本试验采用现场流行病学调查、临床检查、病理剖检、病料细菌学检测及PCR检测对新疆石河子市某规模化牛场成年牛与犊牛的死亡病因进行了诊断.结果表明,该场2016年3~5月份共有67头牛发病,死亡14头,其中成年怀孕牛41头,死亡8头,病死率为19.51%;2~8周龄犊牛发病26头,死亡6头,病死率为23.07%.成年牛与犊牛均表现出体温升高、口腔溃疡、腹泻,部分成年牛表现流产、产死胎、跛行等;剖检可见病死牛肠黏膜溃疡、脱落、出血等;无菌采集病死牛心血及肝组织接种于LB肉汤培养,但未检测到相关病原菌;采用BVDV特异性引物对气管拭子和肠内容物拭子进行RT-PCR检测,得到预期286bp目的条带,与Genbank登录的部分BVDV参考株的同源性为90.6%~92.6%.最终确诊,该规模化牛场成年牛与犊牛的死亡病因主要是BVDV感染.%To determine the cause of death of adult cows and calves in a large-scale dairy farm in Shihezi Xinjiang. Field epidemiological investigation, clinical examination, pathologic examination, bacteriological examination and PCR detection were carried out. Sequence analysis of PCR products was carried out. After field investigation and laboratory diagnosis, 67 cows were killed and 14 cows were killed in March to May, of which 41 cows were pregnant and 8 died. The fatality rate was 19.51%, 26 calves of 2 ~ 8 weeks were killed and 6 calves died. The fatality rate was 23.07%. Adult cows and calves are showing elevated body temperature, mouth ulcers, diarrhea, some adult cattle performance miscarriage, stillbirth, limp, etc. Necropsy can be seen dead intestinal ulcer, shedding, bleeding, etc. The results of RT-PCR showed that the expected band of 286bp was obtained by tracheal swab and intestine swabs, which were different from those of the BVDV reference strains registered in Genbank.There were no detectable bacteria in the liver tissue after inoculation of LB broth. The homology was 90.6%~92.6%. It is indicated that the death of adult cows and calves was caused by BVDV in the scale cattle farm.
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