Dairy Cattle Nutrition – The Basics

Dr. L. E. ChaseDepartment of Animal Science

Cornell University

Today’s Dairy CowThe dairy cow is a marvel as a

biological manufacturing plantThe “average” New York dairy

cow produced 20,071 lbs. of milk per lactation in 2009

The “average” New York dairy cow produced 10,885 lbs. of milk per lactation in 1970

This is an 84% increase!

Today’s Dairy Cow - 2We have a number of herds in NY

with herd average milk production > 30,000 lbs/cow

What is the biological limit to milk production?

How can an individual cow in a herd produce > 200 lbs of milk per day when housed in a group fed a ration balanced for 85 lbs. of milk?

Current World Record - HolsteinEver-Green-View My 1326-ET3x, 365 days = 72,170 lbs milkAverage = 198 lbs/day!

What About Jersey’s?World record – 2007Mainstream Barkly Jubilee2x, 365 days = 49,250 lbs. milk4.6% fat, 3.3% milk true proteinAverage of 135 lbs. milk/day!Was on supplemented rotational

grazing for part of the record

World Lifetime Milk Production Record Cow

8/2004 = 442,690 lbs milk> 52,000 Gallons!!!!

Milk - - 100 lbs (13 lbs of dry matter) - 4.9 lbs. of lactose (sugar)- 3.6 lbs of milk fat - 3.1 lbs. of milk true protein

Manure -- 190 lbs of total manure - 60 – 70 lbs of urine - 120 -130 lbs fecal material

What Does a Cow Producing 100 lbs. of Milk Excrete/Day?

What Does a Cow producing 100 lbs. of Milk Need to Make Each Day? - 7 – 8 lbs of glucose (sugar)- 3 – 4 lbs. of microbial protein- 2 – 2.5 lbs of absorbed amino

acids

How Much Does This Cow Eat & Drink?55 – 60 lbs. of feed dry matter

intake - 120 – 130 lbs of wet feed - Assumes ration is 45% dry matter

Drinks 30 – 35 gallons of water

Why is DMI Important?Must be a package size that the

cow can be expected to consumeRelated directly to potential milk

production, feed cost and PROFITEssential if rations are formulated

on a nutrient density basisCan’t do problem solving without

DMI

What Controls DMI?

Ration Energy ContentLow High

Intake

Energy

DM

Factors Affecting Dry Matter IntakeCow FactorsMilk Milk Solids SizeMaturityDays in MilkGeneticsTransition InsultsMastitis StatusForage FactorsMaturityTexture/Particle DistributionCondition - moldCondition - pHCondition - fermentation

Environmental FactorsAir Quality - ventilation Ambient TemperatureRelative HumidityHaircoat ConditionAccess to FeedSocial OverheadAccess to StallManger/Bunk SurfaceStall ComfortLightingbSTRation Intended vs. Utilized*

Concentrate FactorsComplement with ForageTextureCondition - moldCondition - freshness

People FactorsWho is responsible for every other factor listed above?!

Factors Which Influence DMI

45%

22%

6%

17%

10%

MilkFeedBCSBWEnv.

High Producing Dairy HerdsDo they attain high levels of milk

production by increasing ration nutrient density or do they have higher levels of DMI?

Monitoring DMIUse scales that work + moisture

testerKnow what is fed, refused,

consumedHow many cows are in the

group?Graph intake & milk productionCalculate “actual” versus

“predicted” grain disappearance rate

What Nutrients Does A Cow Need?WaterProteinCarbohydratesLipids/fatsMineralsVitaminsEnergy???

WaterNutrient required in the largest

quantity per dayMilk is about 87% waterThe cow’s body is about 56 to

81% water (784 to 1134 lbs. for a 1400 lb. cow)

Predicted Daily Water Intake for Lactating Cows

05

1015202530354045

Gallons

40 60 80 100 120 140

Milk, lbs/day

45 F85 F

Murphy et. al., 1983

Intakes of Other Animal Groups

Group Gallons/ dayDry cows 5 – 10

Heifers (>5 months) 5 – 10Calves (< 5 months) 1 - 5

Is This Clean Water?

Would You Drink this Water?

Would You Drink this Water?

Nutrient

Definition:◦ A dietary essential for one or more species of

animalAll animals do not require the same

nutrientsLaboratory analyses determines the

nutrients we feed◦ Fiber vs ADF

Ruminants have simpler dietary nutrient requirements because many are supplied by the rumen bugs

Nutrient Use and EfficiencyThe first use of any nutrient is

meet the maintenance requirement of the animal

This is a fixed cost related to body weight and

EnergyNot a nutrientObtained from several sources

◦Carbohydrates - CHO◦Fats - 2.25 times the energy◦Proteins – Via deamination

Net Energy MeasuresEnergy level in a feed or ration

can be expressed in a variety of ways.

