Frequency of detection of bovine herpesvirus 4 in cattle during outbreaks of infectious diseases on big dairy farms
The results of the detection of the BoHV-4 in cattle during outbreaks of infectious diseases in big dairy farms of Siberia using the polymerase chain reaction (PCR) in real time are presented. The glycoprotein L gene sequences were used as amplification targets. According to PCR results, the virus genome was found in 27,7 % of samples from animals with respiratory, gastrointestinal and gynecological diseases. Most often, the virus was present in nasal swabs of calves aged 2 - 3 months (80,0 %), lungs (46,2 %) and bronchial lymphnodes (38,5 %) with pneumonia. In cows, the virus was detected in 20 % of samples with diarrhea and in 10 % of samples with gynecological pathology. Most often, BoHV-4 was present as a mono agent. In respiratory diseases of calves, it was found as a mono agent in 58,1 % of the samples, and in association with BoHV-1 in 21,6 %, with cattle coronavirus (BoCV) in 20,3 % of samples of the biomaterial. In gastrointestinal diseases in calves, the virus was present as a mono agent. In gynecological pathology in cows, BoHV-4 was detected as a mono agent in 10 % of samples, and in association with the BVDV1 in 6 % of cases. The presence of some viruses simultaneously in an animal can enhance the severity of the pathological process during respiratory and gynecological pathologies of animals due to their synergistic interaction with each other.