Dr. Glenn Selk, Professor-Animal Reproduction Specialist Animal Science - Oklahoma State University, Stillwater, OK
Many new technologies have been made available to the beef industry over the last 50 years. Few technologies have the potential return on investment as do growth promoting implants for nursing calves. The term "implant" is used to refer to a group of products used in the cattle industry that increase rate of growth by placing an absorbable product under the skin on the back of the ear. Each type or brand of implant has its own specific applicator, which is used to properly administer the implant. Implants contain natural or synthetic anabolic compounds that produce physiological responses similar to hormones that are already produced in varying quantities in the body. Calves intended for "natural" or "organic" markets should not be implanted.
Implants cleared for use in nursing calves contain a lower dose of the active ingredient compared to products cleared for use with older cattle. These "calf" implants are typically administered when calves are between 2 and 4 months of age. Research summaries have shown that implants given during the suckling phase will increase average daily gain of steer calves by 0.1 pound per day. The response in heifer calves is slightly higher at 0.12 to 0.14 pound per day. Over 150 days of the remaining nursing period, this additional gain can amount to 15 pounds in improved weaning weights in steers and 18 to 21 pounds in weaned heifer calves.
The value of this additional weight gain is difficult to accurately predict. Heavier calves often are priced slightly less per pound than lighter calves. In today's market, a conservative estimate of 75 cents per pound of added gain should be appropriate to evaluate the efficacy of implanting. Assuming a cost of $1.00 per implant, a $10 to $12 return on each implant dollar invested can be expected.
Producers often raise the question, "Is it safe to implant replacement heifers?" Research has shown that heifer calves implanted one time at about 2 months of age had very little impact on subsequent conception rates or calving difficulty. Heifers that were implanted at birth, after weaning, or multiple times had lower reproductive rates than non-implanted heifers. Bull calves that may remain as bulls to become herd sires should not be implanted. Once again, the key is to read and follow label directions precisely. (Source: Selk, G. E., 1997. Implants for Suckling Steer and Heifer Calves and Potential Replacement Heifers. Symposium: Impact of Implants on Performance and Carcass Value of Beef Cattle. P-957. Oklahoma Agricultural Experiment Station. )