共查询到19条相似文献，搜索用时 274 毫秒
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1意义1．1充分发挥优秀种公牛的改良作用。一头优秀公牛一生中可生产20万头份0．25mL的细管冻精并承担10万头适龄母牛的配种,其改良率提高了10倍以上。1．2显著提高母牛受胎率肉牛细管冻精是符合国家标准的优质冷冻精液,采用人工授精技术,母牛的受胎率可提高8％以上． 相似文献
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对新疆呼图壁种牛场１９９４年出生的６５头母牛生长期内７个月龄阶段的相对增重率与初始产奶量的相关关系进行了研究。结果表明，初始母牛的产奶量与生长期体重的增重率有一定的相关关系。其中６月龄体重相对３月龄时的增重率每上升１％，头胎产奶量将增加１５．５６千克；１５月龄相对１２月龄时的增重率每下降１％，头胎产奶量将增加２５．８２千克。 相似文献
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为了加快优质奶牛遗传资源的推广，上海光明乳业奶牛育种中心从加拿大进口一批冷冻胚胎。我们于２００１年３月１３日至４月２５日在上海第七牧场给８０头后备母牛采用非手术子宫移卵方法，移植冻胚８６枚，使３６头受体牛受孕，移植成功率为４２％。１试验材料与方法１．１ 胚胎８６枚加拿大冷冻胚胎。１．２ 受体牛的选择选择１５月龄以上体重达３７５千克以上健康的后备母牛８０头。１．３ 牛的准备为使受体牛群能集中移植，在性周期８－１７天采用氯前列烯醇肌肉注射０．４ｍｇ，实施同步发情，对观察到发情牛只及时做好记录。受体牛发… 相似文献
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转基因奶牛胚胎移植技术的试验研究 总被引：2，自引：1，他引：1
2006年6月至2010年3月以来,北京奶牛中心与中国农业大学合作,在北京奶牛中心良种场开展了转基因牛胚胎移植试验研究。本试验利用中国农业大学培育的转基因母牛作为供体,进行超数排卵生产体内胚胎,将获得的胚胎移植给15～15.5月龄荷斯坦母牛受体。截止2010年3月21日,累计移植转基因奶牛胚胎87枚,移植受体牛87头,妊娠48头,移植妊娠率为55.17%;产犊43头,成活34头,犊牛成活率为79%;经中国农业大学研究人员检测,有14头公牛携带转入目的基因,这14头公牛已全部进入北京市种公牛站饲养。目前,有10头公牛到了试采精月龄,精液经农业部牛冷冻精液质量监督检验测试中心(北京)检测,质量符合国家标准。 相似文献
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《当代畜牧》2015,(5)
分析不同剂型的种公牛冷冻精液质量检测结果。选择20头公牛作为研究对象,根据冷冻精液方式的不同把20头公牛精液随机均分为两组,一组为对照组选择10头公牛精液进行颗粒冷冻,另一组为观察组选择10头公牛精液进行细管冷冻。根据公牛冷冻精液的质量标准,对两组公牛精液质量指标进行对比分析,分析两组公牛精液冷冻后的活力和精子有效数、精子畸形率及精子存活时间等。观察组与对照组公牛精液按照不同剂型冷冻后,精液质量存在很大差异,观察组精液冷冻的方式明显优于对照组,两组对比差异明显,具有统计学意义(P0.05)。观察组选择细管冷冻的方式更适用于实际工作中,为细管冷冻精液实践工作中提供重要的参考依据。 相似文献
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含野血牦犊牛,家牦犊牛增重效果观察 总被引：1，自引：0，他引：1
１９９４－１９９６年在海南州赛什牧场对采用野牦牛冻精人工授精和１／２野血公牛本交两种方法配家牦母牛产生的１／２野血牦犊牛３５头和１／４野血牦犊牛４８头，跟踪定量观测。结果：１／２野血牦犊牛和１／４野血牦犊牛的平均初生重分别比家牦犊提高了７．６５％，８．８６％，平均１８月龄重分别比家牦犊牛提高４７．１６％，１７．２２％。 相似文献
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人工授精是采用假阴道人工采集种公牛的精液,通过质量检查和稀释后,再把精液通过器械注入母牛生殖道内,以代替公牛、母牛自然交配的配种方法.
