Implications of Crossbreeding on Dairy Cattle Improvement

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Implications of Crossbreeding on Dairy Cattle
Improvement

• Paul VanRaden and Ashley Sanders
• Animal Improvement Programs Laboratory
• Agricultural Research Service, USDA, Beltsville,
  MD
• paul_at_aipl.arsusda.gov, asanders_at_aipl.arsusda.gov

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Crossbreeding Theory Holstein ? Brown Swiss
Protein Yield
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Crossbreeding Research

• Document current levels of crossbreeding in the
  US from DHI data.
• 3500 parent-identified crossbreds cows born in
  1997.
• 600,000 sire-identified Holsteins.
• 35,000 sire-identified Jerseys.
• Determine if crossbreeding makes sense in dairy
  cattle.
• If yes, advise breeders on possible selection and
  mating systems across breeds.

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Crossbred and Purebred Data

• Yield and SCS data
• 572 herds each with at least 5 crossbred cows.
• 10,442 F1 crossbred cows born since 1990.
• 140,421 purebred herdmates (80 were Holstein).
• Productive life data
• 41,131 crossbred cows born since 1960.
• 726,344 purebred herdmates.
• Other traits
• Body size breed means and heterosis from
  literature.
• Udder, feet and legs, calving ease, etc. values
  were 0.

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Breed Differences Heterosis for Economic Merit
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Merit of F1 Holstein Crossbreds
Compared to 2000 genetic base for Holstein
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Mates for Holstein Cows
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Separate or Combined Breed Evaluations

• Separate data sets reduce bias in evaluations
  within breeds, but some information is lost
• Crossbred cows evaluated inaccurately or not at
  all
• Conversion formulas to compare cows across
  breeds
• New Zealand, Australia, and the Netherlands
  include crossbreds and account for heterosis in
  evaluations.
• USDA-DHIA evaluations exclude crossbred cows
  unless identified as part of a grading-up
  program.

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Sires with Many Crossbred Daughters
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Conclusions
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Conclusions

• Currently
• Heterosis was about 4 for yield traits, (unfavorable) for SCS, and 1 for PL.
• Profit from Jersey ? Holstein and Brown Swiss ?
  Holstein crosses was higher than from Holsteins
  when compared at PTA 0.
• Fewer extreme PTA bulls are found in minor
  breeds.
• Matings with high additive merit and low
  inbreeding make sense.

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Complete Outcross Pedigree!

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• Future daughter inbreeding 5.6
• Average for active AI Holsteins 4.9
• Inbreeding when mated to Jerseys 0.0