Active immunisation of lambs with a monoclonal antibody against clenbuterol

An experiment was undertaken with 50 Texel x Suffolk-Cheviot lambs (54+/-8. 8 days of age) to investigate the effects of active immunisation with a mur ine monoclonal antibody against clenburerol on growth and carcass character istics. Animals on treatments 1 and 2 each received 0.1 mg of clenbuterol a ntibody while animals on treatments 3 and 4 received 0.1 mg of antibody enc apsulated within a synthetic polymer. Diethylaminoethyl (DEAE)-dextran was used as the adjuvant in treatments 1 and 3 and saponin in treatments 2 and 4. Control animals were immunised with saponin only. Four immunisations wer e given at 4-week intervals. Animals were slaughtered 3 weeks after the fin al immunisation. Each vaccine evoked a similar level of antibody response w hile the control group showed no titres. Lamb growth rate did not vary sign ificantly between the vaccinated and control groups. Dressing proportion wa s higher (P < 0.05) in treatments 1 and 4 compared with the control group. Carcass length was greater (P < 0.001) in each of the vaccinated groups com pared with the control group. None of the carcass fat depth measurements va ried significantly between the control and vaccinated groups. (C) 2001 Else vier Science B.V. All rights reserved.