverage from previous years, which was

346 days per year. This reductionsuggests that the preconditioned cattlewere able to recover faster with treat-ment and return to their pens sooner.

Most cattle fell into the selectquality grade category (69.2 percent);only 21.4 percent were choice. Amongyield grade categories, the highestpercentage of cattle fit into the yieldgrade category 2 to 3. Seventy-onepercent of the cattle fit within yieldgrades 0 and 3, which coincides wellwith industry specifications.

Preconditioning is beneficial tocattle. They experience lower mortalityrates, fewer sick pen head days, lowermorbidity rates, lower percent shrink,fewer days on feed and higher averagedaily gains. Further, there was a tremen-dous amount of variation in net return,performance factors, carcass parametersand health costs among the steers enteredin the Louisiana Calf-to-Carcass Pro-gram, a reflection of variability thatexists in the beef industry. Upon receiptof this information, each producer isstrongly encouraged to review the dataon his or her cattle and take steps,including genetic selection and manage-ment, to reduce these variables andproduce a product that meets the needsand specifications of the beef industry.Value-based marketing at all segmentsof the industry is becoming more of areality, and those who know whatconstitutes value and have a product thatmeets those demands will be competitivein the marketplace.

Louisiana Forage Bull TestProgram

In 1998, the Louisiana Forage BullTest Program was established to evaluatethe post-weaning performance of bullsraised under pasture conditions for futureherd sire potential. This is a cooperativeprogram with Prison Enterprises’ DixonCorrectional Institution, and the evalua-tion/test site is at that facility’s feedlot inJackson, La.

Upon the bulls’ arrival at the testsite in early November, they areweighed, vaccinated, treated for internaland external parasites, given an ear tagID, measured and sorted into two groupsbased on body weight. The bulls get atwo- to three-week adjustment periodbefore the start of the evaluation, duringwhich they are maintained on a dry lotand fed a balanced ration at about 1.5percent of their body weight and havefree access to hay, water and mineralsupplements.

Bruce Olcott, an associate professor at LSU’s School ofVeterinary Medicine, left, and his students, including AnnDavidson, right, help with the calf preconditioning program.At far right is Ron Del Vecchio.


During this period the bulls adjust totheir new environment, establishdominance within each group andrecover from any illnesses associatedwith the transportation and relocation.

At the end of the adjustment period,the bulls are turned out on pastureplanted in Jackson ryegrass for a two- tothree-hour period for two to three days.The time is then increased gradually tohelp the bulls prepare to eat the ryegrassforage full-time. Jackson ryegrass is usedbecause of its high level of production,cold tolerance and rust resistance.

On average the bulls lose a littleweight during the adjustment period, asexpected. The bulls are weighed again atthe start of the test, after 90 days on testand at the end of the test period. Bodyweights are collected just these fourtimes because of the disruptive nature ofmoving the bulls through the chute,which can lead to injury. Also, aftermoving around, a group of bulls appearto have to re-establish dominance,leading to rowdy behavior, which mayresult in injuries. The goal is to collectenough data to fully evaluate the bulls’performance while, at the same time,managing the animals to keep injury at aminimum. The maximum number ofbulls that can be managed at the evalua-tion site is 100 head.

During the 1998-1999 evaluationperiod of November 23, 1998, to April19, 1999, there were 99 bulls consignedby 33 different producers from 23parishes. The average daily gain for allbulls ranged from 2.2 to 4.9 pounds perday. The overall average daily gainamong all bulls was 3.45 pounds perhead per day. The average total weightgain for the bulls was 511 pounds in 148days. The age of the bulls at the end ofthe performance test period ranged from13.5 months to 20.5 months.

During the 1999-2000 evaluationperiod of December 9, 1999, to May 11,2000, there were 86 bulls consigned by18 different producers from 12 parishes.The average daily gain for all bulls ontest ranged from 1.7 to 4.2 pounds perday. The overall ADG among all bullswas 3.3 pounds per head per day. If welook at total weight gain, the bullsaveraged 506 pounds of gain in 154days. The age of the bulls at the end ofthe performance test period ranged from13.5 months to 20.5 months.

At the conclusion of each forage-based performance test, rib eye area andfat thickness measurements were takenusing ultrasound technology. A bullsoundness examination (BSE), includinga scrotal circumference measurementalso was conducted on all bulls.

The first two years of this programhave resulted in outstanding weightgains. At a flat rate cost of $275 per bull,the cost per pound of gain has averaged54.1 cents. The factors that contributedto this include an abundance of ryegrassavailable to the bulls at all times, a highquality health program(booster vaccinations forrespiratory diseases, twotreatments for internal andexternal parasites, promptveterinary care at the first signof any given condition), freeaccess to mineral supple-mented with Bovatec andquality genetics of the bulls.

Performance BullTest

The performance testingprogram of beef bulls at theLSU AgCenter’s Dean LeeResearch Station in Alexan-dria is designed to evaluate

the post-weaning performance of bullsunder a full-feed grain ration for futureherd sire potential. This program is oneof the oldest and longest running tests inthe United States. More than 6,000 beefbulls representing more than 20 breedsand consigned by more than 400Louisiana purebred beef cattle producershave been evaluated since the firstperformance test was conducted in 1958.

This program began as a joint effortbetween the Department of AnimalScience and the Dean Lee ResearchStation. Twenty-nine bulls representingthree breeds consigned by 19 breederswere entered in the first test. The threebreeds were Hereford, Santa Gertrudisand Angus. Average daily gains rangedfrom 1.61 to 2.63 pounds per day. Onlysix were offered for sale at the end of thetest, and only three were sold. Thesebulls were purchased for $490, $300 and$200.

Many changes have been madesince then. In 1981, the decision wasmade to feed the bulls in a group ratherthan individually, which allowed more

Ronald Del Vecchio fastens numbered name tags foridentification. Louisiana producers delivered 360 calves tothe three sites for the preconditioning program in 2000.

Dr. Jenine Avellini, a veterinarycontrol treatments to each calgain experience working with this LSU AgCenter program.

Dr. David Sewell, left, and Ann Davidson, both veterinarystudents, prepare vaccines to administer to the calvesbrought in for the Louisiana Calf-to-Carcass Program.

Photos by John Wozniak

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Figure 1. Average daily gains of bulls onwinter and summer tests by decade.


bulls to be evaluated. The breed of bullsconsigned to the test also has changed.Hereford bulls were popular in the late1950s and 1960s. The Continentalbreeds, especially Simmental, began toincrease in number during the 1970s andbecame the most numerous of thedifferent breeds tested in the early 1980s.During the 1990s, the Angus andCharolais breeds have had the highestnumbers of bulls on test.

Another change is that the actualperformance of bulls on test, as mea-sured by average daily gain, has im-proved over the years. As shown inFigure 1, during the 1960s average dailygains were approximately 2.5 pounds perday. Body weight gains have graduallyincreased to the point where today thebulls are gaining approximately 3.6pounds per day. This shows that Louisi-ana purebred cattle producers haveselected cattle that perform better andtherefore are more efficient.

The ration used has been fairlyconstant over the years and is a completeration categorized as a high fiber,

Glen Gentry records the body weight of each calf with anelectronic digital scale at the LSU AgCenter’s IdlewildResearch Station.

growing ration. It consists of 40 percentcorn, 20 percent crimped oats, 20percent cottonseed hulls, 10 percentcottonseed meal and 10 percent molas-ses, minerals, vitamins and an ionophore.This ration contains 68 percent totaldigestible nutrients (TDN) and 13percent crude protein. Both the rationand clean water are available free choice.

Two tests are conducted each year.Bull calves born in December, January,February and March are tested duringNovember to March. Bull calves born inSeptember, October and November aretested during June to October. Since1981, at the conclusion of each test, abidding sale has been organized. Bullsare compared within breed, and only thebulls that have an above-average averagedaily gain and adjusted yearling weightwithin their breed are eligible for thesale. As of March 2000, only one sale isheld. The bulls that would have beenoffered in the October sale are eligible toreturn in March. This change willincrease the overall number of bullsoffered in the sale and allow buyers to

purchase slightly older bullsalong with the younger bullsjust completing the Novem-ber to March test. Figure 2shows the average sale pricereceived for bulls by decadefrom 1960 to 2000.

The cost of having abull performance tested inthis program is about $350.This includes a $50 nomina-tion fee and feed charges of70 cents per pound ofweight gain. For example, abull that gains 3.5 poundsper day would be charged$324.40. (3.5 pounds x112days =392 x .7 = $274.40 +

$50 nomination fee for a total charge of$324.40).

The testing program is under thecontrol of the LSU AgCenter’s Perfor-mance Testing Committee. This group isresponsible for policies and proceduresas it pertains to the actual performancetesting procedure. A second group, theLouisiana Bull Testing Association, wasorganized in 1981. Its function is tosponsor and promote performance testedbull sales in Louisiana.

A new testing facility was com-pleted in 1994. It is a feedlot facilitycontaining 10 pens that are 20 feet wideand 200 feet long. Self-feeders contain-ing the complete ration are under a barnthat is 30 feet wide and 200 feet long.Shade cloth provides the bulls with anadditional shaded area to help minimizeheat stress. A sprinkler system and fanshave been recently added.

