The use of a non-specific defence mechanism inducer in calves exposed to bovine herpesvirus-1 infection: Preliminary trials

The efficacy of an immunomodulator, the Baypamun (Bayer AG), was tested in calves which were subsequently exposed to bovine herpesvirus-1 (BHV-1) infection. Two groups of calves, of 8 animals each, were used for two trials. In one trial, 4 calves were treated with the immunomodulator and the remaining 4 were left as untreated controls. Two hours after the first injection of Baypamun, all calves, i.e. the treated and the untreated ones, were challenged with BHV-1. Comparing them to the untreated controls, the calves which were given the immunomodulator developed milder signs of the disease and shed a significantly lower concentration of virus. In the second experiment, 4 calves were given Baypamun and 4 calves were not, as above, but they were not inoculated with BHV-1; however, they were housed together with the calves of the former group (experimentally infected with BHV-1). The 8 calves all became infected but those that had been treated with Baypamun did not show any clinical signs of the disease, whereas the untreated calves underwent a clinical response which was considered to be typical of BHV-1 respiratory infection, as usually seen under natural conditions. In this case the shedding of virus by the calves treated with the immunomodulator also underwent a significant reduction. On a testé l'efficacité d'un immunomodulateur, le Baypamun (Bayer AG), chez des veaux que l'on a ensuite exposés à l'infection de l'herpesvirus-1 des bovins (BHV-1). Deux groupes de 8 veaux ont été utilisés pour deux expériences. Dans la première, on a inoculé l'immunomodulateur à 4 veaux, et 4 ont été laissés comme contrôles non traités. Deux heurs après la première injection de Baypamun, on a soumis tous les veaux—traités et non traités—à BHV-1. Par rapport aux contrôles non traités, les veaux auxquels l'immunomodulateur avait été injecté ont développé des signes moindres de la maladie et présenté une concentration de virus considérablement inférieure. Au cours de la seconde expérience, on a, comme ci-dessus, injecté du Baypamun à 4 veaux et laissé les 4 autres sans traitement, mais on ne leur a pas, ensuite, inoculé de BHV-1; toutefois, on les réunis aux veaux du groupe précédent (expérimentalement infectés avec BHV-1). Les 8 veaux ont tous contracté l'infection, mais ceux qui avaient été traités avec le Baypamun ne montraient aucun signe clinique de la maladie, tandis les veaux non traités ont présenté une résponse clinique que l'on a considérée comme étant typique de l'i