Growth performance in heavy lambs experimentally treated with 17 ß-estradiol.

European and Italian legislation have banned use of growth promoters in livestock since 1988, but epidemiological data show that anabolic drugs are still being used illegally. Recent surveys carried out on the cattle farms in Northern Italy have confirmed the presence of growth-promoting hormones. Authors report data on growth performances in 80 Valle del Belice × Comisana weaned lambs experimentally treated with 17 beta-estradiol with 0.5 ml solution of oil Depot Estradiol ® (containing 5 mg of 17β-estradiol valerate) by intramuscular injection into the thigh. The experiment was founded by the National Ministry of Health, to validate histological test for surveillance and control of growth-promoting hormones in sheep. This study confirmed the strong correlation between clinical and anatomopathological features and growth performances of treated animals. Otherwise, no significant differences were found on in vivo performance of the lambs. Estradiol treatment showed heavier shoulders and necks on treated lambs, while the loins were significantly lighter. Moreover, lamb-estradiol-treated groups showed lower separable and inseparable fat percentage than lamb-control groups.