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FAQs about implants and implanting

“Why use implants?”

Few beef management practices are more cost-effective or offer a higher return on investment than properly used growth-promoting implants.

It has been shown that a well-planned and properly introduced implant program can:

  • increase average daily weight gain by 7% to 17%,1 and 
  • improve feed efficiency by 4% to 12%.1



“For how long have growth-promoting implants been improving efficiencies in cow-calf production?”

Beef producers have been using growth-promoting implants for more than 30 years to safely and efficiently increase the profitability of their operations.


“What types of growth-promoting implants are used in beef production?”

There are two types of implants cattle producers can use.

  • Estrogenic implants trigger the production of the hormone that naturally increases bone and muscle growth in the calf.
    • Ralgro® . The active ingredient in Ralgro, zeranol, is an anabolic agent and therefore not sex specific. Zeranol stimulates the pituitary gland of the animal to produce increased amounts of somatotropin, the animal's own natural growth-promoting agent.
  • Androgenic implants help build muscle mass by increasing muscle synthesis and decreasing the normal rate of muscle loss. Trenbolone acetate (TBA) and testosterone proprionate are the androgenic components of some implants on the market.
    • The active ingredients in Revalor® implants are trenbolone acetate and estradiol-17ß the active form of estradiol.



“What should I consider when structuring an implant program for my beef cattle?”

There are key points to consider when selecting the appropriate products to include in an implant program tailored to your needs and objectives.

  • Select the implant according to:
    • the age and body condition of the animal;  
    • the energy content of rations;  
    • the animal’s position in the production cycle;
    • the projected marketing date;
    • the quality grade goals.
  • Implement implant strategies from low to moderate to high potency throughout the life of the animal.
    • Using a high potency implant too early can result in an early increase in the animal’s muscle mass. This means more energy would be used to maintain muscle mass, leaving less energy available for growth.  
    • In addition, an implant strategy that is too aggressive too early may inhibit the development of fat deposition sites in muscles, reducing the grade quality of beef.


“Can I implant heifer calves that may be herd replacements?”

Heifer calves that are intended to be replacements can be implanted once between 30 days of age and weaning, with no effect on future reproductive performance.



“Are hormones safe?”

Hormones used in beef do not pose a health risk to humans, according to independent studies by major international bodies, including:

  • the World Health Organization (WHO),
  • the United Nations' Food and Agriculture Organization (FAO),
  • the European Community Scientific Committee, and
  • the FAO/WHO Joint Expert Committee on Food Additives.

A normal adult male produces 136,000 nanograms (ng) of estrogen every day. (A nanogram is one billionth of a gram.) By comparison, a six-ounce serving of beef contains approximately 3.8 ng of estrogen.2

Revalor® and Ralgro® implants have zero withdrawal period. In addition, the site of the implant is in tissue not intended for consumption.


1. Floyd J.G., N.J. Van Dyke, L.A. Kriese. Implants for growth promotion in beef cattle. Alabama Cooperative Extension System ANR-1020.
2. Canadian Animal Health Institute. Hormones: A safe, effective production tool for the Canadian beef industry.

REVALOR® is a registered trademark of Intervet International B.V. Used under license.
RALGRO® is a registered trademark of Intervet Inc. Used under license.