Estimators of Sire Merit

Sire Evaluation for Economic Merit

Procedures for selecting sires are compared in terms of making maximum genetic progress in economic lnerit. A quadratic index, a simplified form of the quadratic index and a linear index to evaluate economic merit, and a restricted index to improve milk as much as possible while holding milk fat percentage constant, all result in nearly equal expected genetic progress in economic merit. Selecti...

Impact of Changes in Genetic Improvement Programs and Annual Cycles on Holstein Service Sire Merit

Monthly averages of Holstein service sire PD from January 1960 through December 1985 were examined to determine if a relationship existed with changes in evaluation methodology. Monthly average of service sue PD for registered cows from January 1971 through December 1985 suggested three linear periods of increase. Regression of PD on sequential month were significantly different for periods def...

Tracking the merit of merit pay

Five Measures of a Sire

SUMMARY Lactation milk and fat records of 6,949 daughters, 6,201 different dams, and the contemporary D.H.I.A. herd averages of 2,420 herds were studied, to compare five measures of a dairy site's transmitting ability. They were the daughter average, daughter-dam difference, equal-parent index, daughter-contemporary herd difference, and daughter-contemporary-herd index. The daughters and dams w...

The Importance of Sire Selection