采用人工授精技术,可提高优良公牛的配种效率,特别是在使用冷冻精液技术的情况下,1头种公牛1年可配母牛达万头以上,并实现远距离异地配种,减少生殖道疾病的传播.对推动牛的杂交、改良和提高繁殖力,具有重要意义. 相似文献
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几年来，我们应用三合激素、氯前列烯醇及氯前列稀醇配合孕马血清处理１５６头乏情母牛，结果３组的催经分别为８４．８％、７９．５％、８６．９％，同时配种后第一期受胎率分别为４．４％、３２．２％和４８．４％。试验表明第三组的催情率和受胎率都比较好，是提高母牛受配率的有效方法之一。 相似文献
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The objective of this study was to evaluate the fertility of sexed semen compared with conventional semen with regard to the puberty and breeding ages of Holstein dairy heifers subjected to double Ovsynch protocol with fixed time of artificial insemination. A total of 468 Holstein heifers were divided into two groups. The first group was 122 dairy heifers inseminated via conventional semen, while the second group was 346 heifers inseminated with sexed semen. The puberty and breeding ages of heifers were determined from the farm records. Estrus was synchronized using the double Ovsynch protocol. Numbers were estimated for pregnancy at 40 and 60 days post insemination, embryonic loss, and abortion. The results revealed that the heifers inseminated with sexed semen had a significantly lower first-service pregnancy rate (51.45%) than those inseminated with conventional semen (61.47%). Heifers achieving puberty before 350 days old had a higher pregnancy rate. Embryonic losses and abortion rates did not differ between the two types of semen. Holstein heifers subjected to Ovsynch protocol with sexed semen had an acceptable first-insemination pregnancy rate. Even the applications of sexed semen reduce the reproductive fertility and pregnancy rate in Holstein heifers.
相似文献12.
Effects of oestrus synchronisation and fixed-time artificial insemination on the reproductive performance of dairy heifers 总被引：1，自引：0，他引：1
AIM: To compare the reproductive performance of heifers after oestrus synchronisation and fixed-time artificial insemination with non-synchronised heifers bred by herd sires. METHODS: Heifers from 10 spring-calving herds were randomly divided into two groups by herd, breed and age. Heifers in one group (the synchronised group, n = 478) were synchronised with a combination of progesterone, oestradiol benzoate and PGF2alpha, and inseminated 50-54 hours after progesterone treatment. Returns to first service were resynchronised with progesterone treatment 16-21 days after the fixed-time artificial insemination. Heifers in the other group (the control group, n = 470) did not receive any treatment and were bred by herd sires. RESULTS: The conception rate of synchronised heifers to the fixed-time artificial insemination was 51.2% and to the artificial insemination after resynchronisation 40.4%. The pregnancy rate at the end of the breeding season was lower (p<0.001) for the synchronised (92.9%) than for the control (97.2%) group. The interval from start of breeding to calving was earlier for synchronised (295.9 +/- 22.5 days, mean +/- s.d.) than for control (298.5 +/- 17.3 days) heifers. CONCLUSION: Results from this study indicate that the oestrus synchronisation programme used in the present study can reduce reproductive performance by increasing the empty rate compared with natural mating. 相似文献
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不同月龄巴杜公猪精液品质分析 总被引：1，自引：0，他引：1
《中国畜牧杂志》2019,(11)
为研究不同月龄巴杜种公猪的精液品质差异,本实验选择8～12、13～18、19～24、25～30、31～36月龄各6头巴杜种公猪,进行精液品质检查。结果表明:随着月龄增加,巴杜种公猪精液的各项指标呈现规律性变化,19～24月龄的采精量、精子密度和精子活率显著高于其他月龄段,且精子畸形率显著低于其他月龄段;24月龄之后采精量、精子密度和精子活率缓慢下降,而畸形率则逐渐上升。本研究结果可为合理选择配种日龄、人工授精公猪的使用年限及人工授精的输精量提供数据支撑,为巴杜种公猪精液的合理应用及提高猪场经济效益提供参考依据。 相似文献
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Transmission of bovine virus diarrhoea virus (BVDV) by artificial insemination (AI) with semen from a persistently-infected bull 总被引：2，自引：0，他引：2
