A survey of reproductive success in South African Thoroughbred horse breeding from 1975 to 1999

The data and an analysis of the statistical summaries from the 'Return of Mares' of the General Stud Book of The Jockey Club of Southern Africa from 1975-1999 are presented. The total number of mares covered per season ranged from 7393 (1992) to 5180 (1995). The total living produce in the period surveyed was 95 317 foals. The categories of data examined include: the total number of mares covered per season; the total numbers and percentage of their living produce; the total numbers and percentage dead produce, 'slips' and foals born dead, barren and 'no return' mares; and the total number of live twins reported. The percentage live foals per season increased from 52 to 62% and the percentage barren and 'no return' mares declined from 35.50 to 28.40% over the period surveyed. The number of live twins reported showed a dramatic reduction from 156 to 5. These apparent improvements are ascribed to a combination of factors including advances in veterinary knowledge and technology. The findings are similar to those reported by similar surveys of national Thoroughbred populations from North America and Germany. There is an indication to broaden this annual survey by recording additional parameters more accurately reflecting reproductive efficiency rather than a cumulative annual total of live foals.     

Starvation and overwinter do not affect the reproductive fitness of Rhipicephalus sanguineus

Rhipicephalus sanguineus is the most widespread tick in the world, being able to survive under different climate conditions. In this study, the longevity of R. sanguineus was investigated under laboratory and natural climate conditions in southern Italy. Moreover, the reproductive fitness of females after overwintering was assessed. In the environment, unfed larvae, nymphs and adults were able to survive for up to 34, 40 and 385 days, respectively. However, the longevity of larvae (44 days), nymphs (54 days) and adults (584 days) in the laboratory was longer. Adult ticks that had overwintered under natural climate conditions were able to feed and give rise to viable larvae, after 40 weeks of starvation. Thereby, it is demonstrated that R. sanguineus is able to overwinter in southern Italy, without any prejudice to its fitness. These findings advance our knowledge on the natural history of R. sanguineus in nature and provide new insights into the epidemiology of certain tick-borne diseases in southern Europe as well as into the risk for their introduction in northern European countries.     

Detection of trichomonad species in the reproductive tracts of breeding and virgin bulls

Trichomoniasis is a sexually transmitted disease of cattle and a large bowel diarrheal disease of cats caused by Tritrichomonas foetus. Recently, other species of trichomonads have been identified from the prepuce of virgin bulls. It is not clear whether these non-T. foetus isolates are common (nor) or is it clear whether they are also present on the prepuce of breeding bulls. To answer these questions, we first developed an immunofluorescent assay (IFA) with T. foetus-specific monoclonal antibodies for comparison with a T. foetus-specific PCR assay. Results showed that all PCR positive isolates were also IFA positive, whether the isolates were from cats or cattle and PCR negative isolates were IFA negative. Bovine non-T. foetus (non-Tf) trichomonad isolates were detected by both assays in 14 virgin bulls, 10 breeding bulls, 21 bulls of undetermined breeding status (presumably breeding bulls) and 2 cows. These isolates from virgin bulls were mostly Tetratrichomonas spp. whereas the non-Tf isolates from most breeding bulls and the two cows were Pentatrichomonas hominis. All T. foetus isolates were from breeding bulls or bulls of undetermined breeding status. This IFA test which discriminates between T. foetus and non-Tf may be useful as a diagnostic assay, since no effective legal treatment is available, bulls positive for T. foetus are culled. With increasing reports of T. foetus large bowel infection in cats, these monoclonal antibodies may also be useful for diagnosis of feline infection. Since two isolates of non-Tf trichomonads were obtained vaginas of breeding cows, it may be that these parasites are sexually transmitted like pathogenic T. foetus.     

