Ovarian morphology and reproductive function of Holstein heifers as a function of whole milk drinking rate during rearing

The purpose of the study was to determine the norm of whole milk drinking during the rearing period of heifers on ovarian morphogenesis and their reproductive ability. Two groups of newborn calves were formed for this study. The animals in the group were selected according to the principle of analogues taking into account live weight, line, age of cows of mothers in calves of 25 heads each (control, experimental). Calves of the experimental group received whole milk for 60 days in the amount of 360 kg, and calves of the control group in the amount of 300 kg, as usual in the farm. During the study we studied the morphological histological parameters of the ovary and the reproductive ability of heifers. According to the results of experimental studies, it was found that drinking whole milk of 360 kg during the rearing period, provides an increase in the weight of the ovary at 3 and 2 months of age by 23.79 % and 31.71 %, respectively, then in heifers given whole milk of 300 kg. Morphological and morphometric parameters characterizing the degree of development of the ovary in the studied groups of heifers with the norm of milk drinking during the rearing period of 360 kg indicate the level of structural transformations in the sex gland, which contributed to an increase in the fertilization of heifers by 10.0 % as compared to the control.