Twelve heifers that did not have antibodies to bovine virus diarrhoea virus (BVDV) were inseminated with semen from a bull that was persistently infected with the virus and contained 10(4.0)-10(6.5) TCID50 0.1 ml-1. All 12 became infected, as indicated by seroconversion within 2 weeks of insemination. Four control heifers were inseminated with virus-free semen. The virus was not transmitted to these animals in spite of close contact with the heifers inseminated with the infected semen. All the heifers became pregnant and gave birth to clinically normal calves at term. However, one calf was born persistently infected with BVDV. After the birth of this persistently-infected calf the control heifers and their calves seroconverted. The study demonstrates that BVDV may be transmitted in cattle by artificial insemination (AI). Therefore entry of persistently-infected animals into AI centres should be prevented. 相似文献
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JL Yániz F López‐Gatius I García‐Ispierto G Bech‐Sàbat B Serrano C Nogareda JA Sanchez‐Nadal S Almeria P Santolaria 《Reproduction in domestic animals》2010,45(4):699-705
The aim of this study was to determine if the factors affecting the abortion rate in dairy herds with high incidence of Neospora‐associated abortions are different in pregnancies of cows and heifers chronically infected with Neospora caninum. In heifers (n = 229), an increase in the cumulative number of days with a mean relative humidity (RH) lower than 60% during the second trimester of gestation increases the risk of abortion. Yet, the likelihood of abortion was 7.6 times lower for pregnant heifers inseminated with Limousin bull semen, compared with those inseminated with Holstein‐Friesian bull semen. In pregnancies of parous cows (n = 521), an increase in rainfall and in the cumulative number of days with a mean RH lower than 60% during the second trimester of gestation increased the abortion rate. However, in contrast, an increase in the lactation number produced a decrease in the abortion rate, with a likelihood of abortion 4.8 times lower for pregnant cows inseminated with Limousin bull semen, and three times lower for those inseminated with Belgian Blue bull semen, compared with dairy cows inseminated with Holstein‐Friesian bull semen. Finally, the likelihood of abortion was 3.2 times lower for pregnancies of parous cows with low antibody titres against N. caninum (6–30 units) as compared to those with high antibody titres (≥30 units), whereas in heifers this variable had no effect. The practical recommendations of the present study include the control of the cow environment during the second trimester of gestation, the priority of culling for parous cows with higher antibody titres against N. caninum and the insemination of Neospora‐seropositive cows with semen from the Limousin breed. 相似文献
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Two hundred and ninety two dairy cows received a subcutaneous injection of a 2.5 ml solution containing 10 microg GnRH-analogue (Receptal, Hoechst A.G.) 0-6 hours before insemination, while 284 cows acting as controls were injected with 2.5 ml of sterile pyrogen-free water at the same time. The two groups, the treated and the control, were formed by matching (pairing) each oestrous cow with another on the basis of interval from calving to first mating, condition score, and age on the day of first mating after calving. The cows were in 3 factory supply dairy herds, which were visited daily during the first 3 weeks of the mating season. All the cows presented for mating each day were inseminated by the same technician using 0.5 ml of ambient-temperature semen containing 2 million spermatozoa per insemination. The semen used on any particular day originated from one ejaculate of one bull (same batch number). The cows were manually examined for pregnancy 2 to 3 months after their first insemination. A similar response was seen in all three herds irrespective of the interval from calving to mating. First mating pregnancy rates were 9.3% higher in the Receptal-treated cows than in the control group (P = 0.025). It is suggested that Receptal may have a beneficial effect on the pregnancy rate of cows that have recently ovulated as well as on those having delayed ovulation. 相似文献