玉米赤霉烯酮的毒害作用及对种猪繁殖性能的影响

玉米赤霉烯酮是一种非甾体雌激素样作用的霉菌毒素。大量研究表明,玉米赤霉烯酮具有生殖发育毒性、免疫毒性,对肿瘤发生也有一定影响。本文综述了玉米赤霉烯酮的毒性毒害作用及对种猪繁殖性能的影响,以引起养殖者的高度重视。     

妊娠期日粮、母猪健康会影响仔猪的成功生长

正对仔猪而言,正确的饲喂是至关重要的,即使在其出生前。母猪妊娠期、分娩期和整个哺乳期的日粮会对其本身、其所产仔猪和养猪生产者产生持续不断的好处。猪的饲喂更像一场马拉松比赛而非短跑。到达上市体重的赛程可能需要200 d的时间,并且一切始于一个成功的开始。要成功地使仔猪拥有一个最佳的开始,生产管理的重点应该放在仔猪出生前的生长上,即始于对母猪的护理。     

The role of reproductive technologies in breeding schemes for livestock populations in developing countries

The world is faced with the challenge to meet the increasing demand for livestock products while conserving animal genetic resource diversity and maintaining environmental integrity. Genetic improvement of local breeds can help to improve the livelihood of the livestock keepers, to increase the production of animal products and to conserve genetic diversity. Implementing breeding schemes in developing countries has proven to be very difficult. The objective of this paper is to discuss the role of reproductive technologies for the creation and dissemination of genetic improvement in livestock populations in developing countries. In the paper opportunities are discussed for implementing breeding schemes which minimize the need for extensive pedigree and performance recording. It is shown that genetic progress can be generated in a small population. Community-based breeding schemes offer a good starting point for involving farmers in improving local breeds. Artificial insemination to exchange genetic material between communities offers an opportunity to increase the rate of genetic improvement while restricting the rate of inbreeding. Furthermore, artificial insemination is a promising technique for dissemination of genetic gain to producers at a relatively low cost. Opportunities to use semen sexing in a crossbreeding scheme are presented. It is concluded that tailor-made solutions and long-term commitment are needed in order to meet the needs of farmers to increase their livelihoods and to meet the needs of the growing population of consumers.     

Effects of Mycoplasma gallisepticum on reproductive success in house finches

Long known as a pathogen of poultry, Mycoplasma gallisepticum (MG) was first detected in house finches in 1994. The disease rapidly spread throughout the eastern United States and Canada and was associated with debilitating disease and high mortality in house finches. However, in the late 1990s, the proportion of infected finches dying as a result of infection with MG decreased, and asymptomatic infection was more common among wild birds than in the past. We documented MG infections in breeding house finches and concluded that adults of both sexes transmit the infection to dependent young, probably after hatch. MG infections of breeding adults occurred late in the breeding season and were found in birds completing significantly more nests than birds that never tested positive for MG, implying that higher rates of reproduction carry a cost in the form of increased risk of infection. We found evidence of an MG-induced delay in dispersal of nestlings from their natal area and demonstrated a significant impact of infection on nestling growth.     

生猪养殖产业链相关行业利润分配分析

本文主要分析了生猪养殖产业链相关行业利润分配问题,并对生猪养殖如何应对行业利润分配不均提出了建议,呼吁政府和行业有关管理部门参与宏观调控管理,促进行业和社会生产和谐健康有序发展。     

不同饲喂方法对种用母猪繁殖性能的影响

母猪膘情与其繁殖性能及仔猪出生成本存在密切关系,我们选用同批次、出生时间在±15d,对猪瘟、蓝耳病、伪狂犬、口蹄疫抗体检测为阴性(-)的健康后备猪30头,分为3组。在相同条件下,对3组母猪分别饲喂质量相同但重量不同的饲料来控制各组母猪的膘情,通过配种时间、母猪淘汰率、分娩情况等指标来比较各组的优劣。结果表明:后备母猪(空怀母猪)过肥过瘦都会造成很大的经济损失,过肥比过瘦更为严重。只有使后备母猪(空怀母猪)维持合理膘情(7～8成膘)才能提高母猪的繁殖性能,且每头仔猪生产成本较其他饲喂方法可降低约50元人民币。     

The occurrence and distribution of maedi-visna virus infection in lower Austrian sheep breeding establishments

