Getting More from the Calf Crop: Calfhood Implants

Growth-promoting implants are one of the most economical technologies available to beef producers. Implanting calves during the suckling phase improves weaning weight and creates an opportunity for producers to capture more value for each calf to improve profitability. Despite data that strongly support heavier weaning weights with a calfhood implant, implants in the suckling calf phase are less adopted than implants used in the feedlot phase.

Why are calfhood implants underutilized¹?

• Unfamiliarity with the weight advantage
• Concerns about the impact of calfhood implants on subsequent performance
• Perception that non-implanted calves receive a premium on sale day
• Concerns about the use of calfhood implants for replacement heifers

The Value of a Calfhood Implant

Calfhood implants consistently increase growth rate in suckling calves, resulting in more saleable weight. There are two calfhood implants available for calves weighing up to 400 lbs:

Steer	Heifer	Company	Implant	Active Ingredient(s)	Potency	Min (days)	Max (days)	Ideal (days)
X	X	Merck	Ralgro	36 mg zeranol	Low	30	100	60–90
X	X	Zoetis	Synovex-C	100 mg progesterone and 10 mg estradiol benzoate	Low	30	100	60–90

 

Calves must be 45 (Synovex-C) to 60 (Ralgro) days of age before an implant can be administered. At this age, a calf’s potential for lean growth has increased, and an implant can allow the calf to use nutrients more efficiently and increase lean muscle accretion, resulting in improved weaning weight. Calves that received an approved implant during the suckling calf phase are on average 23 pounds heavier at weaning than non-implanted calves^2,3. This additional weaning weight can substantially increase returns. At current calf prices, an additional 23 pounds of weaning weight can add $80 to $100 in value per calf, while the implant itself only costs a few dollars. Few management practices in the cow-calf sector offer a comparable return on investment.

Effect of a calfhood implant on subsequent performance

There are misconceptions that calfhood implants will hinder performance in later phases of production. Pritchard and colleagues⁴ compared steer calves that were implanted during the suckling phase with non-implanted calves, managed them similarly after weaning, and followed through the feedlot. At the time of weaning, implanted calves weighed 22.0 pounds heavier than non-implanted calves. Calves that received a calfhood implant were 20.1 pounds heavier at the end of the feedlot growing period and had 15.0 pound heavier final BW compared to the steers that did not receive a calfhood implant. Postweaning daily gain in the growing and finishing phase did not differ among steers that received a calfhood implant and their non-implanted cohorts. These data suggest the calfhood implant did not negatively impact performance in subsequent phases, and some of the added growth during the suckling phase was sustained through subsequent phases.

Like any management tool, implants should be used strategically. Implants potency should be proportional to the calf’s size/age, growth rate, and nutritional status. Suckling calves are given a low potency implant. As the animal matures, implants with increased potency are used in subsequent production phases to match their increased size, growth rate, and energy intake.

Price received for implanted vs non-implanted calves

Kansas State faculty Dr. Glynn Tonsor and Dr. David Renter partnered with Merck Animal Health to evaluate 2025 Superior Livestock Auction data from 860,433 calves⁵. There was no significant difference in price per pound between implanted and non-implanted calves.

With an additional 23 lb of weaning weight on implanted calves and no difference in price per pound, producers who skip a calfhood implant are leaving money on the table.

Considerations for implanting replacement heifers

As with steers, implanting heifers improves daily gain resulting in heavier weaning weights than non-implanted heifers. However, concerns exist related to potential impacts of exogenous estrogen on fertility of replacement. The heifer’s age at implant administration appears to have the largest impact on reproductive success. Research shows that implanting heifers between 1 and 4 months of age minimizes the risk to later fertility^6,7,8.

The bottom line

Calfhood implants remain one of the most profitable technologies available to cow-calf producers. A single low-potency calfhood implant can add approximately 15 to 25 pounds of weaning weight with minimal investment.

For producers marketing conventional calves, implanting at branding or another early processing opportunity may be one of the easiest ways to capture additional value from their calf crop.

Talk with your veterinarian, nutritionist, or extension personnel to choose the right product and timing for your calves.

 

1. Sperber J., Nuttleman B., MacDonald, J. Benefits of implant use in the cow/calf and backgrounding sectors. Vet Clin North Am Food Anim Pract. 2026; 42: 59-71.
2. Selk G. Implants for Suckling Steer and Heifer Calves and Potential Replacement Heifers. Proceedings from a National Symposium: Impact of Implants on Performance and Carcass Value of Beef Cattle. 1997.
3. Bayliff C.L., Redden M.D., Cole J.R., et al. Effects of Ralgro at branding and Revalor-G at weaning on growth performance of steer calves. Prof Anim Sci. 2017; 33:108–12.
4. Pritchard R., Bruns K., Boggs D. A comparison of lifetime implant strategies for beef steers. South Dakota Beef Report. 2003.
5. Glynn T. Tonsor and David Renter. Kansas State University. Evaluation of 2025 Superior Livestock Auc tion data. Available at: https://www.merck-animal-health-usa.com/species/cattle/ cattle-insights/beef/how-to-add-value-to-weaned-calves. Accessed October 2, 2026.
6. Sprott L.R., Corah L.R., Kiracofe G.H., et al. Effects of Ralgro and DES implants during the suckling period on later reproductive performance of beef heifers. Kansas Agricultural Experiment Station Research Reports 1979;0(1).
7. Hancock R.F., Deutscher G.H., Nielsen M.K., et al. Effects of Synovex C implants on growth rate, pelvic area, reproduction, and calving performance of replacement heifers. J Anim Sci 1994;72:292–9.
8. Rosasco S.L., Schmitz L.H., Cox S.H., et al. Effects of growth-promoting implants administered during the suckling phase on growth, conception rates, and longevity in replacement beef heifers grazing native range. Transl. Anim. Sci 2018;2:180–4.