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ARS Home » Research » Publications at this Location » Publication #207802
Title: State and National Standardized Lactation Averages by Breed for Cows Calving in 2005

Author
item Norman, H
item Thornton, Laura

Submitted to: AIPL Research Reports
Publication Type: Government Publication
Publication Acceptance Date: 2/1/2007
Publication Date: 2/1/2007
Citation: Norman, H.D., Thornton, L.L. 2007. State and National Standardized Lactation Averages by Breed for Cows Calving in 2005. AIPL Research Reports. K2-05 (2-07).

Interpretive Summary:

Technical Abstract: Means for dairy cow lactation data used in national genetic evaluations and other USDA research are useful for indicating trends and describing cow populations. Breed lactation means are on a 305-day, twice daily milking, mature-equivalent basis from cows contributing to genetic evaluations. Data for State and national lactation averages were from year 2005 calvings. National averages for prior years have been computed to reflect the change from reporting of crude protein to true protein. Component percentages were computed from mean standardized milk and component yields; protein testing is at or near 100% except in California and Nevada. Numbers of lactations initiated in 2005 and eligible to contribute to genetic evaluations, and mean standardized yields were documented by State and breed. Brown Swiss, Holstein, and Jersey calvings for 2005 were up from last year by 1.6, 3.3, and 5.7%, respectively, but calvings for Ayrshires, Guernseys, and Red and Whites continue to decline and dropped by 3.2, 3.5, and 4.4%, respectively. Milk yield was up slightly in all breeds from 1.8 to 3.1%. Fat and protein production generally showed increases from the previous year as well (1.9 to 3.4%).