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Virginia Cooperative Extension -
 Knowledge for the CommonWealth

Don't Just Use an AI Bull

Dairy Pipeline: September 1999

Bennet Cassell
Extension Dairy Scientist, Genetics and Management
Virginia Tech
(540) 231-4762

The August 1999 USDA bull proofs include 623 active AI Holstein bulls and 90 active AI Jersey sires. All those bulls give farmers choices, but there is a temptation to think of all active AI bulls as equal or nearly so in genetic merit. Since only about a half dozen proven bulls and an equal number of young sires would be sufficient for our 130-cow herds in Virginia, producers need to make decisions about which active AI bulls to use. The average active AI Holstein bull has a proof of 1,614 lbs. for PTA milk, 53 lbs. for PTA protein, 1.50 for PTA type, and 1.15 for udder composite. The average active AI Jersey has a PTA for milk of 1,443, a PTA of 50 lbs. for protein, and is 2.29 for PTA type. Those numbers look high and sound impressive, but they are averages. As a comparison, the top ranking active AI Holsteins will have PTAs for milk well above 2,000 lbs. At least 8 active AI Holstein bulls are above 3,000 lbs. while at least 6 are at or above 90 lbs. of protein. The Jersey breed has at least 6 bulls over 2,000 lbs. of milk. The best type bulls have PTA's well over 2.00. The dairy industry has had access to exceptional genetics for so long that it is easy to forget just what an asset those bulls really are. We don't have quotas and government guarantees for prices like producers in some countries have, but no dairy farmers anywhere have access to better bulls than are available at reasonable cost to US producers every month of the year. Take advantage of this asset by using the best proven bulls available to sire replacement heifers for your herd.

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