Abstract:

In Russia, the number of beef cattle until recently was concentrated mainly in Kalmykia and adjacent regions. However, the lack of purposeful breeding has led to the fact that the purebred livestock of Kalmyk meat breed has significantly decreased and lost its unique qualities. Introduction of embryo transfer biotechnology can solve the problem of restoring breed qualities under the condition of accelerated reproduction of genotyped livestock. The aim of the research was to study Kalmyk breed response to polyovulation considering further increase in transferrable embryo productivity - the main indicator specific to each breed. As the formation of the breed took place in pasture conditions with a pronounced seasonal sexual cycle, there were doubts about the possibility of using embryo transfer technology in any season. The experiments were carried out on Kalmyk cows at Kalmytskoye farm in 2010 and at the Regional Research and Production Center for Reproduction of Farm Animals, Kalmyk State University, in 2022. The results of the study showed that it was better to synchronize sexual hunting using prostaglandins after 3-4 months after calving (May-October). According to the results of immunogenetic testing, 10 breeding cows and 2 breeding bulls were selected as donors. In September-October, in order to test the embryo transfer method in nomadic animal husbandry, the first work was carried out to stimulate poliovulation and obtain embryos from 3 donor cows. A total of 23 embryos and eggs were obtained, 10 of which were suitable for transplantation. Transferrable embryos were frozen on a ZEM-4 software freezer after equilibration in 1.5 M ethylene glycol cryoprotector solution.

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