Humoral responses to a multivalent vaccine in age-matched lambs of different bodyweight and nutrition.

K-agglutination, pilus-enzyme-linked immunosorbent assay (ELISA) and outer membrane protein-ELISAs were used to assess humoral responses after vaccination with a commercial, multivalent, ovine foot rot vaccine (Dichelobacter nodosus whole cells) in three groups of nine-month-old lambs of markedly different bodyweight, nutritional history and dietary protein supply. Mean bodyweights of lambs in low (L), medium (M) and high (H) bodyweight/nutrition groups were 22, 32 and 48 kg, respectively, at the time of vaccination. Few significant differences in humoral responses to vaccine antigens were found between groups. However, lambs in group H tended to have lower levels of antibody to a greater number of component antigens than did lambs in the other groups. These results suggest that low bodyweight due to poor nutrition is unlikely to affect the response of sheep to multivalent foot rot vaccines.