BILATERAL OVULATIONS FOR THE DAIRY BREEDS: DIAGNOSTICS, PREVALENCE, PRACTICAL VALUE

Abstract

Results of monitoring research of morphological features of ovaries of cows of dairy breeds in 0th day of a follicular phase of a sexual cycle are presented. By differential manual technic diagnostic method one significantly established that the frequency of cases of bilateral ovulations of follicles is influenced by the level of milk production: amongst cows, that have milk production lower, than 5 thousand, this phenomenon was found in 12,88% of cycles, and among highly productive cows (6 000–10 000 kg) – only in 4,34% of cases. Significantly more frequent prevalence of bilateral ovulations was found amongst thoroughbred cows (7,34% of cycles) in comparison with local cattle (0,82% of cycles). Genetic influence on the frequency of bilateral ovulations is significantly established by the statistical analysis of data: amongst cows of red and red-and-white breeds – 10,96% of cycles were with bilateral ovulations, and amongst black-and-white cattle, respectively – 6,57%. For the first time the biological value of bilateralism of development of the dominating cow follicles is experimentally established. Among females with double ovulations after insemination the pregnancy was fixed by 1,5–6,4 times more often, than among cows with single ovulations (respectively, for the herds of Ukrainian Red Dairy and Ayrshire breeds). Pair gonads of cows are key bodies in dairy cattle reproduction, therefore studying of ovary morphogenesis and identification of biological resources of reproduction are important tasks in herd reproduction problem solving under the conditions of industrial milk production technologies.