Cow-calf pairs are getting moved to green grass and it is a good feeling to see them out grazing. While weaning may be a ways off, calf growth that leads to excellent calf weaning weights is a major goal of this phase of the cow-calf business. If someone asked you to give them $1.50 per steer calf at spring turn out, in return, for every 37 head (your cost is $56), they will give you an additional 550 lb steer calf at weaning. Would you take the deal? This is essentially the return cattleman can expect if they place a small hormone implant into the ear of each suckling steer calf at turn out.

In 1997 Selk from the Oklahoma Agricultural Experiment Station summarized 23 research projects evaluating performance of suckling steer calves implanted between 30 and 90 days of age, with 36 mg of a product containing the growth-promoting Zeranol. At the end of the experiment they documented a 5.3% increase in average daily gain. Over a 130 day pasture period implanted steers would wean off 13 pounds heavier than their non-implanted counterparts. Since genetics have changed and improved over the years, it is important to note that Bayliff and colleagues (year) recently found similar results when they studied a group of cattle in Oklahoma. In a 130 day pasture period, suckling steers weaned off 17 pounds heavier than their non-implanted counterparts. Additionally, work by Pritchard and colleagues at SDSU in 2015 documented implant technology can increase weaning weights of suckling steers by 22 pounds.

The SDSU study looked at the effects of suckling calf performance from implants based on timing of the implant and age of dam. They implanted calves in May or August and classified dams into two groups: less than or greater than four years of age. Overall steers from mature dams weaned heavier calves than younger dams. Steers from mature dams that were implanted in May, weaned off 40 pounds heavier than their non-implanted counterparts. However, if they were implanted in August they only added an additional 17 lbs. Conversely, steers from young dams (< 4 years of age) implanted in August weaned off 25 pounds heavier than non-implanted steers. Steers from young dams implanted in May only posted a 9 pound increase in weaning weight. Cow age definitely impacts the response that cattlemen can expect from using implant technology. Planning the implant timing based on the dam’s age will give the best possible response in suckling calves. Implant earlier in the grazing season for steers suckling older dams or later in the grazing season for steers suckling younger dams.

The amount of added gain potential that implants provide would make one think nearly every steer turned out should have one in its ear. However, according to the 2008 National Animal Health Monitoring System (NAHMS) survey, the use of implant technology in suckling calves has actually declined from 14 percent to 9.8 percent over a ten-year period. The reasons for this decline are not fully known or understood. Some of these non-implanted calves are likely being sold into specialty or branded programs that prohibit anabolic implant use. However, another reason cattle managers leave suckling implants out of their tool box is the “stigma” that calves implanted in the suckling phase are discounted at the sale barn.

In 2015 Rogers and colleagues published results from studying the effects of growth-promoting implant status on sale price of beef calves sold through livestock video auction services from 2010 to 2013. Over the three years they noted about 28% of the weaned steers marketed had received an implant prior to weaning. They found that implant status of calves had no effect on the sale price of beef calves. In other words there were no discounts as a result of using implant technology or more over no cattle received premiums for their non-implant status.

Another reason suckling calf implant use may have declined is the thought that previously implanted calves do not respond as well to subsequent implants in the growing and finishing phase. Two SDSU studies, one by Pritchard and colleagues (2015) and one by Web and colleagues (2017) further studied the impact of suckling calf implants on post-weaning live animal and carcass performance. Both studies found there were no effects on average daily gain, or feed efficiency in the receiving, backgrounding or finishing phase if a calf was previously implanted during the suckling phase of life. Both studies found there were no negative impacts from suckling implants on subsequent carcass characteristics.

So after ruminating on all that—who will take the deal proposed in the first paragraph?


  • Bayliff, C. L., M.D Redden, J. R. Cole, A.L. McGee, C. Stansberry, M. E. Corrigan, W. Burdett, and D. L. Lalman. 2016. Effect of Ralgro at branding and Revalor-G at weaning on growth performance of steer calves. The Professional Animal Scientist 33:108-112.
  • Pritchard, R. H., A. R. Taylor, S. M. Holt, K. W. Bruns, And H. M. Blalock. 2015. Time of suckling implant influences on weaning weight, post-weaning performance, and carcass traits in steer calves. Pages 40-45 in South Dakota Beef Report. South Dakota State Univ., Brookings, SD.
  • Rogers, G. M., M. E. King, K. L. Hill, T. E. Wittum, and K. G. Odde. 2015. The effect of growth-promoting implant status on the sale price of beef calves sold through a livestock video auction service from 2010 through 2013. The Professional Animal Scientist 31:443-447.
  • Selk, G. Implants for suckling steer and heifer calves and potential replacement heifers. 1997. P. 40–49 in Symposium: Impact of Implants on Performance and Carcass Value of Beef Cattle. P-957. Oklahoma Agric. Exp. Stn., Stillwater, OK.
  • USDA. 2008. Beef 2007-08, Part III: Changes in the U. S. Beef Cow-Calf Industry, 1993-2008. USDA: APHIS:VS, CEAH. Fort Collins, CO #518.0509.
  • Webb, M. J., A. A. Harty, R. R. Salverson, J. J. Kincheloe, S. M. S. Zuelly, K. R. Underwood, M. K. Luebbe, K. C. Olson, and A. D. Blair. 2017. Effect of nursing-calf implant timing on growth performance and carcass characteristics. J. Anim. Sci. 95:5388-5396.

Source: SDSU iGrow