Over the last couple of years twonew services have been offered toproducers to obtain additional data ontheir bulls. Breeding soundness examsand ultrasound measurements for ribeyearea, fat thickness and marbling are nowan integral part of the evaluation. Theseservices are contracted with a privateveterinary practitioner and a certifiedultrasound technician. The additionalcost for these procedures has been $25each.

During each test period, perfor-mance information is mailed to theparticipants every 28 days. Bull perfor-mance information, along with the rulesand regulations, a calendar, nominationforms and vaccination records, also canbe found on the web: http://www.agctr.lsu.edu/wwwac/research/deanlee/bulltest

Figure 2. Average selling prices for spring andfall sales by year.

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Gentry and Olcott record data on each calf. The othertwo sites in this LSU AgCenter program are McNeeseState University and Louisiana Tech University.

ary student, applies parasite calf. LSU veterinary studentsith animals while helping with.


Controlling


Horn FliesHorn Flies lthough the horn fly is only one of

many pests of livestock, it is the one thatcosts the cattle industry the most.Economic losses to the horn fly in theUnited States are estimated at more than$800 million annually, and cattleproducers spend at least $60 million eachyear on insecticides to control this pest.Nationwide, the weaning weight ofcalves of cows protected from horn fliesis at least 14 pounds heavier than that ofcalves of cows infested with horn flies.In Louisiana, horn flies can be found oncattle almost year round with populationpeaks in the spring and fall. Because ofthe high number of fly generations peryear in the South, insecticide resistancedevelops more rapidly. Based on theprice of $1 per pound, expending anestimated $2.50 for fly control wouldyield an extra $11.50 income per calf atweaning after adjusting for the cost ofcontrol.

LSU AgCenter scientists conductstudies on horn fly control techniquesand their effect on beef production andon horn fly susceptibility to insecticides.

Results indicated there was little or noeffect of spring horn fly populations onthe weaning weight of fall-born calves.Fall-born calves have access to highquality forage during the spring andspend large amounts of time grazing.Weight change of cows and calves wasunaffected by horn fly control. Weightgain is more likely affected by foragequantity than by cow milk production.

This study at Rosepine was the firston the economic impact of horn flies onfall-calving beef cow production, andthese studies should be repeated underdifferent conditions (geographic, forage,breed, etc.) before any potential eco-nomic benefit of horn fly control in thespring for this production system isdiscounted.

Battling resistanceSince the horn fly spends almost its

entire adult life on livestock, mostinsecticides and application techniqueshave been successful in controlling it atsome point. However, these successstories are followed by significant loss ofcontrol or resistance development overtime. Confirmed reports of resistance toorganochlorines and organophophoruscompounds occurred in the 1970s, anddescriptions of resistance to pyrethroidear tags were numerous in the 1980s.Recently, resistance to the newerorganophosphorus impregnated ear tagshas appeared. Therefore, it can beconcluded that the horn fly developsresistance to persistent exposure toinsecticides whether the persistence isdue to the molecular structure of theinsecticide or the release system.

LSU AgCenter studies demonstratethat continuous use of a single insecti-cide treatment is not an appropriatestrategy. At the Red River Station inBossier City, pyrethroid (Saber) tagswere used from 1989 to 1991. In the firstyear of use, the tags provided 13 weeks

Lane Foil, Professor, Department of Entomol-ogy, LSU AgCenter, Baton Rouge, La.;Montgomery Alison, Coordinator, Macon RidgeResearch Station, Winnsboro, La.; Sidney M.DeRouen, Associate Professor, Hill FarmResearch Station, Homer, La.; Millard Kimball,Research Associate, Red River Research Station,Bossier City, La.; David G. Morrison, AssistantDirector for Animal Sciences, LouisianaAgricultural Experiment Station, LSU AgCenter,Baton Rouge, La.; David W. Sanson, AssociateProfessor and Research Coordinator, RosepineResearch Station, Rosepine, La.; and Wayne E.Wyatt, Associate Professor, Iberia ResearchStation, Jeanerette, La.

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Lane Foil, Montgomery Alison, Sidney M. DeRouen,Millard Kimball, David G. Morrison, David W. Sansonand Wayne E. Wyatt

Yearling cattle weight gainIn a study at the LSU AgCenter’s

Hill Farm Research Station in Homer,scientists found that with fly control,yearling cattle had a 27-pound additionalweight gain average over 100 days.Under the conditions of this study, thisweight gain was achieved with moderatelevels of horn fly control. A total of 246yearlings (196 steers and 50 heifers)were used in the study. Cattle with 25percent or 50 percent Brahman breedingresponded similarly to horn fly control.An average of 87 flies per animal wasobserved on treated yearlings versus 275flies on animals not treated. Thisreduction influenced weight gainssignificantly, and these data do notcontradict the currently acceptedeconomic threshold of 200 flies peranimal.

Fall-calving beef cowproduction

To measure the effects of horn flycontrol on fall-calving beef cow produc-tion, a three-year study was conductedat the LSU AgCenter’s RosepineResearch Station at Rosepine. Theobjectives were to monitor horn flypopulations on fall-calving cows fromearly spring to mid-summer and todetermine the effects of horn fly controlduring the last three months beforeweaning on weight gains and weaningweights of fall-born calves. The 87 fall-calving cow-calf pairs used in the studywere allotted into two equal groups.Cows in one group were treated withpyrethroid-impregnated ear tags whilethe other group received no treatment.Illustration by Elma Sue McCallum

Doing research on horn fly control involvescounting the horn flies on the animals. Somecows are tame enough that researchers canstand close enough to get the count.However, most are not calm enough for this,so researchers use binoculars to count.



of control. But by 1991, the period ofcontrol was just three weeks (Figure 1).At the Rosepine Station, organophospho-rus impregnated ear tags (Terminator)were used from 1989 to 1992. Controlprovided by these tags declined from 16weeks to one week during the four-yearstudy (Figure 2).

Studies at the Red River stationcontinue to demonstrate that usingpyrethroid tags results in selection forpyrethroid resistant flies within threeyears, regardless of the type of pyre-throid used. At Rosepine, our data

Lane Foil talks about horn fly control at arecent field day at the Rosepine ResearchStation in Rosepine, La.

Figure 3. Weeks of control byyearly alternation betweenpyrethroid and organophosphateear tagsEarly recommendations for preventingdevelopment of resistance includedalternating pyrethroid and organophosphatetreatments yearly. After seven years ofrotation studies, results did not support thisstrategy.

Figure 2. Weeks of control oforganophosphate ear tags atRosepine and reversal with pour-onadditionTerminator tags were used from 1989 to1992. The period of control provided bythese tags declined from 16 weeks to oneweek during the four-year study. A falltreatment with Ivomec in 1993 wasfollowed by an apparent reversal oforganophosphate resistance.

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the filter paper assay also indicateddevelopment of resistance.

Alternating chemical classes of tagsyearly has been proposed as a strategyfor slowing the development of insecti-cide resistance in local horn fly popula-tions. Our data did not indicate that thiswas an effective strategy at the Northeastand Macon Ridge stations. This ap-proach may be effective elsewhere, butour studies are the only actual fieldstudies that have been conducted to testthe recommended strategy of yearlyalternating between tags of differentchemical classes. Since alternatingchemical class of tags yearly does notslow development of resistance, adding ayear of fly control with products otherthan ear tags in a three-year rotation maybe appropriate.

A current recommendation is thatpyrethroid ear tags should not be usedexcept once every three years. We haveinitiated studies at two locations todetermine if this is an appropriaterecommendation for horn fly control inLouisiana. In 1994 and 1997, pyrethroidtags (Atroban) were used at the IberiaStation; only organophosphate tags wereused in 1995 and 1996. The organophos-phate tags provided 12 to 18 weeks ofcontrol, a level of control indicative ofan organophosphate-susceptible horn flypopulation. The pyrethroid tags providedzero weeks of control in 1994, but fourweeks of control were observed in 1997.Our preliminary studies indicate that

Photo by Linda Foster Benedict

indicate that continued use of organo-phosphate products for a four-yearperiod can select for flies resistant to allof the organophosphate compoundsavailable. Organophosphate resistanceappears as a gradual loss of control fromyear to year, rather than the rapid loss ofcontrol associated with pyrethroidresistance. Some laboratory studiesindicate that using mixtures of organo-phosphates and pyrethroids continuouslymay slightly delay the development ofresistance. We have not tested mixturesin the field because selection for resis-tance to two chemistries at once couldresult in total loss of control.

Early recommendations for prevent-ing development of resistance includedthe alternating of pyrethroid and organo-phosphate treatments yearly. After sevenyears of rotation studies at the Northeastand Macon Ridge research stations, wefound no support for the strategy ofyearly rotation between pyrethroid andorganophosphate ear tags. Although eartags had not been used for fly control atthese stations before 1991, the pyre-throid tags provided only six to sevenweeks of control in that year. Theorganophosphate tags provided nine to11 weeks of control in 1992, but this didnot help reverse the pyrethroid resistanceobserved in 1991. The efficacy of bothtags declined over the next six years inspite of yearly rotation between chemicalclasses (Figure 3). Yearly changes insusceptibility to insecticides detected by

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Figure 1. Weeks of control ofpyrethroid ear tags at Red RiverSaber tags were used from 1989 to 1991.The period of control was reduced from 13weeks to just three weeks in three years.


pyrethroid tags should be used only onceevery third year in Louisiana.

