大额牛(Bos frontalis)与瘤牛(Bos indicus)的种间杂交研究

Study on the Interspecies Crossbreeding Between Mithun(Bos frontalis) and Zebu(Bos indicus) Cattle

【目的】探讨大额牛(Bos frontalis)与瘤牛(Bos indicus)杂交利用潜能及杂交育种前景。【方法】选用婆罗门(Brahman)母牛,以CUE-MATETM(孕酮阴道栓)+PG(氯前列烯醇)法同期发情处理后用大额牛冷冻精液对其进行人工授精(artificial insemination,AI),调查记录母牛产犊时间、妊娠期及犊牛性别等;测定大额牛与婆罗门牛杂交F1(大婆F1)、大额牛和婆罗门牛的初生体重及6、12和18月龄的体重;进行大婆F1的核型分析;对大婆F1的繁殖性能进行研究。【结果】①婆罗门母牛的同期发情率、妊娠率和产犊率分别为83.87%、60.56%和45.07%,母牛(n=24)的平均妊娠期为(290.83±5.26)d;②大婆F1中母犊占71.88%,分别显著高于大额牛和婆罗门牛(P<0.05)、极显著高于大额牛与黄牛杂交F(1大黄F1)和BMY牛(P<0.01);③大婆F(1n=29)初生体重及6、12和18月龄平均体重分别为(26.69±4.84)、(153.08±37.58)、(219.34±31.31)和(302.06±28.92)kg,分别比大额牛(n=18)高68.18%、37.12%、45.07%和40.13%(P<0.01);分别比婆罗门(n=45)低14.40%(P<0.01)、5.23%(P>0.05)、13.12%(P<0.01)和12.76%(P<0.01);0—18月龄大婆F1中公牛和母牛平均日增重分别为(503.09±44.91)g和(502.89±53.54)g,分别比大额牛高35.98%和39.85%(P<0.01),但分别比婆罗门牛低16.49%(P<0.01)和6.63%(P>0.05);④大额牛、婆罗门牛和大婆F1的染色体数目(2n)分别为58、60和59;大婆F1母牛(n=2)的初妊娠年龄、初妊娠体重和初产年龄分别为(16.00±2.83)月龄、(342.50±30.41)kg和(26.00±2.83)月龄,且年产1犊;⑤对5头、15—24月龄大婆F1公牛进行电刺激采精,均未采集到精液。【结论】大额牛和瘤牛杂交,其杂种牛生长发育快,适应性强,杂种优势明显;F1代母牛可繁育,且成熟早,繁殖力强;但F1代公牛是否可繁育有待进一步研究。

[Objective] The potential of interspecies crossbreeding utilization and its foreground between Mithun（Bosfrontalis）and Zebu （Bos indicus） cattle were studied. [ Method] Firstly, after treated by CUE-MATETM （progesterone-releasing intravaginal device） and PG for synchronization estrous, Brahman cows were inseminated artificially with Mithun＇s frozen semen. And gestation length and calving time of cows and calf sex ratio were investigated. Besides, the body weight of Mithun and Brahman crossbreed at birth, 6 months, 12 months and 18 months of age were measured and karyotype and reproductive performance of hybrids F1 （Mithun×Brahman） and so on were analyzed and investigated. [Result] The rates of synchronization estrous, pregnancy and calving of Brahman cow were 83.87%, 60.56% and 45.07%, respectively. The average gestation length was （290.83±5.26） d （n=24）. The percentage of female calf in crossbred F1 （Mithun×Brahman） was 71.88%, higher than those of Mithun and Brahman （P〈0.05）, and significantly higher than those of crossbred Fl （Mithunxyellow cattle） and BMY cattle, respectively （P〈0.01）. The average body weight at birth, 6 months, 12 months and 18 months of crossbred F1 （Mithun×Brahman）（n=29） was （26.69±4.84） kg, （153.08±37.58） kg, （219.34±31.31） kg and （302.06±28.92） kg, respectively, which were 68.18%, 37.12%, 45.07% and 40.13% higher than those of Mithun （P〈0.01）, but 14.40% （P〈0.01）, 5.23% （P〉0.05）, 13.12% （P〈0.01） and 12.76% （P〈0.01） lower than those of Brahman. The average daily gain （ADG） of crossbred F1 （MithunxBrahman） from birth to 18 months of age was （503.09±44.91） g and （502.89±53.54） g for male and female, which were 35.98% and 39.85% higher than those of male and female of Mithun （P〈0.01）, but 16.49% and 6.63% lower than those of male （P〈 0.01） and female （P〉 0.05） of Brahman. The chromosome numbers of Mithun, Brahman and their crossbred F1 （MithunxBrahman） were 2n=58, 2n=60 and 2n=59, respectively. The average age and body weight of crossbred F1 （MithunxBrahman） at first pregnancy and their primiparous age were （16.00±2.83） months, （342.50±30.41） kg and （26.00±2.83） months, respectively, which gave one calf per year. The semen collection of 5 crossbred F1 （MithunxBrahman） at 15-24 months of age was failed by electro-ejaculation treatment. [ Conclusion ] Interspecies crossbreeding of Mithun×Zebu performed better in rapid growth, wide adaptation and significant heterosis. And the crossbred female Fl was of better reproductive capacity, precocity and high reproductive efficiency. However, the fertility of male crossbred F1 will remain to be studied in future.