214 EFFECT OF OOCYTE SOURCE ON THE DEVELOPMENTAL CAPACITY OF SOUTH AFRICAN IN VITRO-PRODUCED INDIGENOUS CATTLE EMBRYOS

The present study was undertaken to determine whether the source of oocytes (slaughterhouse ovaries from feedlot cows or naturally grazing indigenous cows) would affect in vitro bovine embryo production. Bovine oocytes (n = 1047), aspirated from slaughterhouse ovaries from feedlot cows and naturally grazing indigenous cows were randomly allocated to Sanyo, Forma, and Thermo 5% CO2 incubators. Oocytes were then in vitro matured in TCM-199 plus 10% fetal bovine serum, 1 μg mL–1 for both FSH and LH at 39°C for 24 h, and fertilized in Brackett and Oliphant (BO) medium per treatment group at 39°C. Presumptive zygotes were cultured in vitro per treatment group. Total cleavage and blastocyst rates were recorded postfertilization. Data were analyzed by ANOVA. Preliminary results demonstrated that there was no effect of incubator or source of oocytes on cleavage and 8-cell embryos. However, the cleavage and embryo developmental rate tended to be lower for the feedlot group, regardless of the incubator used (Table 1). In conclusion, this study suggests that slaughterhouse ovaries obtained from South African indigenous cows from a feedlot resulted in a lower blastocyst formation rate. Further studies are currently underway to count the cell numbers and to conduct embryo transfer. Table 1.Comparison of three different incubators and source of oocytes on embryo development in vitro This work was funded by the South African National Department of Agriculture, DST-PDP, and the National Research Foundation (NRF, Grant. Nos. RT21 and 24000).