LSU AgCenter scientists haveconducted studies where separate herdswere maintained on different pasturesusing different treatments for horn flycontrol. This allows more separationbetween pyrethroids and organophos-phates. From 1989 to 1991, organophos-phate and pyrethroid insecticidal ear tagswere tested in this manner at the HillFarm and the Iberia stations. Resultsshowed no reduction in control.

LSU AgCenter scientists also haveexamined possible resistance manage-ment using mid-summer/fall treatmentswith pour-on endectocides. We havedemonstrated the apparent reversal oforganophosphate resistance with falltreatments of the pour-on endectocide,ivermectin (Ivomec), at Rosepine. Theefficacy of the 20 percent diazinon(organophosphate) tag increased fromone week in 1993 to 12 weeks in 1994following an intermediate (fall)ivermectin treatment. The efficacy ofthe 40 percent diazinon tag went fromtwo weeks in 1994 to 12 weeks in 1999with the intermediate fall ivermectintreatment. LSU AgCenter scientists havehad similar, but less dramatic, resultswith mid-summer treatments for manag-ing pyrethroid resistance, and replicatedstudies are currently under way on thatsubject.

In summary, we have an activeprogram on horn fly management that ismade possible by cooperative researchthroughout the state. At least for now,several management strategies allow usto control the economic damage causedby horn flies.

Photos by Millard Kimball

The walk-through flytrap was designed70 years ago andprovides a simple, yeteffective, way to helpcontrol for horn flies.It consists of astructure that allowsonly minimal lightbecause the fliestend to leave theanimal more readilyin the dark. Fewcattle producers usethe traps, however,because the cattlemust be trained towalk through them,and only mild-tempered animals will do this. The farmermust construct the trap gradually and traincattle to pass through it to get water andfood. As the cattle go into the trap, some ofthe flies leave the animals and are trappedin the sides which have screen baffles. Stripsof fabric hang from the top of the trap tobrush off flies. The trap pictured was testedat the LSU AgCenter’s Red River ResearchStation in Bossier City for four years. Hornfly counts for the cows using the trap werebelow the 100 flies per side economicthreshold for the entire 15 weeks of thestudy each of the four years. Furthermore,the calves nursing the cows that used thetrap gained more weight than calves nursingnontreated cows. Weaning weights were anaverage of 8 pounds heavier for the treatedgroup.

Walk-through Fly Trap

Beef Cattle Management Tips (#2701). Economic infor-mation to help the cattle producer make decisions. Includesvaccines, diseases and chart for body condition scoring. 16pages.

Louisiana Beef Cattle Production (#2239). A compre-hensive guide, including pasture management, health, breedingand marketing. Diagram for cattle handling facility, cuts of beefand parts of beef animal. 28 pages.

Louisiana residents may obtain up to five free copies of any onepublication by visiting their parish extension office or clickingon the publications’ button at the LSUAgCenter’s website:www.lsuagcenter. com.

Horn Fly Control with Backrubbers (#1343). Fact sheetwith instructions for building a cable backrubber.

Control External Parasites in Beef Cattle (#1418). De-tailed charts on use of various pesticides for horn flies, horseflies, stable flies, mosquitoes, ticks, lice, cattle grubs, mangemites and screwworms. Includes information on herbicideresistance management.

Important Fly Pests of Louisiana Beef Cattle (#2617).Information about control and economic importance of blood-sucking insects.

Monthly Beef Cattle Management Calendar & Work-book (#2712). A listing of to-do’s with space for personalnotes. 28 pages.

LSU AgCenter Beef Management Publications


n Louisiana, internal parasitism is amajor impediment to efficient growthand productivity in cattle. Gastrointesti-nal nematodes and lungworm areprevalent throughout the state, and theliver fluke is a problem in the bottom-lands along major river systems andtributaries and in coastal marsh areas.

A primary requirement for effectiveprevention and control of infection anddisease caused by these internal parasitesis to understand their population dynam-ics and the seasonal trends of infection inrelation to weather and management.Such studies have been conducted inLouisiana. The first of these dealt withdevelopment and survival of nematodesoutside of their host, called free-livingstage, on small experimental pastureplots. Later studies looked at grazing todetermine seasonal patterns of infectionfrom different types of nematodes.

Conditions for nematode larvaldevelopment on pastures are optimal inlate fall and spring. Except in rareinstances of extended periods of severecold, winter conditions in Louisiana donot seriously impede nematode develop-ment and survival. Summer conditionsdo not favor long survival of larvae onpasture. Studies of seasonal prevalenceof nematode infections in grazing cattleat three Louisiana locations confirmedand expanded results of small plotstudies. These later studies showed thatnematode infections of cattle generallyincrease in the fall, may be sustained orincrease in winter and reach peak levelsin spring. High temperatures andalternating wet and dry conditions in

Internal Parasites of Cattle:Seasonal Patterns of Infection and Control

summer reduce the survival of mostnematode parasite eggs and larvae onpasture.

Studies reveal that liver flukeinfection in cattle is most prevalent inlate fall and spring. Summer conditionsare as harmful on development andsurvival of fluke immature stages in thesnail intermediate host and on pasture asthey are for free-living stages of nema-todes on pasture.

Control OptionsOptions for control of internal

parasites continue to be based on goodanimal and pasture management proce-dures and use of anthelmintics, whichare dewormers. Clorsulon and Valbazenare the only drugs available for flukecontrol, and neither has any effect onimmature flukes. Recommendations areto treat in fall and again in spring, ifrainfall is heavy during winter and earlyspring.

There are more treatment options fornematodes than for liver flukes. Theseoptions include the older benzimidazoledrugs – oxfendazole (Synanthic),albendazole (Valbazen) andfenbendazole (Safeguard). Theavermectin/milbemycin drugs are newerand include ivermectin (Ivomec),doramectin (Dectomax), eprinomectin(Eprinex) and moxidectin (Cydectin).

A major feature of the newerproducts is a longer time or persistenceof activity. These drugs can remainactive in the animal for three to sixweeks compared to only two to threedays for the older products. Also, thenewer products have a higher level ofefficacy against most types of nema-todes, and all help to control externalparasites.

In addition, use of eprinomectin andmoxidectin requires no withdrawalperiod before slaughter. Eprinomectinalso has no milk withdrawal time.

In Louisiana, timing of treatment iscritical. Although it is not the mostconvenient time for cattle producers,

July and August can be the mosteffective period to treat adult cows. Themore traditional treatment time in the fallis still effective for controlling nema-todes, flukes and ectoparasites, and itcoincides with weaning of spring-borncalves.

In the case of younger cattle –spring-born calves and replacementstock – treatment in late fall is mostappropriate. These calves need to betreated then because of their vulnerabil-ity to infection and their rapid growthrate that could be inhibited by infection.Following an initial treatment in late fallwith one of the newer drugs, a secondtreatment 10 to 12 weeks later in springprovides good protection from infectionduring November through May, whenyoung cattle may be exposed to highlevels of infection on pastures.

Unlike parasitic nematodes of sheepand goats, nematodes in cattle have sofar not developed resistance toanthelmintics. One reason may be thatcattle are treated for parasites less oftenthan sheep or goats. Cattle producersshould still be cautious in their frequencyof anthelmintic treatments.

Alternative methods for controllingparasites of cattle, such as vaccines andbiological control, are being investi-gated. Technical problems in develop-ment and application remain unsolved.In any cattle herd, only a minority ofcattle have the heaviest infections andcontribute the most to contamination of apasture with infective larvae. Some workhas been conducted, but more intensiveresearch by the U.S. Department ofAgriculture has been initiated to under-stand the genetic makeup of cattle inrelation to susceptibility and resistance toinfection with nematodes and otherinfectious diseases. As an alternative orsupplement to use of anthelmintic drugsin cattle nematode or fluke parasitism,progress in genetic research couldproduce a new era of parasite controlthrough improved resistance of cattle toinfection.

James C. Williams, Professor, Department ofVeterinary Science, LSU AgCenter, BatonRouge, La.; Alvin F. Loyacano, Professor, DeanLee Research Station, Alexandria, La.; Andy A.DeRosa, Instructor, Department of VeterinaryScience, LSU AgCenter, Baton Rouge, La.; andJeffrey A. Gurie, Research Associate, Dean LeeResearch Station, Alexandria, La.

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James C. Williams, Alvin F. Loyacano, Andy A. DeRosa and Jeffrey A. Gurie


Cattle producers have long recognized the benefits of cross-breeding. Incorporation of a percentage of Brahman breedinginto the cow herd has become a general practice in the South.Unfortunately, sustaining a particular percentage of Brahmanbreeding in the cow herd over several generations is difficultfor many producers and almost impossible for producers withsmall herds.

Synthetic breeds, such as Brangus and Beefmaster, involvingBrahman and British (Angus, Hereford and Shorthorn) breeding,were developed to be used as general purpose straightbreds(mating of bulls and cows of like breed makeup) to stabilizepercentage Brahman breeding across generations for both largeand small producers. Some of these synthetic breeds have beenavailable to Louisiana producers since the 1940s and 1950s. Newbreed resources that have become available since then includesynthetic breeds (Gelbray, Simbrah) involving Brahman and Con-tinental (Gelbvieh, Simmental) breed composites.

