| This project takes Awang sheep in Qamdo area of Tibet as the object to explore the superovulation and embryo cryopreservation technology of Awang sheep,aiming at the promotion and application of integrated demonstration embryo transfer,embryo freezing and other technologies in Awang sheep,so as to facilitate the development of Awang sheep.Conservation,propagation and promotion of improved varieties.In this experiment,using hormone drugs from different origins and different doses,superovulation treatment was carried out on Awang sheep in different months,and embryo freezing and thawing transplantation were carried out using two different methods,and the following experimental conclusions were drawn:1.Using domestic(Ningbo)high-dose FSH,Belgian FSH and two kinds of FSH consecutively superovulated Awang sheep,the average number of corpus luteum was12.08±4.69,7.00±3.97 and 7.64±3.14 respectively,and the number of embryos recovered was all The numbers were 6.58±2.81,4.55±4.96 and 3.75±3.67,respectively.The average number of corpus luteum and the average number of recovered embryos were significantly higher in the domestic high-dose FSH group than in the Belgian imported FSH group and the two FSH successive superovulation groups(P<0.05).Preliminary tests showed that the domestic(Ningbo)hormone had better effect on superovulation in Awang sheep,and the average corpus luteum number and recovered embryos were higher.2.Using domestic hormones with different doses of superovulation,the average number of corpus luteum in the domestic high and low dose groups was 12.08±4.69 and 8.58±4.68,respectively,and the average number of recovered embryos were 6.58±2.81 and 6.92±4.34,respectively.The number of embryos were 3.75±3.67 and 5.08±4.75,the embryo recovery rates were 54.48% and 80.58%,and the available embryo rates were 56.96% and 73.49%,respectively.There was no significant difference between the two groups(P>0.05).The low-dose domestic FSH group had a more stable superovulation effect on Tibet Awang sheep.3.The superovulation of Awang sheep was performed in different months.The results showed that the number of available embryos in the superovulation group in July(3.95±4.23)was significantly lower than that in the superovulation group in October(5.45±4.03)(P<0.05).The average number of recovered embryos,embryo recovery rate and available embryo rate in the 7-month group were lower than those in the 10-month group,and the average number of corpora lutea was relatively stable with no significant difference(P>0.05).The results showed that the number of available embryos in Awang sheep after superovulation treatment in different months has a certain effect.4.When Awang sheep underwent repeated superovulation,the average number of corpora lutea after the first superovulation was 12.24±4.15 and the average number of recovered embryos was 8.76±4.09,which were significantly higher than the average number of corpus luteum 6.33±3.66 in the second superovulation.The number of embryos was4.93±3.57,and the superovulation results were significantly different between the two groups(P<0.01).Repeated superovulation was performed after two and a half months interval of Awang sheep,and the effect of repeated superovulation was lower than that of the first superovulation.5.The study on hormones and the body weight of Awang sheep,the test results showed no significant difference between the domestic high and low dose groups when the body weight ≥ 50 kg(P>0.05),but the effect of the two groups of Awang sheep with superovulation body weight ≥50 kg was stable.6.In the study on the number of fresh embryos transferred,the pregnancy rate of the recipients transplanted with two morula embryos and the ratio of lambing recipients to the transplant recipients were higher,both reaching 81.81%,and the lambing rate was 57.58%,which was comparable to other groups.The data were significantly different(P<0.05).The number of fresh embryos transplanted and the different developmental stages of Awang sheep were studied.The pregnancy rate and lambing rate of recipients transplanted with two morula embryos were higher in this experiment.7.The results of embryo freezing in this experiment showed that the recipient pregnancy rate of the programmed frozen embryo group was 35.48%,which was significantly better than the 13.63% recipient pregnancy rate of the vitrification group(P<0.05).At present,the cryopreservation of Awang sheep embryos is still in the experimental stage,and its accurate freezing effect needs to be confirmed by expanded experiments.Excluding external factors or operational errors,there are differences in the freezing effect.Tibet Awang sheep has the best superovulation effect using domestic(Ningbo)FSH hormone;when Awang sheep is generally in estrus(October),the embryos are more available after superovulation;the superovulation interval is two and a half months,and the first superovulation effect is achieved Better than the secondary superovulation effect;the pregnancy rate and lambing rate are better when two morula embryos are transplanted at the same time.Therefore,it is very feasible to popularize embryo transfer technology for Awang sheep in Tibet.In this experiment,104 embryos were transferred from Awang sheep,and 56 recipients were transplanted.B-ultrasound monitored the pregnancy of 40 recipient ewes.The pregnancy rate was 71.42%,55 lambs were produced,and the embryonic lambing rate was 52.88%.Awang sheep frozen embryos transferred 104 embryos,and a total of 84 recipients were transferred.B-ultrasound monitored the pregnancy of 25 recipient ewes,the pregnancy rate was 29.76%,27 lambs were born,and the embryonic lamb rate was 25.96%. |
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