ACTIVE IMMUNIZATION AGAINST CORTISOL IN FEMALE CROSSBRED LAMBS DOES NOT ALTER GROWTH RATE OR BODY COMPOSITION

Border-Leicester Merino x Poll Dorset weaner lambs were vaccinated intramuscularly with an emulsion (3 ml) containing cortisol:human serum albumin (500 WI8 Freunds complete adjuvant and saline (n=20) or vehicle alone (n=20) at 100, 170, 225 and 291 days (group mean age). . Anti-cortisol antibody titres (i.e. l/dilution of plasma) were made by radioimmunosssay (RIA) on plasma obtained via jugular venipuncture, on the day of vaccination 'and 7 days thereafter. Unfasted live weights were measured at approximately 28 day intervals. Half the animals were slaughtered at 35 kg and the remainder at 50 kg live weight. Chilled carcass weight was recorded after 16 h at 4OC. The 12th rib was exposed and photographed for analysis of eye muscle area and back fat.