Interest in these new breeds prompted a five-year (1988-1992) study in which Brangus, Beefmaster, Simbrah and Gelbraysires were used in purebred matings to dams of like breeds(Brangus bulls mated to Brangus cows) and in crossbred matingsto Brahman-Hereford crossbred cows. This mating schemeprovided a comparison of the British-derivative and the Conti-nental-derivative synthetic breeds in both straightbred and cross-bred situations.

Calves were born in the spring and weaned in the fall at theIdlewild Research Station. Difficulty with calving was low andsimilar for all cow types. Calf birth weights were heavier forGelbray- (82 pounds) and Simbrah-sired (86 pounds) calves thanfor Brangus- (77 pounds) and Beefmaster-sired (77 pounds)calves. Brangus, Gelbray and Simbrah straightbred calves wereheavier at birth than calves of Brahman-Hereford crossbredcows. Birth weights were similar for Beefmaster-sired calves ofBeefmaster and Brahman-Hereford crossbred cows.

Preweaning daily gains and weaning weights were higher forContinental- (2.0 pounds/day and 483 pounds) than for British-sired (1.9 pounds/day and 453 pounds) calves. Simbrah-siredcalves gained 0.1 pound more per day and were 35 poundsheavier at weaning than Gelbray-sired calves. Preweaning dailygains and weaning weights were lower for Brangus (1.65 pounds/day and 408 pounds) and Beefmaster (1.83 pounds/day and 439pounds) straightbred calves than for Brangus- (2.1 pounds/dayand 492 pounds) and Beefmaster-sired (2.0 pounds/day and 474pounds) calves of Brahman-Hereford crossbred cows. Withinboth the Gelbray- and the Simbrah-sired calves, preweaning dailygains and weaning weights were similar for both straightbred andcrossbred cow types.

Brangus (1,098 pounds), Gelbray (1,111 pounds) and Simbrah(1,208 pounds) cows were heavier at weaning than Brahman-Hereford crossbred cows (997 pounds). Brangus and Simbrahcows were also taller at the hip than Brahman-Hereford cross-bred cows.

Following weaning, steer calves were shipped about 50 milesto the St. Gabriel Research Station, where they were wintered onhay and supplement rations and allowed to graze availableryegrass pastures in the late fall and the spring of the followingyear. Steers were then shipped in mid- to late-May about 90 milesto the feedlot facilities at the Iberia Research Station and placedon a high concentrate ration. Straightbred Angus steers from theIberia Research Station were included in this phase of theevaluation. Steers were weighed and evaluated for fat cover overthe 13th rib every 28 days. After a minimum of 84 days on feed,steers that had attained 0.4 inches of backfat were transported tothe Department of Animal Science for processing.

Angus steers tended to be lighter initially (679 versus 716pounds), required less time on feed (140 versus 195 days) andwere 183 pounds lighter (1,034 versus 1,217 pounds) at the endof the feedlot trial than the Brahman-influenced steers. Initialweights (705 versus 728 pounds) were similar for British- andContinental-sired steers, but British-sired calves required fewerdays (183 versus 207 days) to attain 0.4 inches of backfat and wereremoved from the feedlot at lighter weights than the Continental-sired steers (1,175 versus 1,259 pounds).

The heavier final feedlot weight of Continental-sired com-pared to British-sired calves was largely due to Simbrah-siredsteers, which had heavier final feedlot weights (1,321 versus 1,198pounds) than the Gelbray-sired steers. Initial and final feedlotweights and days on feed were similar for Brangus- (708 pounds,1,177 pounds and 180 days) and Beefmaster-sired (701 pounds,1,173 pounds and 185 days) steers. Daily gains during the feedlotphase were similar for all breed types (average gain of 2.6 poundsper day) and reflect that steers were removed from the feedlotat similar physiological points.

After transit to Baton Rouge and immediately before slaugh-ter, steers were weighed again. Perhaps because of the relativelack of heat tolerance of Angus steers compared to the Brahman-influenced steers, Angus steers exhibited 1 percent more shrinkthan did the other breed types (3.8 percent versus 2.8 percent).

The Gelbray and Simbrah cows were either superior orequal to the Brangus and Beefmaster cows and were equal to theBrahman-Hereford crossbred cows. They were heavier, how-ever, and would presumably cost more to maintain. The value ofheavier weaning weights should be tempered with possibleincreases in herd input costs. An evaluation of feedlot perfor-mance should indicate the performance acceptability of thesesynthetic breeds of cattle for market outlets leading to commer-cial feedlots. The biggest differences between the Continental-sired steers and the British-sired and Angus steers are the longertime on feed and the heavier weights required to reach a desirablelevel of fatness. Although heavier weights at a prescribed level offatness may be viewed as a benefit, the increased number of daysin the feedlot is not.

Comparing Beef Breedsby Birth, Weaningand Feedlot Performance

Wayne E. Wyatt, Associate Professor, Iberia Research Station,Jeanerette, La.; Thomas D. Bidner, Professor; Paul E. Humes, Professorand Head; and Donald E. Franke, Professor, all Department of AnimalScience, LSU AgCenter, Baton Rouge, La.

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oday, assisted reproductivetechnologies allow us to make markedchanges in the genetics of farm live-stock. One success story is artificialinsemination (AI). Use of this technol-ogy from the 1950s through the 1990sincreased average milk production percow more than 300 percent in dairyherds in the United States. Yet, feed costfor the increased production was reducedby more than 30 percent. How did thishappen? The top progeny-tested sireswere used to inseminate a multitude ofdairy cows, and their geneticallyimproved daughters were used asreplacement females for herds. Increasedgenetic selection for milk productionusing frozen semen for AI and improvedherd management dramatically changedthe North American dairy industry. Thissuccess story occurred because research-ers developed the technology, andprogressive producers used it to staycompetitive in the marketplace.

Embryo TransferAn assisted technology that received

considerable interest from cattle produc-ers beginning in the late 1970s wasembryo transfer. Although the firstembryo transfer that produced a live calfwas reported in 1951 at the University ofWisconsin, not until 1976 were thenonsurgical transfer procedures devel-oped for cattle. This led the way forcommercial, in-field use of this technol-ogy. Although beef cattle prices,industry promotion and producer interestenhanced the use of this technology inthe late 1970s and early 1980s, embryotransplantation today is more often usedby dairy producers than by beef cattleproducers.

Today, we use less of the follicle-stimulating agent over fewer days forour donor cows and fewer sperm cellsper donor insemination. However, the

actual methodology has changed littlesince the 1970s. With more experiencedembryo transfer professionals in thefield, the embryo recovery rates areexpected to be higher than 75 percent,with five to eight good quality embryosper donor collection. Using good qualityembryos, 65 percent to 75 percenttransfer pregnancy rates are nowexpected using this procedure.

In recent years, a single embryo on-the-farm collection approach has becomepopular with progressive dairy produc-ers. This approach uses no folliclestimulatory hormones in the donor cows.Single embryos are collected from thetop milk-producing cows in the herd andthen transferred to cows in the bottomportion of the milking herd. Producerscan also buy and store frozen embryosfor transplantation year round. Today,both dairy and beef cattle producers buyfrozen embryos from private andcommercial companies. This is predictedto be a market growth area in the future.The potential for using frozen embryosin breeding herds appears to be unlim-ited.

UltrasonographyOther assisted reproductive tech-

nologies were developed in the 1980sand 1990s. Some are more mechanicalthan biological in nature. For example,ultrasonography was developed initiallyin the livestock industry to evaluatemuscle mass in the live animal. Withmodifications, primarily in the probestructure and software, this technologyhas become an important multi-useinstrument for livestock producers.Today, ultrasound field units are used toevaluate the ovaries for follicle develop-ment of cattle before and after AI todetermine if the female ovulated.Ultrasonography also is used in preg-nancy testing, including detecting fetalheart beat (starting after 22 days ofgestation) and sexing the fetus during thefirst trimester of pregnancy.

Electronic Heat DetectionAnother new technology reaching

the commercial market in the 1990s waselectronic heat (estrus) detection forcattle. With this system a small circuit

switch transponder is glued on the rumpof the cow. This transponder sendsinformation to a transmitting tower andto a receiver attached to a computer inthe house or barn. Since each electronictransponder is uniquely identified, thenumber of mounts made by herdmatesand the duration of those mounts arestored in computer data files for thatanimal. This allows producers to identifythe first time during a 24-hour period afemale on the breeding list stood to bemounted by another animal. This tech-nology takes a lot of the guesswork outof the timing of AI in both naturallyovulating and superovulated embryodonor cows. Although the initial cost ofan electronic estrus detection system ishigh, its overall value is well worth theexpense.

Embryo SexingThe procedure for sexing embryos

before transplantation is now available tocommercial embryo transplant stations.This new DNA technology for embryosexing is accurate, user friendly and canbe completed within six hours after theembryos are harvested. At least onecommercial company sells a completecattle embryo-sexing kit for in-field use.The capability of sexing embryos in thelaboratory gives producers the option ofselecting bull or heifer calves for marketand reproductive management purposes.

