Analysis of the effectiveness of the GnRH analogue use in the protocol of superovulation of donor cows

Abstract

The aim of the study was to estimate the effectiveness of the drugs containing a synthetic analogue of gonadotropin-releasing hormone (hereinafter referred to as GnRH) and to determine the best drug that stimulates the follicle ovulation in the ovaries of donor cows for obtaining the maximum number of high-quality embryos. The hormone stimulation of donor cows was carried out in Centre for Reproductive Technologies, LLC (Syreyka, Kinel district, Samara region) in the period from 2018 to 2022. The cows that were treated beforehand with follicle-stimulating hormone and having three or more dominant follicles were selected for the experiment (n=264). Three groups were formed depending on the GnRH product. In group I (n=31), we administrated "Fertagil" intramuscularly at a dose of 2.5 ml per animal. In group II (n=132), the drug "Veterlin" was applied and also at a dose of 2.5 ml per animal. In group III (n=101), the drug "Surfagon" was used at a concentration of 10 micrograms and at a dose of 5 ml per animal. 12 and 24 hours after administration of the drug, artificial insemination of donor cows was performed by the rectocervical method. Embryos were flushed on the 7th day of the induced estrus cycle. During the morphological evaluation of the obtained embryos, it was found that the largest number of high-quality embryos was detected in group II, where we used "Veterelin". When recalculating the total number of high-quality embryos on average per donor, this indicator was 8.7 embryos, which significantly exceeded the results obtained in group I by 1.2 pcs. (PЈ0.05) and in group III - by 1.4 pcs. (PЈ0.01).