Methods of artificial regulation of estrous cycle of Aberdeen Angus breeding stock

Abstract

The research aim is to study the efficiency of using the OvSynch and Co-Synch schemes with subsequent resynchronization on beef cows and heifers of the Aberdeen Angus breed. The hormonal state of animals and the biochemical blood serum parameters were chosen as factors determining reproductive function. The purpose is to study the efficiency of applying the OvSynch and Co-Synch synchronization protocols on cows and heifers of the Aberdeen Angus breed depending on the hormonal state of the inseminated animals and the biochemical blood serum parameters. The rate of fertilization in cows inseminated according to the OvSynch protocol was determined to be 5.0 to 8.5 % higher during the first stage of insemination and 5.5 % higher during the second stage of insemination. In the group of heifers, the best fertilization results were obtained while using the Co-Synch protocol (59.3 %). Giving cows a second injection of GnRH, on day 9 of the OvSynch protocol, 16 hours before insemination, provided an average rate of fertilization of 52.3 %, which is 3.4 % higher compared to the 14-hour interval between GnRH injection and insemination. The concentration of steroid and gonadotropic hormones, including cortisol, estradiol, FSH and LH, in experimental animals during insemination corresponded to the estrus phase. The results of biochemical blood tests indicate a number of metabolic inconsistencies in the animal body. Changes in the biochemical blood serum parameters in animals that did not become pregnant followed the same patterns as in those that became pregnant. However, the level of increase or decrease in parameters was less pronounced. The results obtained can be used in arranging artificial insemination in breeding and commercial agricultural organizations engaged in beef cattle breeding, as well as in teaching process of zootechnical and veterinary disciplines in agricultural higher educational institutions of the Republic of Belarus.