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DAIRY HERD NUTRITION

DAIRY HERD NUTRITION. pp. 435-442; 446-449. GOALS IN FEEDING A DAIRY HERD. Maximize milk production Maintain reproduction Prevent metabolic diseases Ketosis Milk fever (parturient paresis) Displaced abomasum Control feed costs Minimize nutrient excretion.

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DAIRY HERD NUTRITION

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  1. DAIRY HERD NUTRITION pp. 435-442; 446-449

  2. GOALS IN FEEDING A DAIRY HERD • Maximize milk production • Maintain reproduction • Prevent metabolic diseases • Ketosis • Milk fever (parturient paresis) • Displaced abomasum • Control feed costs • Minimize nutrient excretion

  3. EARLY LACTATIONTHE DAIRY COW’S DILEMMA

  4. FACTORS AFFECTING DM INTAKE OF DAIRY COWS • Milk production • Week of lactation • Peak feed intake follows peak milk production

  5. NDF concentration

  6. Fat concentration of diet • Feeding > 5% fat reduces DM intake • Worse problem with unsaturated fats • Diet moisture • Feeding diet > 50% moisture reduces DM intake • Improper adaptation to high grain diet reduce DM intake • Metabolic diseases (ketosis or milk fever) reduce DM intake

  7. IMPLICATIONS OF CHANGES IN FEED INTAKE OF DAIRY COWS • Increase in feed intake follows increase in milk production in early lactation • High level of feed intake increases rate of passage • A reduction in digestibility of 4% for each increase in DMI of 1x maintenance (Typically DMI will be 3x maintenace) • Reduction greater on high grain diets than high forage diets • Reduces ruminal protein degradability

  8. Energy Requirement of Dairy Cows • In lactating dairy cows, it has been shown that energy is utilized for maintenance, lactation and pregnancy with approximately equal efficiency • 60 – 70% with an average of 64.4% Lactation BW gain Energy balance 0 Maintenance Reqt 112 kcal ME Or 73.5 kcal NE/kg.75 ME intake • As a result, the energy requirements for all expressions • are expressed as one term, NEl

  9. NET ENERGY REQUIREMENT FOR MAINTENANCE OF DAIRY COWS • Calculation • NEl, Mcal/day= 0.08 kg BW.75 • Factor affecting maintenance • Extra activity % increase • Flat pasture, close 10 • Hilly pasture, far 50 • Temperature • Cold • Assume NEl concentration of diet reduced by 8% • Heat • Assume a 25% increase in maintenance • Pregnancy % increase • Day 190 60 • Day 270 86 • Growth % increase • 1st lactation 20 • 2nd lactation 10

  10. NET ENERGY FOR MILK PRODUCTION BY LACTATING DAIRY COWS • NEl, Mcal/kg milk = .0929 x Fat% + .0347 x CP% + .0395 x lactose% • Example (Assume 3.4% CP and 5.8% lactose) % fatMcal/kg 2.5 0.59 3.0 0.64 3.5 0.68 4.0 0.74 • Simply added to maintenance

  11. NEL REQUIREMENTS OF 680 KG COW PRODUCING 10,000 KG MILK/YR

  12. FIBER REQUIREMENT OF DAIRY COWS • Adequate fiber of the appropriate length is necessary to: • Maintain milk fat percentage • Maintain rumen health (Parakeratosis, Laminitis, Displaced abomasum) • Maintain feed intake • Recommendations • Minimum amount of forage = 40% DM • 1989 NRC • Minimum NDF = 28% (75% from forage) • Minimum ADF = 18% • 2001 NRC NDF requirement ForageDiet Minimum NDF, %DMMinimum NDF, %DM 19 25 17 29 15 33

  13. Adjustments in fiber requirement • Starch source • High moisture corn 27% NDF (Minimum) • Barley 27% NDF (Minimum) • Forage particle size • Desire length of chop of forage at ¼” 15 to 20% of particles > 1.5” • Method of feeding • Feeding separate components will increase the NDF requirement • Dietary buffers • Can lower NDF requirements • Buffers (fed at 0.5 – 1.5% of DM) • NaHCO3 • MgO • KHCO3 • Unpalatable • Will increase rumen pH, but doesn’t solve all problems associated with low fiber