In a period of one year blood samples of 374 sheep of Lower Austrian flocks were examined in intervals of two months for antibodies against Maedi-Visna (MV). Further on specific attention was paid to the prevalence of MV-infection in the flocks. The antibody-titers were determined by means of agar gel-immunodiffusion test. In 5 (23.8%) of 21 flocks 45 (12.0%) of the sheep were seropositive. Seroprevalence varied within the examined breeds: 19 (27.1%) of 70 Karakul-sheep, 18 (28.1%) of 64 East-Friesian milk-sheep, 7 (9.4%) of 74 Merino sheep and 1 (0.9%) of 111 mountain sheep. None of 55 black-headed sheep showed MV seropositive reaction. Clinical symptoms of Maedi-disease were especially observed in milk-sheep and for the first time in Austria in Karakul-sheep. Unfavorable housing conditions (insufficient room, bad climatic conditions), breed specific behavior patterns (crowding of Karakul-sheep) and a high prevalence of MV infections promote a high incidence the disease.     

Prevalence of Chlamydia infections in breeding sows and their importance in reproductive failure

To investigate the prevalence of chlamydial infection and their significance for reproductive disorders in sow breeding herds in Germany, blood samples of 1493 pigs were taken for a serological survey by enzyme-linked-immunosorbent-assay (ELISA). Antibodies to Chlamydiae were found in 33% of the samples, in all herds investigated responders could be detected. The rate of seropositive animals in different farms varied from 4.3% to 72.7%. The percentage of positive responders in the farms correlated positively with the occurrence of MMA-syndrome (mastitis, metritis, agalactia), return to oestrus and diseases of the piglets. Also these herds showed less weaned piglets per sow and litter. Comparison of seronegative and seropositive sows within single farms revealed also worse reproductive data for seropositive sows. A significant relationship could be found between farms with a high quota of sero-positive sows and poor hygiene status as well as poultry keeping. As a second step 124 cervical swabs and 9 aborted piglets were investigated for chlamydial antigen by capture-ELISA and polymerase chain reaction (PCR). Using the capture-ELISA for investigation only 3 probes with chlamydial antigen could be detected, however, examination by the more sensible PCR gave positive results in 50% of the probes. 20% of the PCR-positive animals were clinically healthy sows, 80% of the PCR-positive probes originated from sows with reproductive disorders. A significant relationship could be shown between PCR-positive probes and the incidence of abortion and litters with stillborn piglets and piglets with low viability. Swabs from 93 of the 124 sows were investigated as well for other bacterial pathogens of reproductive disorders. A high degree of micro-organisms of different species could be detected in 70% of the samples of sows with reproductive disorders and in 35% of the samples of clinically healthy sows. Species differentiation of the chlamydial antigen positive samples was done by southern blot hybridisation. Herewith C. psittaci could be diagnosed in all positive samples. Additionally 8 probes revealed a mixed infection with C. psittaci and C. trachomatis. The results of the present study show, that the prevalence of chlamydial infections in breeding herds is high and underline the importance of chlamydial infections for reproductive disorders. Single chlamydial infections as well as mixed infections with other pathogens must be considered.     

环境温度对发酵床养殖公猪繁殖性能的影响

微生物发酵床养殖是一种生态养殖模式,在冬天具有很好的保暖作用,减少了日粮的损耗,但在夏天,缺少散热的功能,对育肥猪和种猪的养殖影响较大。实验对某微生物发酵床生态养猪场的4头种公猪,通过连续观测公猪舍环境温度、垫料温度及公猪的精神状态,检测公猪血液生化指标、精子活率、精子质量、精子密度及生化指标项目。结果发现1号公猪的总蛋白水平较高,其它生化指标差异不显著;4头公猪中只有4号公猪精子活率达到70%,其余公猪精液中精子活率低于10%,大量死精。结果表明微生物发酵床养殖对公猪繁殖性能的影响较大。     

云南水牛改良育种及繁育体系建设

本文针对云南水牛功能作用的改变、市场需求变化、云南丰富的水牛资源的开发利用和现行的杂交改良情况，对未来的发展重点领域、新品种培育的遗传资源和技术路线等进行了讨论，对指导云南省水牛产业的综合开发具有一定的意义。