PRODUCTION TRAITS OF RED AND WHITE RELATIVE TO BLACK AND WHITE HOLSTEINS

Canadian red and white (RW) and black and white (BW) Holsteins were compared for several production traits based on genetic evaluations of 32 RW and 883 BW bulls, and performance data of 4161 RW and 8691 BW cows. Differences (P < 0.05), favoring BW, were observed for milk and milk fat yield of cows, and for milk fat and milk protein yield evaluations of bulls. There was, however, a large genetic overlap between the populations for all traits studied. Pleiotropic effects associated with the color gene were not detected as being important. Phenotypic trends for milk yield, milk fat yield, and milk fat percent were significantly greater for BW than RW cows (P < 0.01). Genetic trends were greater for RW cows, though not significantly (P > 0.05). Key words: Dairy production, genetic trends, Holstein (red and white), Holstein (black and white)