  14. PROTEIN REQUIREMENTS OF LACTATING DAIRY COWS • Metabolizable protein requirement follows milk production • MP reqt, gm/d = (Maintenance + (Milk production, gm x .036))/.67

  15. Meeting the protein requirements of dairy cows • Increase crude protein concentration and reduce protein degradability in early lactation • No NPN use • Lower crude protein concentration and increase protein degradability in mid- and late lactation • NPN may be used in late lactation to limits • Supply enough degradable protein to meet microbial needs during dry period to 3 weeks prior to freshening • NPN may be used to limits

  16. Ca AND P REQUIREMENTS OF DAIRY COWS • Ca and P requirements follow milk production and pregnancy

  17. PHASE FEEDING OF DAIRY COWS

  18. EARLY LACTATION • First 70 days of lactation • First 3 weeks are most critical • Relationship of intake and milk production Week of peak Milk production 6-8 Feed intake 8-12 • Results • High producing dairy cows can’t meet energy requirements and fiber requirements in early lactation

  19. Implications • Meet the cow’s fiber requirements and accept the loss in cow weight. • A dairy cow in good condition (BCS 3.5on 5 point scale), but not overly fat, can safely lose up to 15% of her bodyweight in first 70 days. • Energy mobilized from tissue related to BCS BCSMcalNEl 2 375 3 399 4 417 5 432 • Example • A cow at BCS 4 losing 1 BCS will produce 417 Mcal/0.74 Mcal/kg 4% FC milk = 564 kg FCM • Cows should not be at a condition score >4 coming into lactation • Will be susceptible to ketosis and displaced abomasum

  20. Body weight lost should be replaced during late lactation • Advantages Efficiency Stage of lactationME to tissueTissue to milkTotal Late lactation 75 82 61.5 Dry period 60 82 49.2 Diet to milk 64.4 • Additional advantages of replacing weight in late lactation • Easier to feed grain to lactating cows • Because of higher feed intake of lactating cows, easier to meet fiber requirement while feeding grain

  21. Maximize feed intake • Don’t have cows at BCS>4 (5 point scale) • Use premium or supreme quality forage • Properly adapt cow to grain • Introduce to lactation grain mix 2 weeks before calving • Increase grain mix at 1 lb/day in early lactation to lactation diet • Delay fat supplementation until week 5 to 7 • Do not feed DDGS at greater than 20% of the DM • High fat and fiber • Increase concentration of CP, Ca, and P in diet • Can’t mobilize these nutrients as readily as energy • Utilize sources of rumen undegradable protein and protected amino acids (lysine, methionine) • Supplement • Salt 0.5 % DM • Trace mineral • Vitamin A 5,500 IU/kg DM • Vitamin D 1,500 IU/kg DM • Vitamin E 40 IU/kg DM

  22. MID TO LATE LACTATION • Mid lactation 70 to 140 days • Late lactation 140 to 305 days • Replace body energy stores • Will breed when positive energy balance occurs • Balance diet to meet energy and nutrient requirements • Maximum Grain = 2.5% BW • Minimum Forage = 1.5% BW

  23. Can utilize supplemental fat to increase energy concentration Supplemental fat sourceMaximum fat in diet, %DM Unprotected fat (Tallow) 5 Fat in seed (Soybean, Cottonseed) 7 Ca-salt of long-chain fatty acid 7 • Problems with excess fat • Milk fat depression • Trans-10, cis-12 linoleic acid produced from hydrogenation of fatty acids in rumen of cattle fed high grain diets inhibits fatty acid in the mammary gland • Reduced feed intake • Reduced milk protein • Need to supplement RUP • Reduced digestion of Ca and Mg • Excessive fatness if BCS>3.5

