摘要
犏牛是牦牛与奶(肉)牛杂交的后代,具有明显的杂种优势,是牦牛育种改良的重要方向之一。由于雄性犏牛不育,杂种优势无法稳定遗传。因此,利用现代繁殖育种技术是解决此问题的关键。本研究利用牦牛屠宰场的卵巢收集卵母细胞,与奶(肉)牛的冻精进行体外受精,将获得的胚胎移植到同期发情的犏牛体内,建立生产犏牛新模式。结果表明,用荷斯坦牛、西门塔尔牛和娟姗牛的冻精与牦牛卵母细胞体外受精,受精率无显著差异(P>0.05),但显著高于牦牛种内体外受精(P<0.05)。胚胎发育动力学结果表明,犏牛胚胎的体外发育速率显著高于牦牛胚胎(P<0.05);雄性犏牛胚胎的发育显著快于雌性胚胎。用孕酮阴道栓、马绒毛膜促性腺激素(eCG)和氯前列腺烯醇(PG)组合的同期发情处理方案,诱导犏牛发情效果较好,发情率显著高于单独使用PG组(P<0.05)。获得了全球首批试管犏牛(7头),实现了犏牛生犏牛新模式。获得的试管犏牛体型丰满、生长迅速、1周岁的体质量达160 kg,是同龄牦牛的2倍。综上,本研究建立了一套高效的犏牛体外生产技术体系,充分利用了母犏牛的繁殖性能,为挖掘优秀母犏牛的繁殖潜能和加速扩繁犏牛奠定了基础,对实现少数民族地区牧民增收与生态保护具有重要的意义。
The cattle-yak,the hybrid offspring of female yak with male milk(meat) cattle,shows obvious heterosis,which is one of the important directions of yak breeding improvement.As a result of male cattle-yak sterile,the heterosis can not be stable genetic.Therefore,utilization of modern breeding technology is an effective way to solve this problem.In this study,yak ovaries from slaughterhouse were used to collect oocytes and in vitro fertilization with frozen semen of milk(meat) cattle.The embryos were transplanted into cattle-yak uterine horns after synchronous estrus to establish a new model for cattle-yak production.The results showed that there was no significant difference(P>0.05) in the fertilization rates among the frozen semen from Holstein cow,Simmental and Jersey cattle(P> 0.05),but significantly higher than that of yak semen group(P<0.05).The results of embryonic development kinetics showed that the in vitro developmental speed of cattle-yak embryos was significantly higher than that of yak embryos(P<0.05),the development of male cattle-yak embryos was significantly faster than that of female embryos.The estrus rate and estrus synchronization was significantly higher in CIDR combined with equine chorionic gonadotropin(eCG)and prostaglandin(PG)than that of only CIDR with PG group(P<0.05).Seven cattle-yak calves were obtained with this model for the first time in the world.The cattle-yak calfe are healthy and strong,and rapid growth.One year old calfe can weigh up to 160 kg,is twice than that of the same age yak.In summary,this study has established a set of efficient production technology system for cattle-yak,making full use of the reproductive performance of the female cattle-yak,which laid a foundation for excavating the breeding potential of excellent female cattle-yak and accelerating the spread of cattle-yak.This model has great helpful for increasing income of local herdsmen and ecological protection of Tibetan plateau.
引文
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