Study On Influencing Factors Of Efficiency During Embryo Transfer Of Sheep In Estrus

In the recent years the technique of embryo transfer (ET) has become a mature technique and has application in the production of the livestock husbandry. Large numbers of practical productions have proved that the success rate of oestrus season for sheep embryo transfer was obviously higher than the non-oestrus season. So how to improve the efficiency of embryo transfer is also an important factor to affect the increasing of pure breed and good breed of sheep. The efficiency of embryo transfer is that make the largest number of receptors being pregnant in the limited time of oestrus season. On the premise of good success rate, making good use of receptors reasonably is a valid means to improve the efficiency of embryo transfer, so to attain goal of making good use of the manpower resources and material resources, and create the biggest benefit. This experiment was carried on at Long Da Stock Corporation of Breeder of Sheep in Mudanjiang city of Heilongjiang province between August to November in 2003 and between August to October in 2004, the goal is to solve some technical problems which are met in the process of transition from small scale experiments into large scale practical use in ET of sheep. In oestrus season we treated the receptors of sheep with self-made releasing intravaginal sponge suppository with progestogen and the hormone of PG-CL for estrus synchronization, and then the receptors were transplanted with frozen embryos. We did some researches about the influencing factors to efficiency of ET and success rate of ET, among them included: The effect of estrus synchronization and influence of receptors'oestrus on ET. The next three periods order of oestrus of receptors after once treatment of synchronously. Influence of different oestrus duration on ET. Influence of different operators on ET. Influence of treated by PG-CL on oestrus of receptors. Judge the pregnancy of receptors after ET. Influence of different years on ET. Influence of different batches of receptors on ET. Influence of different growth phases of receptors' ovary on ET. This experiment optimized the program of ET in oestrus season, and laid a foundation to the large scale commercial production. The conclusions of the experiment including:1. In oestrus the effect of estrus synchronization is stable by using progestogen sponge suppository of self-made, and the cost is lower. The progestogen sponge suppository is a good kind of product for ewe estrus synchronization and it is fit for locale production.2. Before ET, If can not make use of ram to test oestrus of receptors in locale situation, the date of ET can be calculate by the date of taking away the suppository, and the do not affect the success rate of ET.3. In oestrus once treatment of estrus synchronization to a large batch of receptors, in the second and the third estrus periods the receptors which unsuitable for ET or return estrus after embryo transferred could be transferred embryo again, the estrus order of the receptors is...