Growing Beef Newsletter
June 2026, Volume 16, Issue 12
The role of β-agonists in sustainable cattle production
Aimee Wertz-Lutz, IBC Director and ISU Extension feedlot specialist
The term sustainability gets used extensively in cattle production today, and the term seems to have different meanings depending on where it is used. McAtee et al. 2024 defines sustainable food production as the balance between environmental responsibility, economic viability, and social acceptability. While implementation of any technology that improves production efficiency (fewer inputs per unit of output) generally benefits economic viability of livestock production, it also contributes to environmental responsibility, although that is not always highlighted, and sometimes the social acceptance of a technology within livestock production faces challenges.
The development of the β-agonist Experior shifted the approach to developing technology to address both environmental responsibility and economic viability of sustainable cattle production. β-agonists are a group of FDA-regulated feed additives that shift nutrients toward lean tissue growth and away from fat tissue accretion. The promotion of lean tissue growth incorporates greater dietary nitrogen into muscle growth, resulting in less nitrogen being excreted into the environment. Commercially available β-agonists include β1-agonists (Optaflexx and Actogain) and β3-agonist (Experior).
There are nuances to the different types of β-agonists on the market. Most notably, Experior is longer-acting because the β3 adrenergic receptors do not desensitize as do the β1 receptors. FDA claims for β1-agonists (Optaflexx and Actogain) are for increased rate of gain, improved feed efficiency, and increased carcass leanness when fed for the last 28 to 42 days of the feeding period at a rate of 70 – 430 mg/hd/d. The limited feeding window is because the β1 adrenergic receptors desensitize over time and are less responsive to the agonist. Whereas the FDA claim for Experior (β3-agonist) focuses on the environmental claim of reduced ammonia gas emissions per pound of live weight and hot carcass weight in beef steers and heifers fed in confinement for slaughter the last 14 to 91 days of the finishing period at a rate of 13 to 90 mg/hd/d. The wider feeding window is because β3 adrenergic receptors do not desensitize and this provides producers greater flexibility with regard to initiation of feeding and marketing.
Research has demonstrated that the Experior product also results in increased rate of gain, improved feed conversion, and increased live and hot carcass weight. While currently available β-agonists have different FDA claims, dosage rates, and feeding lengths, both positively impact economically important traits in cattle as well as mitigate environmental emissions. Beta-agonists, however, have been reported to result in lower quality and yield grades. The impact on yield and quality grades can be a detriment or a benefit, depending on the feeding strategy. In the current market environment that favors long-fed heavy cattle where higher yield grades are a concern, use of a β-agonist may lessen the risk of yield grade 4 and 5 carcasses, which are discounted, and the extended feeding period for these cattle may compensate for the negative impacts of the β-agonist on quality grade. However, when feeding cattle for less than 200 days where heavier final weights are not a goal, attention to β-agonist dose, duration of its feeding, and marketing grids becomes more important to avoid quality grade discounts.
Mobility scores of cattle being fed β-agonists also should be considered when choosing a β-agonist. McAtee et al. 2024 reported that greater than 95% of cattle fed Experior or Optaflexx received a mobility score 1 (Normal, walks easily, no apparent lameness, no change to gait), suggesting limited to no impact of either β-agonist on mobility. Sustainable food production, defined as the balance between environmental responsibility, economic viability, and social acceptability, is a goal of livestock producers and consumers. Proper selection and use of technologies such as β-agonists, where research supports positive impacts on cattle production traits, as well as environmental metrics that contribute to improved economic viability, is important to attaining the goal of sustainable food production.
McAtee TB, Renter DG, Murphy T, Betts NB, Depenbusch BE. Cattle, carcass, economic, and estimated emission impacts of feeding finishing steers lubabegron or ractopamine hydrochloride. Transl Anim Sci. 2024 Mar 8;8:txae031. doi: 10.1093/tas/txae031. PMID: 38707257; PMCID: PMC11067785.
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