Determination of Percentage of White Coat Color from Registry Certificates in Holsteins

¹ Dairy Science Department, University of Florida, Gainesville 32611

Drawings from a random sample of 32 registry certificates were used to evaluate procedures for measuring the percentage of white coat color of Holstein cows. Measurements were obtained using a planimeter and by visual evaluations of two inspectors. Mean white percentage of the total cow, excluding face, was 27.8%. With the planimeter, correlations between white percentages on the drawing of the total cow and on the upper and lower body sections were .99 and .92; correlation between right and left sides of the same drawing of the total cow was .96. Percentage of white exhibited greatest variability relative to the mean when measured in the upper body (CV = 122). From upper body, white percentage was correlated >.97 between inspectors and planimeter and >.98 between inspectors. If errors were distributed normally, confidence limits of correlations would be narrow; e.g., 95% limits of correlation .96 are .92 to .98. However, percentage of white appears to be a nonnormal variable skewed to the right. Attempts to transform data to avoid a departure from normality were not successful; additional attempts using other transforms seem warranted. Visual appraisal appears to be an efficient procedure for evaluating percentage of white coat based on registry certificates.

Key Words: registry certificates • coat color • Holstein

Submitted on February 12, 1992
Accepted on July 24, 1992