In Vitro FertilizationFor 15 years researchers have been

developing in vitro fertilization (IVF)procedures for cattle. IVF technologyhas been commercially available to dairycattle breeders only since the early1990s. IVF is a multi-step process thatrequires a well-equipped laboratory anda skilled technician. The IVF procedureinvolves harvesting the eggs (oocytes)from the cow’s ovaries and fertilizingthem in the laboratory. The resultingembryos are held at cow body tempera-ture in an incubator for seven or eightdays and then transferred nonsurgicallyto recipient females at the same stage oftheir estrous cycle. The pregnancysuccess rate for good quality IVF-derived embryos is expected to rangefrom 50 percent to 65 percent. Success

New Assisted Reproductive Technologiesfor Use in the Cattle Industry

Joel Carter, Oscar Perez, Richard Denniston and Robert A. Godke

Joel Carter and Oscar Perez, both GraduateStudents; Richard Denniston, Instructor; andRobert A. Godke, Boyd Professor, Department ofAnimal Science, LSU AgCenter, Baton Rouge,La.

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rate is lower if the embryos have beenfrozen and then thawed before transfer.

The IVF procedure offers analternative to cattle producers who havegenetically valuable cows that, for somereason, are unable to produce viableembryos through standard embryocollection and transfer procedures. Thistechnology can be used with oocytesharvested from older, nonovulatingcows, females with physical injuriessuch as a broken leg, and problem cowswith an abnormal cervix. Success hasbeen reported using IVF procedures onsupplemental oocytes obtained fromcows with cystic ovarian disease.

Today, oocytes are harvested fromthe female by transvaginal, ultrasound-guided collection procedures developedby the LSU AgCenter and others. Toretrieve the oocytes for IVF, a trainedprofessional inserts an ultrasound-guidedstainless steel needle through the vaginalwall near the cervix to extract oocytesfrom the follicles visible on the ovaries.The procedure is conducted on the small,medium and large follicles on bothovaries of the donor female. Thisapproach also can be used on oocytesharvested from prepubertal heifers andduring the first trimester in pregnantcows and horses.

With IVF, the potential exists formore embryos to be produced in ashorter period, because the procedurecan be repeated on the same cow three tofour times a month. At the LSUAgCenter, we harvest oocytes from earlypostpartum (less than 40 days) beefcattle, before the female begins cyclicactivity. This allows for the productionof one or more extra calves from the cowbefore she is mated for a natural preg-nancy.

Semen SexingAnother promising assisted repro-

ductive technology is sexed semen forartificial insemination. Being able to sexsemen has been a dream of scientists andlivestock producers for decades. In thelate 1980s, a USDA senior scientist atBeltsville, Maryland, reported a proce-dure that was capable of sorting spermcells of rabbit semen using a high-speed,laser-controlled cell sorter. This method-ology was also successful in farmanimals. Briefly, sexing semen involvesusing high-speed cell sorters that directsperm into batches containing eithermore than 90 percent X-chromosome(female-producing) sperm or more than90 percent Y-chromosome (male-producing) sperm.

A Colorado-based company andColorado State University are evaluatingsexed cattle semen using deep uterinehorn artificial insemination techniques.The results to date indicate that theoffspring are the predicted sex more than90 percent of the time. At the LSUAgCenter, a transvaginal, ultrasound-guided artificial insemination procedureis used to deep-uterine inseminateproblem breeder cows and superovulatedembryo donor cows. The next step willbe to use sexed semen with these newdeep-uterine insemination methods.These trials are under way.

Beef producers could use the X-chromosome bearing sperm when heifersare needed for herd replacements, thusincreasing the rate of genetic improve-ment of the herd. First-calf heifersshould produce smaller calves at birth, ifthey produce primarily heifer calves.Correspondingly, if Y-chromosomebearing sperm were used, then primarilybull calves would be produced in thesame herd.

Animal CloningThe cloning of

adult sheep (Dollyand her sistersreported in 1997)stimulated a greatdeal of interest innuclear transfer(cloning) technologyby the livestockindustry. One methodof constructingcloned embryos is totake a cell from anembryo or a develop-ing fetus and transferit to an unfertilizedoocyte from whichthe female genomicDNA has beenmechanicallyremoved. The oocyteis then “activated,” asthough it had beennaturally fertilized,and the nucleus“reprogrammed” forsubsequent normalembryo developmentto occur. Once thedonor cell populationhas been prepared,hundreds of clonedembryos can beproduced each weekin the laboratory byusing oocytes

extracted from the ovaries of animalsdestined for slaughter.

Cloned sheep, goats and cattle werefirst produced from embryos more than15 years ago by another type of cloning,termed embryo splitting. Using a fineglass needle or a razor blade chip tobisect the embryo, scientists can producegenetically identical offspring. Thepregnancy rates using this embryomicrosurgical technique are similar tothose of intact embryos from the samedonor female. Unfortunately, the bestsuccess rate came from bisecting theembryo into two halves, giving theopportunity for only two offspring to beproduced from a single embryo.

More recently, there has been amajor breakthrough in animal cloning.With Dolly, the famous sheep, cells forcloning were harvested from the mam-mary gland of an adult ewe. Thesemammary cells were incubated in alaboratory to produce a much largerpopulation of these dividing cells for the

Brett Reggio, graduate student in animal science, uses thisequipment to perform microsurgery, such as embryo cloning. Thisequipment is part of the Embryo Biotechnology Laboratory, whichis located at the LSU AgCenter’s St. Gabriel Research Station.



nuclear transfer procedure. The produc-tion of Dolly in Scotland was importantbecause it was the first mammal pro-duced from an adult somatic cell (a cellother than an egg or a sperm). Thepotential for the use of this new technol-ogy amazed the world. Today, adult cellclones have been produced in mice,sheep, cattle and recently goats. Cloningwill provide cattle producers an opportu-nity to reproduce genetically valuablefounder animals (seedstock).

Cloning technology will providecattle producers with ready access toproduction-tested breeding seedstock,thus increasing the accuracy of selectionin their breeding herds. Cloning F1terminal-breed males to produce malesfor market steers might be the ultimatebeef production management system.With this scenario, fewer cows would be

The success of any artificial insemination program dependson the successful and accurate detection of the onset of estrus,or heat, in female animals. Injecting a herd of beef females withluteolytic agents (prostaglandins), such as Lutalyse and Estrumate,will synchronize estrus in most of the group. The ability toconcentrate estrous behavior allows the producer more insemi-nation opportunities in the herd during the course of the breedingseason. Little research has been reported, however, on theeffects of synchronization on beef cattle estrous behavior.

An experiment was conducted to determine if the use ofluteolytic agents affected the behavioral parameters of the beeffemale compared with that of naturally cycling females. This studywas conducted with beef cows and heifers at TransOva Geneticsin Sioux City, Iowa, during spring and summer. A total of 1,812estrous cycles occurring between April 15 through September 15were analyzed, including 816 natural estrous cycles and 996prostaglandin-induced estrous cycles.

Data were retrieved from the HeatWatch database, which isa computerized system used to detect estrus (DDx, Inc., Denver,Colo.). The mount data included animal identification, date, timeof mating and duration of each mount. The system was used todetermine the exact time of the onset of estrus.

The mean temperatures at the location of the study rangedfrom 77.3 to 83.2 degrees F. The exact breed types of these beeffemales were not available for this study, although approximately80 percent of them were Angus or Angus-cross. The beef femaleswere housed in dry lots and received corn silage daily. Based onobservations of body condition, the females would have scoresranging between 7 to 8, on a 1 to 9 scale, with 9 considered obese.The cattle were observed twice daily, once in the morning andonce in the afternoon, to appraise their health status and identifyany animals with lost electronic patches.

In this study 4,800 estrous periods were identified andsorted using computer programs. Criteria used to determine theonset of estrus were four individual animal mounts within a six-hour period. Any females that did not meet this criteria were notincluded in the data set. The criteria for the cessation of estrus infemales was the absence of at least four mounts within a six-hourperiod. The estrous profiles of naturally cycling females (controls)were compared with those profiles of prostaglandin-inducedfemales (treated).

Females induced with prostaglandin exhibited a longer, moreintense estrus than females with a natural estrous cycle. Theprostaglandin-induced females exhibited significantly more totalmounts (47 versus 42), more total seconds stood (163 versus144) and a longer estrus (12.7 hours versus 12.2 hours) thanfemales that had a natural estrous cycle.

In summary, there was a significant difference between theestrous profiles of the prostaglandin-induced and naturally cyclingfemales for the parameters of estrus observed by the HeatWatchsystem. The values for number of mounts per hour, number ofseconds stood per mount and number of seconds stood per hour,however, were similar between treatment groups.

The use of luteolytic agents was found to enhance thefemale’s expression of estrus based on the increased duration,increased number of mounts per estrus and increased number ofseconds stood per estrus when compared with naturally cyclingbeef females. This increase in estrous activity, coupled with theprostaglandin-induced synchronization of the breeding group,should make the detection of estrus more accurate and easier forthe producer.

Glen T. Gentry Jr., Graduate Student, Department of Animal Science;Ronald P. Del Vecchio, Associate Professor and Beef Specialist; andRobert A. Godke, Boyd Professor, Department of Animal Science, LSUAgCenter, Baton Rouge, La.

