Aim: The aim of the presented study; oocyte number and quality obtained from bovine ovaries procured from abattoir and evaluation of the relationship between different quality oocyte maturation rate for in vitro embryo production.

Materials and Methods: For this purpose, 370 ovaries were transported with 0.9% isotonic sodium chloride containing 100,000 IU penicilin-streptomycin and brought to the laboratory within 2-4 hours. 40 of the ovaries were not used in the study due to their cyst and adhesion nature. 1894 oocytes were obtained from the remaining 330 ovaries by aspiration method. The quality of the obtained oocytes was evaluated as A, B, C and D quality according to the cytoplasm density and the distribution of the cumulus cells around the oocyte. 1384 of them, A and B quality, were left to maturation with a commercial maturation medium (BO-IVM,Bioscience, UK)at 38.8 °C with atmospheric O₂ at s5.5% CO₂ for 24 hours. Results: With the aspiration method, including 800 A, 584 B, 450 C and 60 D quality a total of 1894 oocytes were obtained. In addition, it was determined that the number of 2.42 A, 1.76 B, 1.36 C and 0.18 D per ovary was reduced. Only A and B quality oocytes were used for maturation. The maturation rate was determined as 90.3% in A quality oocytes and 83.3% in B quality oocytes (p?0.01). The total maturation rate of the study was determined as 87.4%.

Conclusion: As a result, it was determined that maturation rates change according to oocyte quality and maturation rates reduce with the decrease in quality. Therefore, it was concluded that it is necessary to evaluate the oocyte quality before maturation.