BVDV and BHV-1 Infections in Dairy Herds in Northern and Northeastern Thailand

Abstract

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.

Bovine Viral Diarrhoea Virus (BVDV) in Dairy Cattle: A Matched Case-Control Study

“…In Finland, a very low prevalence of positive herds was also found, which was probably related to the low cattle and herd density in that country (Niskanen, ). Another study that used the same ELISA as ours revealed a moderate level of exposure to BVDV (73%) and a lower proportion (13%) of herds with high BVDV antibody titres (Kampa et al., ). Countries that share international borders with Brazil, like Argentina and Uruguay, performed studies on herd prevalence using a different ELISA than ours and found 93.1% and 100%, respectively (Guarino et al., and Carbonero et al., ).…”

Seroprevalence and risk factors associated with infectious bovine rhinotracheitis in unvaccinated cattle in southern Veracruz, Mexico

“…Seroprevalence of BHV-1 in cattle has been reported worldwide in dairy and beef herds, and some risk factors for the presence of BHV-1 antibodies in cattle include large herd size, older age, dairy herds with presence of beef cattle, high density of herds within an area, purchased cattle, and herds located close to BHV-1 positive herds (van Schaik et al, 1998;Boelaert et al, 2005). However, information from developing countries is limited (Kampa et al, 2004). In Mexico, seroprevalence of BHV-1 has been reported in dairy (Escamilla et al, 2007;Segura-Correa et al, 2010) and beef (Solis-Calderon et al, 2003;Cordova-Izquierdo et al, 2009) cattle throughout the country, but no information is available on the seroprevalence of this virus in dual-purpose (Bos taurus / Bos indicus) cattle, commonly found in the tropical regions of Mexico.…”

Seroconversion to bovine viral diarrhoea virus and infectious bovine rhinotracheitis virus in dairy herds of Michoacan, Mexico

“…However, as pointed out by Rush et al (2001) even herds with similar management could have different IR, because of differences in animal contact patterns within herds, sources of PI animals, differential susceptibility, cattle density and virulence of the BVDV strains in the herd. Some studies show that culling of PI animal and good biosecurity measures might decrease the prevalence (Self-clearance) of BVDV (Kampa et al 2004, Lindberg and Houe 2005, Stahl et al 2008. The principal factors for introduction or reintroduction of an infection into a herd are purchase of PI animals, dams carrying PI foetus or contact with PI cattle from an infected herd (Bitsch et al 2000).…”