| The present study selected young and high production Houstein dairy cows as experimental animal, systematically study the technologies of superovulation and embryo cryopreservation, attempt to give some theory foundations and practical advices to commecial embryo transfer program. In the first study, 32 diary cows were placed into three groups and systematically compared the superovulation effects under different methods.lt is found that group one' s( CIDR+pFSH(CA)+PG-600) punctural osetrus rate is lower than that of group two(CIDR+pFSH(CA) +Cloprostenol) or group three(CIDR+pFSH(C)+Cloprostenol, 70%, 100%, 100%, respectively). There was a significant difference in ovarien-volume-increace among three groups (42. 57 + 23. 18, 22.94?.97,12.91?8.68, respectively, P<0. 05) . Group two' s mean number of corput luteal (CL) is more than group one or group three(8. 5, 7. 5, 7. 2, respectively),but no significant difference(P>0. 05). Group one' s mean follicales is more than that of group two or group three(2. 1, 0. 3, 0. 2, respectively),with significant difference between group one and group two or group three; group one' embryo recovery rate is lower than that of group two or group three(45%, 86% and 81%,respectively), with a significant difference;there are not a significant differnce among three groups in the embryo valid rates of (80%, 75% and 60%, respectively, P>0. 05). It was conclude that : ã‚›s a superovulation method of dairy cow, CIDR+pFSH(CA) +PG-600 is not, a good method, further more, PG-600 is popular used to swines as a synchorinzed oestrus medicine, it can not produce a better effect to dairy cows' synchorinized oestrus; (2)pFSH(china made)is charactrised by low cost and easy buying,it has a good effect when use to dairy cows as a superovulation chemical, comparing with pFSH(American made), notorious for there high cost and difficult buying, the effect of superovulation have no significant difference, and its be recoramented to use in the commercial embryo programs; (3) CIDR+ Cloprostenol is a good method to synchronize oestrus of dairy cows. No matter what period of ovary when treating begin,the punctual oestrus is high, so it can be used in the factorizeproduction of embryos to decrease the wastage of labour power and money; (4)the existance of dominant follicals is inferior to embryo recovery, so the number of big follicals in ovary when treating begin is connected with low recovery, but the reasons are not clear.In the second study , the cryopreservation effct of different methods or cryopreservation agents on embryos of diary cows in vivo production were compared.It was found that among the traditional rapid freezing procedure including Ethlene glycol group, glycerol group and One-step-freezing group , the Ethlene glycol group get the highest freezing-thawing recovery rate of blastocyst (100%). The morphologically normal rate of ethlene glycol group is the highest among three groups(90%, 85. 7%, 87. 5%, respectively) as well as the development rate (88.8%, 83.3%, 66. 6%, respectively), with no significan difference(P > 0.05). The morphologically normal rate and development rate of frozen-thawed blastocyst in vitrification group were lower than that of any traditional rapid freezing groups(71. 4%, 40%, respectively). The development rate of blastocyst is higher in Ethlene glycol than that of glycerol group or of one-step-freezing group(88. 8%, 83. 6%, 66.6%, respectively), with no significant difference(P > 0. 05).The ethlene glycol group has a significant higher development rates than the vitrification group(88. 8%, 40%, P<0. 05). Morphological normal rates of frozen-thawed morulaes among three groups (Ethlene glycol group, glycerol group and One-step-freezing group) are significant difference(80%, 80%, 66.6%),but the development rate is lowest in one-step-freezing group compared with that in Ethlene glycol group and glycol group. The morphological normal rate of frozen-thawed morulaes in vitrification group is lowest than that of each group that encounted traditional freezing procedure, b...
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