mu beef cow/calf series - missouri state...
TRANSCRIPT
NutritionWritten by:David L. Lalman, beef nutrition specialist, animal science extensionJohn A. Paterson, Jr., beef nutrition specialist, animal science extensionHomer Sewell, professor emeritus, animal science
Published by University Extension, University of Missouri-Columbia
Produced by the Office of Extension and Agricultural Information
For information on how to order additional publications in the BeefCow/Calf series, see MU publication M147, University Extension andYour Beef Cow/Calf Operation, or contact your local extension center.
On the cover: Cows have the ability to convert forages into beef.During much of the year, they can get by on low-quality grazing. But,during some parts of their reproduction cycle, when they are nursingcalves and preparing to be rebred, extra attention must be givento their nutrition. ~
MU Beef Cow/Calf Series
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Contents
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Protein supplements : Figuring protein requirements, Nonprotein nitrogen (urea), Bypass protein,
Urea verses plant protein, Use of salt to restrict consumption of protein and energy supplements,
Feeding protein at intervals
Buying protein supplements 1
Supplementing crop residues Protein, Wheat straw
Creep feeding beef calves
Vitamins Vitamin A, Vitamins D and E
Minerals Calcium and phosphorus, Sodium and chlorine (salt), Potassium, Trace minerals
Mineral mixtures for feeding free-choice, Magnesium, Magnesium and grass tetanyOccurrence of grass tetany, Supplements to prevent grass tetany
Tables
.6
16
.22
.23
Table 1. Winter rations for 500-lb. calves Table 2. Winter rations for I,OOO-lb. pregnant cows during the last third of pregnancy
Table 3. Winter rations for cows in first four months of lactation Table 4. Supplemental feed recommended with cornstalks Table 5. Mineral requirements and maximum tolerable levels for beef cattle Table 6. Daily nutrient requirements for growing bull, steer and heifer calves Table 7. Requirements for breeding cattle Table 8. Feed composition
,
Topic PageFinding balanced, economical herd rations 1
Production goals, Stress points
Feeding the breeding stock at different ages Feeding developing heifers, Feeding pregnant heifers, Feeding pregnant cows
Feeding lactating cows, Feeding bulls
Winter rations for cows Wintering with hays and crop residues, Wintering on fescue pasture
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A nutritionally balanced feed
ration helps cattle producers
achieve production goals faster
and more efficiently.
Eed rations for beef herds must be economical yet meet the nutri-tional requirements of the various classes of cattle. T wo essentials forthe herd manager to know are the daily nutrients required by each classof cattle in the herd and the nutrient composition of the feeds. Withthis knowledge, formulating rations is simply a matter of combiningfeeds to meet the herd's nutrient needs. These nutrient needs are influ-enced by age, sex, rate-of-gain, point in the reproduction cycle, animalweight and amount of milk produced. Daily nutrient requirements ofbull, heifer and steer calves are given in Table 6. Requirements for beefbreeding cattle are given in Table 7.
The average nutrient composition of feeds often used for beef cattleis shown in Tabl~ 8. For a more accurate ration formulation, you need alaboratory analysis. Area extension livestock specialists can provide anup-to-date list of laboratories offering feed-testing services.
When cattle graze or have free access to harvested forage, theamount eaten daily is difficult to predict. Uncertain consumption com-bined with nutrient variability of roughages means that beef cows maybe getting insufficient nutrients even though the ration would be ade-quate under most situations. Therefore, the appearance and perfor-
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Nutrition 1
economICal
herd rations
fiance of the herd should be monitored closely at all times to see if thecattle ar~ getting a balanced diet. ~
Production goals When developing a feeding program, consider these productiongoals for your beef herd:
.90 to 95 percent calf crop born within a 60~day calving period.
.A calf from each cow every 12 months.
.Heavy weaning weights (500 pounds plus).
Stress points To reach these goals, feeds must meet the nutritional needs of theherd throughout the breeding season. Be aware of the following stresstimes when heifers and cows are most likely to have nutrient deficiencies:
.Heifers -when they are being developed to breed at 13 to15 months in order to calve at 22 to 24 months of age andwhen they are being prepared to rebreed after a first calf.
.Cows -in the last 90 days of pregnancy and first 90 days oflactation.
Feeding the
breeding stock
at different ages
Feeding developing heifers
Heifers nursing their first calves often have low pregnancy rates.Inadequate nutrient intake after calving is often at fault. First'calf heifersneed nutrients for their own growth in addition to those needed for milkand reproduction. First-calf heifers take longer to rebreed for their secondcalf, so breed them 30 days sooner than the rest of the herd.
Heifer calves must come into heat at 12 to 14 months of age if theyare to calve at 23 months of age. The weight at which a heifer reachespuberty and comes into heat is influenced by breed and projectedmature size. The ideal weight to breed most British breeds is at 600 to700 pounds, compared to 725 to 775 pounds for Simmental, Charolaisand similar'size breeds. If a heifer weighs 400 to 500 pounds whenweaned at seven months (210 days), she must have an average dailygain of 1 to 1.25 pounds for the next seven months to reach puberty andsettle at 14 months of age.
)
Rations for bred heifers shouldhave a higher nutrient content
than those fed to cows. A heifer'sfeed must keep both her and her
unborn calf growing.
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2-
Beef Cow/Calf Series
Fall-weaned calves should gain 1 to 1.25 pounds daily during thewinter to reach breeding weight at 14 months of age. Table 1 listsrations to give about 1 to 1.5 pounds daily gain on 500-pound calves.
