应用猪精液抑制素主动免疫法诱导黄牛孪生

 2 70头经产母黄牛分成 3组 ,每组 90头 ,分别在产后 13个月用 2mg(Th组 )或 1mg(Tl组 )精液抑制素和福氏完全佐剂进行主动免疫 ,34周后进行加强免疫。加强免疫所用抑制素剂量减半 ,佐剂为福氏不完全剂。另一组牛用不含抑制素生物活性的精液提取物和上述佐剂进行主动免疫和加强免疫 ,用作对照组 (C组 )。母牛发情时 ,间隔 8 12h用冷冻精液进行人工授精。在主动免疫和加强免疫后 812d采集颈静脉血 ,收集血清 ,分别用双扩散凝胶沉淀法和酶联免疫吸附测定法测定抗抑制素抗体的效价。根据记录完整的 2 4 7头牛资料 ,发现Th组 87头母牛中有 73头(83.9% )发情 ,其中 5 1头排单卵 ,19头排双卵。妊娠期末 ,15头产双胎 (孪生 2 6 .3% ,15 / 5 7)。而在T1组 (72头 )和C组 (88头 )中 ,分别只有 4 4头 (6 1.1% )和 5 5头 (6 2 .5 % )母牛发情 :其中排双卵的母牛分别为 4头和 0。妊娠期末 ,孪生率分别为 3.1% (1/ 32 )和 0 (0 / 34)。分析血清抗体水平 ,证明排双卵的母牛血清抗抑制素水平显著高于排单卵和不排卵的母牛 ,排卵数与抗抑制素抗体水平呈正相关 (r=0 .75 0 7,P <0 .0 1)。     

生殖激素诱导母牛双胎效果及机理研究

用生殖激素（PMSG和纯化的FSH）诱导母牛双胎进行了试验研究。PMSG处理组：选产后50d以上12头参试母牛，按其发情顺序随机分成3个组，每组4头牛，3组牛在发情周期的第10d分别各肌注PMSG2000IU，1650IU，1350IU，间隔48h再肌注氯前列烯醇2支（4mL），发情后按常规进行人工授精，同时再肌注与PMSG等量的抗PMSG，间隔12h再输精1次。上述3组牛每组随机选2头牛在输第一次精的同时肌注LRH－A_3200μg，以比较其对双胎率有无影响。纯化FSH处理组：选产后50d以上的6头参试母牛按发情顺序随机分成2组，一组FSH总剂量为6mg，另一组为5mg。其处理方法是在发情周期的第10，11，123d每天早、晚各1次给参试牛肌注FSH，在第一次肌注FSH48h后肌注氯前列烯醇2支（4mL），发情后正常输精，间隔12h再输精1次。上述6头参试牛中随机选3头牛于输第1次精的同时肌注LRH－A_3200μg。每头参试牛于不同生理时期，包括肌注生殖激素的当天，24h，48h；肌注氯前列烯醇后24h，48h；发情后48h，排卵时，妊娠后第5d，20d，60d。从颈静脉各采血1次，共采10次，每次10mL，离心后分离血清，用放免法测定上述各生理时期血清中P_4，LH，E_2水平，分析与单、双胎的关系。结果表明（1）适量的PMSG（1350～2000IU）和纯化FSH（5mg）均能诱导母牛     

牛羊多胎性状的分子遗传基础研究

本研究采用了RAPD、PCR RFLP、微卫星、PCR SSCP、序列分析等方法对2个牛品种(秦川牛和荷斯坦奶牛共60头)、6个中国固有绵羊品种(多胎品种小尾寒羊,双胎品种大尾寒羊,单胎品种兰州大尾羊、蒙古羊、同羊和哈萨克羊共197余只`进行了分子遗传基础研究,旨在寻找牛羊多胎性状合适的分子标记,为进一步对牛双胎基因、绵羊多胎基因的探索和高繁殖率牛羊的选育提供科学依据.     

牛双胎的研究与应用

牛双胎可显著的提高生产效率，对母牛和犊牛没有明显的不良影响，不利之处是异性双胎造成母犊不孕、。双胎是可以遗传的，双亲的影响较大；不同品种间的双胎率差异显著；另外胎次、季节、营养均影响双胎率。目前常用的提高双胎率的方法是通过遗传选择、激素诱导、激素免疫、胚胎移植等方法。但如果结合标记辅助选择法（MAS）、性别控制、及转基因与克隆技术将有助于快速提高双胎率，提高生产效益。     

新型黄牛双胎素的应用研究

我们应用改进后的双胎素新配方，在豫西地区对１５２头秦川母牛进行试验，使１５２头母牛的情期双卵发育率达到７６．５％，双卵排放率达到６９．７％，双胎妊娠率达到５７．６３％，活产双胎率达到４０．６８％，试验证明，黄牛双胎素的研究已经达到了可以进行推广应用的阶段。     

Artificial Induction of Twinning by an Active Immunization of Beef Cows Against Inhibin Partially Purified from Porcine Seminal Plasma

