Social isolation may influence responsiveness to infection with bovine herpesvirus 1 in veal calves

An experiment was performed to develop a model to study the impact of stres s on responsiveness to infection with bovine herpesvirus 1 (BHV1) in veal c alves. Social isolation after previous group-housing was used as a putative ly stressful treatment. Group-housed specific pathogen-free veal calves (n= 8) were experimentally infected with BHV1 at the age of 12 weeks. Half of t he calves were socially isolated at the time of infection. Clinical, virolo gical and serological responses to BHV1, and adreno-cortical reactivity to exogenous ACTH were examined. In comparison with group-housed calves, calve s socially isolated at the time of infection showed a diminished clinical a nd fever response, and delayed viral excretion after primary infection with BHV1. Four weeks after social isolation, basal cortisol levels before, and the integrated cortisol response after administration of a low dose of ACT H, were significantly depressed in socially isolated calves. The results su ggest that social isolation in veal calves influences the response to an ex perimental BHV1 infection. A possible mechanism is discussed. (C) 2000 Else vier Science B.V. All rights reserved.