INFLUENCE OF PARENTS ON THE MAXIMUM MILK YIELD OF BROWN SWISS AND SYCHEVSKY COWS BREEDS

Abstract

We studied the influence of parents on the maximum milk yield in mature cows-daughters of reliable origin in the Smolensk region breeding farms on samples of 207 individuals of the brown Swiss breed from the agricultural production cooperative "Druzhba" and 290 Sychevskaya (Сollective enterprise "Rybkovskoe"), born since 2009. Mothers and daughters are ranked according to the degree of the trait development into three classes of the variation series. Both breeds are characterized by a typical distribution with a slight shift in the frequency of daughters towards the class of mothers, in the absence of its reliable effect on the milk yield of daughters. The daughters from the best group and everyone else almost have equal milk yield with mothers. The best cows come from mothers of different classes, about half of whom are from the highest, with a productive index close to the average. A low degree of father’s influence (less than 20%) in the samples on the frequency of distribution of their daughters by classes of the variation series, depending on the maximum milk yield, was determined. The correlation coefficient of the bull parental index (BPI) and milk yield does not exceed 0.2. In the best daughters group, the influence of fathers is not confirmed. With the combination of mothers and fathers no definite patterns were revealed in the role of parents in the qualitative change of daughters relative to mothers, both in the sample as a whole and in the best daughters.