Color and exterior characteristics of first-calf heifers of dairy breeds

Abstract

The exterior of 945 first-calf heifers of Holstein and Ukrainian Black-and-White and Red dairy breeds in the breeding herd LLC "Agricultural enterprise "Svitanok" of the Donetsk region was studied by the type and the main measurements of the body structure. During the fourteen-year period of improvement of the breeding herd, an improvement in the exterior of the cows was noted with an increase in the conditional proportion of Holstein blood, which was accompanied by an increase in the milk productivity of the cows. The genetic factor of paternal origin has the most significant influence on the variability of the external features of first-calf heifers. Paternal origin determined 8,8‒45,9% of the variability in the measurements of first-calf heifers, 10,5‒40,5% of the variability in the descriptive features of linear classification by type, 22,6% of the variability in the proportion of non-pigmented skin areas, and 57,6% of the variability in the milk productivity of first-calf heifers.