Superovulation And Large-Scale Transfer Embryo In Goats And Sheep

It is important to improve the efficiency of embryo production, the pregnancy rate and survival rate of embryos in MOET program, which is crucial to expand the breeding flock or superior individual in goat and sheep. This study involves the key embryo-transfer technology and associate technology in Boer goat and Poll Dorset sheep. The results are listed as follows.1. Superovulatory treatments were performed using Nb-FSH , Ch-FSH and Nb-FSH plus Ch-FSH by selection of optimal scheme in Boer goats. The total number of recovered embryos per does was 17.82±8.41, 17.33±8.84 and 17.97±9.88, and the transferable embryos were 14.97±7.56, 13.78±6.15 and 14.31±6.63, respectively. These results indicated that the best superovulation response and the high embryo yields were obtained by using the domestic gonadotrophins and optimal superovulatory protocols.2. Boer goats were repeatedly superovulated for four times, and superovulatory treatments were conducted at 2 month intervals. The mean response rates were 93.99%, 80.00%, 63.64% and 50.00% in the first, second, third and fourth treatments, and transferable embryos recovered were 14.80±6.91, 14.00±7.01, 9.09±7.18 and 7.83±6.09. When at annual intervals, response rates were 95.00%, 85.00%, 81.25% and 70.83% respectively. The recovery of transferable embryos among the different repeated superovulations was not significantly different (P> 0.05). This indicates that one-year interval was reasonable for continuous superovulation.3. The superovulatory protocols of the FSH dosage were adjusted in repeated superovulation according to the effect of first superovulation. The treatment by increasing FSH dosage can make good response for the donors which were poor or no response in the first superovulatory treatment. There were more than 70% of the effective donors in the second superovulatory treatment.4. The results show the correlation between the body weight of young Boer goat and the number of total embryos (ova) and transferable embryos. The higher number of total embryos (ova) and transferable embryos could be recovered in young does whose body weights were more than 36 kg. The body weight of young does is closely related to superovulation. A good feeding before puberty would be beneficial to reproductive potentials.5. The transportation of donor does within 4 h before embryo collection didn't have a significant effect on embryo recovery number, embryo survival rate and the subsequent pregnancy in recipient does. Either, the transportation of embryos at 36.5oC to 38oC within 2 h before embryo transfer did not significantly affect the embryo survival rate and subsequent pregnancy rate. However, the transportation of embryos at 20oC resulted in a significant (p<0.05) low survival rate (41.7%) and pregnancy rate (42.0%). The transportation of recipient does resulted in a significantly lower pregnancy rate (42.0%) and embryo survival rate (32.1%) than those of the transportation of donor does and embryos. These data suggest the transportation of donor does be the best method for embryo transfers on the farm. Alternatively, the supply of fresh embryos kept at body temperature (36.5oC) was preferred for short and long distances between farms.6. Medical chitosan were used to prevent postoperative adhesion in Boer goat embryo transfer program. Adherence rate of the donor does was only 37.5% after 4 times'surgery in the chitosan anti-adhesion treatments, while the adherence rates were 100% in 32% dextran plus heparin treatment and the control group with physiological saline.7. In breeding season, there was no significant difference in the ratio of synchronized estrus and recipient utilization between the sheep breeds which were performed by the same protocol. However, in anestrous season, the ratios of estrus synchronization and recipient utilization were very low in both Tong sheep and Inner Mongolia sheep. The small tail sheep was the best recipients. Meanwhile, the treatment of synchronized estrus with intravaginal progestagen or in combination with PMSG were better than that those of PGF2αor PGF2αin combination with PMSG.8. The estrus synchronization was compared in different treatments of goats during spring or autumn. The results demonstrated that the treatment of intravaginal progestogen plus PGF2αwas a efficient method for estrus synchronization in either breeding season or non-breeding season. The treatment of estrus synchronized by intravaginal progestagen plus PGF2αin combination with PMSG or FSH may increase the functional corpora lutea number. The interval from intravaginal progestogen withdraw to estrus onset was shorter, but did not affect duration of estrous, the pregnancy rate of recipient and survival rate of embryos. The study indicated that the treatment of FSH with 20IU-30IU may improve recipient utilization and administration of 300IU PMSG was the suitable dosage for estrus synchronization in goats in spring.9. Intramuscular injection was replaced by intravenous injection of Su-Mian-Xin to anesthetize goat and sheep. The dosage of anesthesia was reduced significantly, and the revulsiue duration and resuming duration of intravenous anesthesia were shorter than those of intramuscular anesthesia. After 0.5 h analepsia, most goats could forage and ruminate, and were conscious. And After 1 h analepsia, all could return to normal condition. The results demonstrate that Su-Mian-Xin anesthetic intravenous injection was safe, effective and less dosage, which is superior to intramuscular injection.10. Superovulatory treatments were conducted in Poll Dorset sheep, the results show that gonadotropin FSH from Canada Fotropin V (Ca-FSH) was successfully used for superovulatory treatment with 160 mg to 200 mg dosage per ewe and recovered 12.91±7.80 embryos. Multiparous ewes for superovulation treatment were significantly better than nulliparous ewes (P<0.05). The successive superovalution treatment significantly reduced embryo collection but did not affect transferable embryo number. The ewes with natural estrus lead to significantly higher number of recovery embryos (13.83±4.64) and transferable embryos (12.00±5.76) than those in induced estrus (7.00±4.92; 4.22±3.42) and unknown estrus cycle (5.94±3.38; 3.19±2.56, P<0.05). The delayed estrus ewes 24 h post superovulation produced significantly fewer recovery and transferable embryos (0.92±1.51 vs. 0.42±0.90) than those with estrus on time (P<0.01). Furthermore, more transferable embryos were recovered from ewes with normal corpus luteum than those with corpus luteum regression (5.88±5.09 vs 3.59±4.30 and 8.83±5.75 vs. 6.66±5.41, P<0.01). These results suggest that a comprehensive treatment method by using the Canadian FSH (Fotropin V) or the other two Chinese FSH combination,plus choosing multiparous and natural estrus ewes with normal corpus luteum may obtain an optimal embryos collection and embryo transfer in sheep.11.The model in this paper could promote industrialization, large-scale development and commercial operation of MOET in China. This study established the beneficial assessment models in goats and sheep embryo transfer. The model could be used for embryo transfer project approval, impact assessment and other research related to MOET. The series of technology were optimized in this study to promote goat and sheep breeds and to speed up the superior population, which will play an important role in theory and applications.