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• Factors Related to Quantity And Quality of OocytesCollectedfromAbattoir Bovine Ovaries

  Nguyen Van Thanh, Vu Minh Lam, Nguyen Duc Truong, Nguyen Hoai Nam, Do Thi Kim Lanh

  Received: 17-04-2023 / Accepted: 29-08-2023

   Abstract PDF (VIETNAMESE)

  The study was conducted to evaluate the influence of breed, body condition score (BCS- Body condition scores), ovary volume and the largest follicle size on some parameters related to the number and quality of bovine oocytes (classify as A, B level were good oocytes and C, D level were not good oocytes). The results showed that there was no significant difference on the average number of follicles on the ovary surface, the number of oocytes obtained, and the ovary volume between the cattle breeds but the average mass of follicles/ovary. Specifically, the average volume of follicles/ovary in Yellow cattles (6.11g) was higher than in Dairy cattles (2.66g, P <0.05). BCS did not affect the mean follicle size, mass, and the total number of follicle obtained. Ovarian mass, the largest follicle size had an influence on the total number of follicles and the number of oocytes obtained. Ovaries with a mass of 5-10g having the average total number of follicles, the total number of A, B and C, D follicles accounted for the highest number (11.21 follicles; 3.9 and 6.51 oocytes). Similarly, the number of A-B and C-D oocytes obtained from the ovary with the largest follicle size ranged 3-7mm were 4.06 and 7.09, respectively (P <0.005).

• Improvement of the Efficiency of Bovine in vitroFertilization Embryo Production

  Do Thi Kim Lanh, Nguyen Thi Ngoc Anh, Hoang Thi Kim Chi, Nguyen Thi Hong Nhung, Nguyen Ba Truong, Su Thanh Long, Nguyen Van Thanh

  Received: 18-08-2020 / Accepted: 07-12-2020

   Abstract PDF (VIETNAMESE)

  The present study was conducted to improve the efficiency of in vitroproduction of bovine embryos. Bovine oocytes were matured either in BO-IVM or TCM199 medium then evaluated the maturation rates by orcein staining. After maturation, bovine oocytes were in vitro fertilized (IVF) in a medium with frozen-thawed sperms at different concentrations (1, 2, or 5 ×106sperms/ml) for 12 hours. The fertilization process was then evaluated at 3, 6 or 12h of oocytes and sperms co-incubation to determine the optimal sperm concentration and co-incubation time. Denuded zygotes were then transferred into SOF medium with or without pre-cultured cumulus cell to evaluate the cleavage rates at day 3 and blastocyst formation rates at day 7. There was no significant difference in the maturation rate of bovine oocytes cultured in BO-IVM or TCM199. Fertilization of bovine oocytes with frozen-thawed sperms at 2 ×106sperms/ml for 6 h significantly improve the fertilization rate and blastocyst formation rate (69.87% and 29.1%). The cleavage rate and blastocyst rate of cattle fertilized oocytes cultured in SOF medium with pre-cultured cumulus cells were higher than those of embryos cultured without cumulus cells (76.34% and 34.16% vs 54.23% and 27,22%, P <0.05). The optimal conditions for in vitro produced cattle embryos can be performed as the maturation of the oocytes with TCM199 medium, fertilization at 2 ×106sperms/ml for 6 hours, then cultured in SOF medium with pre-cultured cumulus cells.