Growing Beef Newsletter
April 2026, Volume 16, Issue 10
Getting the most out of Experior: balancing performance and marbling
Ty Skartvedt, graduate student, and Dr. Dathan Smerchek, assistant professor, Iowa State University
Over the past several decades, cattle inventory has declined while total beef production has increased (Rook & Denton, 2026). One of the primary reasons for this elevated level of production is the use of growth-enhancing technologies, specifically things like beta-agonists. A majority of feedlot cattle (85%) are fed a beta-agonist prior to harvest (Samuelson et al., 2016). Lubabegron fumarate, better known by the tradename “Experior” (Elanco, Greenfield, IN), is a beta-ligand approved to reduce ammonia emissions per unit live and carcass weight when fed for the last 14 to 91 days on feed (FDA, 2018).
While Experior is approved with an environmental claim, multiple studies show it also acts as a powerful growth promotant. Previous research on beef steers supplemented with 3.2 g/ton dry matter (DM) for the final 37 to 63 days showed substantial improvements in growth performance and carcass traits. Key benefits included higher final body weights, average daily gain, and feed efficiency, along with increased hot carcass weights, dressing percentages, and increased ribeye area (Eekhoff et al., 2025; Henderson et al., 2026; Ortner et al., 2024; Park, 2025). However, along with these improvements in growth performance and carcass characteristics, some evidence indicates Experior can reduce marbling scores (Edmonds et al., 2024; Teeter et al., 2021; Vogel et al., 2023). Because marbling is a primary economic driver for cattle marketed on a grid, managing this risk is crucial. As with most growth-enhancing technologies, understanding how dose, duration, and timing affect carcass variables is necessary to protect marbling and overall value.
In a recent study at Iowa State University we evaluated how the length of time Experior is fed prior to harvest affects cattle performance and carcass outcomes. In this study, yearling steers were fed Experior for the final 0, 21, 49, or 77 days on feed leading up to harvest. All cattle receiving Experior were fed at a rate of 3.2 g/ton DM. Steers were on feed for a total of 101 days at the Iowa State University Beef Nutrition Farm, and all cattle received a high-potency combination implant (Synovex Plus; Zoetis LLC, Madison, NJ) when the trial began.
In this experiment, we fed Experior for 49 or 77 days prior to harvest increased live body weight by 35 and 38 lbs, respectively, compared to the control group. Performance metrics also improved, with average daily gain increasing by 4.2% to 5.2% and feed efficiency improving by 7% to 10%. The observed improvements in live gains carried over to the rail, where Experior increased hot carcass weights by 22 and 26.5 lbs, respectively, for the 49 and 77 day feeding durations.
A key takeaway from this study is the relationship between feeding duration and carcass quality. When we fed Experior for 49 days or fewer, there was no negative impact on marbling score. However, when we extended the duration to 77 days there was a 12% decrease in marbling score. Based on these results, a 49-day feeding duration was able to capture significant weight gain while maintaining marbling score.
Financially, we observed that Experior provided a positive return on investment across all tested durations (21, 49, and 77 days). Compared to steers not fed the product, Experior use resulted in an ROI between $39 and $58 per head on a dressed basis.
With cattle prices at record highs, maximizing gain and carcass value is critical. This data shows that feeding Experior for 49 days can improve growth performance and carcass weight with minimal impact on carcass quality. However, extending use to 77 days increases the risk of lower marbling scores.
When managed correctly, Experior serves as a tool for producers to improve growth rates, feed efficiency, and hot carcass weights with minimal impact on quality. For further questions, please contact your local extension specialist.
Literature Cited
Eekhoff, M. K., Smerchek, D. T., McGill, J. L., & Hansen, S. L. (2025). Enhancing steer growth and efficiency through growth promoting technologies. Translational Animal Science. https://doi.org/10.1093/tas/txaf168/8404417
FDA. (2003). Freedom of information summary original new animal drug application nada 141-221 Ractopamine Hydrochloride (OPTAFLEXXTM 45) Type A Medicated Article For Beef Cattle. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/754
FDA. (2018). FOI Summary for the Original Approval of NADA 141-508. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/5005
Henderson, J. A., Mcgill, J. L., Hansen, S. L., & Hall, K. (2026). The impact of copper status on lubabegron fumarate-induced growth and adipose immune cell infiltration in beef feedlot steers. Journal of Animal Science. https://doi.org/10.1093/jas/skag047/8489913
Kube, J. C., Holland, B. P., Word, A. B., Allen, J. B., Calvo-Lorenzo, M., McKenna, D., & Vogel, G. (2021). Effects of various doses of lubabegron on calculated ammonia gas emissions, growth performance, and carcass characteristics of beef cattle during the last 56 days of the feeding period. Translational Animal Science, 5(3), 1–5. https://doi.org/10.1093/tas/txab137
Ortner, B. M., Genther-Schroeder, O., & Lonergan, E. (2024). Supporting muscle growth of feedlot cattle administered growth enhancing technologies through strategic zinc supplementation [Thesis]. https://doi.org/10.31274/td-20250502-63
Park, B. (2025). Mechanisms of lubabegron action in beef cattle involve skeletal muscle remodeling and nutrient repartitioning [ProQuest Dissertations & Theses Global]. https://www.proquest.com/docview/3280267776?pq-origsite=gscholar&fromopenview=true&sourcetype=Dissertations%20&%20Theses
Rincker, P. J. (2024). Experior: Development History, Commercial Launch, and Research Plans. Meat and Muscle Biology, 8(1), 1–4. https://doi.org/10.22175/mmb.18051
Rook, M., & Denton, A. S. (2026). CattleFax Provides Optimistic 2026 Price Outlook at CattleCon. https://www.drovers.com/markets/cattlefax-provides-optimistic-2026-price-outlook-cattlecon
Samuelson, K. L. et al. , (2016), M. E. Hubbert, M. L. Galyean, & C. A. Löest. (2016). Nutritional recommendations of feedlot consulting nutritionists: The 2015 New Mexico State and Texas Tech University survey. J. Anim. Sci, 94(6), 2648–2663. https://doi.org/10.2527/jas.2016-0282
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