Abstract: The growth rate of meat-producing animals as well as the yield and quality of the meat obtained therefrom is improved by administering to the animal prior to its sexual maturation an effective amount of a female gonadal steroidal compound; namely, an estrogen or progestagen compound and preferably a mixture thereof, sufficient to delay development of the gonadal function of the animal, e.g., spermatogenesis. Such administration is terminated sufficiently prior to slaughter of the animal that the administered steroidal compound has been substantially completely removed from the animal's system which before slaughter exhibits levels of the corresponding natural hormones therein substantially within normal limits. In mammals, administration is preferably by injection, but in fish, shellfish and poultry, the active steroidal compound is incorporated at low levels in the usual feed therefor.