Abstract:
The objective of this work was to evaluate the effects of donor, season of the year, sire, and type of semen on in vitro embryo production of the Sindhi breed (Bos indicus). To this end, 434 in vivo ovum pick up (OPU) sessions, performed in 152 oocyte donors, were evaluated using sex-sorted or unsorted semen from 22 sires. The following variables were analyzed: donor; age of the donor; season of the year; sire; type of semen; recovered, viable, and degenerated oocytes; and cleavage and blastocyst rates. The effects of the donor and sire were observed on recovered, viable, and degenerated oocytes, and on blastocyst rates. The year was split into rainy season, from October to March, and dry season, from April to September. In the rainy season, the proportion of viable oocytes increased, while the proportion of the degenerated ones reduced. Donors with less than six years of age had a higher proportion of viable oocytes and a lower proportion of degenerated ones. Unsorted semen obtained the best cleavage and blastocyst rates. Donors with up to six years of age show the greatest proportion of viable oocytes, and the greatest number of viable oocytes is produced during the rainy season. Unsorted semen shows the best rates for cleavage and blastocysts.
Index terms:
Bos indicus; donor; OPU; seasonality; semen