Relationships among Type, Production, and Stayability in Holstein Cattle

Abstract

Records on 558,654 Holstein cows in the northeastern USA were used to calculate sire summaries for milk, fat and stayability for 36, 48, 60, 72 and 84 mo. Predicted Difference Type was obtained from the Holstein-Friesian Association of America. Genetic correlations between production and stayability ranged from .20-.55 with the lowest genetic correlations with 36 and 48 mo. stayability. Genetic correlation between type and stayability were -.11, -.14, -.15, -.11 and -.09 for 36, 48, 60, 72 and 84 mo. stayability. Stayabilities at different ages are correlated closely genetically. Sires selected for high first lactation production will have daughters which last longer. Screening bulls on 48 mo. stayability would be the most desirable because of high genetic correlations with production and older stayabilities and because bulls can be evaluated at a younger age.