EPIDEMIOLOGIC ASSOCIATION BETWEEN ANTIBODY-TITERS AGAINST BOVINE VIRUS DIARRHEA VIRUS, RINDERPEST DISEASE VIRUS AND INFECTIOUS BOVINE-RHINOTRACHEITIS VIRUS IN A BUFFALO HERD

The association between antibody titres against bovine virus diarrhoea virus (BVDV), infectious bovine rhinotracheitis virus (IBRV) and rind erpest disease virus (RPDV) in buffaloes was investigated in a cross-s ectional study. Thirty-six lactating buffaloes from a herd in Landhi C attle Colony, Karachi were bled and serum samples subjected to a micro -neutralisation test at the Plum Island Animal Disease Center, USA, to categorise each buffalo either as positive or negative against each 3 viral antigens. Log-linear analysis was used to evaluate the associat ion among 3 categorical variables. The ''best-fitting'' log-linear mod el was the model of complete independence. This model includes all 3 m ain effects (BVDV, IBRV, RPDV), suggesting that the seropositivity of buffaloes against these viral antigens tended to occur independently. Estimates of parameters of the model showed that the proportion of buf faloes seropositive (97.2%) to RPDV antigen tended to be higher than e xpected, whereas the proportion of BVDV seropositive (30.6%) and IBRV seropositive (16.7%) buffaloes tended to be smaller than expected.