Causes of death in beef cattle in southern Brazil

We determined the prevalence of diseases and pathogens associated with mortality in beef cattle in the State of Rio Grande do Sul, Brazil, based on pathology laboratory submissions. Postmortem examinations were conducted on 1,277 beef cattle that died between 2008 and 2018. Information regarding age, time of the year, breed, and regional location were analyzed statistically. Most cattle were from the surrounding region of Porto Alegre, and 78.7% of the analyzed cases had diagnostic value. The diagnostic category with most cases was infectious and/or parasitic diseases (60%), followed by toxic and toxicoinfectious (25%). Most cases occurred in the fall. Major disease conditions identified included hemoprotozoal infection (18.2%), rabies (8.2%), and plant intoxications by Senecio spp. (8.5%) and Pteridium arachnoideum (4.6%). Hemoprotozoal infection occurred at a higher frequency in young cattle, mainly in animals up to 1 y old. Intoxication by Senecio spp. was more frequent in cattle 2–3 y old.     

Sequence and unique phylogeny of G genes of bovine respiratory syncytial viruses circulating in Japan

Bovine respiratory syncytial virus (BRSV) is an etiologic agent of bovine respiratory disease. The rapid evolutionary rate of BRSV contributes to genetic and antigenic heterogeneity of field strains and causes occasional vaccine failure. We conducted molecular epidemiologic characterization of BRSV circulating in Japan to obtain genetic information for vaccine-based disease control. Phylogenetic analysis of G and F gene sequences revealed that all of the isolated Japanese BRSV strains clustered in the same genetic subgroup, which was distinct from the 9 known groups. We assigned the Japanese group to subgenotype X. The Japanese isolates formed 2 temporal clusters: isolates from 2003 to 2005 clustered in lineage A; isolates from 2017 to 2019 formed lineage B. The alignment of the deduced amino acid sequences of the G gene revealed that the central hydrophobic region responsible for viral antigenicity is conserved in all of the isolates; unique amino acid mutations were found mainly in mucin-like regions. Our results suggest that BRSV has evolved uniquely in Japan to form the new subgenotype X; the antigenic homogeneity of the viruses within this group is inferred.     

MSTN基因对牛肌动蛋白细胞骨架调节通路的影响

为探究肌肉生长抑制素（myostatin,MSTN）对牛骨骼肌生长发育的作用机制,本研究前期利用定量蛋白质组学与磷酸化蛋白质组学分析野生型蒙古牛（MG.WT）和MSTN^+/-蒙古牛（MG.MSTN^+/-）腿臀肌肌肉组织中蛋白质水平和磷酸化修饰水平的差异变化,使用已建立的牛骨骼肌卫星细胞体外诱导成肌分化模型,检测设计合成的MSTN siRNA （si-MSTN）干扰效果;采用实时荧光定量PCR和Western blotting方法检测转染si-MSTN的增殖期（GM）和分化第3天（DM3）牛骨骼肌卫星细胞中肌动蛋白细胞骨架调节通路相关基因的mRNA和蛋白水平的表达变化,研究敲低MSTN表达对肌动蛋白细胞骨架调节通路的影响。结果显示,在MSTN^+/-蒙古牛肌肉组织中共鉴定到16个肌动蛋白细胞骨架调节通路相关基因表达丰度上调;转染si-MSTN细胞中的MSTN表达水平极显著降低（P<0.01）;在转染si-MSTN的GM期牛骨骼肌卫星细胞中,肌动蛋白细胞骨架调节通路相关基因ENAH、ACTN4和Cdc42的mRNA水平均显著升高（P<0.05）,PFN1、RhoA和ACTN4的蛋白水平均显著或极显著升高（P<0.05;P<0.01）;在转染si-MSTN的DM3牛骨骼肌卫星细胞中,ENAH、CFL1、SCIN和Cdc42基因mRNA水平均显著升高（P<0.05）,RhoA基因mRNA水平极显著升高（P<0.01）,PFN1和ACTN4的蛋白水平均显著升高（P<0.05）。结果表明,干扰MSTN可以促进肌动蛋白细胞骨架调节通路相关基因的表达,探明了MSTN可能通过介导肌动蛋白细胞骨架调节通路影响牛骨骼肌卫星细胞增殖和成肌分化的分子机制,为进一步研究MSTN对牛成肌分化的调控机制提供参考。     