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Pay attention to the energy and protein in a heifer's ration the fol-lowing winter while she is carrying a calf. Heifers that are thin andundernourished at calving will have poor settling rates. The percentprotein and energy needed by heifers in late pregnancy are similar to therequirements for mature cows in early lactation that have average milk-ing ability. Therefore, the rations listed in Table 3 are adequate for year-ling heifers in the last third of pregnancy.
Feeding pregnant heifers
Feeding pregnant cowsWatch the body condition of pregnant cows. Cows in average fleshin the fall can lose 10 to 25 percent of their weight during pregnancyand still be in proper condition to nurse a calf and rebreed. Cows willlose about 100 to 130 pounds at calving. This weight loss represents thebirth weight of the calf, fluid and fetal membranes. About one-half ofthe fetal weight develops the last 60 days of pregnancy.
A practical way to condition cows for calving is to feed them sothey will gain about 100 pounds the last three or four months of preg-nancy (see Tables 2 and 3). At this rate, they neither lose nor gain bodyweight. Instead, the extra nutrients are used to add weight to the devel-oping fetus. After calving, the cow would weigh about the same as shedid three or four months before calving.
r-Table 1.Winter rationsfor SOO-lb. calves.
Ration 1 2 3 I 4 5 6
10 3
7.~
310
Rations for 11b. daily gain: (Ibs
Alfalfa hay
Grass hay
Forage sorghum silageCorn silage
Milo or corn grain
Protein suppl. (40%)
Dicalcium phosphate*
Vitamin A
25 32:iO
3 3 2.5
0.5
2.0 2
0.5 0.70.03+
Rations for 1.5 Ibs. daily gain: (Ibs.)
9 3
6
3
8Alfalfa hay
Grass hay
Forage sorghum silageCorn silage
Milo or corn grain
Protein suppl. (40%)
Dicalcium phosphate*
Vitamin A
20 27
355 5 5
0.50.1+
4.0 4.00.50.06+
0.70.06+
0.02
+
'Supply 15,000 to 20,000 I vitamin A per head daily
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Nutrition 3
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Cows fed energy~deficient rations before calving are slower to comein heat. One sign of energy shortages during pregnancy is when cows failto rebreed in time to calve every 12 months.
Don't overfeed. Calving problems may be related to overconditioningof the cow and to calf size. But don't starve cows in the last one~third ofpregnancy in an attempt to produce a smaller calf and decrease calvingdifficulties. Starvation makes the pregnant mother draw nutrients fromher body tissue and skeleton to develop the fetus. In many cases, suchcows have trouble rebreeding. In severe cases, it leads to calving problems.
Feeding lactating cows
~
The daily protein and energy (total digestible nutrients, or TON)needed by a cow increases in late pregnancy and increases again aftershe starts lactating. A cow with average milking ability needs about 50percent more daily protein and 30 percent more energy after she calvesand starts lactating than she needs when dry and in mid-pregnancy.Cows that are heavy milkers need even greater amounts of nutrientsduring lactation to produce the extra milk..Energy has a big effect on a cow's milk production in early lactation.Phosphorus and protein also may need to be added to cow rations. Manyroughages have inadequate levels of phosphorus for cattle. Protein isoften deficient in winter rations of lactating cows unless some legumeforage is fed.
A cow must come in heat and conceive by 85 days after she calvesin order to produce a calf every 12 months. Nutrient intake after calv-ing influences the pregnancy rate in a herd for the next year. After calv-ing, a cow must have extra energy, protein and other nutrients, not onlyfor milk but also to prepare her reproductive organs for pregnancy.Studies show that when cows lose weight after calving, fewer of themconceive at first service and somewhat fewer cows show heat early inthe breeding season.
Unless they are fleshy, cows should gain one-quarter pound to one-half pound a day for the first 90 days after calving to have good repro-ductive performance. Some scientists think this Qain is so important for
A cow needs about 50 percentmore daily protein and 30 percentmore energy after she calves and
begins lactating.
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Beef Cow/Calf Series4
Daily feeding of youngbulls helps themstay in top condition.
reproduction purposes that they recommend checking the weight gainof a sampling of cow every two weeks for the first 60 days to be surerations are adequate.
Feeding bullsRations for bulls should not differ greatly from those used for cows.Because mature bulls are larger than cows, they should receive a corre-spondingly larger amount of feed. Rations used for pregnant replace-ment heifers will be suitable for young bulls except that more grain willbe needed to get the growth usually desired on maturing bulls.
Young bulls weighing 700 to 900 pounds should gain 2.2 to 2.7pounds daily to express their growth potential. They should be fed aration containing from 9.5 to 10.5 percent crude protein on a dry matterbasis. One pound to 1.25 pounds of grain per 100 pounds of body weightand free-choice hay should achieve this rate of gain.
One pound of 40 percent protein supplement per head daily will beneeded if the hay contains less than 50 percent high-quality legume. Ifgood-quality corn silage is full-fed, the grain allowance should bereduced to about three-quarters of a pound of grain for each lOO poundsof body weight. A similar amount of grain will be needed with good-quality pasture to get maximum growth on young bulls.
Watch the condition on young bulls. Keep them growing, but don'tget them overly fat. Check the adequacy of your rations by weighingyoung bulls every month. Mineral and vitamin requirements for bullsare similar to those for heifers.
