Phenotypic Value of Corrective Matings In Holstein Cattle. 1. First Generation

¹ Department of Dairy Science, The Ohio State University, Columbus 43210

One hundred seventy-six Holstein cows were assigned to be used for foundation matings to determine effects of corrective mating for type on type traits, production, and longevity of first generation daughters. At parturition, cows were paired by age within two herds and assigned randomly to corrective or control (random mating) groups. A sire pool in each herd was based on minimum levels for production and type. Each sire selected for the corrected member of the pair also was assigned to the random member. Animals continued in the same group for the duration of the experiment, and all subsequent daughters were considered to be first generation offspring. Data were collected from January 1982 to January 1991. The final data set contained 430 first generation daughters. Variables studied to determine effects of corrective mating on first generation daughters were first classification and linear type trait scores, first lactation twice daily milking 305-d mature equivalent milk and fat, lifetime production of milk and fat, sire PTA for milk, percentage of survival, percentage of daughters showing improvement over dam's worst trait, and phenotypic variation between groups. No significant group differences existed for any of the calculated measures. Results suggests that, once careful selection of a sire pool has been implemented, specific assignment of mates of those sires is of little importance.

Key Words: corrective mating • pheno-typic value • sire selection

Submitted on March 23, 1992
Accepted on August 12, 1992