601657 Disclosed is a method for improving feed utilization efficiency or increasing the rate of weight gain in a non-human animal, wherein the method comprises administering to the nonhuman animal an amount of zilpaterol or a salt thereof, an amount of melengestrol acetate, an amount of monensin or a salt thereof and an amount of tylosin or a salt thereof, wherein the amount of zilpaterol is about 1 to about 200 mg/animal/day, the amount of melengestrol acetate is about 0.01 to about 2 mg/animal/day, the amount of monensin is about 10 to about 500 mg/animal/day, and the amount of tylosin is about 10 to about 150 mg/animal/day. Also disclosed is a composition comprising zilpaterol, melengestrol acetate, monensin and tylosin and the use of zilpaterol, melengestrol acetate, monensin and tylosin in the manufacture of a medicament for improving feed utilization or increasing the rate of weight gain.
