Federal law does not permit the use of growth hormones in dairy cattle, veal calves, poultry or pigs. Hormones used for growth purposes in beef cattle are typically formulated into small pellets that are implanted under the skin on the back side of the animal’s ear. The implants dissolve slowly under the skin and are discarded with the ear when the animal is processed. The active ingredients, which are primarily naturally occurring hormones, are either estrogens or androgens.
American consumers have historically preferred grain-finished beef, meaning the cattle have spent most of their lives consuming grass in pastures, but spend their last four to six months being finished on a diet of grains, forages and nutritional supplements in a feeding operation.
Most male cattle (bulls) are neutered early in life and become steers. Bulls produce hormones that cause aggressive behavior and can result in injury to themselves and other animals, but those same hormones cause them to grow faster and produce more lean muscle and protein than steers. In the same manner, young heifers produce hormones, but at much lower levels than mature or pregnant heifers. Implanting young steers and heifers with a fraction of the amount of hormones they would naturally produce as mature bulls or heifers, enables them to grow faster, using less feed. Producers save money, and in turn are able to efficiently produce more affordable beef for consumers, using fewer cattle, and fewer natural resources.
A University of Minnesota Extension Service study found that growth promotants increase U.S. beef production by more than 700 million pounds while saving more than 6 billion pounds of feed. Analysis of the study concluded that if beef production practices from 1955 were still used today, beef producers would need 165 million more acres of land (almost the size of the state of Texas,) and still might not equal today’s beef production.