Reproductive seasonality influences oocyte retrieval and embryonic competence but not uterine receptivity in buffaloes

Improved the in vitro blastocyst development in oocytes recovered from cyclic buffaloes

This study examined the impact of cyclicity (with or without cycle corpus luteum; CL) on oocyte quality and embryonic development in buffaloes. We collected oocytes from the ovaries of slaughtered buffaloes (N = 158 cyclic; n = 316 ovaries and N = 177 acyclic; n = 353 ovaries). Blood progesterone concentration and number of oocytes per ovary were higher in cyclic buffaloes. Cyclic buffalo ovaries produce higher oocytes with I + II and fewer III + IV grades. Oocytes from cyclic buffaloes had a higher maturation rate based on cumulus expansion, cleavage rate and embryo development to the 8-cell, morula and blastocyst stages than acyclic buffaloes. In conclusion, oocytes recovered from the ovaries of the cyclic buffaloes showed improved oocyte competence and subsequent in vitro blastocyst development.

Surgical Description of Laparoscopic Ovum Pick-Up in Buffalo Calves

The technique of laparoscopic oocyte aspiration has been increasingly used in animals; however, there are few records of its use in buffaloes. To describe this technique, six suckling Murrah buffaloes aged between 3 and 5 months were used. Three laparoscopic ovum pick-ups were performed in each animal, with intervals of 15 days between surgeries, completing a total of 18 procedures. The technique used three surgical ports with optics and a high-definition video camera. The introduction of the first portal and insufflation of the abdomen was performed through the open technique, with aspiration using a 20 G needle transabdominally and a vacuum pump calibrated at 50 mmHg. The mean complete surgical time from anesthesia to the removal of the animal from the litter was 49 ± 9.8 min. There were 27.8% cases of insufflation on the wrong side of the omentum. The oocyte recovery rate of 60.3% remained within the normal range. However, the rate of viable oocytes recovered was low, with only 40.8% of those recovered undergoing in vitro embryo production (IVEP). These data demonstrate that this simple, minimally invasive technique is an excellent reproductive tool for the genetic improvement of buffalo species.

Factors Affecting the Efficiency of In Vitro Embryo Production in Prepubertal Mediterranean Water Buffalo

Embryos from prepubertal water buffalo can be produced using laparoscopic ovum pickup (LOPU) and in vitro embryo production (IVEP). However, to date, it is unclear what factors and environmental conditions can affect LOPU-IVEP efficiency in prepubertal animals, especially buffalo. In this study, we explored the impact of season, age and individual variation among female donor animals, as well as the effect of the sire used for in vitro fertilization. Donor animals between 2 and 6 months of age were stimulated using gonadotropins prior to LOPU, which was performed at two-week intervals. Following in vitro maturation and fertilization, the resulting embryos were then cultured to the blastocyst stage until they were either vitrified or transferred into recipient animals. The number of follicles available for aspiration and embryo development rates was stable throughout the year. As animals became older, there was a slight trend for fewer COCs recovered from LOPU and better embryo development. There was a large individual variation in both ovarian response and the developmental competence of oocytes among donors. The bull used for fertilization also had a significant impact on embryo development. Upon embryo transfer, pregnancy rates were not affected by the number of embryos transferred per recipient. The best pregnancy rates were achieved when transferring blastocysts, compared to compact morula or hatched blastocysts. Finally, vitrification had no effect on pregnancy rate compared to fresh embryos.