Resumo

NARVAEZ, Héctor Javier et al. Effect of plasma progesterone on competition for in vitro embryonic development of Bos taurus taurus and Bos taurus indicus cows. Cienc. Tecnol. Agropecuaria [online]. 2022, vol.23, n.2, e2003.  Epub 31-Abr-2022. ISSN 0122-8706.  https://doi.org/10.21930/rcta.vol23_num2_art:2003.

Studies have shown that progesterone has a direct effect on oocyte quality and early embryonic development. The objective of this study was to evaluate the effect of plasma progesterone (P4) concentration on in vitro embryo development in Bos taurus taurus (Holstein) and Bos taurus indicus (Gyr) cows. Multiparous Holstein and Gyr cows were used, and they were presynchronized with the application of two doses of D-cloprostenol with an interval of 11 days. They were latter distributed in one of three experimental groups induced to different plasma levels of progesterone: control group was synchronized using only D-cloprostenol without exogenous progesterone, low progesterone group received an auricular implant of norgestomet of second use, and high progesterone group received two new auricular implants of norgestomet. The plasma progesterone concentration was significantly different (P < 0.05) for both Holstein cows (0.22 ± 0.15, 2.23 ± 0.17 and 5.32 ± 0.22 ng/mL) and Gyr cows (0.24 ± 0.19, 2.05 ± 0.17, 4.85 ± 0.20 ng/mL) between control, low progesterone, and high progesterone groups respectively. Gyr cows presented differences (P < 0.05) in the cleavage rate of the low progesterone group in relation to the control and high progesterone groups (87.9 % ± 0.11 vs. 77.5 % ± 0.13 and 76.4 % ± 0.10, respectively) and in the variable blastocyst rate of the low progesterone group (48.3 % ± 0.16) in relation to the control group (35.8 % ± 0.10) and the high progesterone group (30.4 % ± 0.20). It is concluded that there is an effect of progesterone on embryonic development of Gyr cows. However, this effect is not evidenced in Holstein cows.

Palavras-chave : cattle; follicular aspiration; follicular wave; in vitro embryo production; norgestomet; ovarian follicles.

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