Validation of a von Willebrand factor antigen enzyme-linked immunosorbent assay and newly developed collagen-binding assay

No single test is comprehensive enough to detect all of the variants of von Willebrand Disease (VWD), making determination of both concentration and function of von Willebrand Factor (VWF) important for an accurate diagnosis. The objective of the study was to validate a newly developed VWF collagen binding assay (VWF:CB) and VWF antigen enzyme-linked immunosorbent assay (ELISA) developed at the Ontario Veterinary College (OVC VWF:Ag). Linearity, sensitivity, and coefficients of variation were determined. The Asserachrom VWF:Ag ELISA was used as the reference assay for this study. Concordance correlation and Bland-Altman plots were used to evaluate agreement between both VWF:Ag assays. The VWF:CB accuracy was assessed by degree of association with the VWF:Ag assays, and the VWF:Ag to VWF:CB ratio. All assays were assessed for their ability to distinguish between VWD negative and VWD positive patients. Linearity, intra-assay coefficients of variation, and inter-assay coefficients of variation were acceptable for both the newly developed VWF:CB (R² = 0.97, average CV = 4.4, and 15, respectively) and OVC VWF:Ag assays (R² = 0.96, average CV = 7.9, and 5.9, respectively). Agreement between the OVC VWF:Ag assay and reference assay was excellent (ρ_c = 0.89), and although differences between assay results precluded interchangeable use of the assays, both successfully distinguished VWD positive and VWD negative dogs (P < 0.0001). The VWF:CB showed a strong association with both VWF:Ag assays (R² = 0.86, 0.82) and VWF:Ag to VWF:CB ratios (≤ 1) were as expected. The excellent performance of both assays in this validation study confirm their reliability and potential for clinical application.     

郏县红牛皮肤真菌病的流行性调查及治疗体会

本文以场内生产情况为例,记录了牛皮肤真菌病的症状、治疗及诊断和防治措施,以期给同行提供参考,共同探讨。     

猪场生物安全体系中十个通道的设计应用

2018年8月开始,非洲猪瘟在我国快速多点发生,该病是高度接触性传染性疾病,目前无有效的疫苗和药物控制,各大公司和养殖户开始了猪场生物安全体系的升级改造。两年后我国大部分猪场的成功复产,全国生猪出栏量的大幅提升,证明了生物安全措施巨大效力;同时在严格的生物安全措施下创新了精准剔除、快速复产等操作,进一步证明了生物安全措施的有效作用。文章主要介绍猪场生物安全体系中入口(大门)和出口(后门)最为关键防线处的通道设计,方便所有的生物安全操作能够高效落实,切断病原轻易进出猪场的途径。     

半干旱区玉米行距调整增密对群体冠层结构及产量的影响

为增加玉米种植密度,构建不同的群体冠层结构,以玉米不同行距配置为基础,研究乳熟期玉米群体的光能利用情况,分析不同行距配置对冠层结构及产量、产量构成因素的影响。结果表明,玉米产量与群体消光系数达到显著相关,且为负相关。在吉林省半干旱区玉米宽窄行行距70-30 cm和宽窄行行距80-30 cm配置下玉米群体对光能资源的利用达到最佳,且有效提高玉米群体产量,增产分别达到8.06%和22.82%。     

养猪场户如何做好非洲猪瘟的防控

非洲猪瘟是一种急性、热性、高度接触性传染病^[1],近两年来给我国养猪业带来了灾难性的影响。因此,在当前阶段做好现有养猪场户的防控工作尤为重要。文章结合我国养猪特点和防控形势,从养猪从业者角度介绍了非洲猪瘟的特点、传播方式、综合防控措施及防疫职责,以期为广大生猪养殖者做好非洲猪瘟防控提供参考。     

后非洲猪瘟时期洋三元（DLY）商品母猪作种用的可行性分析及建议

自从2018年非洲猪瘟在中国暴发以来,为了尽快恢复产能,我国很多猪场在生产上开始采用洋三元商品母猪留作种用。通过收集某大型猪场的二元（（LY）母猪和洋三元（DLY）商品母猪的生产记录,统计两者在生产成绩上的差异,并综合其他文献来分析洋三元商品母猪留作种用的优缺点,给出改进的措施,为后非洲猪瘟时期养猪生产提供参考。     

A study on Theileria parva bovis carrier state

In two trials, Theileria parva bovis (which causes ‘January disease’ of cattle in Zimbabwe) produced a carrier state, over the 7–12 months after infection. Very severe clinical reactions were caused by infections from small numbers (29–43) of adult Rhipicephalus appendiculatus ticks, which had engorged on immunized cattle in the field. The transmission from healthy recovered cattle housed indoors was less efficient, even with high numbers of ticks (300). Two out of seven attempts were successful and disease reactions were rather severe. A non-pathogenic Theileria assumed to be Theileria taurotragi was transmitted in three out of seven attempts.     

鸡传染性法氏囊病组织病毒液（B87株）生产工艺探讨

通过计算ELD50,将已知效价的鸡传染性法氏囊病（B87株）生产种毒分几个滴度进行稀释,分别接种SPF鸡胚,结果各组鸡胚随病毒接种量的提高,高峰期死亡时间逐渐靠前,高峰期死亡率也逐渐增加,抗原效价也逐渐提高,抗原产量也有明显变化,病毒滴度以102.0ELD50/0.1mL接种鸡胚更合适。