Piroplasmids of livestock in Tunisia

Several species of piroplasms of livestock are present in Tunisia; some of them are of high veterinary importance. This paper reviews the species already reported in Tunisia on the basis of clinical observations, parasitological routine diagnostic and serological surveys, as well as those considered as potentially present according to epidemiological argumentations. The genus Theileria includes four species reported in Tunisia: T. annulata, T. buffeli, T. ovis, and T. equi. The ovine malignant theileriosis agent, T. lestoquardi, appears to be absent in Tunisia. Five species belonging to the genus Babesia were reported in the country, namely B. hovis, B. bigemina, B. divergens, B. caballi, and B. ovis. Furthermore, two more species, B. major and B. motasi, are potentially present in zones where their vectors of the genus Haemaphysalis occur.     

Patterns of livestock depredation and cost‐effectiveness of fortified livestock enclosures in northern Tanzania

Human–carnivore conflicts and retaliatory killings contribute to carnivore populations' declines around the world. Strategies to mitigate conflicts have been developed, but their efficacy is rarely assessed in a randomized case–control design. Further, the economic costs prevent the adoption and wide use of conflict mitigation strategies by pastoralists in rural Africa. We examined carnivore (African lion [Panthera leo], leopard [Panthera pardus], spotted hyena [Crocuta crocuta], jackal [Canis mesomelas], and cheetah [Acinonyx jubatus]) raids on fortified (n = 45, total 631 monthly visits) and unfortified (traditional, n = 45, total 521 monthly visits) livestock enclosures (“bomas”) in northern Tanzania. The study aimed to (a) assess the extent of retaliatory killings of major carnivore species due to livestock depredation, (b) describe the spatiotemporal characteristics of carnivore raids on livestock enclosures, (c) analyze whether spatial covariates influenced livestock depredation risk in livestock enclosures, and (d) examine the cost‐effectiveness of livestock enclosure fortification. Results suggest that (a) majority of boma raids by carnivores were caused by spotted hyenas (nearly 90% of all raids), but retaliatory killings mainly targeted lions, (b) carnivore raid attempts were rare at individual households (0.081 raid attempts/month in fortified enclosures and 0.102 raid attempts/month in unfortified enclosures), and (c) spotted hyena raid attempts increased in the wet season compared with the dry season, and owners of fortified bomas reported less hyena raid attempts than owners of unfortified bomas. Landscape and habitat variables tested, did not strongly drive the spatial patterns of spotted hyena raids in livestock bomas. Carnivore raids varied randomly both spatially (village to village) and temporally (year to year). The cost‐benefit analysis suggest that investing in boma fortification yielded positive net present values after two to three years. Thus, enclosure fortification is a cost‐effective strategy to promote coexistence of carnivores and humans.     

Comparison of pulsed-field gel electrophoresis patterns of antimicrobial-resistant Escherichia coli and enterococci isolates from the feces of livestock and livestock farmers in Japan

Seven hundred thirty-nine animal strains and 662 livestock-farmer strains, consisting of Escherichia coli and enterococci, were examined for their pulsed-field gel electrophoresis (PFGE) and antimicrobial-resistance patterns. Two hundred fifty-eight and 203 PFGE patterns were found among 739 animal strains isolated from animals comprising broilers, pigs and cattle, and 662 human strains isolated from livestock farmers, respectively, from 27 farms in Japan. These results demonstrated that the PFGE patterns found among E. coli and enterococci strains from animals and livestock-farmers were heterogeneous and considerably diverse. The strains having both the identical PFGE pattern and the same drug-resistance pattern were defined as a single clone in this study. Seven types of E. coli and enterococci clones were shared among animals within the same farms and between the different farms housing the same animal species. The 25 strains (3.4%) of 739 E. coli and enterococci animal strains belonged to these seven types of clones. Only three types of E. coli clones were shared among animals between the different farms housing different animal species, but no identical E. faecalis or E. faecium clones were found between different animal species farms. The 15 strains (2.0%) of 739 E. coli and enterococci animal strains belonged to these three types of clones. Additionally, the 11 strains (1.5%) of 739 E. coli and enterococci strains isolated from animals were identical clones to strains isolated from livestock farmers of the same farm. These results suggest that the transmission of animal clones to livestock farmers or vice versa is less common.     

Antimicrobial resistance in humans,livestock and the wider environment

Antimicrobial resistance (AMR) in humans is inter-linked with AMR in other populations, especially farm animals, and in the wider environment. The relatively few bacterial species that cause disease in humans, and are the targets of antibiotic treatment, constitute a tiny subset of the overall diversity of bacteria that includes the gut microbiota and vast numbers in the soil. However, resistance can pass between these different populations; and homologous resistance genes have been found in pathogens, normal flora and soil bacteria. Farm animals are an important component of this complex system: they are exposed to enormous quantities of antibiotics (despite attempts at reduction) and act as another reservoir of resistance genes. Whole genome sequencing is revealing and beginning to quantify the two-way traffic of AMR bacteria between the farm and the clinic. Surveillance of bacterial disease, drug usage and resistance in livestock is still relatively poor, though improving, but achieving better antimicrobial stewardship on the farm is challenging: antibiotics are an integral part of industrial agriculture and there are very few alternatives. Human production and use of antibiotics either on the farm or in the clinic is but a recent addition to the natural and ancient process of antibiotic production and resistance evolution that occurs on a global scale in the soil. Viewed in this way, AMR is somewhat analogous to climate change, and that suggests that an intergovernmental panel, akin to the Intergovernmental Panel on Climate Change, could be an appropriate vehicle to actively address the problem.     

