单克隆抗体ELISA检测犊牛粪便中冠状病毒抗原

用两株单克隆抗体混合后包被ＥＬＬＩＳＡ微孔板，加牛冠状病毒抗原，加经白陶土处理过的兔抗牛冠状病毒免血清，再加上辣根氧化物酶标记的羊抗兔ＩｇＧ抗体，加底物质显色间接ＥＬＩＳＡ检测牛冠状病毒抗原获得成功。用此方法检测细胞培养的牛冠状病毒上清液，其敏感度高出血凝试验（ＨＡ）８倍，从武汉市附近３个奶牛场采集犊牛腹泻粪便１０５份，用单抗ＥＬＩＳＡ检测牛冠状病毒抗原，共检出阳性３６份，并与血凝及血凝抑制试验，     

Efficacy of a mephentermine‐based product as a vasopressor and a cardiac performance enhancer when given intramuscularly to cattle

The goal of this study was to confirm the vasopressor and cardiac effects of POTENAY^® INJETÁVEL (POT), a mephentermine‐based product, given to cattle with induced vascular/cardiac depression. Ten healthy Holstein cattle (206 ± 13 kg) followed a randomized‐complete‐block design (RCBD) utilizing crossover study design. Each animal randomly received (1 ml/25 kg, IM) of either POT (n = 10) or volume‐matched placebo control (0.9%NaCl, CP, n = 10). A subset of animals (n = 5) received POT first (day 0) while the remaining (n = 5) received CP; after a six‐day washout period, cattle received the opposite compound. Animals were anesthetized and catheterized for systemic/left ventricular hemodynamic monitoring. Myocardial dysfunction/hypotension was induced by increasing the end‐tidal isoflurane concentration until arterial blood pressure was 20% lower than at baseline and remained stable. Once the animal was determined to be hypotensive and hemodynamically stable, steady‐state hypotensive baseline data (BL2) were acquired, and treatment with either POT or CP was given. Data were acquired post‐treatment at every 15 min for 90 min. POT improved cardiac output (+68 L/min, ±14%, p < 0.05), MAP (+14 mmHg, ±4%, p < 0.05), HR (+22 bpm, ±8%, p < 0.05), and peak rates of ventricular pressure change during both systole (dP/dt_max: +37 mmHg/s ±13%, p < 0.05) and diastole (dP/dt_min: +31 mmHg/s, ±7%, p < 0.05). No improvements were noted following placebo‐control administration. Results indicate that POT improves cardiac performance and systemic hemodynamics in cattle with induced cardiovascular depression when given as single intramuscular injection.     

A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators

Hemodynamic perturbations, partly resulting from abnormal vasoconstriction of digital vessels, have been implicated in the pathogenesis of bovine and equine laminitis. This study compared the responsiveness of isolated bovine (BDA) and equine (EDA) digital arteries to pharmacological agents that stimulate receptor systems involved in the regulation of normal vessel tone. The role of the endothelium and the short‐ and longer‐term effects of an experimentally induced endothelial damage were also evaluated. Species‐related differences were found in the vessel reactivity to all of the receptor agonists tested. In intact BDA, as compared to intact EDA, norepinephrine was a more effective vasoconstrictor, 5‐hydroxytryptamine a more effective but less potent vasoconstrictor, isoproterenol a less effective vasodilator and carbamylcholine a less potent vasodilator. In BDA, but not in EDA, the contractile responses to norepinephrine and 5‐hydroxytryptamine were enhanced immediately after endothelium removal. However, the contractile reactivity of denuded BDA returned to basal values following overnight incubation. The differences suggest species specificity for the pathophysiology of digital vasomotor tone and function in horses and cattle.     

Contagious bovine pleuropneumonia within the 19th century miasmatic landscape

When contagious bovine pleuropneumonia (CBPP) was first detected on a farm north of Melbourne, at Bundoora, in 1858, the predominant theory of miasma was being challenged by contagionist theories of disease transmission. This well‐documented case was recorded during a period of change in the scientific assessment of disease and therefore affords an exploration of what aspects of the landscape were considered important for livestock health at the time. Although the introduction, vaccination programs and eventual eradication of CBPP on mainland Australia has been well explored, scholars have neglected this aspect of the disease's history. By comparing 19th century records of farmland with how the site appears today, it is also possible to highlight the limited information provided by contemporary texts, while at the same time developing an appreciation of the ways in which the perception of the rural landscape has changed. This differing perception has implications for the utilisation of these sources for veterinary and environmental historians seeking to understand the mid‐19th century agricultural landscape and how it relates to animal health.     

Effect of bovine seminal plasma on bovine endometrial epithelial cells in culture

The purpose of this study was to investigate the effect of seminal plasma (SP) from bulls of known fertility on bovine endometrial epithelial cells (bEEC) in culture. The bEEC from passage 5, approximately 5.0–13 × 10⁵ cells per flask, were challenged with SP from bulls of high or low fertility (n = 3 and 2, respectively) or PBS (control), at 1% (75 μl) or 4% (300 μl) and were incubated for 72 hr (n = 13 per challenge). Total cell number and viability of bEEC after challenge with 1% SP from either high‐ or low‐fertility bulls (75H or 75L, respectively) did not differ from controls. In contrast, challenge with 4% of SP from high‐ or low‐fertility bulls (300H or 300L) negatively affected bEEC cell number and viability. Challenge with 300 L had a greater adverse effect than 300H. These results suggest that the negative effect of bovine SP on bEEC is both dose‐dependent and fertility‐dependent.     

