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1.
Cloprostenol, a prostaglandin analogue, was administered intramuscularly to a total of 35 cycling buffalo cows and heifers in two doses, each of 0.5 mg, given 11 days apart. Out of five cows and 12 heifers subjected to observations after the second injection of cloprostenol (day 0), all except one heifer responded. Signs of oestrus were most marked on days 3 or 4. Eighteen treated heifers were kept with buffalo bulls for four days after the second injection while a control group of nine heifers was kept with bulls for 21 days. The first-service conception rate, diagnosed by rectal palpation at 60 days, was 33 1/3 per cent in both groups. Twelve treated heifers were artificially inseminated at 72 and 96 hours after the second injection of cloprostenol, using fresh semen diluted in egg yolk--citrate extender. The first service conception rate at 60 days was 30 per cent.  相似文献   

2.
Twenty four maiden heifers were bred by natural route by a specific immunotolerant bull, that was persistently infected with Bovine Viral Diarrhoea virus (BVD virus). The quality of the bull's semen was normal. Twelve heifers became pregnant in the first oestrus cycle and the remaining twelve in the second oestrus cycle. This leads to the conclusion that such persistently infected bulls may have good fertilisation results. Nevertheless, it is felt that bulls persistently infected with the BVD virus must be excluded from artificial insemination centres because of the risk of introducing BVD virus in a herd by the semen.  相似文献   

3.
Natural venereal infection of heifers with IBR virus resulted in vulvovaginal lesions in 9 of 12 heifers at 3 weeks after introducttion to bulls, and virus was isolated from 5 of the 9 affected animals. The infection was not associated with any effect on conception. Experimental nasal and conjunctival infection of 18 heifers pregnant for 3, 5 or 7 months with a genital strain of IBR virus caused mild rhinitis or conjunctivitis in all inoculated animals and virus was recovered from 14 animals at 8 days after inoculation. No effects on pregnancy were recorded.  相似文献   

4.
A study was undertaken to determine the effectiveness of a progesterone-releasing intravaginal device (PRID) and prostaglandin F2 alpha (PGF2alpha) in synchronizing oestrus in N'dama and Bunaji cows and heifers and the fertility following artificial insemination at the synchronized oestrus. A total of 116 cows and heifers (58 N'dama and 58 Bunaji) were used in two separate trials. In the first trial, oestrus was synchronized using a PRID, which was inserted for 12 days; in the second trial, oestrus was synchronized by giving two injections of PGF2alpha 13 days apart. Only animals that did not respond to the first injection were given the second injection. At the end of each treatment period, the animals were observed for oestrus for 7 days and inseminated approximately 12 h following detection of oestrus. Standing to be mounted was the single criterion used to judge an animal to have been in oestrus. PGF2alpha and PRID were both effective in synchronizing oestrus in N'dama and Bunaji cows and heifers. The respective oestrus response rates, pregnancy rate and conception rates for PRID and PGF2alpha were 85.7%, 53.6% and 62.5% for PRID, and 91.7%, 68.3% and 74.6% for PGF2alpha. N'dama cattle showed significantly (p<0.05) better oestrus response rate, pregnancy rate and conception rate than Bunaji cattle following both PRID and PGF2alpha treatments. The pregnancy rate and conception rate following PGF2alpha treatment were better (p < 0.05) than for PRID, although the oestrus response rate did not differ. It is concluded that both PRID and PGF2alpha are effective in synchronizing oestrus in N'dama and Bunaji cattle in the hot humid zone of Nigeria and the fertility to artificial insemination at the synchronized oestrus was normal and acceptable. Thus, PRID and PGF2alpha can effectively be used in intensive breeding programmes for the rapid multiplication and distribution of both cattle breeds, especially the N'dama, which is a unique and beneficial animal genetic resource for the tsetse infested hot humid zone of Nigeria.  相似文献   

