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Coping With Alfalfa Winterkill

Coping With Alfalfa Winterkill. Randy Shaver, Ph.D. Department of Dairy Science University of Wisconsin - Madison University of Wisconsin - Extension. Coping With Alfalfa Winterkill. Alternative Forages - Oats & Peas Silage - Ryegrass Silage High Corn Silage Diets

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Coping With Alfalfa Winterkill

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  1. Coping With Alfalfa Winterkill Randy Shaver, Ph.D. Department of Dairy Science University of Wisconsin - Madison University of Wisconsin - Extension

  2. Coping With Alfalfa Winterkill • Alternative Forages - Oats & Peas Silage - Ryegrass Silage • High Corn Silage Diets • Low Forage Diets - Minimum Forage Guidelines - Forage Replacers

  3. Alternative Forages

  4. Small-Grain Silage vs. Alfalfa SilageDairyland Labs, 2004; >2000 samples of each forage

  5. Small-Grain Silage vs. Alfalfa SilageDairyland Labs, 2004; >2000 samples of each forage

  6. Small-Grain Silage vs. Alfalfa SilageDairyland Labs, 2004; >2000 samples of each forage

  7. Oats vs. Oats & Peas SilageUndersander, 2000;10 oat varieties at Arlington, WI

  8. Small-Grain Silage vs. Alfalfa or Corn SilageUSDFRC,Mertens, 1996

  9. Small-Grain Silage vs. Alfalfa or Corn SilageUSDFRC,Mertens, 1996

  10. Impact of Small-Grain Silage MaturityArieli & Adin, JDS, 1994 11 days between early and late cut

  11. Harvest & Use of Oats & Peas Silage • Harvest at boot stage for milk-cow feed, and milk to soft-dough stage for dry cow/heifer feed • Field wilt to 60%-65% moisture for horizontal silos and 55%-60% moisture for uprights • Chop length similar to that for alfalfa/grass silage • Variable composition depending on proportion of oats vs. peas and maturity at harvest • Test to determine nutrient composition - Wet Chem vs. NIRS? • Balance rations

  12. Ryegrass vs. AlfalfaHoffman et al., JDS, 1993

  13. Annual Ryegrass Maturity vs. QualitySulc et al., Agron. J., 1993 Ryegrass companion crop for alfalfa establishment

  14. Ryegrass Silage vs. AlfalfaSilageHoffman et. al, JDS, 1998

  15. Ryegrass Silage vs. AlfalfaSilageHoffman et. al, JDS, 1998 Late bud alfalfa and boot ryegrass

  16. Harvest & Use of Ryegrass Silage • Harvest at boot to early bloom stage • Field wilt to 60% moisture for horizontal silos and 55%-60% moisture for uprights • Chop length similar to that for alfalfa/grass silage • Cutting, blowing, unloading concerns? • Test to determine nutrient composition - Wet Chem vs. NIRS? • Balance rations

  17. High Corn Silage Diets

  18. High Corn Silage Diets • NDF, NFC, Starch & NEL vary widely in CS- Accurate CS analysis critical for diet formulation • CS suggested maximum- 2/3rds to 3/4ths of forage DM • If 3/4ths or more CS in diet DM, remaining forage as coarse-chop hay or straw for TMR particle size • Minimum NDF-forage of 18% or greater • WCS provides a margin of safety

  19. Dietary Fat • Basal rations usually contain 3% fat (DM basis) • High production rations usually formulated to 5% - 6.5% total fat (DM basis) • Supplemental fat usually a combination of oilseeds, animal fat, and(or) rumen-inert fat • With high-CS diets, reduced milk fat test may occur via effects on trans fatty acids • May need to reduce level of supplemental fat and(or) feed greater proportion of rumen-inert fat

  20. CP • Recommended Dietary Allowances- Early to Mid Lactation - 16.5% to 18.0% (DM basis) - Late Lactation - 13.5% to 15.0% (DM basis)

  21. RDP • Support N needs of rumen microbes - High ruminal digestion of CHO to VFA - High ruminal microbial protein production • RDP should comprise 60% - 65% of CP • RSP should comprise 30% - 33% of CP • With high-CS diets, may need to feed urea (2 to 4 oz.) or raw soybeans (2 – 3 lb.)

  22. RUP & Amino Acids • Meet amino acid needs of high-producing cows • RUP should comprise 35% - 40% of CP or 6.5% of DM • Limit use of CGM, DDG, & BDG in high-CS diets because of their low lysine content • Best RUP sources for high-CS diets are heat-processed soybeans or SBM & blood meal • Among these RUP sources, evaluate QC& cost

  23. Macro-Mineral Content of Corn Silage vs. AlfalfaSource: US-Canadian Feed Tables (1982)

  24. Macro-Mineral Sources

  25. Dietary Buffers • Neutralize diet acidity and ruminal acid production • NaBicarb-Mag Ox (3:1 ratio) recommended at 0.75% - 1.0% of lactation TMR DM • K-Carbonate - Can partially replace Na-Bicarb, K supplement • CaCarb - Post-ruminal buffer, Ca supplement • Free-choice Bicarb? - (Mix 3:1 with salt to limit intake) • Na or K buffers should not be fed to dry or pre-fresh cows, because they will elevate DCAD

  26. Dietary Buffers Based on NRC-01--summary of 41 trials

  27. Bunk Stability • Commercially-available propionic-acid based products usually with some acetic acid or benzoic acid • Buffered products that are non-corrosive • < Growth of yeast and < heating • Used as TMR additive to improve bunk life • Application Rate: 2 - 4 lb. per ton as-fed TMR • Cost: $1.00 per lb. product • Target Use: Unstable TMR; Hot, humid weather

  28. Diet Carbohydrate Guidelines

  29. NRC-01 adapted to provide margin of safety

  30. %Diet forage to meet minimum NDF from forage

  31. Forage Replacement

  32. By-Product Break-Evens

  33. Conclusions--Distiller’s Research Summary • Lactation responses and current economics support the inclusion of DG in diets for lactating dairy cows • 5-15% of diet DM was the most favorable inclusion rate • Reduced DMI & milk fat % may be watch-outs when feeding wet DG • Diet CP & amino acid status and forage base influence the DG responses High fat diets, non-inert fat sources, high corn silage diets, low forage diets, high NFC diets, fine diets, & rumensin can interact to reduce milk fat test

  34. Visit UW-Madison Dairy Science Department’s Website http://www.wisc.edu/dysci/

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