Effect of Synchronization on Beef Cattle Estrus

needed to produce annual replacementheifers, so more F1 recipient femalescould be available to produce the clonedF1 males for use as the market steers.This assumes that the new cloningmethodology becomes more efficientand is economically feasible.

In summary, advances in assistedreproductive technologies have occurredrapidly in the last decade. Even scientiststhemselves are often amazed at the rateof progress made in the development andapplication of these technologies. Theavailability and the cost of some of thesenew technologies still remain in ques-tion. There is little doubt about theirpotential effectiveness to commercialcattle production, at least in the shortrun. It is obvious that including newtechnologies will require more intensivemanagement by cattle producers. These

new technologies appear to have, ifeconomically practical, an opportunityfor changing the genetic potential offarm animals at a faster rate than byconventional methods.

In the future, market-assistedselection for both single and multiplegene traits will become a potent assistedreproductive technology for embryosand newborn offspring. The challenge isidentifying those traits important enoughto merit the application of these newassisted reproductive technologies.Assisted reproductive technologies willlikely play a larger role in embryoproduction and in the production of herdreplacements. Our research approach isto develop those new assisted reproduc-tive technologies that have economic,agricultural and medical applications.



rtificial insemination (AI) allowsdistribution of genes from a superior bullto many females without incurring theexpense of buying the animal. Since theearly 1950s, introduction of superiorgenetics through AI by dairy producershas resulted in an increase in milkproduction. Most purebred beef produc-ers now use AI in varying degrees, eitherinseminating a few of their top femalesor depending solely on AI for their calfcrops.

Although the genetic potential of acalf crop (increased weaning weights,increased weight gains, increased feedefficiency and desirable carcass traits)can be enhanced by using AI, thisprocedure takes a lot of time and effort.For AI to be effective and efficient,estrus detection and time of inseminationare crucial. Research has shown thatearly and accurate detection of thefemale’s estrus is directly related topregnancy rates following AI.

Though time consuming, detectingestrus is not as difficult as most think.

Estrus detection should be conducted atleast three times per day (early morning,mid afternoon and late evening) for atleast 30 minutes. For best results,insemination should take place 10 to 12hours after the first signs of standingestrus. The time needed for inseminationand estrus detection is substantial whenfemales are not synchronized. Theamount of time required could bereduced significantly if synchronizationprotocols are used, and females areinseminated based on time mating, notvisual signs of estrus. For synchroniza-tion to be worth the time and cost, atleast a 60 percent pregnancy rate in theherd needs to be achieved.

Results from research designed todetermine what type of synchronizationprotocol yields the best pregnancy ratesin a timed breeding protocol have beenvariable. Some researchers have reportedpregnancy rates as high as 70 percent,but these findings are not typical. Inmost studies, pregnancy rates for femalesinseminated based strictly on time

Glen T. Gentry Jr., Graduate Student, Depart-ment of Animal Science, LSU AgCenter; JoeLamb, Area Program Specialist, GenexCooperative, Baton Rouge, La.; Ronald P. DelVecchio, Associate Professor and Beef Specialist,LSU AgCenter; Bruce M. Olcott, LSU VeterinarySchool; and Robert A. Godke, Boyd Professor,Department of Animal Science, LSU AgCenter,Baton Rouge, La.

SynchronizingBeef Femalesfor ArtificialInsemination

Glen T. Gentry Jr., Joe Lamb,Ronald P. Del Vecchio, Bruce M. Olcott

and Robert A. Godke

This estrus-detection device is manufactured by HeatWatch. It is placed in this orange pouch and attached to the cow’s tailheadregion with adhesive.

A signal from the sensor attached to thecow is sent to the antenna on top of thistower and then transmitted to a computer.The system measures the time and durationthe cow is mounted. This tower is at theLSU AgCenter’s Idlewild Research Stationand is used in research on estrous behavior.

Photos by John Wozniak

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SynchronizingBeef Femalesfor ArtificialInsemination


mating fall between 30 percent and 40percent.

The variable pregnancy rates aftertimed insemination may be related toovarian follicular waves. All females in abreeding group are at different phases oftheir follicular waves at the start of thesynchronization protocol. Because ofthis, administering a luteolytic agent,such as Lutalyse, results in differentdurations of time between injection andovulation, affecting pregnancy ratesoften negatively.

At the LSU AgCenter’s IdlewildResearch Station, an experiment wasconducted to determine the effectivenessof breeding either on the visual detectionof estrus or timed insemination onsynchronized crossbred females. Twosynchronization protocols were used,Syncro-Mate B and Ovsync, in 63Brahman x Hereford first-cross beeffemales 55 or more days postpartum andall 6 years old. All were multiparous,meaning each had given birth to morethan one calf. These females werestratified by days postpartum and bodycondition score and assigned to treat-ments either using Syncro-Mate B (28)or Ovsync (35). Females were fitted with

HeatWatch rump-mounted transducersand monitored to determine the onset ofestrus in each female.

Females allotted to the Syncro-MateB group were implanted withnorgestomet implants and injected withestradiol valerate and norgestomet on thefirst day of treatment. On day 9, implantswere removed and females receivedprostaglandin. In the Syncro-Mate Bgroup, calves were not allowed to nursefrom day 9 until insemination. Syncro-Mate B females were time-inseminated52 hours after implant removal.

Females in the Ovsync group wereinjected with a gonadotropin-releasinghormone on the first day of treatment,and on day 7, females received prostag-landin. At 30 hours, following injectionwith prostaglandin, the Ovsync femalesreceived another gonadotropin-releasinghormone and were inseminated 18 hourslater. Calves were not allowed to nursefrom day 7 until post-insemination.

Females in either treatment groupthat expressed estrus more than 24 hoursbefore their designated time of insemina-tion were inseminated approximately 12hours after their first observed mount.Pregnancy in both treatment groups was

determined by ultrasonography 30 to 35days post insemination.

Overall pregnancy rates were similarbetween the two synchronizationprotocols. Furthermore, pregnancy ratesof females inseminated either onobserved estrus or at a predeterminedtime were not different across treatmentgroups. More females in the Syncro-Mate B group (57 percent) exhibited anearly estrus compared with the Ovsyncgroup (29 percent). Regardless ofsynchronization protocol, significantlymore pregnancies resulted from femalesinseminated based on observed estrus(81 percent) compared with femalesinseminated based on time mating (35percent) in this study.

The results of this experiment agreewith other reports that pregnancy rates ofbetween 30 percent and 40 percent canbe expected when females are insemi-nated based strictly on time mating. Torepeatedly achieve acceptable AIpregnancy rates, we feel females shouldbe inseminated based on the visual estrusdetection. Efforts will continue at thesestations to search for ways to achieveconsistently high pregnancy ratesfollowing timed insemination.

The patch is placed on the tailhead region of the cow. Secure in a pouch is the estrus-detection device.These cattle are at the LSU AgCenter’s Idlewild Research Station near Clinton, La.




BeefCalving rate in Louisiana (number of live calves born

annually per number of cows in the breeding herd) tends to beless than 80 percent. This low reproductive rate hurts profitpotential. Body condition in beef cows at calving is consideredan important factor influencing pregnancy rate, which is thenumber of cows becoming pregnant per total of number ofcows in the breeding herd. Body condition scoring (a visualscoring of overall body fatness) of cows is something most beefproducers can easily be trained to determine. Research con-ducted at the Rosepine Research Station and other researchstations in the South examined the use of body conditionscores (1 = very thin and 9 = very fat) as a method of improvingpregnancy rates in mature cows (5 to 10 years of age). Theseresearchers found that mature cows needed to be in moderatecondition (a score of 5) to achieve acceptable rebreeding ratesfollowing calving.

Lifetime cow productivity is optimum when young cowscalve initially at an early age and every year thereafter. Calvingyoung cows at 2 years of age places a high demand on theirbody energy reserves (fat), because they are still growing.Because of an average gestation of 285 days and the desirabilityof rearing a calf within a 365-day period, a cow must becomepregnant within an 80-day period after calving. The rebreedingof young cows has been recognized by the Louisiana Cattlemen’sAssociation, the Louisiana Farm Bureau Federation and theLSU AgCenter as one of the major production problems ofLouisiana beef producers.

Because of this concern, research was begun to evaluatechanges in body weight and condition score before calving (90-day winter period) and body condition score at calving as theyinfluence calving performance, rebreeding rates and calf growthof pregnant, 2-year-old, spring-calving heifers. This researchwas conducted at the LSU AgCenter’s Central, Dean Lee, HillFarm, Iberia, Rosepine and St. Gabriel research stations. Breedtypes of the 475 young cows varied and represented the breedresources available to Louisiana beef producers. Pregnantheifers were weighed and scored for body condition in the falland fed one of three diets during the winter. The dietscontained different energy levels (high, medium and low) andwere designed to allow the heifers to either gain, maintain orlose weight and body condition score (BCS).

