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Take a look at your genetic improvement program
Dairy Pipeline: May 2006
Bennet G. Cassell
Extension Dairy Scientist,
Genetics & Management
(540) 231-4762; email: firstname.lastname@example.org
Just how good are the proven AI bulls you use in your herd? Do you use AI
more or less than other herds? Do you rely on AI young sires more or less than
average and just how good are they compared to proven bulls? Here are state
DHI averages for March 2006 to use as benchmarks. Average herd size in Virginia
is 149 cows, of which 105 cows (70%) carry service to some bull.
There will be some "pedigree slippage" by the time the proofs are out
on the youngsters, but they will still compete very well with proven bulls at
the 64th percentile. Another category of service sire is reserved for "all
other bulls". Generally these are herd bulls kept to cover problem breeders
or used in place of AI sires. Very seldom is any genetic information available
for them. Check your herd's figures by looking at the "Genetic profile of
service sires" on the DHI herd summary 202. Good goals for a herd breeding
program would be:
- The average Virginia herd on DHI uses 14 different proven AI bulls to breed
71 cows (5 mates per proven AI bull.)
- Genetic merit for proven bulls is $307 for Net Merit, which ranks at the
64th percentile against all active AI proven bulls.
- Eight young sires in AI are mates for 17 other cows (two mates per young
- Pedigree merit is higher ($389 for Net Merit) than the proofs for proven
Virginia herds do use AI extensively in the lactating herd, but sire selection
could be more intense in many herds. Before buying semen, check the rank of
each bull for Net Merit. Stay above the 80th percentile for Net Merit on the most
recent sire summary. There are plenty of choices for different traits within
the top bulls for Net Merit.
- Rely on proven AI sires for 80-85% of all services.
- Strive for average rank for proven bulls above the 80th percentile.
- Use AI young sires for remaining services with no services to "other"
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