COMPARATIVE-EVALUATION OF SPECIFIC VACCINES AND IMMUNO-MODULATORS IN DISEASE-CONTROL OF BEEF-CATTLE

Two field trials were undertaken to evaluate specific vaccines and Biological Response Modifiers (B.R.M.) with regard to disease control of beef cattle. Clinical data and laboratory results strongly suggested a genetically determined resistance to transportation stress of some cattle breeds, with possible important consequences on the occurrence of multi-factor diseases. Plenty of calves showed detectable levels of serum interferon and a remarkable activation of at least some lymphocyte populations in the first days after arrival. In general, B.R.M.-treated cattle could better react against environmental pathogens, as evidenced by both clinical and laboratory findings. Several data emerged that even the efficacy of specific vaccines could be largely accounted for by a positive modulation of non-specific immunity; this latter feature can be mainly referred to adjuvants and/or some bacterial antigens.