The correlation between dairy productivity traits in the herd of holsteinized cows of Black and White breed

Abstract

It is important to study the nature of the association between the characteristics of milk productivity in breeding work with cattle. The purpose of the researches was to study the correlation between the traits of milk productivity in the herd of holsteinized cows of Black-and-White breed. A signifi cant low negative correlation r=–0,108 (P < 0,01) and r=–0,125 (P < 0,001) has been found between the traits of milk yield and the mass fractions of fat and protein for the 1st lactation. It should be noted that for the 1st, 2nd lactations and on average for the fi rst three lactations between the mass fractions of fat and protein a reliable average positive correlation has been determined from r=0,512 (P < 0,001) to r=0,565 (P < 0,001), for the 3rd lactation a high positive correlation has been found r=0,613 (P < 0,001). It has been found for all three lactations that milk yield had high, positive and reliable correlation coeffi cients with milk fat yield from r= +0,958 (P < 0,001) to r=+0,974 (P < 0,001) and milk protein yield from r=+0,995 (P < 0,001) to r=+0,997 (P < 0,001). This can serve as an indicator of possible eff ective selection based on these characteristics. In order to determine the infl uence of sires on the content of mass fractions of fat and protein in the milk of their daughters, the degree of correlation of these characteristics has been studied. Correlation coeffi cients between milk yield and fat mass fraction were negatively low from r=–0,139 (P < 0,01) to r=–0,280 (P < 0,05). The correlation between milk yield and protein mass fraction has been found from the average negative value of r=–0,372(P < 0,05) to the positive low indicator – r=+0,234 (P < 0,001). The correlation coeffi cients have been obtained for milk productivity indicate the individual characteristics of individual sires.