The first-calf cows of dairy breeds estimation by udder measurements and their use in index breeding of udder linear traits

Abstract

The purpose of this study was to estimate the udder morphological traits of first-born cows of Holstein and Ukrainian Black-and-White dairy breeds by measurements, their assessment by the udder-mass-metric index and establishing the degree of relationship between linear type traits of the udder. 86 heads of Holstein and 112 heads of Ukrainian Black-and-White dairy breed from the herd of private enterprise "Burynske" in Sumy region were used in the research. The udder mass-metric index included live weight of cows, body and udder measurements, and its volume. The advantage of the firstborn cows of Holstein breed over peers of Ukrainian Black-and-White dairy breed in terms of udder measurements was established. In animals of Holstein breed, the udder-mass-metric index was on average 15.0, and in Ukrainian Black-and-White dairy cows – 13.1 conventional units, with a difference of 1.9 conventional units, with reliability at P<0.001 in favor of Holstein cows. A significant relationship has been established between udder-mass-metric index and milk productivity. The degree and reliability of relationship between udder parts measurements of the first-born cows of Holstein and Ukrainian Black-and-White dairy breed differed by significant variability, from -0.422 to 0.713 and from -0.486 to 0.698, respectively. The degree and reliability relationship between the udder parts measurements of the first-born cows of Holstein breed (their values are placed below the diagonal) with a slight difference repeat the indicators of correlation coefficients in the peers of Ukrainian Black-and-White dairy breed. The highest correlation was obtained between the anatomically related udder parts – of the front teats length and diameter with the rear ones, and the distance between them. The general conclusion indicates that cows of Ukrainian Black-and-White dairy and Holstein breeds are generally characterized by excellent morphological indicators of the udder, which define its development, including in terms of adaptability to machine milking. Linear measurements make it possible to more objectively evaluate the udder of cows based on development of its parts, and existence of a positive relationship between them and amount of milk yield provides the basis for the effectiveness of cows’ selection based on udder traits in practical breeding, which will help increase the milk productivity of animals.