Sergeeva O. Morphofunctional peculiarities of ovaries and uterus of heifers of Black and Speckled breed in the industrially contaminated regions of Donbas.

The thesis presents the results of the investigation of morphofunctional peculiarities of ovaries and uterus of heifers of Black and Speckled breed in the postnatal period of ontogenesis from birth to the 20-month age that were reared on the territories with the average level of contamination by heavy metals. The data of the investigation and the analysis of the results received testify to the negative influence of the industrial exotoxicants (the combination of cadmium and lead) on morphogenesis of the reproductive organs of heifers at all stages of postnatal ontogenesis and it is the trustworthy cause of the development of hypofunction of ovaries that is manifested by hypoplastic type of its development in the new-born heifers. Hypofunction of ovaries is characterized by the delay in the sexual maturity of heifers, by the development of cystic and sclerocystic syndromes, it reveales the inhibiting influence on the postembryonic morphogenesis of uterus. In the period of sexual function formation the above changes are the cause of decrease in its luteolytic action that causes the persistency of yellow body and it is one of the factors of postpartum complications in cows and cow-heifers. The data received testify to the fact that the deficient level of zink revealed in the summer rations of heifers (the deficiency - 82%) is one of the factors of the increase in the toxic action of such industrial pollutants as combinations of cadmium.