Abstract #17

# 17
M. H. Mapeka*1,2, F. V. Ramukhithi1, C. M. Pilane1, D. Norris2, C. Banga1,2, K. C. Lehloenya3, 1Agricultural Research Council, Animal Production Institute, Germplasm Conservation and Reproduction Biotechnologies, Irene, Republic of South Africa, 2Faculty of Science & Agriculture, Department of Animal Production & Agricultural Economics, University of Limpopo, Limpopo, Republic of South Africa, 3Department of Animal & Wildlife Sciences, University of Pretoria, Gauteng, Republic of South Africa.

The aim of this study was to determine the sperm fertility rate by embryo production in vivo and in vitro in South African bulls and further compare the embryo quality developed from different oocyte recovery methods. A total of 15 frozen semen straws (5 Bonsmara; 5 Nguni; 5 Boran) were thawed and evaluated for sperm motility characteristics using sperm class analyzer. The fertilizing ability of frozen–thawed semen was assessed by performing AI and in vitro fertilization. For AI, 6 cows were superovulated and inseminated with frozen–thawed semen followed by flushing on Day 7 post-insemination and then evaluated for embryo developmental stages. For IVF, oocytes were retrieved using two recovery methods namely ovum pick-up (OPU) and ovary aspiration. A total of 383 (106, OPU; 277, ovary aspiration) oocytes were matured in M199 + 10% fetal bovine serum (FBS) maturation medium at 38.5°C for 24h. Oocytes were washed in Bracket and Oliphant’s fertilization medium, co-incubated with frozen–thawed (Boran) semen at 38.5°C for 6 h, and then cultured in SOF-BSA medium, incubated at 38.5°C, 5% CO2 for 7 days, and further evaluated for embryo development. Data were analysed by ANOVA. Total sperm motility was >70% in all breeds. Boran had a significantly (P < 0.05) higher total post-thaw sperm motility (93.2 ± 3.6) compared with Nguni (75.1 ± 4.2) and Bonsmara (80.7 ± 6.9). Furthermore, Boran had higher (P < 0.05) progressive motility (39.7 ± 3.4) and rapid motility (36.1 ± 5.9) compared with other breeds. Interestingly, Boran produced significantly (P < 0.05) higher blastocyst rate (56.34%) compared with Bonsmara (38.03%) Nguni (31.08%). Superovulation and OPU resulted in a significantly higher (P < 0.05) number of blastocysts (10.5 ± 3.3 and 10.5 ± 3.3) respectively, compared with aspiration (1.3 ± 3.3). Moreover, the OPU method yielded a significantly higher (P < 0.05) number of grade 2 blastocyst (3.0 ± 0.1) compared with aspiration (0.50 ± 0.1). However, there was no significant (P > 0.05) difference in the number of grade 1 and grade 3 blastocysts obtained when the 3 recovery methods were used. In conclusion, the Boran breed showed better a sperm fertility rate following in vivo and in vitro embryo production. The superovulation and OPU methods resulted in higher numbers and better quality blastocysts compared with aspiration.