Stilbestrol for Growing-fattening Cattle

The production of beef in South Dakota is one of the largest industries in the state. Those in the business of producing beef are constantly looking for newer methods of management, nutrition and breeding which will economically increase the production of beef. It has been shown that adding diethylstilbestrol to the rations or implanting diethylstilbestrol pellets in the ears will generally economically increase beef production by increasing rate of gains and feed efficiency. Several questions have been raised by livestock producers and research workers since the introduction of stilbestrol in beef cattle production. Some questions are: Does the administration of stilbestrol affect carcass grade, or the properties of lean to fat in a carcass? What are the effects of administering stilbestrol over a long period of time? Does the administration of stilbestrol lose its advantages when administered over a long period of time? Is there any advantage of administering stilbestrol in only certain phases of beef cattle production or should it be administered continuously from weaning to slaughter? What are the advantages of administering stilbestrol in each of the three major phases from weaning to slaughter? How does orally administered stilbestrol compare to implanted stilbestrol? How long does it take a stilbestrol implant to be absorbed in ears of cattle? Is the stilbestrol pellet residue found in the ears of cattle at the time of slaughter still potent? The experiments reported in this thesis were designed to help answer some of these questions