5.
Summary

Twenty four maiden heifers were bred by natural route by a specific immunotolerant bull, that was persistently infected with Bovine Viral Diarrhoea virus (BVD virus). The quality of the bull's semen was normal. Twelve heifers became pregnant in the first oestrus cycle and the remaining twelve in the second oestrus cycle. This leads to the conclusion that such persistently infected bulls may have good fertilisation results. Nevertheless, it is felt that bulls persistently infected with the BVD virus must be excluded from artificial insemination centres because of the risk of introducing BVD virus in a herd by the semen.  相似文献   

6.
【目的】试验旨在研究以褪黑素和地诺前列腺素组成的复合添加剂对奶牛性控冻精解冻后精子质量及奶牛人工授精后受胎率的影响。【方法】30份奶牛性控冻精样均分为2组:试验组和对照组,试验组添加由24 ng/mL褪黑素、1.5 mg/mL地诺前列腺素及精液稀释液组成的250 μL复合添加剂,对照组添加250 μL精液稀释液,试验组和对照组均与解冻后的奶牛性控冻精按照1∶1(V/V)进行混合,室温孵育0、2及4 h,通过免疫荧光染色分析精子活率、顶体完整率、高能线粒体活性精子比率;对216头青年奶牛和82头头胎奶牛输精后通过28 d早孕检测来确定受胎率情况。【结果】与对照组相比,经复合添加剂处理0 h的性控冻精活率、顶体完整率及高能线粒体活性精子比率均无显著变化(P>0.05);经复合添加剂处理2 h的性控冻精活率、顶体完整率、高能线粒体活性精子比率均显著升高(P<0.05);经复合添加剂处理4 h的性控冻精活率和顶体完整率均无显著变化(P>0.05),高能线粒体活性精子比率显著升高(P<0.05)。在输精试验中,试验组青年奶牛和头胎奶牛中的受胎率分别为65.22%和48.21%,均显著高于对照组(P<0.05)。【结论】以褪黑素和地诺前列腺素组成的复合添加剂可以促进解冻后奶牛性控冻精精液品质以及青年奶牛和头胎奶牛输精后的受胎率。  相似文献   

7.
One hundred and nine pure bred Holstein Friesians were injected intramuscularly with 0.125 mg of a synthetic Gn-RH analogue at the time of the first service to study the effect of Gn-RH on the fertility of inseminated cows. Sixty-four cows or 58.7 per cent were diagnosed as pregnant after one insemination compared to 54 animals or 49.5 per cent in the untreated control group. Total pregnancy rate of 81.65 per cent was 8.3 per cent higher than in the controls, while the services per conception rate improved from 1.49 to 1.39. Gn-RH administration at the time of oestrus could improve herd fertility through its including effect on follicular rupture and regulatory influence on ovarian function.  相似文献   

8.
SUMMARY Effects of body weight, condition score, ovarian cyclic status and insemination regimen on pregnancy rates were investigated in 164 Bos indicus heifers synchronised with norgestomet-oestradiol and pregnant mare serum gonadotrophin (PMSG). Oestrus detection techniques were also compared. Heifers were inseminated at either a fixed time (group 1, n = 83) of 48.0 ± 0.2 h (mean ± SEM) after implant removal or at 8.9 ± 0.5 h after oestrus was detected (group 2, n = 81). Group 2 heifers that were not detected in oestrus by 72 h after implant removal were inseminated at that time. Oestrus was detected for the purpose of insemination using heatmount detectors. Tail-paint and oestrogen treated, chin-ball harnessed steers were used to compare the efficiency of oestrus detection. The probability of ovarian cyclicity increased with increasing body weight and condition score (P < 0.001). A higher proportion of heifers that were acyclic at the commencement of treatment, compared with cyclic heifers, were detected in oestrus at the time of insemination in the fixed-time inseminated group (P <0.01). Analysis of covariance revealed that intervals from implant removal to oestrus were influenced by ovarian cyclic status (P < 0.01) and insemination group (P < 0.05). A higher pregnancy rate (%± SEM) was obtained in acyclic compared with cyclic heifers in the group 1 heifers (50.0 ± 10 vs 28.1 ± 6; P = 0.055) but not among the group 2 heifers (45.8 ± 10 vs 49.1 ± 7; P = 0.787). The probability of pregnancy was found to be associated negatively with body weight (P = 0.01) while a higher pregnancy rate was obtained in the group 2 compared with group 1 heifers (48.2%vs 34.9%; P = 0.093). The efficiency of oestrus detection was highest using heatmount detectors compared with tail-paint and chin-ball harnessed steers (90.7%vs 37.0% and 23.5%, respectively; P < 0.0001). We conclude that pregnancy rates can be increased in extensive environments when insemination follows oestrus detection using heatmount detectors compared with a fixed-time insemination. The fertility of heifers inseminated at a fixed time is influenced by ovarian cyclic status due to its influence on oestrus-to-insemination intervals.  相似文献   