Bulls used for breeding should be kept in medium flesh. Bulls thatare too thin or fat will not have the best sexual activity. Don't let overlyfat bulls down during the breeding season. A mature bull often loses 200to 300 pounds during the breeding season. This means he will need togain 1 to 1.25 pounds daily during the rest of the year to be back in con-dition for the next season. A small amount of grain or other extra feedmay be needed 60 days before the breeding season to get mature bulls inproper condition. Body condition of the bull is an indication of whether
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Nutrition 5
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an extra feed allowance is needed as the breeding season approaches.Mature bulls can be maintained largely on pasture and other roughage.Bulls should be conditioned to pasture and not turned out with cowsdirectly from a dry lot. They need rations with approximately 7.5 per-cent protein (dry matter). No extra protein will be needed ifgood-quali-ty grass hay is fed or if 25 percent or more of the hay is composed oflegumes. Vitamin and mineral supplements used for cows will be satis-factory for mature bulls.
It will take 14 to 16 pounds of TDN and 2.2 pounds of crude pro-tein daily to maintain a 1,800- to 2,000-pound mature bull. Thisamount of TON is contained in 25 to 30 pounds of hay or 60 to 75pounds of corn silage.
Rations for pregnant and lactating cows during the winter areshown in Table 2 and Table 3. Modifications in these rations will benecessary because feedstuffs will vary in energy and nutrient content.
More grain may be needed than is given here if your feeds are lowerin quality and energy. Also, cows weighing more than 1,000 pounds willneed more daily feed than shown in these rations. Rations consistingtotally of grass or legume roughages for lactating cows are borderline inenergy even when the roughages are of the best quality.
Winter rations
for cows
Wintering with haysand crop residues .
Rations (Ibs
2 3
Good-quality roughageConstituentsTable 2.
Winter rations for 1,OOO-lb.pregnant cows during
the last third of pregnancy.
Moisture % 1 4 5 6, ,
4 3
10Legume hay, goodGrass hay, good 21
Corn silage, good 67
Forage sorghum silage 70
Grass or grass-Iegume haylage 62
Protein supplement (40%)
Mineral mix**
4055 60
50 250.33
++ + + + +
Other roughage
Constituents
Rations (Ibs.)
8 9 10 11 12Moisture % 7
906770
11 10 15 9 13
20
33?
7 8
9
Corn cobs, cottonseed hulls,
wheat straw, or cornstalks
Corn silage
Forage sorghum silageAlfalfa meal, dehydrated
Legume hay, goodGrass hay, good
Protein supplement (40%)
Molasses (wet)
Ground shelled cornVitamin A *
Mineral mix**
251 ,5
5
2
+
+
4
+
+
+
+
+
+
--.*Supply 15,000 to 20,000 I.U. vitamin A per head daily.**Include minerals to meet cows daily needs. See Tables on pp. 20- 23
Beef Cow/Calf Series6
,-,Reproductive performance should be watched closely on lactating
cows, especially when they are fed only roughage rations. You may needto add 3 to 5 pounds of grain per head daily to all-roughage rations toensure rebreeding.
A free-choice mineral supplement containing 8 to 12 percent phos-phorus should be fed with these rations.
Wintering on fescue pastureFescue pastures provide much of the winter feed for many Missouribeef herds. The protein, energy and other nutrients in winter grassesdecline after Jan. 1. If plenty of forage is available, dry, mature, pregnantcows should receive enough protein and energy throughout the winterfrom fescue pasture. Some good-quality grass hay or mixture hay will beneeded when snow covers the fields or in late pregnancy if cows becometoo thin. Cows should also have a phosphorus mineral supplement con-taining vitamin A.
Weaned calves and cows in the first 90 days of lactation usuallyneed about 1 pound of a 40-percent p!otein supplement and 3 to 4
1,OOO-lb. cows with average milking ability*
Rations (Ibs.)
3 4
Table 3.Winter rations for cows in first fourmonths of lactation.Moisture % 1 2 5 6
18r-
Legume hay, goodGrass hay. good
Corn silage 67
Forage sorghum silage 70
Grass or grass-Iegume haylage 62
Ground shelled corn
Protein supplement (40%)Vitamin A **
Mineral mix
4
0.5
+
+
" Also appropriate for yearling heifers in the last third of pregnancy
** 36,000 I.U. per cow daily
1,1 OO-lb. cows with superior milking ability
Rations (Ibs.)
9 10Moisture % 7 8 11 12
Legume hay, goodGrass hay, good
Corn silage 67
Forage sorghum silage 70
Grass or grass-Iegume haylage 62
Ground shelled corn
Protein suppl. (40%)Vitamin A ...
Mineral mix
155
5
75+
+
~ 37,000 I.U. per cow daily
Nutrition 7
Protein is often deficient in winterrations of lactating cows unless
some legume forage is fed.
pounds of grain or its equivalent in molasses or other feeds for satisfacto-ry nutrition when they graze winter fescue pasture. This is especiallytrue after Jan. 1.
Trials at the University of Missouri Agricultural Experiment Stationand stations at other universities indicate that fescue pastures, whichhave high levels of endophyte fungus and lack legumes, are inadequatein energy for lactating cows many months of the year. In one study,flushing cows with grain increased the settling rates of spring-calvingcows bred after June 1 and fall-calving cows bred after Oec. 15, whenthey grazed pure stands of fescue. Feeding 4 to 6 pounds of corn per headdaily, starting 15 days before breeding and continuing until the cowswere bred (40 to 60 days), increased conception. A more economicalapproach may be to maintain legumes in the fescue stands and establishfescue stands free of endophyte fungus (see MU publication M152,Forage Management arIA Hay HanAling).
Cows will eat a maximum of about 2.1 pounds of dry matter foreach 100 pounds of body weight. Rate of passage through the digestivetract and daily intake will be less for poor-quality, low-protein feeds.Adjust rations for moisture differences in silage and other high-mois-ture feeds. It takes one-third more pounds of silage with 70 percentmoisture to supply the same dry matter contained in silage with 60 per-cent moisture.
