The influence of different time modes of OPU sessions on the development of ovarian follicles in heifers of the Sychev breed

Since the effectiveness of OPU is influenced by a large number of factors, including the breed and individual characteristics of animals, it is necessary to select the optimal OPU modes for different breeds of cattle. It is worth noting that it is particularly relevant to study the factors affecting the effectiveness of OPU/IVP in the framework of creating cryobanks of embryos of domestic cattle breeds, since they have a limited number. This study was conducted at the L.K. Ernst Federal Research Center for Animal Husbandry on heifers of the Sychev breed recognized by the gene pool.
The aim of the work was to study the effect of the frequency of OPU sessions (1 or 2 times a week) on the pattern of ovarian follicle development in relation to the quantity and quality of extracted oocytes.
During the study, it was found that with a decrease in the interval between OPU sessions from 7 to 3–4 days, there was an increase in the number of medium-sized aspirated follicles (by 73.8%) with a simultaneous decrease in the number and proportion of degenerated oocytes. Thus, in the group undergoing OPU twice a week, the proportion of usable oocytes was 62.8% versus 53.3% in the group in which the sessions were performed once a week. At the same time, the proportion of aspirated follicles from the total number of ultrasound-visible follicles did not differ between the groups (78.6% versus 78.4%). Taking into account the results obtained, the optimal mode of conducting OPU sessions on Sychev heifers was considered to be twice a week.

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