Superovulatory response in Brahman donor cows using follicular ablation before superovulation protocols

Objective. The objective of this study was to determine the effect of follicular ablation at the beginning of a superovulation protocol (SOP) on the superovulatory response of Brahman donor cows. Materials and methods.Twenty Brahman cows were used, randomly distributed in two groups: control group (G1, n = 10), synchronization of the follicular growth wave was performed by the combination of estrogens (2.5 mg, estradiol benzoate) and progestagens (1 gr intravaginal implant); four days after starting the SOP with porcine follicle stimulating hormone (FSHp); and the ablation group (G2, n = 10), follicular ablation was performed and one day after, the SOP treatment with FSHp was initiated. In both groups, embryo collection was performed seven days after the first artificial insemination. Results.The G2 had a higher proportion of quality 1 embryos (p0.05). Conclusions.Follicular ablation increased the percentage of quality 1 embryos, suggesting that the implementation of this technique, as a strategy to synchronize the beginning of a new wave of follicular growth when using SOP, improve embryo quality in Brahman donor cow

Respuesta superovulatoria en vacas donantes Brahman usando ablación folicular previo a protocolos de superovulación

ABSTRACT Objective. The objective of this study was to determine the effect of follicular ablation at the beginning of a superovulation protocol (SOP) on the superovulatory response of Brahman donor cows. Materials and methods. Twenty Brahman cows were used, randomly distributed in two groups: control group (G1, n = 10), synchronization of the follicular growth wave was performed by the combination of estrogens (2.5 mg, estradiol benzoate) and progestagens (1 gr intravaginal implant); four days after starting the SOP with porcine follicle stimulating hormone (FSHp); and the ablation group (G2, n = 10), follicular ablation was performed and one day after, the SOP treatment with FSHp was initiated. In both groups, embryo collection was performed seven days after the first artificial insemination. Results. The G2 had a higher proportion of quality 1 embryos (p0.05). Conclusions. Follicular ablation increased the percentage of quality 1 embryos, suggesting that the implementation of this technique, as a strategy to synchronize the beginning of a new wave of follicular growth when using SOP, improve embryo quality in Brahman donor cows.RESUMEN Objetivo. Determinar el efecto de la ablación folicular en el inicio de un protocolo de superovulación (SPO) sobre la respuesta superovulatoria en vacas donantes de raza Brahman. Materiales y métodos. Se utilizaron 20 vacas de raza Brahman, las cuales fueron distribuídas aleatoriamente en dos grupos: Grupo control (G1; n = 10), la sincronización de la onda de crecimiento folicular fue realizada mediante la combinación de estrógenos (2.5 mg, Benzoato de Estradiol) y progestágenos (1 gr, implante intravaginal); cuatro días después se inició el protocolo de SPO con la hormona folículoestimulante porcina (FSHp); y grupo ablación (G2; n = 10), se realizó la ablación folicular y un día después se inició el tratamiento de SPO con FSHp . En los dos grupos la colecta de los embriones se realizó siete días después de la primera inseminación artificial. Resultados. El G2 presentó una mayor proporción de embriones de calidad 1 (p0.05). Conclusiones. La ablación folicular aumentó el porcentaje de embriones de calidad 1, sugiriendo que la implementación de esta técnica, como estrategia para sincronizar el inicio de una nueva onda de crecimiento folicular en tratamientos de SPO, mejora la calidad de los embriones producidos en vacas donadoras Brahman

Effect of the presence and location of corpus luteum on competence of bovine cumulus-oocyte complexes

This study aimed to determine the effect of presence of the corpus luteum (CL) and its influence on cumulus–oocyte complexes (COCs) obtained from the ipsilateral or contralateral ovary in bovine on the recovery and capacity of the oocytes to sustain mono-spermic fertilization, undergo preimplantation development, and develop to the blastocyst stage. Ovaries were collected at a local slaughterhouse and kept in pairs corresponding to the same animal. In the first experiment the variables evaluated were compared between cows with (CCL+) and without (CCL-) CL, and for the second experiment, comparisons were made between ovaries with an ipsilateral (CL+), contralateral (CL−), and no (NCL). The recovery rate of COCs was higher in ovaries from CCL− cows, and a higher proportion of grade 1 COCs were recovered from this group. A higher proportion of metaphase I oocytes at 7 h of maturation, and a higher rate of cleavage were observed in the CCL+ group; however, a higher proportion of embryos were obtained from the CCL− group. Besides, COCs from the CL+ group had a lower proportion of grades 1 and 2 morphological qualities, lower rate of metaphase II oocytes at 22 h of maturation, and lower rate of formation of two pronuclei, whereas a higher proportion of unfertilized oocytes after in vitro fertilization. On the other hand, the COCs from the CL− group displayed a lower proportion of oocytes with more than two pronuclei, higher cleavage rate, and higher final blastocyst production were obtained when compared to CL+. Thus, the effects of CL on the competence of bovine COCs are different depending on the anatomical proximity of their location in the animal, negatively affecting the quality of COCs located in the same ovary, but not having negative effects on the competence of COCs in the ovaries contralateral to their location. © The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Incluye referencias bibliográficas