One pound of corn has total digestible nutrients (TON) equivalentto 1.6 pounds of good-quality hay or 2 pounds of poor-quality hay.
Ten pounds of alfalfa hay have similar total protein and TON as 2.5pounds of soybean meal and 4.3 pounds of corn.
One pound of good grass hay equals about 2.5 pounds of corn silageand 3 pounds of sorghum silage (30 percent dry matter) in TON andcrude protein.
Remember, grain may be a cheaper source of nutrients than haywhen hay is scarce. Feed your best roughage to calves, first-calf heifersand lactating cows.
Beef Cow/Calf Series8
Figuring protein requirements
An indication of whether a feed is adequate in protein for a particu-lar class of beef cattle can be obtained by matching the protein needs inTables 6 and 7 with the protein concentration given for the feed inTable 8. The principal way protein is added to rations that are low inprotein is by supplying legumes and oil meals.
A dry, mature beef cow in mid-pregnancy needs 7 percent protein inration dry matter, whereas a cow in early lactation needs about 9.5 per-cent. A dry, mature cow will not need protein supplements unless mostof her ration is made up of low-quality roughages such as cereal straw,corn cobs, stalks and over-mature grasses. On the other hand, aroughage ration for a cow in the first four months of lactation must con-sist of high-quality grasses or have some legume composition to be ade-quate in protein. Superior milking cows usually need energy supple-ments with forages.
Nonprotein nitrogen (urea)Thanks to the bacteria and protozoa in the rumen, cattle, sheep andother ruminants use urea to replace part of the protein in their diet. Therumen microorganisms use the urea "to produce microbial protein.Therefore, the protein needs of cattle are met in two ways: by microbialprotein produced in the rumen and by dietary protein that escapes rumi-nal degradation and bypasses to the small intestine for digestion and
absorption.Before a cow's body can use urea, the microorganisms in her rumen
must convert urea to protein for their multiplication and growth. To dothe converting, they must also have energy, carbohydrates and mineralsalong with the urea.
Most roughages are too low in energy for this process to take place.Therefore, cattle on high-roughage rations cannot use urea as efficientlyto meet their protein needs as can cattle on high-grain rations. Theamount of natural protein in a feed and the extent to which this proteinis broken down in the rumen determine the amount of ammonia that isderived from the feed itself. Therefore, less urea can be used withroughages of similar energy concentration that have higher levels ofhighly soluble protein.
This means that cattle would get little use from urea added to agrass hay that had 10 percent total protein. However, urea could be usedto increase the protein equivalent of a hay with similar energy concen-tration and 5 percent total protein. However, urea probably would notbe used to the extent that the protein value in the low-protein haywould be increased from 5 to 10 percent.
Therefore, urea fed with a low-protein roughage may be convertedto enough microbial protein for a dry pregnant cow that needs 7 percentprotein in her diet but would not furnish enough protein for lactatingcows or young growing animals that need 10 to 12 percent protein intheir diets.
Soybean meal is a low-bypass protein feed because an estimated 70to 75 percent degrades to ammonia in the rumen. Protein sources thathave low degradability and supply a large portion of bypass protein aredistiller dried grains, corn gluten meal, meat scraps and blood meal. A
Bypass protein
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Nutrition 9
combination of urea and a high~bypass protein feed should provide betterprotein nutrition with many rations than does soybean meal. The ureawould ensure adequate ammonia levels in the rumen for microbial
growth.
Urea verses plant protein Urea supplements have been popular for beef cows because liquidurea supplements can be self-fed to grazing cows. Also, urea can oftencheapen the cost of protein. It takes about two-thirds of a pound of urea(281 percent CP) and 4.5 pounds of corn to supply the same total pro-tein equivalent and energy contained in five pounds of soybean meal.The relative price of these three feeds largely determines whether ureaor an oil meal supplement is a cheaper source of nutrients.
In experiments in Missouri and other stations, urea supplementshave compared favorably with oil meals as a supplement to corn silageand sorghum silage for lactating cows.
Research indicates that urea supplements are 50 to 65 percent as.efficient as plant protein supplements for cows on winter-range grasses.In other words, one-half to two-thirds as much supplemental plant pro-tein as protein equivalent from urea would be needed for equal perfor-mance on winter range. Cows with larger weight loss were compensatedwith more gain in the summer. The weaning weight of calves was slight-ly less in some trials where urea was compared with plant protein inwinter supplements. Otherwise, reproductive efficiency appears similarfor cows receiving plant or urea supplements.
Cows wintered on range grass supplemented with products likeStarea and biuret, which delay the release of ammonia in the rumen,apparently had less weight loss than cows supplemented with urea.However, plant protein supplements gave best results. Slow-releaseproducts lessen the danger of toxicity when cattle over-consume urea.
Rates of gain for 400- to 600-pound calves on range pastures or grasshay are usually less when urea is substituted for natural protein supple-ments. A period of adaptation to urea improves performance. Feedingnatural protein supplements for the first 30 to 45 days has enabledcalves fed urea with corn silage or grain-roughage rations to have similargains to those fed soybean meal. This adaptation period has improvedthe performance of calves fed urea with hay rations in some studies.
Use of salt to restrictconsumption of protein and
energy supplements
When a protein or an energy supplement, such as grain, is fed freechoice, salt can be used to limit the amount animals consume. The per-cent salt needed in the mixture will vary with the palatability of the
supplement and other characteristics.An elevated level of salt intake is not harmful to the animals if they
drink plenty of water. The kidneys cannot tolerate more than 2.4 per-cent salt in the urine. About 5 gallons of urine are necessary to elimi-nate one pound of salt. Therefore, cattle on high-salt rations mustincrease their water intake to eliminate the excess salt. This is the rea-son that water supplies must be kept from running out or icing overwhen salt is used to control supplement intake.
