Superovulation, Embryo Collection And Cryopreservation In Nanyang Yellow Cattle

Thirty Nanyang yellow cattle were used as experimental animals to investigate factors that influenced their superovulation. The purpose of this study was to establish a stable and efficient operational procedure for superovulation and embryo collection in Nanyang yellow cattle and to cryopreserve their embryos in order further to found the technological basis for the embryo and genetic bank of this species. The main experiment results were shown as follows.1. Seventy-six superovulations in donor Nanyang yellow cattle were conducted effectively in this experiment, resulting in average 12.82 corpus luteum per cattle and total 7.34 embryos per cattle collected, among which 4.28 embryos were available.2. Nanyang yellow cattle were superovulated with FSH＋PG method and CIDR＋FSH＋PG method, respectively. The numbers of corpus luteum, total embryos and available embryos per cattle from these two methods were not different significantly(P＞0.05).3. Nanyang yellow cattle were injected with different dosages (280, 300, 320mg) of FSH made in Canada, among which the number of corpus luteum collected per cattle was not different significantly (P＞0.05). However, total and available embryos collected per cattle with 300mg were significantly more than those with 280 and 320mg (P＜0.05). While among different dosages (280, 300, 320IU) with FSH made in Ningbo of China, the number of corpus luteum collected per cattle was also not different (P＞0.05) and the numbers of total and available embryos with 320IU were significantly more than those with 280 and 300IU (P＜0.05), indicating that 300mg Canadian FSH or 320IU Ningbo FSH per cattle were feasible to superovulate Nanyang yellow cattle.4. The total number and the number of available embryos collected using imported FSH were slightly more than those from domestic FSH, but there was no differences between them.5. Among the donors treated in Summer and Autumn (from May to October) and in Winter and Spring (from November to April), the difference between the collected corpus luteum, total and viable embryos per head were not significant (P＞0.05), but the collected total (8.23) and available embryos (4.71) per cattle in Winter and Spring were slightly more than those in Summer and Autumn (6.57 and 3.90), respectively.6. There were no significant differences of collected corpus luteum, total and available embryos per head among repeated superovulations for three times (P＞0.05). The results indicated that repeated superovulation for three times (the interval of 70-80d) had no impact on the results of superovulation in Nanyang yellow cattle, and there were no obvious difference between results of each time. 7. During superovulation, the numbers of corpus luteum and recovered embryos of intact cows were significantly less than those of multiparity cows (P＜0.05), but the number of available embryos between intact and multiparity cows were almost equal with no significant difference (P＞0.05), suggesting that the intact cows as donors could be superovulated, and the rate of available embryos of intact cows was high.8. After cryopreservation of embryos, 12 frozen embryos were thawed for examination, resulting in normal rate of 91.7% and developmental rate of 83.3% after overnight culturte.