Neither changes in body weight nor changes in bodycondition during the precalving period had an influence on

calving, rebreeding or calf preweaning average daily gain orweaning weight. BCS of the cow at calving influencedrebreeding, however. Average pregnancy rates for cowshaving BCSs of 4, 5, 6 and 7 at calving were 65 percent, 71percent, 87 percent and 91 percent, respectively. Because acow must rebreed within 80 days after calving to maintain a365-day calving interval, it is important to note that thenumber of days from calving to rebreeding was 92, 82, 74 and76 days for cows with BCSs of 4, 5, 6 and 7 at calving. Clearly,body condition score at calving should be no lower than 6 torealize acceptable rebreeding performance. Also, furtherexamination of the research data revealed that it really didnot matter whether a first-calf heifer was gaining or losingweight or body condition before calving, as long as she had aBCS of 6 or 7 at calving.

LSU AgCenter beef research scientists determined that2-year-old cows calving for the first time have a significantlybetter chance of successfully rebreeding within an 80-dayperiod after calving if they have a moderately high level ofoverall body fat (BCS of 6) at calving. This score is higher thanthat recommended for mature cows (BSC of 5) because ofthe greater energy demands of the growing young cow.Biologically, it mattered little if the young cow had gained,maintained or lost overall body fat in winter, as long as shescored the critical body condition score of 6 at calving. But,the additional winter feed cost of increasing fall body condi-tion scores of 4 and 5 to the recommended calving level of6 can be significant. Therefore, it is generally more cost-effective to keep heifers in moderately high body condi-tion at the beginning and throughout the winter.

Wayne E. Wyatt, Associate Professor, Iberia Research Station,Jeanerette, La.; Danny F. Coombs, Professor, Dean Lee ResearchStation, Alexandria, La.; Sidney M. DeRouen, Associate Professor,Hill Farm Research Station, Homer, La.; Donald E. Franke, Professor,Department of Animal Science; Jeffrey M. Gillespie, AssistantProfessor, Department of Agricultural Economics and Agribusiness;Paul E. Humes, Professor and Head, Department of Animal Science;David G. Morrison, Assistant Director for Animal Sciences, LouisianaAgricultural Experiment Station; and T.W. White, Professor,Department of Animal Science, LSU AgCenter, Baton Rouge, La.

Maintaining Adequate Body ConditionImproves the Productivity of Young Beef Cows


he single largest cost in a cow-calfsystem is providing nutrients to theanimals. Between 40 percent and 60percent of total cow cost goes intomeeting the nutrient requirements. Thislarge variation in cost is caused by manyfactors including the amount of nutrientsthe animal harvests compared to theamount of feed used, environmentalfactors such as heat and moisture, theefficiency of nutrient use by the cowherd, and the level and intensity ofmanagement. As a general rule, produc-ers with lower nutrition costs graze theircattle more and feed them less processedfeed.

Profitability in the cow-calf industryis affected by both the cost and amountof production. Inadequate feed can limit

production by decreasing the numberand weight of calves at weaning. Incontrast, providing nutrients above theanimal’s requirement will increaseproduction costs with no benefit.Understanding nutrition principles andforage use is critical for profitableproduction.

Forage Use and GrazingNutrition

Louisiana beef producers have atremendous potential for forage produc-tion because of the warm climate, butextreme heat and humidity in summercan limit forage quality and thus beefproduction.

The quality of a bermudagrass-dallisgrass pasture was evaluated duringa four-year study conducted by theDepartment of Animal Science. Resultsdocumented the decrease in foragequality during the summer. Subse-quently, summer forages were evaluatedat the Rice Research Station usingyearling steers. Results of four years ofgrazing indicated little difference inaverage daily gains among steers grazingcommon bermudagrass, coastalbermudagrass or dallisgrass, but steersgrazing bahiagrass had lower averagedaily gains.

Research at the Rosepine ResearchStation revealed no difference in calfweaning weights when cow-calf pairsgrazed either common bermudagrass orbahiagrass. Yearling steers grazingcommon bermudagrass, however, had athird pound higher average daily gainscompared to steers grazing bahiagrass. Ina subsequent study with yearling heifers,animals grazing common bermudagrasshad higher gains than heifers grazingeither Alicia bermudagrass or Pensacolabahiagrass, but stocking rate and beefproduced per acre were lowest for thecommon bermudagrass treatment. In thisstudy, a high rate of nitrogen (N)fertilizer was used, with applications of

50 pounds of N every 21 days. Resultsfrom these studies suggest that althoughbahiagrass may provide adequatenutrition, yearling cattle will gain moreon bermudagrass pastures.

The development of hybridbermudagrass offered southern produc-ers a chance to increase production fromcow-calf operations. Results from along-term study conducted at the RedRiver Research Station demonstratedthat, with adequate management andmoderate fertilization, one acre ofcoastal bermudagrass will provideenough forage to meet nutritionalrequirements of one and a half cow-calfpairs. Additional research evaluating thepotential for coastal and other hybridbermudagrasses to provide the nutrientsrequired for satisfactory production ofcow-calf and stocker systems has beenconducted at the Hill Farm and theRosepine research stations. Results fromthese studies indicate that althoughproduction can be increased, manage-ment requirements and input costs willprobably increase.

Several research stations haveevaluated the nutrient potential ofryegrass and other cool-season annuals

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David W. Sanson and Danny F. Coombs

David Sanson talks about the best methodsfor storing hay to retain nutrients at arecent field day at the Rosepine ResearchStation in Rosepine, La.

David W. Sanson, Associate Professor andResearch Coordinator, Rosepine ResearchStation, Rosepine, La., and Danny F. Coombs,Professor, Dean Lee Research Station, Alexan-dria, La.

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Photo by Linda Foster Benedict


for beef cattle. Studies have evaluatedstocking rates, different grazing meth-ods, different combinations and varietiesof cool-season grasses, as well as otheraspects of ryegrass grazing. Results haveindicated that ryegrass is an excellentwinter forage throughout the state andcan improve both the production andeconomic efficiency of cow-calfproducers and stocker producers. Inaddition to cool-season annuals, researchat the Rosepine Research Station hasevaluated the use of fescue as a cool-season forage to extend the grazingseason. Results from this study usingspring-calving cows indicate that theforage will provide adequate nutrientsfor maintenance of cow weight and calfgrowth. Conception rates are 20 percentto 25 percent lower, however, than forcows grazing ryegrass or hay plus asupplement.

Researchers at the Rosepine andNortheast research stations have com-pleted several studies evaluating differ-ent forage systems for providingadequate nutrition for cow-calf produc-tion year round. These studies includeddifferent combinations of summergrasses and combinations of winter

annuals and legumes. Results highlightthe effect location and weather patternshave on forage production and subse-quent animal performance.

Several research stations and theDepartment of Animal Science con-ducted a series of cooperative studiesduring the 1980s to evaluate producingslaughter beef on forage diets in Louisi-ana. In general, results showed that it isfeasible to grow calves to slaughterweights on Louisiana forages, but it hasnot been economical for Louisianaproducers to finish cattle on forages.They continue to send cattle to the GreatPlains for finishing on grain.

Research is continuing on the effectsof forage use on cow-calf production atresearch stations around the state.Researchers at the Iberia ResearchStation are evaluating the effect ofstocking rate and grazing systems ofboth warm-season and cool-seasongrasses on performance of cows andcalves. The effect of adding legumes tofescue is being evaluated at the RosepineResearch Station as well as a comparisonof grazing bermudagrass to bahiagrasswith mature beef cows.

SupplementationWinter feeding accounts for more

than half of the nutrition costs in a cow-calf system. This is primarily because ofthe cost of producing harvested foragesand purchased supplements. Molasses-based protein supplements were evalu-ated by Dean Lee Research Stationresearchers using spring-calving cowsconsuming medium-qualitybermudagrass hay. Supplements had noeffect on cow weight change, calfweaning weight or calving percentage.Subsequent research at both Dean Leeand Rosepine research stations hasindicated that a medium-quality grasshay will meet the requirements of agestating cow and supplementing witheither a grain-based or a molasses-basedsupplement with this type of forage hasno benefit.

Researchers at the Dean LeeResearch Station evaluated supplement-ing calves grazing lower quality standingbermudagrass in the fall before grazingwinter annuals. Results from this studyindicated higher gains by the supple-mented calves during the supplementa-tion period. The economics ofsupplementation were marginal tonegative, however. Similar results wereobserved at the Iberia Research Station.Researchers there conducted a two-yearstudy that indicated that feeding soybeanmeal to steers grazing coastalbermudagrass increased gains by a thirdof a pound. Research at the IberiaResearch Station with steers grazingcoastal bermudagrass supplemented withcorn resulted in increased performance,but the economic benefit was marginal.

Research is being conducted at boththe Rosepine and Dean Lee researchstations to evaluate the effect of cornsupplementation for mature cows duringlate gestation on utilization of low-quality hay. Researchers at the Hill FarmResearch Station are evaluating poultrylitter as a supplement for cows andstocker cattle. Also, Animal ScienceDepartment researchers are conductingsupplementation studies at the St.Gabriel Research Station to evaluatesources of protein and energy on growthof stocker cattle.

Photo by Mark Claesgens

The single largest cost in a cow-calf systemis providing nutrients to the animals.Between 40 percent and 60 percent of totalcow cost goes into meeting the nutrientrequirements.


