Outstanding Gir oocyte donors: How does individual factor affect in vitro embryo production efficiency?

AbstractThe oocyte donor plays a pivotal role in bovine in vitro embryo production (IVP) success. The individual factor affects blastocyst/oocyte ratio and determine the existence of outstanding performing animals. The aim of this study was to assess the extent of individual factor effect to IVP efficiency, in a population of Gir oocyte donors. Extreme (high or low IVP efficiency based on blastocyst/oocyte ratio) animals were selected out of a population of 250 oocyte donors (1,734 observations) to form high (>0.48,n = 40), average (0.17–0.48,n = 168), and low (<0.17,n = 42) efficiency donor groups. Cumulus-oocyte complex indicators (total number, IVF-grade number, and IVF-grade/total ratio) were lower (p <  0.05) in high efficiency donors. The number of blastocysts per OPU was analyzed for highest performing bull, and an increase (p <  0.05) in high efficiency donors and a decrease (p <  0.05) in low efficiency donors were noticed, compared to average efficiency donors. The number of pregnancies obtained per OPU was affected (p = 0.017) by donor's efficiency (low: 0.60±0.09$$ 0.60\pm 0.09 $$, average: 1.17±0.07$$ 1.17\pm 0.07 $$, high: 2.57±0.26$$ 2.57\pm 0.26 $$), being 4.3-fold higher in high than in low efficiency donors. We conclude that producing embryos from high efficiency blastocyst/oocyte ratio donors incre ases blastocyst and pregnancy numbers by OPU, being an important indicator for donor selection in IVP programs.

Source: Animal Science Journal - August 9, 2023 Category: Zoology Authors: Clara Slade Oliveira, Paola Maria da Silva Rosa, Agostinho Jorge dos Reis Camargo, Luiz Fernando Feres, Naiara Zoccal Saraiva, Leticia Zoccolaro Oliveira, Luiz Sergio de Almeida Camargo Tags: SHORT COMMUNICATION Source Type: research