Inheritance and Relationships of Workability Traits and Yield for Holsteins

Scores for eight subjectively scored management traits (disposition, milking speed, udder, feet, legs, trouble-free workability, producer-coded yield, and overall satisfaction) were collected by Eastern AI Cooperative, Ithaca, NY for the Dairyman Workability Evaluation Program. Two traits (trouble-free workability and overall satisfaction) were scored by dairy producers on a five-point scale, and the other six traits were scored on a three-point scale. Repeatability of scores from first lactation to second lactation ranged from .37 (milking speed) to .50 (feet and overall satisfaction). Heritability for milking speed (.18) was higher than previous estimates and suggested potential for meaningful response to selection. Heritability of disposition was low (.10) but similar to previous estimates. Trouble-free workability had heritability of .11. Estimates for the other five traits were all ≤.08. Genetic correlations were positive between FCM and milking speed (.30), trouble-free workability (.25), producer-scored yield (.69), and overall satisfaction (.69). Owner satisfaction, as a trait, combined yield and nonyield factors; however, low heritability and high genetic correlation with FCM suggest that owner satisfaction provides little additional opportunity for genetic improvement of dairy cattle.