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Extension > Agriculture > Dairy Extension > Reproduction and genetics > Bull Proofs: Breeding for Success

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Bull Proofs: Breeding for Success

Eric Sonnek

Published in Dairy Star December 11, 2004

One of the most exciting places to be on a dairy operation is in the fresh cow pen. This is where we see calves being born. Especially on the larger dairies, this can be a continuous sight every day. I enjoy this area of the dairy operation because this is where you first see future generations of cows that hopefully will keep the dairy operation productive and profitable for years to come. Approximately nine to ten months before that calf was born, an important decision was made. The question: "to what bull should that cow or heifer be bred?" That decision has a long-lasting impact on the future of the dairy herd.

The November Bull Proofs have recently been completed and many of the bull semen companies are promoting their different bulls. To help sort through this information, let's walk through some of the decisions that are made for breeding programs on dairy farms.

The following chart shows two examples of different traits used in genetic indexes–Lifetime Net Merit Dollars and Holstein USA 's Type-Production Index.

LNM$ and TPI Indexes Use Different Traits










Productive Life



Somatic Cell Score



Udder Composite



Feet & Leg Composite



Size Composite


not used

Daughter Pregnancy Rate


not used

Service Sire Calving Ease


not used

Daughter Calving Ease


not used


not used


Dairy producers need to stay current with indexes as they change over time. Periodically look them over, and then make sure they are meeting or matching the farm's breeding goals. New genetic bases are introduced for all traits every 5 years. The next base change will be done in 2005. The genetic base is determined from the average of cows born in a specific year. In 2005 the base will be set by the average of cows born in 2000.

With today's genetic information and breeding technology, indexes and synchronization programs make breeding cows easier and less time consuming. It makes having a bull on the farm to solve breeding problems less appealing. When combined with good conception rates, the result can be greater genetic improvement for the dairy herd and more satisfaction from those months of waiting for some exciting births in the calving area.

Additional resources:USDA's Animal Improvement Programs Laboratory; National Association of Animal Breeders (NAAB); Global Dairy Sire Genetic Evaluations.

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