9.
Genital samples collected at autopsy from 193 beef cows representing 22 different herds in Northern Australia yielded only one isolate of infectious bovine rhinotracheitis (IBR) virus. Serological evidence showed 59 per cent of similar cows had prior infection with this virus and of 19 sero-positive cows tested, 11 (58-2 per cent) shed detectable IBR virus from the vagina after treatment with corticosteroids. Transitory lesions of the vagina and vulva developed in five of the treated cows. Twenty-six (65 per cent) of 40 sero-positive bulls shed detectable IBR virus into the prepuce after corticosteroid treatment. Except for one bull, virus was not isolated after corticosteroid treatment of sero-negative animals. IBR virus and mucosal disease (MD) virus were not isolated from nasal swabs before or after corticosteroid administration. No correlation was observed between initial circulating antiboyd titre and virus excretion after treatment. There were no significant changes in levels of serum antibody during the virus excretion period.  相似文献   

10.
The present study was performed to test fertility in single‐ovulating and superovulated dairy heifers after insemination with low dose sex‐sorted sperm under field conditions. Some parameters, including the dosage, deposition site and timing, were assessed with the pregnancy rates after artificial insemination (AI). Moreover, the use of oestrus synchronization in combination with sorted sperm was evaluated. Besides that, we also improved the embryo production efficiency in superovulated dairy heifers by optimizing the timing of inseminations and repartitioning the sexed sperm dosage among multiple inseminations. The conception rate (52.8%) in heifers after low dose (2 × 106) insemination with sorted sperm deep into the uterine horn did not differ (p > 0.05) from that (59.6%) of conventional AI (1 × 107 non‐sorted sperm) and that of deep insemination with low dose non‐sorted sperm (57.7%). There was also no difference (p > 0.05) between conception rates after single (51.7%) and double (53.8%) deep insemination with sorted semen. Heifers inseminated with sorted sperm at synchronous oestrus had a lower pregnancy rate (48.1%) than heifers at spontaneous oestrus (53.6%), but this did not reach statistical difference (p > 0.05). The average number of transferable embryos collected in vivo from heifers inseminated with sorted sperm (4.81 ± 2.04) did not differ (p > 0.05) from that obtained from heifers after insemination with non‐sorted sperm (5.36 ± 2.74). Thus, we concluded that the pregnancy rate after deep intra‐uterine insemination with low dose sorted sperm was similar to that of non‐sorted sperm, which was either also deposited at a low dose deep intra‐uterine or into the uterine body. Sychronization of oestrus can be beneficial in combination with sorted sperm to optimize the organization and management of dairy herds. The results from superovulated heifers demonstrated that our insemination regime can be used to obtain a comparable embryo production efficiency with sorted sperm than with non‐sorted sperm.  相似文献   