One rule of thumb is that cattle eat about one-tenth of a pound ofsalt per 100 pounds of body weight when it is mixed with grains or oil
r Cattle eat about one-tenthof a pound of salt per 100 poundsof body weight when mixedwith grains or oil meals.
~
meals. A cow eats 1 to 1.5 pounds of salt daily in these mixtures. Trymixing this amount with the daily allowance of feed as a starting point.Lesser amounts of salt will be eaten at first. Watch consumption of thesupplement, and adjust salt levels to regulate intake of supplement tothe desired amount.
Cows on poor-quality roughage or winter pasture will eat about 5pounds daily of the following two mixtures:
.lOO lbs. salt, 300 lbs. grain, 100 lbs. meal.
.100 lbs. salt, 200 lbs. grain, 200 lbs. meal.It usually takes 25 to 35 percent salt in a mixture to limit intake of
soybean meal or cottonseed meal to 1.5 to 2 pounds daily for cows (seeMU publication 02070, Salt to Limit Intake of Protein and Grain
Supplements).
Feeding protein at intervalsFeeding a protein supplement to beef cows and heifers on winterrange at two- to five-day intervals is about as effective as feeding it daily.Oil meals and legume hays have been fed successfully this way. Do notfeed urea supplements in this fashion; urea can be toxic when cattleconsume too much.
Buying protein
supplements
Whether you mix your protein supplements or buy them commer-cially, a number of things should be considered. The cost of a pound ofprotein is one major consideration. But you need to look further to seehow much of the protein in the supplement is derived from urea. A ureasupplement mayor may not be suitable for your situation. Check thecrude fiber level in the supplements. Those with high crude fiber tendto have lower energy and may have some of the protein supplied by pro-tein products that have low digestibility.
A feed tag lists the percent of crude protein in the supplement andthe percent of crude protein equivalent that is derived from non-proteinnitrogen. For example, a tag may state: crude protein 50 percent
,-
(includes not more than 30 percent equivalent protein from non,pro,tein nitrogen). This means 30 of the 50 pounds -60 percent -of theprotein in 100 pounds of supplement is supplied by non,protein nitro,gen (60 percent).
Protein supplements are often relied upon to supply vitamins, min'erals and medication. Consider the kinds and amounts of these nutri,ents needed when purchasing supplements.
Cornstalks, milo stalks and soybean residue can provide economicalwinter feed for beef cows (see Tables 2 and 4 ).
Cornstalks and other crop residues are valuable sources of roughagefor beef cows. They should be properly supplemented. Carrying capacityfor stalk fields varies with grain yields. Two acres of cornstalks thatyielded 100 bushels of grain an acre will carry a cow for 80 to 100 days.
To get the most efficient use of dropped corn and stalks, an electricfence should be used. Allow one,half an acre of stalks per cow for 25days with one,half acre added each 25 days thereafter. This prevents~attle from gleaning all the better feed first, which often occurs whencows are allowed to range over the total 2,acre allotment. Mature beefcows in mid,gestation and medium flesh have held their weight whencontrolled grazing was used with this stocking rate and only minerals
Table 4.Supplemental feed
recommendedwith cornstalks.
Daily Ration Plus
32% Protein
Supplement ~Type of Product Energy
None
11b.
1. Grazing stalk fields
Dry cow
-first)rJ of grazing period
-last % of grazing period
None
Hay or corn amountdepending oncondition of cow
Lactating cow
-first )!3 of grazing period
-last % of grazing period
Ib.
Ib.
None
4-lbs. corn or full feed
good quality hay.
2. Harvested and ensiled stalks
Dry cow -50 Ibs. stalklage
Lactating cow -60 Ibs.
(full-feed) stalklage
O.51b None
2 Ibs. 2-3 Ibs. corn
3. Dry stalk stalks
This is not a dependable energy source. It should be considered a"supplement" energy source fed in combination with hay, silage ordryaftermath hay. Use protein and corn supplement given above asa guide.
12 Beef Cow/Calf Series
Wheat straw and other cropresidues, when properlysupplemented, are valuablewinter roughages.
and vitamin A were furnished. A protein supplement usually improvescow performance, especially when the residue quality was reduced after30 days of grazing.
ProteinAbout 0.35 pounds per head daily of supplemental crude protein isneeded with crop-residue rations. Protein supplements based completelyon urea may not give optimum performance.
Crop residues are low in phosphorus, so mineral supplements thathave 1:2 or 1:1 ratios of calcium to phosphorus and that supply a mini-mum of one-half ounce of phosphorus daily per cow should be fur-nished. A minimum of 25,000 I.U. vitamin A should be supplied to acow daily because crop residues have little vitamin A activity. Adding25 I.U. of vitamin E per head daily is advised. The fleshing of cows instalk fields should be watched closely. Supplemental feed will be neededwhen snow covers the feed and may be needed during wet, cold weather
periods.Similar recommendations apply to the use of milo residues. Table 4
gives Purdue University scientists' recommendations for supplements tofeed cows grazing cornstalk fields or being fed harvested residues.
Wheat strawWheat straw can make up one~third to one~half of the ration of dry,mature cows that start the winter in good condition. Half wheat strawand half good~quality grass or mixed hay is a suitable combination. One~third hay and two~thirds wheat straw with 1 pound of 40 percent pro~tein supplement added per cow is another possibility.