牛肺疫临床症状及综合防治

牛肺疫又被称为牛传染性胸膜肺炎,是由肺炎支原体感染引发的急慢性呼吸道疾病,临床上主要表现为呼吸急促,呼吸困难,从鼻腔中流出脓性分泌物,主要对患病牛的肺脏、胸膜和淋巴结造成危害,典型的临床特征是肺小叶浆液性肺炎和肺实质纤维素性肺炎,被国际兽医局划归为A类动物疫病,我国将其划归为一类重大动物疫病,发生流行后,需要执行严格的扑杀、无害化处理制度,逐渐净化牛群,避免疫情进一步扩展蔓延到造成更为严重的经济损失。该文主要论述牛肺疫的临床症状和综合防治措施。     

Study on Clinical Efficacy of Oligosaccharide Sulfate and Dextran Sulfate Against Bovine Mastitis

In order to detect the clinical efficacy of oligosaccharide sulfate(DEAE) and dextran sulfate (DS-4000) against bovine mastitis,56 cows with bovine mastitis were divided into 5 groups (DEAE group,DS-4000 group,DEAE＋penicillin group,DS-4000＋penicillin group and penicillin group),and their breasts were perfusion with different drugs twice one day for 3 days.The effective rates of drugs were observed by clinic symptoms.Milk samples were collected before and after treatment of drugs,and the bacterial negative conversion rate of each group were detected by microbial examination.The results showed that total effective rates of 5 groups were 10.00%,20.00%,58.33%,75.00% and 50.00%,respectively,and the bacterial negative conversion rates were 0,12.50%,50.00%,54.55% and 44.44%,respectively.In conclusion,the curative efficiencies of the polysaccharides against bovine mastitis were weak,but it could be improved by combination with penicillin.     

Cloning and Bioinformatic Analysis of L1 Gene of BPV from Guizhou Province

In order to study and analyze L1 gene of bovine papillomavirus（BPV）in Guizhou province,the L1 gene of BPV-GZ01 strain was amplified,cloned and sequenced using bioinformatic softwares and methods,and the secondary structure,tertiary structure,B-cell preponderant epitope,conserved domains analysis, transmembrane domain and signal peptide of L1 gene were predicted.The results showed that the length of L1 gene was 1 494 bp,encoding 497 amino acids.The L1 gene of BPV-GZ01 strain shared an amino acid identities of 98.6%,99.4%,98.4%,94.4% and 91.3%,and a nucleotide identities of 99.1%,99.8%,99.4%,87.6% and 82.8% with those of BPV2,BPV2-SW01,BPV2-AKS01,BPV13 and BPV1 strains,respectively.The results of phylogenetic tree analysis indicated that there was a close relationship between BPV-GZ01 and BPV2-SW01 strains.The prediction of secondary structure of L1 protein indicated that the random coil,extended strand and alphahelix took a higher percentage.The L1 protein was supposed contain 6 potential antigen epitopes.And no transmembrane domains and no signal peptide were found.The tertiary structure of L1 protein was curved spiral structure.These results provided a theoretical basis for immunologic diagnosis and further research of nucleic acid vaccine of BPV.     

Improved development of somatic cell cloned bovine embryos by a mammary gland epithelia cells in vitro model

Previous studies have established a bovine mammary gland epithelia cells in vitro model by the adenovirus-mediated telomerase (hTERT-bMGEs). The present study was conducted to confirm whether hTERT-bMGEs were effective target cells to improve the efficiency of transgenic expression and somatic cell nuclear transfer (SCNT). To accomplish this, a mammary-specific vector encoding human lysozyme and green fluorescent protein was used to verify the transgenic efficiency of hTERT-bMGEs, and untreated bovine mammary gland epithelial cells (bMGEs) were used as a control group. The results showed that the hTERT-bMGEs group had much higher transgenic efficiency and protein expression than the bMGEs group. Furthermore, the nontransgenic and transgenic hTERT-bMGEs were used as donor cells to evaluate the efficiency of SCNT. There were no significant differences in rates of cleavage or blastocysts or hatched blastocysts of cloned embryos from nontransgenic hTERT-bMGEs at passage 18 and 28 groups (82.8% vs. 81.9%, 28.6% vs. 24.8%, 58.6% vs. 55.3%, respectively) and the transgenic group (80.8%, 26.5% and 53.4%); however, they were significantly higher than the bMGEs group (71.2%, 12.8% and 14.8%), (p < 0.05). We confirmed that hTERT-bMGEs could serve as effective target cells for improving development of somatic cell cloned cattle embryos.     

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.