Abstract: A composition for promoting the growth or feed conversion efficiency of meat-producing animals which contains growth-promoting amounts of growth hormone and a zearalin.

Abstract: A method of promoting growth and enhancing feed efficiency in meat producing animals. The 6' esters of zearalanol are effective growth promoting agents in meat producing animals, particularly ruminants, when implanted subcutaneously in said animals to obtain a controlled release of the compositions.Included in this group of compositions are: zearalanol 6'-butyrate; zearalanol 6'-decanoate; zearalanol 6'-hexanoate; zearalanol 6'-laurate; zearalanol 6'-trichloroacetate; and zearalanol 6'-trifluoroacetate.

Abstract: A method of administering micronutrients to animals over extended periods by subcutaneous implant. Important micronutrients, including iron, copper, selenium, zinc, manganese, cobalt, molybdenum, chromium, silicon, iodine, biotin, vitamins E and B.sub.12 are supplied conveniently, and in positive, predetermined amounts by means of subcutaneously implanted pellets containing the micronutrient and a suitable excipient to provide controlled release of the micronutrient over an extended period of time. One example comprises iron dextran in combination with a lactose, fibrin, or other suitable excipient, in the form of a pellet which is subcutaneously implanted behind the ear of piglets to supply sufficient iron for optimum growth and to avoid iron-deficiency anemia. Important trace elements which may also be administered in carefully controlled amounts in suitable salt forms by the method of this invention include nickel, tin, vanadium, fluorine and arsenic.