11.
Bulls shedding bovine viral diarrhoea virus (BVDV) in semen and simultaneously having a high concentration of circulating antibodies may cause reproductive problems and spread the viral infection within cattle populations. To investigate this in detail, three heifers were inseminated with BVDV‐infected semen from a non‐viraemic, seropositive Holstein–Friesian bull, named `Cumulus'. One control heifer was inseminated with semen from a healthy bull that was free of BVDV. All four heifers remained clinically healthy throughout the experiment. The conception succeeded in the control animal and in two of the three heifers inseminated with semen containing BVDV. The heifer with the failed conception was the only one that became systemically infected with BVDV. This animal was deemed non‐pregnant by ultrasonic examination on day 34 after insemination and showed no signs of subsequent oestrus during the entire experimental period. At slaughter, 42 days after insemination, there were no histopathological changes in the ovaries and virus was not detected in ovarian tissue. The fact that seronegative dams served with semen from persistently infected bulls have occasionally produced persistently infected calves together with the present findings and the fact that non‐viraemic, seropositive bulls can constantly shed BVDV, suggest that the use of semen from such bulls in BVDV‐free herds could have far‐reaching consequences, especially if it led to the birth of persistently infected (P1) calves.  相似文献   

12.
本试验旨在探讨应用智能监控系统对荷斯坦泌乳牛发情揭发率和受胎率的改善情况.试验选用澳亚集团东营神州澳亚四场的2 237头泌乳天数为40~200d的各胎次荷斯坦泌乳牛,随机分为2组,未佩带项圈的806头为对照组,另一组佩带有项圈的1 431头为试验组.对照组依靠尾根涂蜡笔进行发情揭发,试验组依靠智能监控系统进行发情揭发,...  相似文献   

13.
Maiden heifers and lactating cows of known ovarian status and of several breeds were treated with a synthetic prostaglandin, cloprostenol, or a synthetic progestagen, norgestomet, at the start of an artificial insemination (AI) program. Animals in the cloprostenol treatment received 2 injections 10 days apart. Over the next 26 days those animals that showed oestrous behaviour were inseminated. Synchronisation rates and calving rates to insemination over the first 7 days were calculated. Those in the norgestomet treatment received an implant of norgestomet plus an injection of norgestomet and oestradiol valerate. The implant was removed 10 days later and the animals were given an injection of pregnant mare serum gonadotrophin (PMSG). They were inseminated at 48 h (maiden heifers) or 56 h (lactating cows) after implant removal. Calving rates to fixed-time insemination were recorded. After completion of the AI program the animals in both treatments were joined with bulls. Overall calving rates (AI plus bulls) were calculated. By day 7 of the program, 82% of the maiden heifers and 76% of the lactating cows in the cloprostenol treatment had been detected in oestrus. By day 21 the respective figures were 99% and 81% Norgestomet treatment had an immediate and a prolonged effect on ovarian activity in those females classified as having inactive ovaries at the start of the AI program. Calving rates of those females to fixed-time AI and overall were similar to those of the females with active ovaries in both treatments. Their calving rates to fixed-time insemination, and overall calving rates for the lactating females, were significantly higher than the corresponding values of their contemporaries treated with cloprostenol and inseminated on observed oestrus over 7 days. For those females classified as having active ovaries at the start of the AI program, calving rates to first insemination and overall were similar for both treatments. Overall calving rates of lactating cows of each breed were, with one exception, higher in the norgestomet treatment than in the cloprostenol treatment. Although norgestomet treatment was more expensive than cloprostenol treatment, the advantage in calf crop resulted in an overall monetary advantage to the norgestomet treatment.  相似文献   