Both rations may need to have 2 or 4 pounds of grain added dailystarting 60 days before cows calve. Supply vitamin A and free~choiceminerals. These rations are suitable for dry, mature cows, not for preg~nant heifers.
Soybean straw that has lost most of its leaves is poor feed. It is diffi~cult to save the leaves when soybean straw is harvested. Pregnant cowsgrazing soybean fields should have about 1 pound of a 32 or 40 percent
,
13Nutrition
protein supplement a head daily. Once most of the leaves and pods areconsumed, the soybean straw must be supplemented with hay or grain.
When feeding harvested soybean straw to dry cows, supplement itwith 1 pound of a 40 percent protein supplement, 5 to 10 pounds ofgrass hay or 2 to 4 pounds of grain per cow daily. Protein supplementswould not be needed if legume hay replaced the grass hay.
After a beef calf is 90 days old, its mother's milk will usually supplyabout one-half of the nutrients it needs for maximum growth. Whetherthe calf will gain extra weight from creep rations depends on the moth-er's milking ability and the abundance and quality of the pasture orother feed that is available to the cow and calf.
Creep feedingbeef calves
,
Creep-fed calves usually weigh 30 to 60 pounds more at weaningthan calves that are not creep fed. It often takes 7 to 12 pounds of acreep ration to produce an extra pound of weaning weight. Creep feed-ing gives bigger and more efficient weight gains when the cows' feedsupplies are scanty and they are milking poorly. Creep feeds give better~esults with first-calf heifers, old cows and herds that are made up ofinherently poor milkers. Fall calving and drought also increase the valueof creep feeding suckling calves.
In some years, it is questionable whether it pays to creep feed whencommercial calves are dropped in late winter and spring. This evalua-tion assumes that 8 to 10 pounds of concentrate are required to producean extra pound of weaning weight and that the extra weight will sell forwhat it costs a feeder to put on this gain. Read MU publication M153,Marketing and Finance, for examples of how to determine if creep feed-ing will be economical for your herd.
Guard against getting heifer calves too fat with creep feeds. Fataccumulation in their udders can reduce their milking ability as cows. Acreep ration that has given good results is one composed of:
.Cracked, shelled corn -60 percent.
.Whole oats -30 percent.
.Soybean meal-10 percent.Milo can be substituted for the corn, wheat bran for the oats and cot-
tonseed meal for the soybean meal. Replacing 10 percent of the corn withmolasses may increase consumption. T wo parts of whole, shelled corn andone part oats, or oats alone, have been used successfully to creep feedcalves (see MU publication G2060, Creep Feeding Beef Calves.)
Another creep-feeding method is to allow calves to graze ahead ofcows or give calves sole access to a plot of high-quality forage such asalfalfa or other legume-grass mixes. The practice is often called creep
grazing.
Vitamins
Vitamin A
The vitamin most likely to be deficient in beef cow rations is vita-min A. Vitamins D and E may be needed in special situations.
Green and yellow plants contain carotene, a pigment that animalsconvert to vitamin A. Cattle consuming feeds high in vitamin A active-ly store the surplus, primarily in the liver. This reserve is used when feedis deficient in vitamin A. Cows are most likely to need vitamin A sup-plementation after lengthy grazing of drought-stricken pastures or when
~
r--fed low-grade feeds in winter. Cows receiving good-quality, green hay~lage, silage or legume hay are not likely to need vitamin supplements.
A chief function of vitamin A is maintaining the epithelial tissue(skin and lining of respiratory, digestive and reproductive tracts) in ahealthy condition. It is also needed for sight when an animal adaptsfrom light to dark.
Signs of vitamin A deficiency in breeding herds include lowered fer~tility and calving percentages. Cows that are deficient in vitamin Aabort, drop calves that are dead or weak, are difficult to settle and havepoor vision at twilight. Pregnant cows that are fed low~carotene feedsshould have 25,000 I.U. of vitamin A supplement daily; lactating cowsshould receive 36,000 I.U.
It is advisable to supply 10,000 to 20,000 I.U. of vitamin A dailywhen calves are under stress, are on preconditioning rations or are beingmaintained on low~carotene feeds in winter. The intramuscular injec~tion of I million to 6 million I.U. of vitamin A in cows is anothermethod of administering vitamin A., Injections should be used whencows show deficiency, when a deficiency is likely to develop or whenfeeding vitamin A is not practical.
Vitamins D and E
.r--
Vitamins D and E are usually included with vitamin A supplementsor injection solutions administered to cattle. Young, growing animalshave a greater vitamin D requirement than mature animals. Vitamin Daids in the metabolic use of calcium and phosphorus. It is necessary informing sound teeth and bones. Rickets is a sign of vitamin D deficiencyin young animals:
Cattle exposed to direct sunlight or those consuming 3 to 4 poundsof sun-cured forage daily should not need vitamin D supplements.
Most rations fed to beef cattle in Missouri are adequate in vitaminE. Alfalfa meal, green leafy forage and whole grains are sources of vita-min E. White-muscle disease in calves and lambs has been preventedand cured with vitamin E. Selenium, a trace mineral, replaces vitamin Ein the prevention and curing of this disease. Vitamin E deficiency low-ers reproduction in rats and other laboratory animals, but this effect hasnot been confirmed in farm animals. Giving 25 to 50 I.U. of vitamin Eper head daily to cows grazing stalk fields or other low-quality roughagesis sometimes recommended. See MU publication GlOSS, Vitamins forBeef Cattle, for more information.
Matching the mineral requirements of cattle given in Tables 10 and11 with the average mineral composition of feeds listed in Table 12gives an indication of the minerals that are most likely to be deficient ina ration.
