A framework for evaluation of on-farm mastitis diagnostics in Australia

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform.     

植物促生菌及其促生机理 (续)

3 植物促生菌的促生长机理 3.1 产生嗜铁素 铁是生命的基本物质.不论是动、植物还是微生物,均需含铁蛋白来参与呼吸等一系列生理活动.尽管地球表面矿物含铁丰富,但土壤中能够直接为植物和微生物利用的铁却不多.土壤中铁主要以三价铁(Fe3+)状态存在,在pH值为7.4时其溶解度为10-18mol/L,此浓度下的铁一般无法满足土壤微生物繁衍和植物生长发育的需要.然而,某些细菌和植物分泌一种专门结合铁的小分子蛋白(siderophores)可从土壤中收集铁,这种物质被称之为嗜铁素.铁一旦与嗜铁素相结合则形成可溶性铁-嗜铁素复合体,并可通过植物和微生物细胞膜的特殊通道进入生物体内.氧化铁在体内还原后被释放并参与生物代谢活动.产生嗜铁素被认为是植物促生菌最主要的直接和间接促进植物生长的有效途径之一.植物促生菌产生的嗜铁素一般都具有高度的铁亲合性和专一性,含有各种能鳌合铁的结构基团(如邻二苯酚结构、羧基结构和乙二胺结构等)来摄取土壤中的铁,这种嗜铁素具有极强的吸收铁的能力,可在铁有效性极低时收集土壤中微量的移动性铁,从而使土壤中可用的铁降低至更为缺乏的程度.     

Plants as de-worming agents of livestock in the Nordic countries: historical perspective, popular beliefs and prospects for the future.

Preparations derived from plants were the original therapeutic interventions used by man to control diseases (including parasites), both within humans and livestock. Development of herbal products depended upon local botanical flora with the result that different remedies tended to develop in different parts of the world. Nevertheless, in some instances, the same or related plants were used over wide geographic regions, which also was the result of communication and/or the importation of plant material of high repute. Thus, the Nordic countries have an ancient, rich and diverse history of plant derived anthelmintic medications for human and animal use. Although some of the more commonly used herbal de-wormers were derived from imported plants, or their products, many are from endemic plants or those that thrive in the Scandinavian environment. With the advent of the modern chemotherapeutic era, and the discovery, development and marketing of a seemingly unlimited variety of highly efficacious, safe synthetic chemicals with very wide spectra of activities, herbal remedies virtually disappeared from the consciousness--at least in the Western world. This attitude is now rapidly changing. There is a widespread resurgence in natural product medication, driven by major threats posed by multi-resistant pest, or disease, organisms and the diminishing public perceptions that synthetic chemicals are the panacea to health and disease control. This review attempts to provide a comprehensive account of the depth of historical Nordic information available on herbal de-wormers, with emphasis on livestock and to provide some insights on potentially rewarding areas of "re-discovery" and scientific evaluation in this field.     

Are Endocrine Disrupting Compounds a Threat to Farm Animal Health,Welfare and Productivity?

Contents The sources and characteristics of endocrine disrupting compounds (EDCs) are reviewed and discussed with respect to their potential effects on farm animal health, welfare and productivity. The importance of certain properties of these compounds in relation to the expression of their biological effects is addressed together with potential routes of exposure. It is concluded that little is known of factors affecting the tissue concentrations of EDCs in farm animals, the concentrations that are required to perturb physiological function in these species, the effects of prolonged exposure to low doses, the effect of cocktails of EDCs and other pollutants or the responses of specific organs and physiological systems that are affected by EDCs. Much of the available information pertaining to EDCs is derived from epidemiological studies of wildlife species and from laboratory animal studies and while these studies have significant limitations, they are considered to be valuable indicators of potential effects in farm animal species. The results of such studies, together with the small amounts of data from studies of ruminants, indicate that there may be significant effects of exposure to environmental levels of EDCs on farm animal health, even although effects are not generally apparent in practice, at this time.