Comparisons of Cows and Herds in Two Progeny Testing Programs and Two Corresponding States

¹ Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061-0315

Data were USDA genetic evaluations of cows and DHI herd profiles from 4154 Holstein progeny-test herds from two artificial insemination organizations, 21st Century Genetics (Shawano, WI) and Genex (Ithaca, NY), and from 6361 additional herds from Minnesota and New York. We grouped herds into four categories: 21st Century Genetics herds, other Minnesota herds, Genex herds, and other New York herds. Herds were eliminated if they contributed fewer than 10 cows with genetic evaluations and birth dates from January 1989 to March 1995. Data included 83 and 74%, respectively, of first-crop daughters of 21st Century Genetics and Genex progeny-test bulls with genetic evaluations from January 1995 to February 1997. Herds were characterized by DHI profile and cow evaluation data. Daughters of progeny-test bulls with extreme production records (outside of 3 SD) relative to herd mean and variance did not appear in disproportionate numbers among the progeny of bulls likely culled or considered for further use. The two organizations appear to have selected larger, genetically superior, and better managed herds from within their respective regions for progeny-testing purposes. We were not able to predict whether a bull in the progeny-testing programs of these two organizations was going to exceed or fail to meet the pedigree prediction from characteristics of herds in which his daughters performed. Differences between parent average and daughter yield deviations for typical young sires appear to result from Mendelian segregation of genes.

Key Words: progeny tests • young sires • pedigree selection • variance

Submitted on July 7, 1998
Accepted on November 23, 1998