Effects of Percentage of White Coat Color on Holstein Production and Reproduction in a Subtropical Environment

¹ Dairy Science Department, University of Florida, Gainesville 32611

Percentage of white coat color was measured visually on registry certificates of 4293 first lactation Holstein cows on eight Florida dairy farms; records of production and reproduction were obtained from DHI. Data were analyzed using derivative-free REML with an animal model to estimate heritability of nine performance measures and to establish their relationships with white percentage. Adjustment of other response variables for white percentage altered heritabilities very little. Regression of milk production on white percentage was 1.91 kg/1% white. Regression coefficients were negative for fat and protein percentages and positive for protein and fat production. Regression coefficients for reproductive traits on white percentage were negative (Le., white was desirable) but were not statistically significant. Probability of survival to second parturition was higher but not significant for cows with higher white percentage, Interaction of white percentage and season for fat percentage and days open was significant. In a subtropical environment, white percentage appears to affect productive and perhaps reproductive performance. Economic aspects of selection for increased white percentage need to be investigated.

Key Words: Holstein • coat color • production • reproduction

Submitted on January 21, 1993
Accepted on March 16, 1993