Growing Beef Newsletter
April 2025, Volume 15, Issue 10
Enhancing efficiency, sustainability, and profitability in beef production with growth promoting technologies
Marissa Eekhoff, ruminant nutrition graduate research assistant, and Stephanie Hansen, professor, Iowa State University
Beef producers are under increasing pressure to enhance production efficiency and sustainability while maintaining economic viability. The U.S. beef cow inventory has declined to historically low levels, reducing the total number of cattle entering feedlots. Simultaneously, industry trends have been encouraging producers to finish cattle at heavier weights to maximize beef yield per animal. These factors underscore the need for strategies that optimize feedlot performance while maintaining economic and environmental sustainability.
Growth promoting technologies provide a scientifically-backed and safe approach to improve feed efficiency, growth rates, net return, and carcass yield without compromising on beef quality. A meta-analysis comparing implanted cattle to non-implanted cattle identified a 17% improvement in average daily gain and a 9% improvement in feed efficiency with the use of implants (1). Steroidal implants and b-agonists can work through additive mechanisms to increase muscle growth and further improve feed efficiency (2). These enhancements benefit producers by increasing revenue, offsetting production costs, ultimately providing increased net returns.
Environmental sustainability can also be optimized in the beef industry with the use of growth promoting technologies. As a whole, growth promoting technologies increase environmental sustainability not only by increasing live and carcass performance, but also by reducing emissions due to improved nitrogen retention through decreased skeletal muscle breakdown, encouraging more nitrogen to remain on the carcass to be utilized for muscle growth (3,4,5). Steroidal implants are the most common use of growth promoting technologies. Beta-agonists are a feed additive and another type of growth promoting technology that shifts how an animal uses nutrients. The nutrients are partitioned to lean muscle growth over fat deposition. There are currently two b-agonists utilized in U.S. beef cattle production - ractopamine hydrochloride (marketed as Optaflexx or Actogain) and lubabegron fumarate (marketed as Experior).
Ractopamine hydrochloride is one of the most extensively researched and validated growth promoting technologies in the beef industry. Experior (lubabegron fumarate) was originally developed as a human anti-diabetic drug (6), and now is approved for use in cattle with the label claim to reduce ammonia gas emissions per unit of live and hot carcass weight in beef cattle. This b-agonist offers a variable feeding window (14 to 91 days), allowing producers to be flexible with market fluctuations.
The environmental and economic impact of growth promoting technologies was recently investigated in an experiment we completed at Iowa State University, funded by the Iowa State Beef Checkoff. Cattle were split into 4 treatment groups:
- CON - no implants or b-agonists
- IMP - Synovex Choice (69 day duration) & Synovex Plus implants (104 day duration)
- EXP - IMP + 36 mg Experior/head/day for 53 days prior to harvest, followed with a 4 day withdrawl
- RAC - IMP + 300 mg Optaflexx/head/day for 31 days prior to harvest
Additionally, all cattle were provided with 100 mg zinc/kg dry matter, which is the common industry supplementation rate, but three times the NASEM recommendations (7,8). We found the administration of growth promoting technologies led to an improvement in live and carcass measures. Final body weights were increased by 11% with the use of growth promoting technologies and hot carcass weights were increased by 12%. Notably, cattle administered Experior expressed the greatest response in hot carcass weight with an additional 20 pounds over cattle who received other technologies and 115 pounds over cattle who did not receive any technology (Figure 1). Beyond supporting additional growth, growth promoting technologies also improved feed efficiency, enabling the cattle to better utilize available feed.
These cattle were not as fat, potentially explaining some mild decreases in quality grades. The administration of implants or Optaflexx did not reduce marbling compared to non-technology cattle, however, the use of Experior did reduce marbling scores by approximately 80 points compared to non-technology cattle. While there wasn’t a difference between cattle grading select, choice, or prime based on treatment, more cattle in the treatment that did not receive growth promoting technologies graded premium choice compared to those receiving technologies. An economic analysis using 14 year averages, actual cattle performance, while setting the non-technology cattle to $0, resulted in an increased net return for producers with the use of growth promoting technologies ($39/steer with Experior, $29/steer with implants, $10/steer with Optaflexx). This response was largely due to increased hot carcass weight and improved feed efficiency in the cattle receiving growth promoting technologies.
