Contributions of Discriptively Coded Type Traits to Longevity of Holstein Cows

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Abstract
Official type classifications and production records of Holstein cows calving between January 1, 1967, and June 1, 1976, were used to estimate contributions of appraisals in 1st lactation of descriptive type traits to 1st lactation and lifetime production, herdlife and 1st calving intervals. Herdlife, production variables and calving intervals deviated from contemporary averages. Contributions of individual type components to these were estimated from least squares constants adjusted for all other descriptive type traits and for linear and quadratic effects of final score, age at 1st calving, herdlife opportunity, stage of lactation and age when classified. Differences in herdlife, lifetime production and 1st calving intervals were generally small but in some instances equalled 10% of means for all cows. Largest differences in lifetime milk yield among alternative codes for a trait were for front end, udder support and miscellaneous codings, all of which exceeded 2000 kg. Largest positive constants for lifetime milk yield were for cows with weak front ends, firmly attached rear udders and bulgy fore udders. Large negative constants were associated with cows having coarse front ends, broken suspensory ligaments, undesirably shaped teats and crampiness. Most type codes considered conformationally ideal were, for a given final score, associated with slightly less than average herdlife and lifetime production.