TDN – Total digestible nutrientsNFE – Nitrogen free extractNet Energy Basis

◦NEM ◦NEL ◦NEG

Expressed as Megacalories of Energy - Mcals

Nutrient CategoriesProteinCarbohydratesLipids/FatsMineralsVitaminsWater

Chemical Analysis Scheme

Protein is Required to:1. Principle component of body tissues2. Enhance feed intake and energy use

Enzymes3. Supply N to the rumen microbes

◦ Ammonia, Amino acids, Peptides 4. Supply amino acids for synthesis of:

◦ Milk protein ◦ Tissue protein ◦ Enzymes, hormones etc.

Protein Terminology

Intake Protein◦IP - What the cow eats

Crude Protein◦Calculated from Nitrogen content of

feed◦Proteins are 16% N◦Multiply N content of feed by 6.25

(100/16)◦Measure of the total protein in a feed

Both true and NPN◦Measured as a % of the dry matter

Protein Terminology

Rumen Degradable Protein ◦ Broken down in rumen and used by the

rumen bugs( RDP)

◦ Soluble Protein (SIP) is the portion of the RDP that is rapidly broken down in the rumen

Rumen Undegradable Protein◦ Not broken down in rumen◦ Also referred to as bypass protein

( RUP)

Protein Terminology

Microbial Protein◦ Refers to protein produced by the bugs in

the rumen ◦ Microbial protein is important because it

supplies ~50% of cow’s total protein requirement

◦ Microbial protein is much higher quality protein than the feed components from which it was produced

◦ As a result you don't have to worry too much about the amino acid (AA) content of the diet or providing the essential AA in diet.

◦ Rumen microbes use protein and degradable energy sources for the production of microbial protein

Amino Acids

Essential and Nonessential◦ Nonessential - synthesized by body◦ Essential - 10 Essential AA’s

Necessary for the animal Must come from diet

Not a concern in most ruminant diets because essential AA’s are synthesized by rumen bugs as microbial protein is produced

However in higher producing animals we see a response to adding certain essential AA’s such as lysine or methionine

CarbohydratesMajor source of energy for cattleMakes up more than 65% of DM in feedsBroken down in rumen to VFA’s, methane,

carbon dioxide and waterTwo types

◦ Structural and NonstructuralTremendous differences in the speed with

which structural and nonstructural breakdown in the rumen. ◦ Structural Slow; Nonstructural - Rapid

Compatible combination important for good rumen digestion

Plant Carbohydrate Fractions(Hall, 2003)

Carbohydrates

NFC Sugars, starch, pectin

Highly RuminallyAvailable

Effective NDF

Physical NDFDigestible NDF

Microbial Digestion

StimulatesChewing

Saliva secretion: 80 gal/d 7 lb Na bicarb 3 lb phosphate buffers

Buffering agents:NH3, forage, protein

Acid Productionfrom VFAs

NDFiber

Carbohydrate Digestion Dynamics

, starch

(sugars)

Physical & Chemical Fiber Recommendations

Chemical NDF◦ 28-32% of ration DM◦ Minimum ~25% (NRC,

2001)◦ 1.2% of body weight

as total NDF intake 1350-lb BW x 0.012 =

16.2 lb NDF intake/d Realistic upper limit on

NDF intake/day Fermentability of NDF

Physical NDF ◦ 550-600 min of

rumination/day◦ ~60% of resting

cows should be ruminating

◦ Rumen pH >5.8◦ ~5-8% >19 mm

Penn State PS◦ peNDF >21% of DM

FatsAlso known as Ether ExtractHighest energy per lbChemical structure

◦ Fatty acids - Hydrocarbon chains ◦ Glycerol

Majority absorbed in small intestines ◦ Few converted to VFA’s

Too much fat in the diet inhibits rumen digestion of cellulose ◦ Fatty Acids inhibit bacteria ◦ Coats fiber to prevent breakdown

Feeding Fat Fat is 225% the energy of CHO or protein

◦ Good way to boost the NEL of a diet ◦ When physically can’t get anymore energy into

the diet with grains and by products Low heat increment so it is good to add in

hot weather Inhibits fiber digestionFats provide energy for the dairy cow but

not the rumen bugs (rumen bugs need carbohydrate energy)

MineralsMineral required by dairy cattle

◦ Calcium for milk production◦ Mineral supplements usually nearly 100 %

DM◦ Minerals, vitamins and other additives take

up space or DM in the ration Provide little or none of the major nutrients.  

◦ When balancing rations leave about 1 – 2 lb of space for these supplements. i.e. If DMI is estimated to be 50lb/day, balance

the ration to meet the NEL, CP, ADF, NDF, and NSC in 49 lb of DM leaving one pound for all the minerals and vitamins etc. that need to be added

Macro MineralsGrams/cow/dayCalciumPhosphorusPotassiumMagnesiumSulfurSodiumChloride

Micro (trace) mineralsMilligrams/cow/dayIronZincManganeseCopperCobaltIodineSelenium

VitaminsWater soluble -  B's & C

Fat soluble - A,D,E & KBugs in the rumen

◦ No requirement for any of the water soluble vitamins.

◦ The bugs manufacture their own B vitamins.

◦ Only supplement the A, D, & E◦ However as milk production increases we

balance the ration for more feed to bypass digestion. We are finding that supplementation of niacin (B3) and others may have a positive affect on animal performance.

Summary