为了调查某规模化奶牛场犊牛腹泻的发病原因,试验采用血清抗体检测、细菌分离培养、寄生虫卵镜检和病毒核酸检测方法对腹泻犊牛的血样和粪便进行了检查。结果表明,该奶牛场牛病毒性腹泻/黏膜病病毒抗体阳性率为65.00%,牛轮状病毒抗体阳性率25.00%,牛冠状病毒抗体阳性率15.00%;分离到1 株结肠弯曲杆菌和1 株空肠弯曲杆菌;所检腹泻犊牛粪便和血液样品中,4 份粪便样品和1 份血液样品检出牛冠状病毒,2 份粪便样品检出轮状病毒,1 份粪便样品和1 份血液样品检出牛病毒性腹泻/黏膜病病毒,同一份粪便样品中同时检出牛病毒性腹泻/黏膜病病毒和牛冠状病毒;通过镜检,球虫卵囊检出率77.78%,在1 份粪样中发现蛔虫卵,2 份粪样中发现其他线虫卵。该牛场流行性腹泻的原因可能为夏季高温潮湿引起犊牛免疫力下降导致的多病原体感染。

In order to investigate and research the main reasons of calf diarrhea in a large-scale dairy farm,blood samples and faeces from sicken calfs were used for pathogen detection of bacteria,viruses and parasites in this study. The results showed that the antibody positive rate of bovine viral diarrhea/mucosal disease virus, bovine rotavirus and bovine coronavirus were 65%, 25.00% and 15.00% respectively. One campylobacter coli and one campylobacter jejuni were isolated. In all stool and blood samples, 4 stool samples and 1 blood sample were positive for bovine coronavirus, 2 stool samples and 1 blood sample were positive for bovine rotavirus, 1 stool sample and 1 blood sample were positive for bovine BVDV and 1 stool sample was both positive for bovine BVDV and coronavirus. The positive rate of cordyceps oocysts was 77.78%,ascaris eggs were found in 1 fecal sample and other angiosperm eggs were found in 2 fecal samples by microscopic examination. It's showed that the causes of massive calf diarrhea in this dairy farm were the decrease of immunity caused by high temperature and humidity in summer, which led to the infection of multiple pathogens.