Minerals
Calcium and phosphorusCows fed grass and legume roughages may need extra phosphorusbut little or no calcium supplementation. Both calcium and phosphorussupplements may be needed if grain, corn cobs, stalks or cottonseedhulls make up a sizable part of the cow's ration.
The need for calcium and phosphorus is increased during growth,late pregnancy and lactation. T able 11 shows that a 1: 1 ratio of calcium
,.-
Nutrition 15
to phosphorus is recommended in diets to maintain cows and bulls. Thecalcium to phosphorus ratio for young growing animals widens to asmuch as 2.5:1.
Salt {sodium and chlorine) Cattle usually exceed their requirements when given free access tosalt. Consumption varies, but cattle will eat more salt with high,roughage or high,moisture feeds. They will eat more loose salt, but theblock form is adequate. Cattle deficient in salt eat dirt, manure andurine in an attempt to get salt. Cattle require 0.1 percent sodium drymatter or 0.25 percent salt in their ration (Table 5).
Potassium Roughage rations usually have enough potassium for beef cattle.However, University of Missouri studies have shown that potassium willleach from winter fescue pasture to levels as low as 0.30 percent of thedry matter. This is much below the potassium level of 0.65 percent ofration dry matter recommended for beef cattle. Therefore, includingpotassium in mineral mixtures could benefit beef cattle grazing fescuepasture from J anuary through March.
Trace minerals Cobalt, selenium, copper and zinc are the trace minerals most likelyto be deficient in cow rations. Cobalt is required by rumen bacteria forsynthesis of vitamin B12. There is evidence that cattle should meettheir cobalt needs every day. Cobalt supplementation is advised for beefcows wintered on low~quality grass forages, cereal straws or stalks. Therequirements for trace minerals in cattle rations and the levels at whichsome trace minerals are toxic to cattle are given in Table 5. ~
Table 5.Mineral requirements
and maximum tolerablelevels for beef cattle.
See tables 1 & 3
0.07 to 0.11
4 to 10
2
5
15
0.10
8
0.5
50
0.10
0.20 to 2.0
50 to 100
0.05 to 0.25
50
1000
0.40
40 20 to 50 1000
6
1See tables 1 & 3
0.65
0.20
0.08
0.5 to 0.7
0.05 to 0.30
0.06 to 0.10
3
2
10
0.10
30
0.08 to 0.15
20 to 40
0.40
500~
From National Research Council, Nutrient Requirements of Beef Cattle, 1984
Mineral mixturesfor feeding free-choice
Free~choice mineral supplements should be formulated to supply thekinds and amounts of minerals that are deficient in feeds being con~summed by cattle. The taste and mineral composition of free-choice mix~tures largely deterIIiine whether cattle will eat enough of a mineral mix-ture to correct the deficiencies of their main diet.
Trace-mineralized salt should be an adequate source of trace mineralsunder most conditions. Iodized salt is recommended with high~nitratefeeds. Statewide surveys have indicated cobalt and selenium are deficientin much of the fescue forage, especially in the region south of Interstate70. Copper and zinc have been below recommended levels in severalanalyses of fescue pasture and hay samples submitted to the University ofMissouri Forage Laboratory. A deficiency of these two minerals appearsto be more of an individual farm problem than a widespread occurrence.
The same free~choice mineral mixture given to a lactating cow on alegume hay diet would not be suitable if she were on a corn silage andsoybean meal diet. The corn~silage ration would need both calcium andphosphorus, whereas the legume hay ~ould need only phosphorus.
Table 12 gives the composition of various mineral compounds fre-quently used in feed formulations. Free~choice mineral supplements forcattle on grass and legume forages should have about 8 to 12 percentphosphorus. A free~choice mixture that is often recommended for cattleon grass and legume forage is composed of:
.40 parts trace-mineralized salt.
.60 parts dicalciufi phosphate or bone meal.This mixture contains 13 percent calcium and 11 percent phospho~
rus. For more information on minerals for beef cows, see MU publica~tions 02080, Minerals for Beef Cattle: Needs, and 02081, Minerals forBeef Cattle Supplements .
MagnesiumStudies have indicated that a lactating beef cow needs approximate~ly 0.7 ounces (20 grams) of dietary magnesium daily to maintain normalserum magnesium levels (2.0 mg/100 ml). A gestating beef cow requiresabout 0.32 ounces (9 grams).
In high~risk situations (see the following section on "occurrence ofgrass tetany"), tests indicate cows need to be fed an average of 2 ounces(57 grams) of magnesium oxide per head daily for best prevention ofgrass tetany. This much magnesium oxide contains 1.3 ounces (36grams) of magnesium, almost twice what research shows the body needsdaily. Underconsumption by some animals in the herd and other factorsare involved in the need for this high level of magnesium intake.Supplementing the cow with 0.6 of magnesium oxide (10 grams magne~sium) usually is sufficient.
Animals need to have a daily intake of magnesium because most of themagnesium is cleared from the blood within 20 to 30 hours after it is con~sumed. Also, there is little or no storage of magnesium by older animals.
Grass tetany is also known as winter tetany, grass staggers, wheat poi-soning tetany and hypo-magnesium. Grass tetany is caused by a physio-logical deficiency of magnesium, which may result from a deficiency ofmagnesium in the feed or factors that lower the utilization of magnesium.
Magnesium and grass tetany
Nutrition 17
Affected animals may become excitable and then show such symp-toms as trembling muscles and grinding of the teeth, followed by violentconvulsions, deep coma and death. Some animals remain quiet but areunable to rise. Cows often resemble those with milk fever; many ofthem have a low serum calcium as well as low serum magnesium.
