新疆南疆安格斯牛繁育场犊牛呼吸道病毒病病原调查

Investigation on pathogen of calf respiratory virus disease in Angus cattle breeding farm in southern Xinjiang

牛呼吸道疾病综合症(BRDC)是世界养牛业的常见传染病。新疆引进安格斯肉牛养殖的历史较短,南疆地区养殖安格斯肉牛尚属新鲜事物,对于BRDC的流行情况规律与特点尚缺乏足够的认识。为了解南疆规模化肉牛场犊牛BRDC的流行现状及主要病毒病感染情况,为南疆地区更好地开展BRDC的防控工作提供数据支持。本试验对引起BRDC的5种常见病毒:牛传染性鼻气管炎病毒(IBRV)、牛腺病毒3型(BAV-3)、牛病毒性腹泻病毒(BVDV)、牛副流感病毒3型(BPIV-3)及呼吸道合胞体病毒(BRSV)进行检测,并对4个安格斯肉牛繁育场犊牛发病率、感染率、混合感染率、各场感染率及不同时间感染率进行统计分析。结果表明,犊牛BRDC主要发病于春夏两季,春季发病率显著升高,夏季达到峰值。样品检测IBRV、BAV-3、BVDV及BPIV-3阳性率分别为:22.0%(50/227),14.9%(34/227),5.2%(12/227),4.4%(10/227),未检测出BRSV;二重感染中以IBRV+BVDV为主,感染率为4.7%(8/170);三重感染为IBRV+BVDV+BAV-3混合感染,感染率为2.3%(4/170),未检测到四重感染,检测结果显示A、B、C场在冬、春和夏季采集检测的样品除BRSV外,其余各病毒均有检出,以IBRV感染率最高,D场仅检出IBRV;混合感染以春、夏两季样品检出为主,且犊牛BRDC主要发病于春、夏两季,亦证明该地区牛场病毒的感染及传播是发生BRDC的主要原因之一;秋季样品检测结果显示病毒检出率大幅降低,且犊牛BRDC发病率大幅减低,因与秋季犊牛群体免疫接种有关。上述4个场区犊牛呼吸道病毒病以IBRV感染为主,并伴有与BVDV、BAV-3等病毒混合感染,主要在春、夏两季发病率升高。因此,应建立定期病原检测、病毒疫苗免疫、剔除持续性感染牛和加强场区生物安全风险管理方面的综合防控。

Bovine respiratory syndrome(BRDC)is a common infectious disease in the world cattle industry.The history of introducing Angus beef cattle breeding in Xinjiang is relatively short.The breeding of Angus beef cattle in southern Xinjiang is still a new thing,and there is still a lack of sufficient understanding of the epidemic law and characteristics of BRDC.This study aims to investigate the epidemic status and main virus infection of calf BRDC in large-scale beef farms in southern Xinjiang,and to provide data support for better prevention and control of BRDC in southern Xinjiang.Five common viruses causing BRDC were infectious bovine rhino tracheitis virus(IBRV),bovine adenovirus type 3(BAV-3),bovine viral diarrhea virus(BVDV),bovine parainfluenza virus type 3(BPIV-3)and respiratory syncytial virus(BRSV)were tested,and the incidence rate,infection rate and mixed infection rate of calves of four Angus beef cattle breeding farms were analyzed.The infection rate of each field and at different times were statistically analyzed.The calf BRDC mainly occurred in the two seasons of spring and summer,and the incidence rate increased significantly in spring,and reached the peak in summer.The positive rates of IBRV,BAV-3,BVDV and BPIV-3 were 22.0%(50/227),14.9%(34/227),5.2%(12/227)and 4.4%(10/227),respectively.IBRV+BVDV was the main secondary infection,and the infection rate was 4.7%(8/170).The triple infection was the mixed infection of IBRV+BVDV+BAV-3,and the infection rate was 2.3%(4/170).No quadruple infection was detected.The test results showed that all viruses except BRSV were detected in the samples collected in winter,spring and summer in field A,B and C.The infection rate of IBRV was the highest,and only IBRV was detected in field D.Mixed infection was mainly detected in spring and summer,and calf BRDC mainly occurred in spring and summer,which also proved that the infection and transmission of cattle farm virus in this area was one of the main causes of BRDC.The autumn samples showed that the detection rate of virus decreased significantly,and the incidence rate of calf BRDC decreased significantly,because of the group immunization of calves in autumn.The above four areas of calf respiratory virus disease mainly infected by IBRV,and were mixed with BVDV,BAV-3 and other viruses,mainly in the spring and summer two quarter incidence rate increased.Therefore,we should establish regular pathogen detection,virus vaccine immunization,eliminate persistent infection(PI)cattle and strengthen the comprehensive prevention and control of biosafety risk management in the field.