14.
Three experimental approaches were used to study transmission of blue tongue (BT), infectious bovine rhinotracheitis (IBR) and bovine virus diarrhoea (BVD) viruses. These were insemination with contaminated semen, experimental infection of embryo donor cows, or transfer of embryos experimentally exposed to virus in vitro to normal recipients. Parameters assessed included number and quality of embryos produced, virus detection (isolation and electron microscopy), serology and histopathology. All superovulated sesceptible cows inseminated with semen containing blue tongue virus (BTV) (n = 2) or infectious bovine rhinotracheitis virus (IBRV) (n = 2) became infected. One cow inseminated with semen containing BTV produced seven virus-free seven-day-old embryos; the second cow failed to produce any embryos. One of two cows inseminated with semen containing IBRV produced two underdeveloped, virus-free embryos while no embryos were produced by the second cow. One of two cows inseminated with semen containing bovine viral diarrhoea virus (BVDV) became infected. Two poorly developed, virus-free seven-day-old embryos were recovered from one of these cows. Superovulated susceptible cows inoculated either intramuscularly with BTV (n = 3) or intranasally with IBR virus (n = 2) became infected. Virus was isolated from some tissues of two BTV-infected cows, neither of which produced embryos. A third BTV-infected cow produced two virus-free embryos collected at necropsy five days after inoculation. One of two cows experimentally infected with IBR virus, produced three embryos but virus was not detected either by electron microscopy (1 embryo) or in cell culture by cytopathic alterations (1 embryo).(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

15.
奶牛人工授精是以人工方法,采用机械手段采集优质种公牛的精液,再经过机械手段将特定处理后的精液输入母牛生殖道的一种生产技术方式。人工授精操作能极大减少种公牛的养殖数量,节约养殖成本,提高优质种公牛的利用效率,加快品种改良进程,促进育种工作的开展。但由于奶牛人工受精是一个侵入性的操作,一旦操作不合理或者各个细节把握不完善,会造成繁殖母牛出现严重的繁殖障碍,降低母牛的受胎率,不利于提高品种改良和扩大养殖效益。该文主要论述奶牛人工受精受胎率的影响因素,提出相应的改进措施。  相似文献   

16.
The ability to synchronise onset of oestrus, and hence the time of breeding and calving, offers potential economic and management benefits to dairy farmers, especially in herds with seasonally concentrated calving patterns. A trial involving 2681 cows in 11 seasonal herds was conducted to evaluate the reproductive performance of lactating dairy cows following oestrus synchronisation with a combination of progesterone, oestradiol and prostaglandin. Cows were randomly assigned within herds to synchronised and control groups, balanced for age, date of calving, body condition and breed. Cows in the synchronised group were treated with an intravaginal progesterone-releasing device containing 1.9 g of progesterone and a gelatin capsule containing 10 mg of oestradiol benzoate 10 days prior to the planned start of the breeding season (Day 0). The device was removed 8 days later on Day -2 and a luteolytic dose of prostaglandin F2alpha was administered 2 days prior to removal of the progesterone-releasing device. Returns to service for cows in the synchronised group were synchronised by inserting a previously used intravaginal device during Days 16-21 after the start of the breeding season. Cows in the control group were left untreated. The percentage of cows being inseminated during the first 5 days was 89.0% for the synchronised group compared to 29.7% for the control group. Compared to cows in the control group, those in the synchronised group had a lower conception rate to the first insemination (52.9% v. 64.3%, p<0.001), a lower conception rate to the second insemination (51.8% v. 62.5%, p<0.001), a higher percentage of empty cows at the end of the breeding season (7.3% v. 5.1%, p<0.05), and more insemination services per pregnancy to artificial insemination (2.0 v. 1.6, p<0.001). There was no difference between the synchronised and control groups in the percentage of cows pregnant to artificial insemination (81.8% v. 85.5%, p>0.10). The mean day of conception from the start of the breeding season was advanced (p>0.0 1) by 1.3 days in synchronised cows (19.9 +/- 0.7 days; mean +/- SEM) compared to control cows (21.2 +/- 0.5 days). It is concluded that the oestrus synchronisation regime used in the present study caused a reduction in fertility, which reduced the potential gains from using such a programme to increase reproductive efficiency in dairy cows.  相似文献   