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During three consecutive years, 67 Belgian white and red dual purpose heifer calves were used to investigate beef production with once-calved heifers. They were divided into three groups, a control group without mating and two experimental groups to be inseminated by Charolais. The first two groups were turned out on pasture during summer, while the third group stayed indoors.The control group was fed extensively, while the other two groups received a high energy ration in order to obtain sexual maturity at about 12 months of age. Calving occurred after 742.3 and 710.6 days, respectively. The number of caesareans amounted to 30 and while the number of stillbirths or calves which died within 24 h after parturition was 15 and 25%.During suckling and fattening and also for the whole lifetime the feed efficiency of the once-calved heifer systems was lower. The daily gain in the complete trial amounted to 609, 558 and 625 g for the intact groups, while dressing percentage was 59.3, 58.7 and 59.4% respectively, for group I and the calved heifers of groups II and III. The difference between the groups was significant for daily gain, but there was no significant difference between maiden and calved heifers for killing-out percentage.The financial returns were low for the maiden as well as for the once-calved heifers. The once-calved heifer system is not fitted for all surplus heifers, due to infertile animals. 相似文献
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性控精液对奶牛体内胚胎质量发育和移植妊娠率的影响 《畜牧与饲料科学》2023,44(1):71-75
[目的] 研究性控精液对奶牛体内胚胎质量、胚胎发育和胚胎移植妊娠率的影响。[方法] 将144头青年奶牛随机分为对照组（63头）和试验组（81头）,使用促卵泡激素（FSH,260 mg/头）进行超排处理。对照组和试验组分别使用常规精液和性控精液输精,并对获得的体内性控胚胎进行移植,对胚胎生产、胚胎质量、胚胎发育和胚胎移植妊娠情况进行统计。[结果] 试验组供体获得的平均可用胚胎数（5.67枚）显著（P<0.05）低于对照组（6.92枚）;试验组供体获得的可用胚胎中A级胚胎比例（62.53%）、B级胚胎比例（35.29%）与对照组（A级胚胎比例66.51%、B级胚胎比例30.97%）相比差异均不显著（P>0.05）;试验组供体获得的可用胚胎中桑葚胚比例（84.10%）显著（P<0.05）高于对照组（61.24%）,囊胚比例（15.90%）显著（P<0.05）低于对照组（38.76%）;试验组的鲜胚移植妊娠率（52.41%）显著（P<0.05）低于对照组（66.13%）。[结论] 与常规精液相比,使用性控精液生产奶牛体内性控胚胎并移植后,平均可用胚胎数、可用胚胎中囊胚比例和胚胎移植妊娠率降低,可用胚胎质量未明显降低;优化性控精液使用方案和胚胎移植技术能够提高体内性控胚胎生产和胚胎移植效率。 相似文献
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Baris Guner Gulsum Selcuk Sevket Guclu Sultan Sengul Ismail Altun Serdal Dikmen Ahmet Gumen 《Reproduction in domestic animals》2021,56(9):1254-1260
The objective of the study was to compare the fertility after using sex-sorted or conventional semen either with oestrus detection (EST) or timed artificial insemination (TAI) in Holstein heifers. Holstein heifers were randomly assigned to one of the following treatments in a 2 × 2 factorial design. Heifers in the EST group were inseminated with sex-sorted (n = 114) or conventional semen (n = 100) after spontaneous or induced oestrus. Heifers in the TAI, subjected to the 5-day Cosynch+Progesterone protocol (GnRH+P4 insertion-5d-PGF2α+P4 removal-1d-PGF2α-2d-GnRH+TAI), were inseminated with sex-sorted (n = 113) or conventional semen (n = 88). Statistical analyses were performed using PROC GLIMMIX procedure of SAS 9.4 (SAS Institute Inc., Cary, NC). Overall P/AI was 60.7% for EST and 54.2% for TAI regardless of types of semen and 68.1% for conventional and 48.9% for sex-sorted semen regardless of insemination strategies. Fertility of heifers inseminated with either sex-sorted (53.5%; 44.2%) or conventional (69.0%; 67.0%) semen did not differ between EST and TAI respectively. Besides, the interaction between the semen type and the insemination strategy was not significant for P/AI. The embryonic loss was significantly greater with sex-sorted semen (17.1%) compared to conventional semen (1.6%). There was no sire effect with sex-sorted semen on P/AI (52.6% vs. 46.2%) and embryonic loss (16.4% vs. 18.0%). As expected, sex-sorted semen resulted in more female calves (89.8% vs. 51.6%) than conventional semen. Thus, sex-sorted semen can be used with 5-day Cosynch+Progesterone protocol to eliminate the inadequate oestrus detection and to increase female calves born in dairy heifers. 相似文献