Date of this Version
This NebGuide discusses the mechanism of action and use strategies for growth promoting implants, including expected responses and cost analysis.
Growth promoting implants have been used extensively in beef production for over 30 years. Significant changes in implants and implanting strategies have occurred. Prior to 1987, available implants were estrogenic agents which metabolically enhanced nutrient use to enhance growth. These products improved feed efficiency 5-10 percent and daily gains from 5-15 percent. In 1987, the androgenic (tissue building) agent, trenbolone acetate, was approved for use in growth promoting implants. This compound had an additive effect with existing estrogenic implants. The androgenic implant enhanced muscle growth and added an additional 2-3 percent to the feed efficiency and 3-5 percent to the daily gains. The return on implant investment varies, but only in rare situations do implants return less than $5 per $1 spent. Implants are available for all cattle except calves less than 45 days old and most breeding cattle. Proper scheduling and use of implants should return in excess of $10 per $1 spent.
Today, implants have become almost designer products with varied doses and combinations of estrogenic and/or androgenic agents. While implants tend to be most effective in feed yards, implanting strategies have been effectively applied to other beef production situations. The growth promoting implants approved for use in the United States are extremely safe. Safe not only for the cattle, but for producers who use the products and for the consumers who consume the beef produced from implanted cattle. There is no withdrawal time for any of the approved implants available in the United States.