Date of this Version
Variance components were estimated from type appraisal data to determine the importance of year, herd, sire, and herd x sire effects upon 49 body, udder, and management traits. Estimates were based on over 16,000 appraisals on daughters of Holstein artificial insemination sires. The variation explained by these effects never exceeded 34% of the total variance. Year effects were almost nonexistent (-2 to 3%). Herd effects were small for all traits except feeding speed, body weight, intensity and persistency of edema, and ketosis, and never exceeded 25%.
Most appraisal traits had low heritabilities. The estimate for milking speed was .23 while estimates for other management traits were less than .08. The estimates for body weight and upstandingness were .40 and .39. Other body traits having estimates from .16 to .21 were sharpness, height of thurls, depth of body, levelness of rump, tightness of shoulders, and height of tail setting. The heritability estimates for udder traits were low. Estimates for only three of 21 udder traits exceeded .14. These were strength of rear attachment, rear teat spacing, and depth of udder.