Comparative effectiveness of the use of various gonadoliberin analogues and the effect of the morphobiochemical composition of blood on the fertilization of cows

Abstract

Synchronization schemes of sexual cyclicity are widely used in dairy cattle breeding to optimize reproductive function in cows and heifers. A comparative evaluation of the use of three synthetic analogues of gonadotropin-releasing hormones (GnRH) in a complex synchronization scheme was carried out, as well as the influence of the morphobiochemical composition of blood on fertilization was determined. For experimental work, 3 groups of full-aged cows were formed, 10 in each. The first group of animals was intramuscularly administered surfagon at a dose of 10 ml, the second – fertagil 2.5 ml, the third - fertagon 5 ml. In cows treated with surfagon fertilization after the first insemination was 70%, fertagil - 20%, fertagon - 50%. According to the results of 3 months of observations, after treatment with surfagon and fertagon, fertilization was 80%, with a multiplicity of inseminations of 1.13 and 1.38 times, respectively, whereas after treatment with fertagil, fertilization was 60% with a multiplicity of 1.67. The morphological picture of blood in infertile cows on the day of artificial insemination was characterized by a lower content of erythrocytes (by 10.7%; P<0.05), lower hematocrit (by 6.3%; P<0.05), with a higher content and concentration of hemoglobin in the erythrocyte (by 7.0%; P<0.05 and 2.9%; P<0.05, respectively). It was also found that infertile cows had lower progesterone levels on the day of insemination. Thus, in the group treated with surfagon, the hormone concentration was 2.7 times lower compared to those fertilized, in animals treated with fertagil 4.2 times (P<0.05), fertagon 2.0 times (P<0.05), which is apparently due to the different functional activity of the pituitary-gonadal system.