Presence of bovine virus diarrhea in association with other pathologies in feedlot cattle

Abstract

Bovine feedlots are intensive production systems of significant importance in Mexico. The present study describes the presence of bovine virus diarrhea (BVD) causing subacute to chronic lesions in feedlot cattle, associated with other pathologies. Animals included in this study were discarded after they received therapy several times due to chronic pneumonia, or anaplamosis. Bovine virus diarrhea antigen was identified by immunohistochemistry in small intestine and myocardium in six cases of chronic suppurative bronchopneumonia with extensive areas of casseous necrotic bronchiectasis, previ­ously diagnosed as Mycoplasma bovis pneumonias (retrospective group, n = 6). Furthermore, based on characteristic histopathologic lesions other nine cases were included (prospective group, n = 9). Bovine virus diarrhea antigen was recognized in two animals with pneumonic lesions, including a case with fibrinous bronchopneumonia as well as sugges­tive lesions of infectious bovine rinotracheitis (1/9), and another one with suppurative bronchopneumonia and myocarditis suggestive of Histophilus somni (1/9). In addition, one positive case was associated to anaplasmosis (1/9). Other two posi­tive cases showed a conspicuous fibrinous peritonitis (2/9). The rest of the animals in this group resulted negative (4/9). Histopathological characteristics of the lesions and their association with the antigen in situ confirm the presence of BVD. This presentation is compatible with the acute infection syndrome. This is the first report of BVD infection and concomitant pathologies in feedlot cattle in Mexico.