Two hundred and seventy multiparous Chinese Yellow cattle (beef) were selected at 1 to 3months postpartum and divided into three groups (90 cows for each). Animals were given both a primary and booster immunizations with a total dose of 3 mg (Group Th) or 1.5 mg (Group Tl) of seminal preparation containing inhibin activity, emulsified with Freund‘s complete adjuvant and incomplete adjuvant (for booster), at 3 or 4-week intervals. Other cows were treated with the same volume of seminal preparation without inhibin activity as procedures mentioned above to serve as a control (Group C). Artificial inseminations were given twice at 8 - 12 h intervals when the cow was in heat. Jugular venous blood samples were collected from each cow and used to assay the presence of antibody against seminal preparation by double-diffusion in agar precipitation test and to detect the titer of inhibin antibody by an ELISA method. Data from 247 cows showed that 83.9% (73/87) of cows were in estrus and ovulated 89 ova altogether, of which 19 cows ovulated twin ova and 15 cows produced twins in Group Th (n = 87). However, only 61.1% (44/72) of cows in Group Tl (n=72) and 62.5% (55/88) of cows in Group C were in estrus and ovulated 46 and 52 ova altogether respectively.The ovulation rate (1.27 + 0.03), calving rate ( 126.3% ) and twinning rate (26.3%) in Group Th were greater than those in Groups Tl or C (P＜0.01). Furthermore, the ovulation rate was associated with antibody titer in sera of immunized animals (r = 0.7507, P ＜0.01). These results indicate that active immunization of postpartum cows against inhibin purified from porcine seminal plasma may increase the ovulation rate and induce twinning, suggesting the potential to develop a method to improve fertility in cows.     

FSHR基因的PCR-RFLP对牛双胎性状的标记分析

FSHR基因5’端（包括侧翼序列和第一外显子）的限制性内切酶TaqⅠ的PCR-RFLP标记研究发现，在秦川牛中双胎母牛的A基因频率（0.5500）和AA基因型频率（0.5000）分别高于单胎母牛的A基因频率（0.3500）和AA基因型频率（0.3000）；在黑白花奶牛中双胎母牛的B基因频率（0.5937）和BB基因型频率（0.6875）均高于单胎母牛的B基因频率（0.5416）和BB基因型频率（0.4167），也就是FSHR基因的5’端的PCR-RFLP标记在一个品种内单胎母牛和双胎母牛之间有一定趋势，但两个品种的趋势不同。     

Birth of a Live Foal after Transabdominal Ultrasound-guided Cardiac Injection of a 200-day Equine Twin Fetus

In horses, development of twins is often problematic and may represent a potential life-threatening condition for the mare and both of the embryos/fetuses. There have been many attempts at various stages of gestation to reduce twin fetuses to a singleton with variable success. Techniques have been described to perform transabdominal ultrasound-guided cardiac injection of a toxic substance into a twin fetus. The case discussed in this report is of a mare that presented at 200 days with twin fetuses. Procaine penicillin was injected directly into the heart of one fetus, using an ultrasound-guided approach. The ultimate outcome was birth of a live healthy filly, followed by the passage of a mummified fetus. This report is the first to describe the procedure in a mare at more than 168 days of gestation, leading to birth of a live foal that lived longer than 3 days.     

Mixed-breed twin production by contralateral direct-transfer of male embryos to beef cow recipients bred to GnRH-based, fixed-time AI

Two experiments were conducted to develop protocols for the use of fixed-time artificial insemination and embryo transfer (TAI and TET, respectively) to increase beef cattle productivity. Suckled beef cows were given GnRH (100 µg im) on Day − 10, and PGF (25 mg im) on Day − 3, with TAI on Day 0 (66 h later), and assigned to either embryo recipient (ER) or no embryo (NR) treatments on Days 6 or 7. Semen from Gelbvieh (GB) beef sires was used for TAI; sexed-male in vivo developed Holstein embryos (HO) were placed nonsurgically (TET) into the uterine horn contralateral to the corpus luteum. In Experiment 1, ovarian status of cows (n = 111; 69 ± 11 d postpartum; mean ± SD on Day 0) in Groups I and II was presynchronized with a single PGF treatment on Day − 24; Groups II and III received GnRH concurrent with TAI, and ER (n = 78) were selected from all groups on Days 6 or 7. Neither presynchronization nor GnRH affected rates of recipient selection, Day 45 pregnancy (43.2, 43.2, and 54.0% for Groups I, II and III, respectively), or calving (40.5, 37.8, and 43.2%). However, treatment with GnRH increased HO-birth rate (8.0, 14.0 and 24.0%; P < 0.05). In Experiment 2, cows (n = 99, 113 ± 10 d postpartum) were assigned on Day 7 to NR and ER, with and without hCG (2500 IU im), following a TAI protocol (as per Group III in Experiment 1). Treatment with hCG increased reproductive rate (1.16 vs 1.44 calves/calving; P < 0.05), but had no significant effect on rates of Day 45 pregnancy (45.3 vs 41.3%), calving (31.2 vs 37.0%) or HO-births (20.0 vs 26.0%). In summary, GnRH-based synchronization rates were 71.2% (based on circulating progesterone concentrations that were < 1.0 ng/mL on Day 0 and ≥ 1.0 ng/mL on Day 7); TET did not affect GB-birth rate, but more calves were produced by ER than NR cows (1.43 vs 1.02 calves/calving; P < 0.01); and weaned calf production was 53% greater for twin- than singleton-suckled cows (392 ± 25 vs 256 ± 11 kg/dam; mean ± SEM, P < 0.05). Therefore, GnRH-based TAI and TET protocols for mixed-breed twin production increased beef cow productivity.     

中国卡拉库尔羊注射双胎素效果试验

对农一师十三团的750只中国卡拉库尔羊注射双胎素,以250只相同条件下饲养的羊作对照,结果注出双胎素的羊双胎率达到25.73%,而对照羊双胎率仅2.8%,净增加双羔22.93%.经核算,每只注射双胎素的母羊可以净增加收入28.54元,经济效益极显著.经试验证明,初产母羊双胎率低,仅12.30%,双羔死亡率达27.27%.6岁以上老母羊双胎率虽达到22.40%,但双羔死亡率高达23.14%.3、4、5岁母羊的双胎率均接近30%,双羔死亡率均在10%上下,试验效果最好.