Effect of follicular size on recovery and in vitro maturation of black Iraqi goat Oocytes

Abstract

The study was conducted on 599 genital system of Iraqi black goat, collected from local slaughter house in Al-Fallujah city and transported to the theriogenology Lab. within one hour of slaughtering, in normal saline in cool box, during the period from July 2010 to July 2011. The reproductive status of the animals were not known. The ovaries were cut by scissors and freed from the surrounding tissues and overlying bursa.The follicles was counted in each ovary, and the diameter of the follicle was measured by automatic vernier, and classified in to small follicle (2-4mm diameter) and large follicle (5-8mm diameter).Only good and fair quality oocytes were selected. The oocytes were washed two times in maturation medium (TCM_199, MEM and TALP), then incubated in appropriate maturation medium in 39◦c temp., 5% CO2 and 90% relative humidity for 24-26h. The presence of first polar body was the criteria for in vitro maturation (IVM) of oocytes. Chi square test were used for statistical analysis.The result showed there were a significant increase (P<0.05) in recovery rate and maturation rate of oocytes recovered from large follicles as compared with that of small follicles. The number of recovered oocytes from large follicles was 1046 out of 1377 follicles with a size between 5-8mm i.e. 75.9%, and the maturation rate was 45.9%, while the recovery rate and maturation rate of oocytes taken from small follicles were 61.06% (1043/1708) and 35.9% (375/1043) respectively. It was concluded from this study that follicular size could be affect the recovery rate and maturation rate of oocytes in vitro.