Predicting the distribution of livestock grazing pressure in rangelands

Abstract Because grazing by livestock is one of the primary threats to rangeland biodiversity, but is unevenly distributed in space, rangeland monitoring programmes need to take account of the distribution of grazing pressure in order to distinguish between grazing‐induced change, seasonal fluctuations and changes that are a result of other threats. Livestock watering places are one of the major influences that give spatial expression to gradations in grazing activity. Using research results from the goldfields of Western Australia, we show how distance from water can be incorporated in spatial models to predict cumulative grazing pressure at different sites within paddocks. Two surrogates of grazing activity are illustrated: one relying on a commercially available model, and one developed from measures of track density. Factors other than distance from water can also have profound effects on the distribution of grazing pressure and its impacts at landscape and regional scales, and we review some of these briefly. Finally, we outline key spatial implications for the design of rangeland monitoring programmes.     

家畜转基因育种研究进展

转基因技术可以将外源基因导入家畜基因组,使其获得新的可遗传性状,为培育优良家畜品种提供了革命性途径。DNA显微注射法和体细胞克隆法是制备转基因家畜最常用的方法。应用转基因技术可以进行家畜抗病育种(抗病毒、抗菌和抗寄生虫),改良家畜的生产性状(胴体组成、奶品质、产毛、繁殖力和生长速度),培育环保型家畜新品种。文章从动物转基因技术入手,阐明其在家畜品种改良方面的研究现状和策略,并探讨家畜转基因育种面临的问题和应用前景。     

The pharmacology of anthelmintics in livestock

The recent development of ivermectin, netobimin, closantel, triclabendazole and clorsulon as well as new ways of using established anthelmintics has significantly improved the potential for parasite control in livestock. It is of interest to note that potential control of F. hepatica has been particularly improved with four of these new anthelmintic drugs being fasciolicidal. In addition to an appreciation of the spectrum of action of the new anthelmintics, a considerable amount of information on the pharmaco-kinetic behaviour, metabolism and mode of action of these drugs has been published. New information on pharmacology of established anthelmintics has provided new insights into the biology of parasites, drug resistance and the options for improved chemotherapy by manipulation of pharmacokinetics and metabolism. Much recent pharmacological research has been concentrated on the BZs and this has been considered here in an attempt to provide a better understanding of this significant group of anthelmintics. The development of new delivery systems, such as intraruminal slow release devices, is potentially useful with most anthelmintics. So far, this new approach to parasite control has been applied most successfully with morantel tartrate.     

Advances in livestock nuclear transfer

Cloning and transgenic animal production have been greatly enhanced by the development of nuclear transfer technology. In the past, genetic modification in domestic animals was not tightly controlled. With the nuclear transfer technology one can now create some domestic animals with specific genetic modifications. An ever-expanding variety of cell types have been successfully used as donors to create the clones. Both cell fusion and microinjection are successfully being used to create these animals. However, it is still not clear which stage(s) of the cell cycle for donor and recipient cells yield the greatest degree of development. While for the most part gene expression is reprogrammed in nuclear transfer embryos, all structural changes may not be corrected as evidenced by the length of the telomeres in sheep resulting from nuclear transfer. Even after these animals are created the question of "are they really clones?" arises due to mitochondrial inheritance from the donor cell versus the recipient oocyte. This review discusses these issues as they relate to livestock.     

禽畜养殖粪便中多重抗生素抗性细菌研究

通过对新乡地区8家养猪场和11家养鸡场饲喂抗生素情况的调研,发现头孢氨苄、阿莫西林、卡那霉素、庆大霉素等4种抗生素是该地区被普遍使用的兽药抗生素。通过多点取样法和微生物培养技术对3家养鸡场和3家养猪场不同养殖时期的粪便进行单一抗生素和多重抗生素抗性细菌的检测,结果表明养鸡场堆置1周的粪便中抗头孢氨苄的细菌比例最高,达到65.90%,对所研究的3种和4种抗生素同时抗性的比例高达8.60%—12.51%和9.73%,明显高于饲喂中药的对照养鸡场样本检测结果(0.02%—2.73%和0.12%)。养猪场堆置1周的粪便中检测到抗头孢氨苄的细菌比例也是最高,达到49.12%上,但养猪场粪便中多重抗生素抗性细菌的比例明显低于养鸡场。同时研究发现,在两种养殖场中,幼龄期粪便中检测到的多重抗性细菌比例明显高于成熟期粪便,这可能与养殖过程中鸡、猪在幼龄期由于防病和促生长等因素而同时大剂量使用多种抗生素有关。     

Trypanotolerance and the value of conserving livestock genetic resources

Studies have been made in two main areas of genetic research on African trypanotolerant (N'Dama) cattle. The first is of the significance for performance and the heritability of trypanotolerance traits and the second is the search for markers of the breed type and the traits of interest. Results demonstrate significant effects of the ability of an animal to control parasitaemia and anaemia on its performance. Initial estimates suggested that parasitaemia measures had a very low heritability, but ability to maintain packed cell volume levels when detected as parasitaemic and to generate an immune response could form the basis of a practical selection approach. The search for markers has so far concentrated on the major histocompatibility complex and on a polymorphic system of common leukocyte antigens. Phenotypes that appeared more characteristic of the N'Dama in comparison with those of East African zebu cattle were examined for associations with trypanotolerance traits. One major histocompatibility complex encoded phenotype and two common leukocyte antigens gave indications of important associations. Planned research will further characterise the breed and define traits of importance to assist in increasing its productivity in Africa and thus in its conservation. The addition of a molecular genetics component to an integrated genetics research programme, principally through involvement in development of a linkage map of the bovine genome, will strengthen these efforts and make it possible to conserve specific N'Dama genes related to productivity.