EVALUATION OF MERIT OF A CORRECTIVE MATING PROGRAM FOR HOLSTEIN CATTLE

Mating appraisal for profit data were provided by 21st Century Genetics. There were 132,791 records on Holstein cows scored from July 1, 1975, through September 30, 1979. The purpose of the program is to aid dairy producers in selecting bulls for corrective matings and to provide type information on bulls. Sires are evaluated from a progeny test, and matings are recommended when the cows are scored. In selecting the appropriate bulls for a cow, basic form is considered first. After basic form, the worst fault of the cow is considered. Three bulls are chosen that are known to sire progeny strong in the major area of weakness of the cow. Legs were the most commonly occurring worst fault (17%), followed by fore udder, rump, feet, rear udder, fat test, and scale, ranging from 8.5 to 9.6%. Correlations between basic form scores of mates were -.59 in progeny of specified mating and -.13 in progeny of unspecified matings. Progeny from specified matings had a higher rate of improvement in feet and mammary scores than progeny of unspecified matings. Sire selection for milk was important, and there was no reduction in selection for milk in the specified matings.