17.
Six experiments were conducted to determine the relationship between the serving capacity of bulls as predicted by a 40-min yard test and their fertility during paddock mating, measured by the conception rate at first oestrus and the pregnancy rate at the end of 10 weeks of mating. Twenty bulls varying in serving capacity from 1 to 11 were mated to 40 heifers each. As serving capacity of the bulls increased from 1 to 7, conception rate increased from 18 to 70%. Average conception rates achieved by 4 bulls with low serving capacity (25.3%), 8 bulls with medium serving capacity (61.4%) and 7 bulls with high serving capacity (72.3%) were all significantly different from one another. Bulls of low serving capacity (1 or 2 services) impregnated a significantly lower proportion of their heifers (40.3%) than bulls with medium (91.2%) or high (95.3%) serving capacity. It was concluded that bulls of serving capacity 1 or 2 (in 40 min) should be considered unsound for breeding. An explanation for the results and their implication in beef production is discussed.  相似文献   

18.
The results of 7569 inseminations performed on 6007 cows in 94 dairy herds were used to investigate the relative importance of time of insemination, bull and inseminator on calving rates in dairy cows. Although the time of insemination in relation to the first observation of oestrus was shown to have some effect, the effect was minimal during the first 24 hours. The maximum difference in expected calving rates between cows served with semen from groups of bulls with a history of either low or high fertility was 20 per cent, and the maximum difference in expected calving rate between cows inseminated by groups of inseminators who had consistently achieved either low or high fertility was 13 per cent.  相似文献   

19.
Fifty-seven cycling buffalo cows of the river type were treated with two doses of 0.5 mg cloprostenol intramuscularly given 11 days apart. Each animal was inseminated twice at 72 and 96 hours after the second injection of cloprostenol. The first service conception rate diagnosed by rectal palpation at 90 days was 38.6 per cent. At the time of insemination the cervix was easily penetrable on both days in only 39 (68.4 per cent) of the animals. They were inseminated at or beyond the internal cervical os, while the others were inseminated in the cervical canal. There was a marked difference in conception rate between those receiving deep inseminations (48.7 per cent) and the others (16.7 per cent). In relation to the interval from calving to insemination the conception rates for those which had calved 60 to 90, 90 to 120 and 120 to 150 days earlier were 16.6, 36.4 and 55.5 per cent respectively. The use of cloprostenol treatment and fixed-time insemination is a useful method of overcoming the problem of oestrus detection in buffaloes. Acceptable levels of fertility can be obtained in those animals which have a sufficiently relaxed cervix to permit semen deposition at the internal os, provided the interval from calving to insemination is more than 90 days.  相似文献   

20.
饲养管理方式对甘南牦牛繁殖力及杂交后代影响的研究   总被引:1,自引:1,他引:0  
[目的]为了研究加强种公牛和母牦牛的饲养管理对母牦牛的繁殖效果和杂交后代生长发育的影响.[方法]本试验用大通牦牛和其冻精杂交甘南牦牛,通过对试验组的种公牛、母牦牛和杂交后代进行补饲、延长放牧时间和提前断奶等措施,研究了203头母牦牛的繁殖效果和其杂交后代的生长发育情况.[结果]表明,自然交配试验组发情率、受胎率、繁殖成活率分别比对照组提高9.19%、11.03%、14.10%,流产率和犊牛死亡率降低3.3%、3.87%;人工授精组发情率、受胎率、繁殖成活率分别提高6.74%、5.48%、10.52%,流产率和犊牛死亡率降低4.07%、4.62%.加强母牦牛的饲养管理,所产犊牛的初生重比传统饲养管理条件下母牦牛所产的犊牛初生重公母分别增加2.92 kg和2.07 kg,提高19.80%和14.22%.6月龄体重分别增加12.82 kg和12.23 kg,提高17.45%和16.88%.[结论] 用大通牦牛改良甘南牦牛,采用人工授精和自然交配都有良好的效果,加强种公牛、母牦牛饲养管理是提高牛群繁殖力的有效方法,对后代生长发育影响明显.  相似文献   

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