DAIRY SCIENCE UPDATE

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DAIRY SCIENCE UPDATE

• SIRE SELECTION AND CROSSBREEDING
• Jack McAllister

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TOOL FOR GENETIC SELECTION DECISIONS
PREDICTED TRANSMITTING ABILITY
PTA
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DAIRY GENETIC EVALUATION TERMS

• PTA Estimated genetic merit an an animal
  transmits to its
  offspring
• PTA Milk, PTA Fat, PTA Protein
• PTA SCS (somatic cell score)
• PTA PL (productive life)
• PTA DPR (daughter pregnancy rate)
• PTA SCD (sire calving difficulty)
• PTA DCD (daughter calving difficulty)

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Current Genetic Indexes(2000)
Lifetime Net Merit Net
Merit(NM)Yield Udder Other
Yield(MFP -
FEED) Lactations Actual Yield
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RELATIVE VALUES() IN LIFETIME MERIT INDEXES
(2003)
NM FM
CM PTAmilk 0 24
-10 PTAfat 22
22 18 PTAprotein 33
9 36 PTApl 11
11 9
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RELATIVE VALUES() IN LIFETIME MERIT INDEXES
(2003)
NM FM CM
PTAscs -9 -9
-7 PTAsize -3
-3 -2 PTAudder 7
7 6 PTAfl
4 4 3
PTAscs -9 -9
-7 PTAsize -3
-3 -2 PTAudder 7
7 6 PTAfl
4 4 3
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RELATIVE VALUES() IN LIFETIME MERIT INDEXES
(2003)
NM FM CM
PTAdpr 7 7
5 PTAscd -3
-2 -2 PTAdcd -2
-2 -2
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SIRE SELECTION

• Production FIRST (80th percentile for FM)
• Type preference among 80th percentile bulls
• Avoid inbreeding
• Set production percentile standards if using a
  mating service

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ESTIMATED CHANGE IN PTA FOR 2000 BASE CHANGE
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ESTIMATED CHANGE IN PTA FOR 2005 BASE CHANGE
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CROSSBREEDING
Heterosis () 100 X (ABBA) - (AB)


2 2
(AB)/2
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Birth weights, mortality, and dystocia in
Holsteins, Jerseys, and their reciprocal crosses
in the Virginia Tech Kentucky crossbreeding
project

• B.G. Cassell1, A.J. McAllister2, R.L. Nebel1, S.
  Franklin2, K.E. Getzewich1, J. Ware2, J.
  Cornwell1, and R.E. Pearson1
• 1 Virginia Polytechnic Institute and State
  University
• 2 University of Kentucky

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Design of the project

• Purebred Holstein and purebred Jersey cows at
  Virginia Tech and Kentucky were the foundation
  females
• Four proven Holstein and four proven Jersey bulls
  at Select Sires were the foundation males
• Project heifers in four breed groups (HH, HJ, JH,
  and JJ) in a diallele scheme
• 40 animals per breed group at VT
• 20 animals per breed group at KY

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Solutions to additive, maternal, and heterosis
effects for birth weights (kg), dystocia, and
mortality
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Conclusions birth weights

• Bigger calves from
• Holstein genes
• Older dams
• Bulls vs heifers
• Single births vs twin births
• Positive additive and maternal effects for
  Holsteins
• No significant heterosis for birth weight.

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Logistic analysis of dystocia using additive,
maternal, and heterosis effects
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Conclusions - mortality

• No significant breed group differences in
  mortality
• Unfavorable additive effects for Holstein genes
• Favorable maternal effects for mortality from
  Holsteins
• No significant heterosis

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Holstein, Jersey Diallel- University of Kentucky
Immune Function
J.V. Ware, S. T. Franklin, A.J. McAllister
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IMMUNE FUNCTION
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PHASE II

• Breeding half of Jersey X Holstein and
• Holstein X Jersey heifers to Brown Swiss and
  half to Scandinavian Red
• Collecting growth, health and reproduction data
  on purebred and crossbred heifers
• Will collect calving, production, reproduction,
  and health data on cows

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Crossbreds ofNormande-Holstein,
Montbeliarde-Holstein, and Scandinavian
Red-Holsteincompared to pure Holsteins for
production
B. J. Heins, L. B. Hansen, and A. J.
Seykora University of Minnesota, St. Paul
American Dairy Science Association 2005 annual
meeting, Cincinnati
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Overview
Seven cooperating dairies in central California
Holstein cows were bred to A.I. sires from
numerous breeds
Montbeliarde (380,000 cows on test in France)
Normande (280,000 cows on test in France)
Scandinavian Red (420,000 cows on test in Norway
and Sweden)
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Actual 305-day production for first lactation
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Minnesota/California Study Calving Results
Conclusions
Holstein-sired calves were born with
significantly more dystocia and with a
significantly greater frequency of stillbirths
than calves sired by Scandinavian Red sires
First-calf Scandinavian Red-Holstein crossbred
cows had significantly less dystocia and
significantly fewer stillbirths than first-calf
pure Holsteins
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Minnesota/California Study Reproduction and
Survival Results
Conclusions

• All crossbred groups survived longer than pure
  Holsteins during first lactation
• Furthermore, all crossbred groups
• - tended to have fewer days to first
• breeding
• - had fewer days open
• - had higher first service conception rates

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