Dairy Cattle Nutrition – The Basics Dr. L. E. Chase Department of Animal Science Cornell University
Today’s Dairy Cow • The dairy cow is a marvel as a biological manufacturing plant • The “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 - 2 • We 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 - Holstein • Ever-Green-View My 1326-ET • 3x, 365 days = 72,170 lbs milk • Average = 198 lbs/day!
What About Jersey’s? • World record – 2007 • Mainstream Barkly Jubilee • 2x, 365 days = 49,250 lbs. milk • 4.6% fat, 3.3% milk true protein • Average 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!!!!
What Does a Cow Producing 100 lbs. of Milk Excrete/Day? • 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 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 consume • Related directly to potential milk production, feed cost and PROFIT • Essential if rations are formulated on a nutrient density basis • Can’t do problem solving without DMI
What Controls DMI? Energy DM Intake Low High Ration Energy Content
Factors Affecting Dry Matter Intake Cow Factors Milk Milk Solids Size Maturity Days in Milk Genetics Transition Insults Mastitis Status Environmental Factors Air Quality - ventilation Ambient Temperature Relative Humidity Haircoat Condition Access to Feed Social Overhead Access to Stall Manger/Bunk Surface Stall Comfort Lighting bST Ration Intended vs. Utilized* Forage Factors Maturity Texture/Particle Distribution Condition - mold Condition - pH Condition - fermentation People Factors Who is responsible for every other factor listed above?! Concentrate Factors Complement with Forage Texture Condition - mold Condition - freshness
High Producing Dairy Herds • Do they attain high levels of milk production by increasing ration nutrient density or do they have higher levels of DMI?
Monitoring DMI • Use scales that work + moisture tester • Know what is fed, refused, consumed • How many cows are in the group? • Graph intake & milk production • Calculate “actual” versus “predicted” grain disappearance rate
What Nutrients Does A Cow Need? • Water • Protein • Carbohydrates • Lipids/fats • Minerals • Vitamins • Energy???
Water • Nutrient required in the largest quantity per day • Milk is about 87% water • The 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 Murphy et. al., 1983
Nutrient • Definition: • A dietary essential for one or more species of animal • All animals do not require the same nutrients • Laboratory 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 Efficiency • The first use of any nutrient is meet the maintenance requirement of the animal • This is a fixed cost related to body weight and
Energy • Not a nutrient • Obtained from several sources • Carbohydrates - CHO • Fats - 2.25 times the energy • Proteins – Via deamination
Net Energy Measures • Energy level in a feed or ration can be expressed in a variety of ways. • TDN – Total digestible nutrients • NFE – Nitrogen free extract • Net Energy Basis • NEM • NEL • NEG • Expressed as Megacalories of Energy - Mcals
Nutrient Categories • Protein • Carbohydrates • Lipids/Fats • Minerals • Vitamins • Water
Protein is Required to: • Principle component of body tissues • Enhance feed intake and energy use • Enzymes • Supply N to the rumen microbes • Ammonia, Amino acids, Peptides • 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 UndegradableProtein • 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
Carbohydrates • Major source of energy for cattle • Makes up more than 65% of DM in feeds • Broken down in rumen to VFA’s, methane, carbon dioxide and water • Two types • Structural and Nonstructural • Tremendous differences in the speed with which structural and nonstructural breakdown in the rumen. • Structural Slow; Nonstructural - Rapid • Compatible combination important for good rumen digestion
Carbohydrates NDFiber NFC Sugars, starch, pectin Effective NDF Highly Ruminally Available Digestible NDF Physical NDF Microbial Stimulates Digestion Chewing Saliva secretion: 80 gal/d 7 lb Na bicarb 3 lb phosphate buffers Acid Production from VFAs Buffering agents: NH3, forage, protein
Carbohydrate Digestion Dynamics (sugars) , starch
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 Physical & Chemical Fiber Recommendations
Fats • Also known as Ether Extract • Highest energy per lb • Chemical 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 digestion • Fats provide energy for the dairy cow but not the rumen bugs (rumen bugs need carbohydrate energy)
Minerals • Mineral 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 Minerals • Grams/cow/day • Calcium • Phosphorus • Potassium • Magnesium • Sulfur • Sodium • Chloride
Micro (trace) minerals • Milligrams/cow/day • Iron • Zinc • Manganese • Copper • Cobalt • Iodine • Selenium
Vitamins • Water soluble - B's & CFat soluble - A,D,E & K • Bugs 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.