Study on In Vitro Bovine Embryo Production with Follicular Oocytes Obtained via Ultrasound-guided Ovum Pick-up (OPU) and Slaughterhouse-derived(SHD) Ovary Aspiration in Korean Native Cows
The present study was carried out for the comparative study on the collection of bovine follicular oocytes by ultrasound-guided ovum pick-up(OPU) and slaughterhouse-derived (SHD) ovary aspiration and in vitro production of bovine embryos with the follicular oncytes in Korean native cows. Bovine follicular nocytes were observed with a 6.5 MHz convex-array ultrasound transducer designed for intravaginal use and the oocytes were collected with the aspiration equipment attached to the ultrasonograph. Bovine ovaries were collected and transported in phosphate buffered saline from the local slaughterhouse, the follicular oocytes were collected by the aspiration method. The collected follicular oocytes in good quality were matured, fertilized and cultured in the media. The total number of the visible follicles and the recovery rate of follicular oocytes were increased in ultrasonography following follicle stimulating hormone(FSH) treatment in Korean native cows. The mean recovery rate of oocytes was 66.2, 52.8 and 41.7% in the FSH-OPU, non-treatment-OPU and SHD ovaries, respectively. The mean number of recorved oocytes per cow were not significantly(P<0.05) different between the FSH-OPU(14.011.54) and SHD(17.1i6.21) groups, but the numbers in both groups were significantly(P<0.05) higher than the number in the non-treatment-OPU(3.71.57) group. The mean number of usable nocytes in Grade T /11 per ovary was 6.3, 4.8 and 1.3 in the cows of the SHD, FSH-OPU and non-treatment-OPU groups, respectively. The in vitro developmental rate to the blastocyst was not significantly different between the oocytes obtained via OPU(37.1%) and SHD(29.3%). Therefore, the ultrasound-guided OPU technique can be applied to the production of excellent embryos from the high-quality cows, and for the large scale production of in vitro bovine oocytes and embryos, the SHD ovary aspiration method is valuable.