  24. Can utilize NPN to limits • No more than 1/3 of the diet CP • No more than 1% of the diet DM • Supplement • Salt 0.5 % DM • Trace mineral • Vitamin A 3,700 IU/kg DM • Vitamin D 1,000 IU/kg DM • Vitamin E 30 IU/kg DM

  25. DRY PERIOD • 60 or 45 days to 14 days pre-calving • Goals • Maintain body condition • Prevent excessive fatness • Feed a high forage diet • Can use some lower quality for to dilute energy • May have to limit feed • Particularly corn silage • Consequence of excessive fatness is ketosis

  26. Ketosis-fatty acid liver • In early lactation, energy must be mobilized from tissue reserves Excessive use of body fat Lack of OAA Lack of carnitine Lack of niacin Overcomes limit of triglyceride to be: • transported from liver as VLDL • oxidized in TCA cycle in liver Fat accumulates Acetyl-CoA in hepatocytes (Fatty liver) Acetoacetate B-OH-Butyrate Impairs gluconeogenisis Impairs feed intake Appear in milk Reduces glucose Increased milk fever Increased displaced abomasum Increased retained placenta Increased mastitis Reduced milk production

  27. Ketosis prevention • Avoid excessive fatness in cows (BCS>4) • Maximize intake immediately before and after calving • Avoid abrupt change to high grain lactation diet at calving • Feed balanced ration • Use high quality forages • Drench cows with propylene glycol (1L/day) for 1 week daily before calving • Propylene glycol is metabolized to lactate that can be used for gluconeogenisis • Supplement with nicotinic acid (6 – 12 g/d) • Increases DMI • Reduces lipolysis • Recommendations • Use in ketosis prone cows • Use from 14 days prepartum to 120 days postpartum • Use palatable carrier

  28. Prevention of milk fever • Milk fever (parturient paresis) Serum Ca, mg/100 Normal 10 Milk fever 4.6 • Occurs immediately before or after calving • Caused by failure of Ca homeostasis • Reduced calcium absorption from small intestine • Reduced mobilization of Ca from bone • Both result from alkalosis caused by a high concentration of cations relative to anions in diet • Prevention • Reduce cation-anion difference • DCAD = ([Na+] + [K+] + .15[Ca+2] + .15[Mg+2]) - ([Cl-] + .6[S-2] + .5[P-3])

  29. Methods to decrease DCAD during dry period • Decrease concentration of cations (particularly K) in diet • K is the cation in highest concentration in dairy rations • Factors affecting dietary K levels • Legumes > Grasses • Immature > Mature • Leaves > Stems • Heavily fertilized > Unfertilized • High temperatures > Cool temperatures Dietary K, % Dietary Ca, %1.1 2.2 3.1 .5 Urine pH 5.8 8.0 8.1 1.5 5.7 7.9 8.2 .5 Milk fever incidence 0/10 4/11 8/10 1.5 2/10 6/9 3/13 • Decrease Na concentration in diet • Decrease Ca concentration of diet???

  30. Method of decreasing DCAD (Continued) • Adding anions to diet • Commonly added anions • CaCl2 • Ca propionate • Ca SO4 • NH4Cl • (NH4)2SO4 • MgCl2 • MgSO4 • Unpalatable and may causes ulcers in mouth and GI tract • Monitor urine pH • Desired range 6.2 – 6.8 • CaCO3, PO4 salts and elemental S are ineffective • Recent studies increasing the anion content of forages by fertilizing with CaCl2 shows promise • Do not use on heifers • Return to positive DCAD after calving

  31. Other considerations in dry period nutrition • Feed 12% CP • To maintain rumen microbial growth • Feed 60 to 80 gmCa/day • Feed 30 to 40 gm P/day • Limit salt to 28 gm/day • To prevent udder edema • Vitamin A 5,500 IU/kg DM • Vitamin D 1,500 IU/kg DM • Vitamin E 40 IU/kg DM

  32. TRANSITION PERIOD • 2 weeks pre-calving • Feed lactation grain mix up to .5 to 1.0% BW • Maintain long hay at .5 to 1.0% BW • Limit corn silage to 1.0% BW

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