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Formulating Diets for Groups of Lactating Cows

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Dr. Bill Weiss of The Ohio State University presented this material for DAIReXNET on February 26, 2015. For the full presentation, please visit our archives at http://www.extension.org/pages/15830/archived-dairy-cattle-webinars

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Formulating Diets for Groups of Lactating Cows

  1. 1. Formulating a diet for a pen of cows Not a single cow Bill Weiss Animal Sciences Wooster
  2. 2. Potential Grouping Strategies 1. Production 4. Repro status 2. Parity 5. Keep pens full 3. Stage of lactation 6. etc. 1. Average and distributions of milk yields 2. Average and distributions of DMI 1. Cow inputs for formulation software 2. DM intake estimates and inputs
  3. 3. Requirement: A pen vs. A cow 0 5 10 15 20 25 30 35 40 5 15 25 Numberofcows Requirement X/day 40 45 50 55 60
  4. 4. Requirement: A pen vs. A cow 0 5 10 15 20 25 30 35 40 5 15 25 Numberofcows Requirement X/day 40 45 50 55 60 XDMI DMI
  5. 5. Distributions will differ (will you even know it?) 0 5 10 15 20 25 30 35 40 Should (will?) distribution affect formulation inputs?
  6. 6. Major Factors Affecting Requirements 0 5 10 15 20 25 30 35 40 45 Mcalorlbs/d 900 lbs 1500 lbs 50 lbs/d 100 lbs/d NEL MPMP NEL BW @75 lbs/d Milk @ 1200 lbs1. Milk yield 2. BW 3. Milk composition 4. Parity (growth) +11% +1% +64% +55% 3.3 F/2.7P vs 4.2F/3.2P ~+13% NEL and MP 1.6 lbs/d vs 0 ~+10% NEL and MP but also BW difference
  7. 7. Major Factors Affecting DMI within a Herd BW Milk yield Similar to relationships to requirements Days in milk - Essentially no independent effect on requirements - Huge effect on DMI
  8. 8. Milk and DMI (>1 Lactation) 30 40 50 60 70 80 90 100 110 0 20 40 60 80 100 120 140 Lbs/day Days in Milk DMI Milk +20% unpub 46 lbs CP intake: – 700 g NELI: -6 Mcal 55 lbs
  9. 9. Nutrient Requirements and DMI estimates Typical within pen ranges in: - BW: Small effect - Milk comp: Small effect - Parity: Small effect - Milk yield: BIG effect - DIM: Can have BIG effect Use pen/herd mean Use mean Use mean Use ??? Use ???
  10. 10. When formulating for a pen: Does the pen include fresh cows (< 3 or 4 Weeks) ? If pen is just fresh cows -intake, intake, intake more than milk -did I mention, intake, intake, intake If pen does not have fresh cows - it’s a lot easier If pen has both - Nutritionally inefficient - Can’t forget early diet effects on peak
  11. 11. What Milk Yield Should be Used for a Group of Post-Fresh Cows ? Formulating to meet requirements for the average cow usually reduces pen average milk yield The 11th Commandment: Don’t formulate for the average cow !
  12. 12. 45 47 49 51 53 55 57 59 61 63 65 4.4 4.6 4.8 5 5.2 5.4 5.6 5.8 6 6.2 6.4 6.6 6.8 7 7.2 7.4 Hypothetical Response Function % Protein Milkresponse
  13. 13. Protein Requirements for a Group of Cows 0 5 10 15 20 25 30 35 40 5 15 25 Numberofcows Protein Requirements 1 2 3 4 5 6 7 8 9 If you feed the average cowYou don’t increase milk for the 50% of cows <average Milk will drop for the 50% of cows producing > average
  14. 14. 110 Cows Avg = 75 lbs SD = 13 Distribution of Milk Yields in One Pen of Holstein Cows 35 lbs 130 lbs
  15. 15. Distribution of Milk Yields in One Pen of Holstein Cows If all cows past peak DMI, “avg” diet would meet or exceed requirements for ~80% of cows ~90 lbs