Occurrence of grass tetany The greatest number of tetany cases usually occur in April and May,but many cases are now seen in the fall and winter.
Tetany occurs most frequently in cows 6 years old and older that arenursing calves under 2 months of age.
Cows grazing grass pasture or consuming grass hay account for mostof the cases. Cloudy, windy, rainy weather with the daytime temperaturebetween 40°F and 60°F seems to affect both the cow and the grass sheconsumes, increasing the incidence of grass tetany.
Tetany seldom occurs when legumes or legume-grass mixtures are amajor portion of an animal's diet. Legumes may contain more thantwice the concentration of magnesium that grasses contain when grown
"on the same soil.Soils that have a high level of available potassium (above 250) in
the top 3 inches are more suspect than others. But tetany can also occurunder other soil conditions.
Supplements to
prevent grass tetany
'""'"\
Keep plenty of magnesium oxide mineral available during dangerperiods such as early spring and after calving. Other magnesium com-pounds can be used, but the availability of the magnesium and palatabil-ity of the compound is a problem with some. Dolomitic limestone is nota satisfactory magnesium supplement for cattle.
To be effective, a mineral mix should contain at least 10 percentmagnesium. Some commercial mineral mixes marketed for the preven-tion of grass tetany contain less. Keep minerals in boxes located at sev-eral places in the field to give all animals ready access.
Feeding some good legume or grass-Iegume hay in danger periods ishelpful because legumes are higher in magnesium than grasses.
In Virginia Polytechnic Institute trials, cows on grass pasture ate 0.6to 1.6 ounces of magnesium oxide daily when fed the following supple-ments: one part trace-mineralized salt; one part magnesium oxide; andone part of either dried molasses, ground shelled corn, cottonseed meal,dehydrated alfalfa meal, or distillers' dried grain with solubles.
Other mixtures to feed include:Mineral mixtures ( figures refer to lbs. ) :a. T race-mineral salt, 30; bonemeal or dicalphosphate, 30; magne-
sium oxide, 30; dried molasses, 10. This mixture provides about18 percent magnesium.
b. Salt 75, magnesium oxide 25.Concentrate mixtures:a. For self-feeding with forage containing 10 percent crude protein.
Ground grain, 65; magnesium oxide, 20; salt, 15.b. For self-feeding with low-protein roughages. Cottonseed meal, 65;
magnesium oxide, 20; salt, 15.c. For hand-fed supplements, use (a) or (b) but omit salt.
Beef Cow/Calf Series18
Table 6.Daily nutrient requirements
for growing bull, steerand heifer calves.
"""'
5.75
7.01
8.19
9.17
10.27
11.21
6.60
8.04
9.41
~
1 800 800 800
800
800
500500500
500500500
'"'""
20 Beef Cow/Calf Series
rTable 6. (continued)Daily nutrient requirementsfor growing bull, steerand heifer calves.
Medium-frame heifer calves
~.
..,-
Nutrition 21
Table 7.
Requirementsfor breeding cattle.
Weight(Ibs.)
ADG
(Ibs.)
DMI
(Ibs.)
CP%(Ibs.)
NEm(Mcal)
NEg
(Mcal)
TDN
(Ibs.)
Ca
(Ibs.)
p(Ibs.)
K
(Ibs.) ~Pregnant yearling heifers -last third of pregnancy
Dry pregnant mature cows -middle third of pregnancy
Dry pregnant mature cows -last third of pregnancy
~
2-yr. heifers nursing calves -1 st 3-4 months postpartum
Cows nursing calves -avg. milking ability -1st 3-4 months
Cows nursing calves -Superior milking ability -1st 3-4 months
8009001000
110012001300
1400
0.00.00.0
0.00.0
0.0
0.0
15.718.720.6
22.323.8
25.3
26.7
14.212.912.3
11.911.511.2
11.0
13.3513.8414.42
14.94
15.4716.19
16.55
12.14
13.0513.80
14.5415.1615.84
16.47
0.0750.0770.080
0.0850.0860.091
0.093
0.0490.0520.056
0.0600.0620.066
0.069
0.1100.131
0.144
0.1560.1670.177
0.187
0.000.00
0.00
0.000.000.00
0.001-""""'.,
22 Beef Cow/Calf Series
Table 8. Feed composition
r CF%
CA%
p%
K
%
~ 1-00-068
1-00-063
1-00-059
909090
150
170
18.0
555860
1151251.31
2.0
26
30
290
260
230
125
141
1.41
0.22
024
022
153171252
1-00-023
1-00-888
1-00-887
2-00-898
1-01-415
3-28-245
QS9
068
074
0.77
071
097
3-28-250
1-01-599
2-01-902
1-03-4283-04-3232-04-484
1-04-480
1-04-538
1-04-560
3-04-581
1-04-882
1-04-884
1-05-044
1-05-172
1-05-175,
Nutrition 23
61 134 3.0 262 1.52 025 260
59 128 23 370 030 035 232
68 157 2.6 300 032 037 232
57 1.21 064 22 38.0 020 026 125
55 115 0.59 2.8 288 153 025 1.62
62 137 079 30 3?3 0:,\4 n1q 141
~
.Issued in furtherance of Cooperative Extension Work Acts of May 8 and June 30, 1914in cooperation with the United States Department of Agriculture. Ronald C. Powers,Interim Director, Cooperative Extension Service, University of Missouri and LincolnUniversity, Columbia, Missouri 65211. .An equal opportunity institution. ~UNIVERSITY OF MISSOURI
COLUMBIA
M151, New 9/93/7MPrinted on recycled paper with soybean oil ink