Viral RNA extraction using an automatic nucleic acid extractor with magnetic particles and genetic characterization of bovine viral diarrhea virus in Tokachi Province,Japan, in 2016–2017

In this study, the viral genome extraction performance of automatic nucleic acid extractors and manual nucleic acid extraction kits was compared. We showed that compared with manual kits, the automatic extractors showed superior genome extraction performance using bovine viral diarrhea virus (BVDV) genome-positive cattle sera and bovine coronavirus/infectious bovine rhinotracheitis virus-spiked cattle nasal swabs. In addition, the subgenotyping of BVDV strains detected in Tokachi Province in Japan during 2016–2017 was performed. Results showed that most of these BVDV strains belonged to subgenotype 1b, while few strains belonged to subgenotypes 1a and 2a. This study showed the high applicability of automatic nucleic acid extractors in extracting multiple viral genomes and the dominant subgenotype of BVDV in Tokachi.     

Approaches to increase recovery of bacterial and fungal abortion agents in domestic ruminants

Abortions in domestic ruminants cause significant economic losses to farmers. Determining the cause of an abortion is important for control efforts, but it can be challenging. All available diagnostic methods in the bacteriology laboratory should be employed in every case due to the many limiting factors (autolysis, lack of history, range of samples) that complicate the investigation process. The purpose of this study was to determine whether the recovery of diagnostically significant isolates from domestic ruminant abortion cases could be increased through the use of a combination of the existing aerobic culture and Brucella selective method with methods that are commonly recommended in the literature reporting abortion investigations. These methods are examination of wet preparations and impression smears stained by the modified Ziehl–Neelsen method, anaerobic, microaerophilic, Leptospira, Mycoplasma and fungal culture. Samples of placenta and aborted foetuses from 135 routine clinical abortion cases of cattle (n = 88), sheep (n = 25) and goats (n = 22) were analysed by the new combination of methods. In 46 cases, bacteria were identified as aetiological agents and in one case a fungus. Isolation of Brucella species increased to 7.4% over two years compared with the previous 10 years (7.3%), as well as Campylobacter jejuni (n = 2) and Rhizopus species (n = 1). Salmonella species (5.9%) and Trueperella pyogenes (4.4%) were also isolated more often. In conclusion, the approach was effective in removing test selection bias in the bacteriology laboratory. The importance of performing an in-depth study on the products of abortion by means of an extensive, combination of conventional culture methods was emphasised by increased isolation of Brucella abortus and isolation of C. jejuni. The combination of methods that yielded the most clinically relevant isolates was aerobic, microaerophilic, Brucella and fungal cultures.     

牛白细胞介素15基因的克隆及在大肠杆菌中的表达

根据GenBankTM中发表的牛IL-15基因序列设计并合成了特异性引物,以经LPS和ConA刺激的牛外周血单个核细胞提取的总RNA为模板,用RT-PCR方法扩增出长度约500 bp的目的基因片段,并将该基因克隆到pMD18-T载体上.酶切、PCR及序列测定结果表明,获得了牛IL-15全长基因的克隆.进一步通过PCR方法得到缺失其N端48个氨基酸的信号肽序列的牛IL-15成熟蛋白基因,将其亚克隆到原核表达载体pET-32a上,构建重组表达质粒pET-IL-15,转化大肠杆菌BL21(DE3),经IPTG诱导,该菌表达以包涵体形式存在的相对分子质量约为33 000的融合蛋白.用Ni螯合层析方法纯化表达的蛋白.Western-blot试验显示表达的重组融合蛋白能与抗6×His的单克隆抗体发生反应,同时也能与鼠抗猪IL-15的多克隆抗体发生明显交叉反应.     

对高寒牧区畜间布鲁氏菌病防控对策的思考

布鲁氏菌病是危害多种动物和人类的传染病,也是我国重点防控的人畜共患传染病之一。受市场等因素调节,牛羊反刍动物数量增加,且动物及其产品流通频繁,动物疫病发生风险加大,许多地方畜间布病呈上升趋势。为切实加强畜间布病防控工作,肃南县按照省、市业务部门的防控要求,结合当地高寒牧区畜间布病流行实际,制订防控工作计划,全面落实动物疫病主动监测、定点检疫、消毒灭源、阳性畜扑杀及无害化处理综合防治措施,取得一定成效。     

Expression,Purification and Activity Evaluation of Mb1230 Gene of Mycobacterium bovis

To explore the value of Mb1230 protein of Mycobacterium bovis in the diagnosis of bovine tuberculosis,we obtained the Mb1230 gene by PCR and constructed recombinant plasmid pET-22b-Mb1230.Recombinant Mb1230 protein was obtained by IPTG induction and purified by affinity chromatography.The activity of the recombinant protein was evaluated by TST test,IGRA test and indirect ELISA.The size of the recombinant protein matched with the theoretical value proved by SDS-PAGE;Western blotting result showed that the recombinant protein could react with mouse anti-His antibody,and had specific band;The results of TST test,IGRA test and indirect ELISA test also showed the recombinant protein had antigenic activity.The results indicated the recombinant protein Mb1230 had good B cell and T cell activity,so,it had the potential application in the diagnosis of bovine tuberculosis.