We also investigated the effect of growth promoting technologies on estimated urinary nitrogen excretion per unit of carcass adjusted gain. As a whole, cattle who were provided growth promoting technologies had reduced urinary nitrogen excretion compared to animals who did not receive growth promoting technologies. Experior is the only growth promoting technology with a claim to reduce ammonia emissions, however, our findings indicate steroidal implants and other b-agonists, such as ractopamine, are able to improve sustainability as well (Figure 2). Growth promoting technologies encourage nitrogen retention on the carcass, developing more saleable lean meat, and overall leading to less nitrogen in the air that can volatilize to ammonina, lessening the environmental footprint of the beef industry.
In an ever-evolving industry, it is imperative for beef producers to maximize production efficiency while minimizing their environmental impact. Growth promoting technologies present an effective solution to achieve both objectives. By leveraging steroidal implants and b-agonists, the beef industry can produce more pounds of high-quality beef with fewer resources, supporting long-term sustainability and economic viability.
Literature Cited:
- Wileman, B. W., D. U. Thomson, C. D. Reinhardt, and D. G. Renter. 2009. Analysis of modern technologies commonly used in beef cattle production: Conventional beef production versus nonconventional production using meta-analysis. J Anim Sci. 87:3418–3426. doi:10.2527/jas.2009-1778.
- Arp, T. S., S. T. Howard, D. R. Woerner, J. A. Scanga, D. R. McKenna, W. H. Kolath, P. L. Chapman, J. D. Tatum, and K. E. Belk. 2014. Effects of dietary ractopamine hydrochloride and zilpaterol hydrochloride supplementation on performance, carcass traits, and carcass cutability in beef steers. J Anim Sci. 836–843. doi:doi:10.2527/jas2013-7122.
- Smith, Z. K., A. J. Thompson, J. P. Hutcheson, W. T. Nichols, and B. J. Johnson. 2018. Evaluation of coated steroidal implants containing trenbolone acetate and estradiol-17β on live performance, carcass traits, and sera metabolites in finishing steers. J Anim Sci. 96:1704–1723. doi:10.1093/jas/sky095.
- Vogel, G. J., A. A. Aguilar, ; Aubrey, L. Schroeder, W. J. Platter, S. B. Laudert, and M. T. Van Koevering. THE EFFECT OF OPTAFLEXX ® ON GROWTH, PERFORMANCE AND CARCASS TRAITS OF CALF-FED HOLSTEIN STEERS FED TO HARVEST A SUMMARY OF FOUR POST-APPROVED STUDIES.
- Carmichael, R. N., O. N. Genther-Schroeder, C. P. Blank, E. L. Deters, S. J. Hartman, E. K. Niedermayer, and S. L. Hansen. 2018. The influence of supplemental zinc and ractopamine hydrochloride on trace mineral and nitrogen retention of beef steers. J Anim Sci. 96:2939–2948. doi:10.1093/jas/sky177.
- Rincker, P. J. 2024. Experior: Development History, Commercial Launch, and Research Plans. Meat and Muscle Biology. 8. doi:10.22175/mmb.18051.
- Samuelson, K. L., M. E. Hubbert, M. L. Galyean, and C. A. Löest. 2016. Nutritional recommendations of feedlot consulting nutritionists: The 2015 New Mexico state and Texas tech university survey. J Anim Sci. 94. doi:10.2527/jas.2016-0282.
- National Academics of Sciences, E. and M. 2016. Nutrient Requirements of Beef Cattle, Eighth Revised Edition. The National Academies, Washington, DC.
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