BVDV and BHV-1 Infections in Dairy Herds in Northern and Northeastern Thailand
1 Division of Parasitology and Virology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
2 Department of Pathobiology, Faculty of Veterinary Medicine, Khon Kaen University, Thailand
3 Department of Ruminant Medicine and Veterinary Epidemiology, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
4 Department of Medicine, Faculty of Veterinary Medicine, Khon Kaen University, Thailand
5 Department of Surgery and Theriogenology, Faculty of Veterinary Medicine, Khon Kaen University, Thailand
Acta Veterinaria Scandinavica 2004, 45:181-192 doi:10.1186/1751-0147-45-181Published: 31 December 2004
Bulk milk samples from 220 dairy herds were collected at 9 public milk collection centres in the northeastern and northern Thailand, and a subset of 11 herds was selected for individual testing. The samples were tested for presence of antibodies to BVDV and BHV-1 using an indirect ELISA. The results from the bulk milk testing demonstrated a moderate level of exposure to BVDV and BHV-1 (73% and 67%, respectively). However, the low proportion of herds with high BVDV antibody-levels (13%) and the low within-herd seroprevalence of BVDV and BHV-1 in the 11 herds (24% and 5%, respectively), particularly among the young stock (15% and 0%, respectively), demonstrated a low prevalence of active BVDV infection and a low rate of reactivation of latent BHV-1. The presence of a self-clearance process was also indicated by the results from the individual testing. Moreover, a surprisingly low prevalence of BVDV and BHV-1 antibody-positive herds at one of the milk centres was found. This centre was established 5–10 years before the others. Our impression is that this reflects the self-clearance process, where consecutive replacement of imported infected animals without further spread has resulted in a nearly total elimination of the infections.
Based on our experiences and on these results we are convinced that this process can continue if there is awareness of herd biosecurity. This is especially important in the context of a future intensification of the dairy production.