| In order to quicken the well-bred step of cattle and sheep popularization and embryo engineering industrialization development, the key technical factors of embryo engineering industrialization, mainly including oestrus synchronization, superovulation, embryo freezing/thawing, embryo transfer, and sex identification and control were studied in this paper. The results were showed bellow: 1. Efficiency of oestrus synchronization for recipient cows by CIDR + PG treatment was better than that by double PG treatment, but no difference between two methods(p>0.05). Recipient cows, which were prepared more than 3 months before treatment could reach the ideal result of synchronization. Cattle during lactating period got low efficiency of oestrus synchronization, so synchronization should be performed 3 months after delivery. Among the synchronized recipient cows, corpus luteum rate in the right side (68.64 %) was remarkably higher than that (31.36 %) in the left side (p<0.01). 2. Donors and recipients of cattle and sheep should be strengthened feeding management and improved nutrition level, because feeding management and nutrition level have a key role to success of embryo transfer. Effects of superovulation were different among different breeds, and superovulation effects of Simmental, Limousion, Angus, Hereford was better than that of Charolais. The average number of available embryos and available embryo rate of heifers were higher than that of adult cows. Superovulation was more effective on the 11th and 12th day in oestrous cycle, the best result on the 9th and 10th day, and available embryos were in high proportion. Meanwhile, available embryo rate had no significant difference among 1 to 4 times insemination after superovulation (p>0.05). The best superovulation dosage of FSH made in China was 8 mg to age of 14 to 15 months heifers, 8.8 mg to age of 16 to 17 months heifers, and 10.4 mg to age of 18 to 19 months heifers, respectively. 3. The scheme of 39 d repeat superovulation interval time was implemented in this research, which could obviously shorten interval time of repeat superovulation, but also achieve ideal effect. When the interval between first and second repeat superovulation was 27 days, the average numbers of available embryos were 6.22 ±2.45 and 4.25 ±3.25, respectively, significant difference between two groups (p<0.05), and oestrus utilization rate were 91.42 % and 75.00 %, respectively, significant difference between two groups(p<0.01); When 39 days, the average numbers of available embryos were 5.44±2.78 and 5.17±2.65, and oestrus utilization rate were 95.03 % and 91.57 %, no significant difference between groups (p>0.05). In 47 and 67 days, there were no significant differences of the average numbers of available embryos between first and second times (p>0.05). Under the grazing condition in Inner Mongolia, the best time of superovulation Hereford's beef cows was between May and June, and the best time of Angus' beef cattle was between August and September. The superovulation results showed that average number of available embryo of Holstein heifers which be superovulated by FSH made in Canada and China were 4.60±3.52 and 5.34±2.68, no significant difference between two FSHs (p>0.05). 4. To cattle embryo transfer, the pregnancy rate of fresh embryos was 61.74%, remarkable higher than that of frozen embryo 45.32 % (p<0.05). There was no significant difference between pregnancy rate of thawed embryo by one-step method or routine method (p>0.05). Pregnancy rate was up to 90.91 % when 6 d blastocysts were transfered into recipients of 6 d by oestrus synchronization treatment, remarkably higher than the pregnancy rate of 6 d morulae and 7 d blastocysts(p<0.05), and was significant difference with pregnancy rate of 7 d morulae(p<0.01). In China, the best embryo transfer season is different in different areas, summer and autumn are better to embryo transfer in the northern area, summer is the best season; Spring and autumn are better in central area, autumn is the best season; Spring and winter are better in southern area, winter is the best season. 5. Superovulating to different district sheep, the result showed: The effect is better from October to beginning of December in the Northeast; Best time of the Northwest is from the last ten days of October to December, North China from the last ten days of November to January and the central plain area from December to January. Ideal time of superovulation for Boer Goats is from January to April and from October to December, the best in November and December. The average number of available embryos of Boer Goat were significant different between 9 days and 15 days after CIDR placed (p<0.01). Oestrus rate of sheep donors which were superovulated simultaneously were 18.10% in 12 h, 75.00 % in 24 h, 6.90 % in 36 h, respectively. The average number of available embryos were the highest in 24 h, no significant difference with that in12 h (p>0.05). Both numbers in 24 h and 12 h were significant different with that in 36 h (p<0.01). 6. All 6 repeated superovulations were up to the ideal result in succession by adoptingdifferent working techniques with routine in the embryo recovery and transfer course. In sheep's embryo transfer, the pregnancy rates of 4-cell embryos, 8-cell embryos, morulae and blastocysts had no significant difference (p>0.05). However, the pregnancy rates of them were remarkably higher than 2-cell embryos, significant difference between them (p<0.01). Pregnancy rate is influenced remarkably when embryos are stayed outside the body more than 2 h. 7. The average number of available embryos from frozen sexed sperm of Canada and China were 4.90±3.81 and 4.69±3.67, no significant difference between them (p>0.05); Average available embryo rate was 51.64 %, AI rate was 73.24 %, regression embryo rate was 21.60 %, and accurate rate of sex control was 91.07 %. High AI rate and available embryo rate were obtained with 2 million low dosage sperm by inseminating into deep uterus angle. 8. Sex of 291 fresh cattle embryos in vivo transferred were identified by LAMP method, pregnancy rate was 54.30 %, and accurate rate was 98.10 %; 47 cows were transferred with frozen embryos, pregnant rate was 36.17 % and accurate rate was 100 %. Fresh embryo transfer was higher than frozen embryo, significant difference between two groups (p<0.01). The average accurate rate of LAMP method was 98.29 % in this experiment. This method for embryo sex identification is simple, convenient, fast, accurate and economy.
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