Genetic Analysis of Milk and Health Traits in Divergently Classified Holstein Friesian Cows

Genetic parameters for milk and health related traits in low and high milk producing Holstein Friesian cows were estimated using farm collected information on the Jos, Plateau, Nigeria. Milk yield and health related records were extracted from database of the West Africa Milk Company Integrated Dairies Limited. An innovative statistical modeling in this study was the application of repeatability animal models to estimate the genetic parameters. The resulting dataset consisted of 5043 lactations from 608 dams and 39 sires. Genetic correlations were obtained by bivariate analyses of all pair-wise combinations between two traits. In high milk yield Holstein, heritabilities estimate recorded for milk yield (0.43), mastitis (0.26) and lameness (0.33) was high while NIS (0.56), PR (0.22), RR (0.67) and PR (0.22) recorded high estimate in low milk yield Holstein cows. Highest genetic correlation was observed between rectal temperature and vaginal temperature (0.91). Lameness had significant (p<0.05), positive and highest environmental correlation with mastitis (0.95). The heritability estimates of health related traits were low to high; therefore, genetic gain through direct selection alone would be slow, yet still positive and cumulative in the divergently classified Holstein Friesian cows on the Plateau.