  16. 16. For a Pen without Fresh Cows MP and NEL for Avg Cow is adequate for about 1.15 X avg milk If average = 75 lbs/d Diet will support 75 x ~1.15 = 85 to 90 lbs/d What about other nutrients?
  17. 17. Diverse Pens and pens w/o Fresh Cows 1. Minerals and vitamins: • Not highly dependent on yield • Use safety factor for uncertainty and antagonism • 1.2 to 1.5 X NRC is usually adequate 2. Fiber (NDF): • Complicated • First, feed mgmt, NDF/starch source, etc • Second, pen demographics • More cows Milk and DIM, then NDF
  18. 18. Rumen Degradable Protein (RDP) - Important for optimal rumen function - Relatively inexpensive - Can stimulate DMI - Excess may impair repro - Excess increases manure N Bacterial requirement, not cow Function of DMI, not milk
  19. 19. Inadequate RDP can limit microbial growth, fiber digestion, and DMI 40 42 44 46 48 50 52 54 56 58 7 8 9 10 11 12 DMI,lbs/day Rumen Degradable Protein, % of DM Cyriac et al., 2008 NRC All Pens 10-10.5% RDP* (slightly more than req’t) * Calculated with NRC model
  20. 20. Feed Environmental Digestible RUP (MP) Inadequate MP (dRUP) will reduce milk (body stores are limited) vs. Modest excess MP inflates feed costs and increases N in manure Feed for average Feed for >Avg Milk vs.
  21. 21. MP specs for a pen with no fresh cows These Cows will be fed if formulated for mean ~ 1 SD Avg = 75 lbs SD = 13 MP-milk = 88lbs These cows will be fed if MP-allow milk = Mean + 1 SD Avg*1.15
  22. 22. Grouping by production (post-fresh) reduces pen variation and will reduce MP-milk targets Example: Pen average milk = 85 lbs Pen SD MP-Allow Milk Target 10 lbs 95 lbs 15 lbs 100 lbs 20 lbs 105 lbs Reflects typical within herd variation (CV=16%) (Finney et al., 2013)
  23. 23. Groups without Fresh Cows: Digestible RUP (MP) Use pen average DMI Max MP allowable milk = Mean + 1 SD If SD not known: Assume SD = < 0.16*mean May need to lower because feed cost/regulations Diet For High Pen Pen DMI = 58 lbs Pen average milk = 90 lbs Pen SD = ? (assume 90*0.16 = 14.4 lbs) MP-allowable milk should = 90+14 = 104 lbs
  24. 24. Diverse Groups without Fresh Cows: NEL Theoretically, NEL allowable milk = avg. milk - above average cows will lose BC - below average cows gain it back Recommendation 1. At pen average DMI, NEL-allowable milk should equal ~1.1 X average milk 2. Adjust based on changes in BCS
  25. 25. Avg DIM = 178 (6 months) Distribution of Lactation Stage in One Pen of Holstein Cows < These guys don’t fit
  26. 26. Diverse Pens with Fresh Cows: Digestible RUP (MP) Depends on how many fresh cows Should bias toward the fresh cow Simulation Results Assumed 10% fresh cows (<25 DIM) Assumed typical lactation curve Use Pen Average DMI MP-allowable milk should ~Avg+1.5 SD or Average *1.24 (i.e., 16*1.5)
  27. 27. Early Lactation Group (< 25 DIM) Primary Goal: 1. Adequate (extra?) RDP 2. Moderate NDF (~30%) and starch (~25%) 3. Highly digestible NDF 4. Lots of bunk space 5. Don’t worry about NEL, get cows to eat MAXIMIZE DMI
  28. 28. Summary - Keep fresh cows (< ~21 DIM) in a separate group and formulate that pen for DMI - For pens without fresh cows •Knowing within pen variation in milk increases formulation accuracy •Max MP-allowable milk = Avg + 1 SD if SD unknown = Avg*1.16
  29. 29. Summary - For diverse pens with fresh cows • Greater overfeeding is necessary • Increased feed costs • Max MP allowable milk = Avg + 1.5 SD or if SD unknown: =Avg * 1.24
  30. 30. OHIO AGRICULTURAL RESEARCH AND DEVELOPMENT CENTER http:// dairy.osu.edu

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