Beef eef products available to consum-

ers have been changing in recent yearsand will continue to change. Processingtechniques and packaging procedureshave been developed to accommodatethe consumer’s desire for convenience,nutrition and safety of meat products.

LSU AgCenter research has playeda major role in these changes. One areaof focus has been ground beef, the No. 1beef product in the United States. A lotof the meat technologies for ground beefpurchased at the supermarket have beeninfluenced by LSU AgCenter research.Experimentation has been conducted onusing protein from other sources toimprove the shelf life, flavor, color andsafety of ground beef. For example, useof bovine blood plasma, red cells anddecolorized red cells decreased thelightness and yellowness of ground beefpatties.

In addition, the way the ground beefis packaged has been influenced by LSUAgCenter research. Much attention hasbeen given to newer packaging technolo-gies using atmospheres containingproportions different from the air aroundus, which is 20.9 percent oxygen, 70percent nitrogen and 0.03 percent carbondioxide. Modified atmosphere packaging(MAP) is increasingly used as more rawmeat is centrally prepacked at theprocessing plant rather than packaged inthe retail store. Still other studies havelooked at use of ozone as an alternativeway to kill pathogens in meat products.

Efforts to improve the utility of beeffrom cull cows involved collaborativeefforts with Auburn University. Thecows received a growth hormone, bovinesomatotropin, which increases muscleprotein. Beef from these cows had lessfat, more moisture and a redder color.

Other research has focused on lipidand pigment oxidation in precooked beefproducts, which affects color, textureand flavor, and on improving binding ofrestructured beef. For example, researchhas examined the influences of heatingconditions on precooked, restructuredroasts.

Nutritional value of beef has beenrelatively controversial. Although beef isone of the most nutrient-dense foods,more attention has been paid to thenegative nutritional concerns such assaturated fat and cholesterol. LSUAgCenter research has focused onpositive nutritional aspects of beef and atimproving beef’s nutritional value.

One research focus has been the“meat factor” in which beef enhances thebioavailability of nutrients such as ironand copper. Bioavailability refers to theefficiency with which our bodies utilizea dietary nutrient. Evidence suggests thatbeef enhances the bioavailability ofcertain minerals and vitamins fromsources that would otherwise be of lownutritional value.

That beef provides an excellentsource of dietary iron in the form ofhighly bioavailable heme iron is well-known. Less well-known is that beefenhances the bioavailability of iron fromnonmeat sources, such as spinach andrice bran, which are known to have highconcentrations of nonheme iron. Themeat factor is now well enough estab-lished scientifically that meat’s presencein the diet is taken into account in theNational Academy of Sciences’ Recom-mended Dietary Allowances for iron.However, little is known about thepotential effect of beef on nutrients otherthan iron. Thus, experiments have beenconducted to determine whether the meatfactor exists for other minerals.

In one project an animal model wasused to evaluate mineral balance foriron, copper and zinc. The only mineralthat evidenced increased absorptionbecause of the presence of beef in thediet was copper. This research was thefirst to show that beef could improve thebioavailability of copper from a nonmeat

source. This observation symbolizes theneed to consider the overall nutritionalvalue of a food when making dietaryrecommendations.

Other research has focused onincorporation of rice bran or rice brancomponents into beef products. Ricebran is an excellent source of manyvitamins and minerals and has beenshown to lower serum cholesterol,although mineral bioavailability islowered by rice bran. Combining ricebran with beef has the potential toenhance nutritional aspects of eachthrough complementary effects.

The research approach we used toenhance the nutritional value of beef wasto develop functional beef products bycombining beef with rice bran. Afunctional food is one that provideshealth benefits beyond its nutritionalvalue. Thus, if a food product werefound to reduce the risk of coronaryheart disease or cancer, it would beconsidered a functional food. Typically,plant foods are viewed as the mainsource of functional foods. Rice bran oilcontains high levels of antioxidantnutrients that have been shown to reduceserum cholesterol and reduce the risk ofcertain types of cancer. Our goal was toincorporate rice bran oil into a restruc-tured beef product to improve from ahealthful standpoint the lipid composi-tion and at the same time reduce thetendency for cholesterol oxidation,which has been associated with coronaryheart disease. Restructured beef roastswere manufactured from lower qualitybeef cuts. Beef was mixed with salt,water and rice bran oil (at the expense offat trim) and formed into restructuredroasts. Also, the vitamin E level in-creased as rice bran oil increased.Vitamin E is one of the antioxidantnutrients touted as having positiveeffects on the healthfulness of foods.

These and other studies on products,processing and packaging have benefitedthe industry by providing information toimprove quality, nutritional value,palatability and safety of beef forconsumers.

Kenneth W. McMillin, Professor, Department ofAnimal Science, and J. Samuel Godber,Professor, Department of Food Science, LSUAgCenter, Baton Rouge, La.

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Processing, Products and PackagingProcessing, Products and PackagingKenneth W. McMillin and J. Samuel Godber


Kenneth McMillin, left, has been awarded patents for a technique he developed for using ozoneto inhibit pathogen growth in ground beef. His research associate is Michael Michel.

Reduction of E. coli in Ground Beef with Gaseous Ozone

Figure 1. E. coli inhibition with ozone gas

The importance of eliminatingfoodborne illness from the food sup-ply has prompted much research oncontrol and destruction of pathogenicmicroorganisms. Pathogens often sur-vive, and some grow at the refriger-ated temperatures for meat process-ing and storage.

The popularity of ground beef,comprising about 45 percent of totalbeef consumption in the United States,makes the control of pathogenic mi-croorganisms critical. Irradiation is ef-fective in destroying pathogenic mi-croorganisms, but obstacles includethe number and expense of facilities toirradiate large amounts of ground beef,approval of packaging materials andexclusion of oxygen from packages toprevent off-odor development. Foodscientists are seeking other effectivepreservation methods to destroyharmful bacteria.

A series of studies has been con-ducted to determine the efficacy ofgaseous ozone on destruction of E. coli and other pathogenicmicroorganisms in meat. Preliminary results indicated that coliformindicator microorganisms, or E. coli, on ground beef patties wereinhibited the same with ozone gas or 80 percent oxygen atmo-spheres compared with nitrogen or air atmospheres.

A study comparing half and maximal output of ozone,approximately 1,000 and 5,000 ppm ozone, on ground beefinoculated with E. coli showed no inhibition by ozone after 48hours of storage compared with control (nontreated) beefpatties. The inoculum concentrations of E. coli were much higherthan would be found in commercial ground beef, which may havegiven some protective effect in buffering the microorganismsfrom the effects of ozone. When ozone was left in packagesrather than being flushed with nitrogen gas immediately aftertreatment of patties, there was a reduction in E. coli concentra-tions after 24 hours of storage at 40 degrees F. Studies with ozoneare conducted by flushing ozone gas into gas-tight packagescontaining the meat. This provides maximal exposure of the beefto the ozone while minimizing loss of ozone gas into the roomatmosphere and exposure to laboratory workers.

Ozonated water is effective at killing bacteria with shortexposure times. This led investigators to compare the effects ofhumidified ozone gas with dry ozone gas. Ground beef patties ofabout 100 grams were formed by hand and inoculated with E. coli.Ozone was generated at 500, 3,500 or 5,000 ppm. The ozone gasstream to be humidified was passed through a specially designedchamber before insertion into packages. Figure 1 shows thatexposure to ozone decreased E. coli counts in ground beef patties,with increasing levels being more effective. Dry ozone gas wasslightly more inhibitory than humidified gas.

The 10 total studies on ozone and ground beef have indicatedthat ozone has the potential to destroy pathogenic bacteria withspecific environmental conditions and ozone levels. Because theconcentrations of E. coli used in the studies were much higherthan levels found commercially, the level of inhibition exhibited inthese studies may prove beneficial for industry adaptation. Linkingof ozone gas exposure with other bacterial growth hurdles, suchas low temperatures or carbon dioxide gas, is being investigated.The availability of different processing technologies to ensure asafe supply of high quality food relies on continued scientificefforts.

Kenneth W. McMillin, Professor, and Michael E. Michel, ResearchAssociate, Department of Animal Science, LSU AgCenter, Baton Rouge,La.



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Reduction of E. coli in Ground Beef with Gaseous Ozone


Non-profit Org.U.S. Postage

PAIDPermit No. 733Baton Rouge, LA

Louisiana Agricultural Experiment StationLouisiana State University Agricultural CenterP.O. Box 25100Baton Rouge, LA 70894-5100

Inside:

The Louisiana beef industry is asdiverse and complex as it iseconomically important to the state.................................................................Page 4

Beef cattle production is the largestsegment of all of American agriculture............................................................... Page 6

Loss of market share to poultry andpork provides a challenge for the beefindustry. .......................................... Page 14

Information-based programs provevaluable to beef producers’ future..............................................................Page 16

From our archive

Group of steers from the New Orleans Livestock Show. May 1936

Early research in Louisiana indicated that Brahman crossbredcattle were superior in many ways to other breeds for theclimate and conditions of Louisiana. See articles aboutcrossbreeding on pages 7, 9, 10, 12 and 25.

A Brahman bull from Palacious, Texas. April 1931

Meat cutting demonstration in Ringgold, La., sometime in the 1930s.

fall 2000 vol. 43, no. 4

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