According to research reviewed by Gram, feeding the feed additive lubabegron to beef steers for the final 91 days before slaughter reduced muscle protein breakdown and cut calculated ammonia gas emissions by 9.21% in a 2026 study of 16 Angus steers. Growth and blood sugar control were unchanged.
Gram Research analysis of a 2026 study in the Journal of Animal Science looked at whether a feed additive called lubabegron, sold as Experior, changes how beef cattle use protein. Researchers fed 16 Angus steers either a standard corn diet or the same diet with the additive during the final 91 days before slaughter. The additive did not change how much the steers ate or how fast they gained weight, and it did not affect blood sugar control. However, the treated cattle broke down less muscle protein, produced less urine, and generated about 9 percent less ammonia gas in their waste. Steers on the additive also had larger ribeye muscle areas. The study is small and short, so these results are promising but not yet proof for every farm.
Key Statistics
A 2026 study of 16 Angus steers published in the Journal of Animal Science found that feeding lubabegron for the last 91 days reduced calculated ammonia gas emissions by 9.21% compared with control steers.
In the same 2026 study of 16 Angus steers, lubabegron did not change glucose or insulin responses, while treated steers showed reduced skeletal muscle protein breakdown and a larger ribeye muscle area (P < 0.01).
The Quick Take
- What they studied: Whether a feed additive called lubabegron changes how beef cattle use protein, break down muscle, handle blood sugar, and produce waste during the last part of their feeding period.
- Who participated: 16 Angus steers, which are castrated male cattle, that began the study weighing about 553 kg (about 1,220 pounds). They were housed one at a time in outdoor pens and split into two randomly assigned groups.
- Key finding: Steers on the additive produced about 9.21% less calculated ammonia gas (P = 0.004), broke down less muscle protein, and had larger ribeye areas (P < 0.01). Growth, feed intake, and blood sugar response did not change. A P value below 0.05 means the difference is unlikely to be due to chance alone.
- What it means for you: For most people, this is a research update about how cattle farms may reduce their environmental impact, not a reason to change your diet. Consumers may see farm practices shift over time, but these findings come from one small study and do not yet prove benefits for other herds.
The Research Details
Researchers used a randomized, block-based design. They sorted the 16 steers into groups with similar starting traits, then randomly assigned each steer to either a control diet or a diet containing lubabegron. Each steer lived in its own outdoor dirt pen and ate a steam-flaked corn-based diet once a day, with food available over a full 24-hour period.
The additive was added at a rate of 3.2 grams per ton of dry feed for the last 91 days. Researchers gave a glucose tolerance test twice during the study to see how the animals handled sugar. They also collected all feces and urine for 5 days to track how much nitrogen, the main building block of protein, the animals kept or lost.
After a 4-day break from the additive, all steers were slaughtered at a USDA-inspected plant and carcass measurements were recorded. Statistical analysis used a mixed models method, which accounts for grouping and repeated measurements, to compare the two groups.
Randomly assigning animals to groups, and comparing them to a control group, helps show whether the additive itself caused the differences rather than some other factor. Collecting all waste over several days gives a direct picture of nitrogen balance, and the glucose test checks for unwanted effects on metabolism. These features make the findings more trustworthy than a simple farm observation, although a small sample still limits how certain we can be.
Strengths include the randomized design, a control group, complete waste collection, carcass measurements, and publication in a peer-reviewed journal. Important limits include the small number of animals (16), a single breed, a single diet, one feeding period, and male cattle only. Some numbers in the published abstract are garbled, so readers who want exact figures should check the full paper. The additive is made by Elanco Animal Health, so it is worth reviewing the paper’s funding disclosure.
What the Results Show
Cattle on the additive did not weigh more or less at the start or end of the study, did not eat more or less, and did not gain weight faster or slower. Feed efficiency was also similar between groups. In this trial, the additive did not appear to change how much weight the animals gained.
The main protein finding was that steers on lubabegron broke down less skeletal muscle protein. Nitrogen retention, which describes how much of the protein in their feed the body held onto, did not differ between groups. The researchers concluded that the additive shifted muscle turnover without changing the overall nitrogen balance.
Urine output dropped in the treated steers (P = 0.02), and calculated ammonia gas emissions were 9.21% lower (P = 0.004). Ammonia is a gas from animal waste that contributes to air quality concerns near feedlots, so this is the most practical environmental result.
Glucose and insulin responses during the glucose tolerance test did not change, which suggests the additive did not interfere with how these steers processed sugar.
The ribeye muscle area, known in the industry as the longissimus muscle area, was larger in steers fed lubabegron (P < 0.01). This measurement is commonly used to judge carcass quality, so the result is notable even though the study was small. Yield grade, a score that estimates the share of usable retail cuts, tended to be higher in control steers (P = 0.09). Because this difference did not reach the usual statistical threshold, it should be treated as a trend rather than a firm result.
The FDA approval of lubabegron was based on reduced ammonia emissions per unit of animal weight, and this study adds detail about the body processes that may explain that effect. It fits a broader area of research on beta-adrenergic modulators, a class of compounds that can change how animals use energy and protein. This paper looks at nitrogen balance, muscle turnover, and blood sugar handling together, a combination that had received limited study in beef cattle. The abstract does not describe detailed comparisons with specific earlier trials.
Only 16 steers were studied, which makes it hard to detect small differences and means one unusual animal could influence results. All animals were one breed, fed one diet, and followed for one 91-day feeding window. Only male cattle were included. Ammonia emissions were calculated from nitrogen measurements rather than measured directly in the air. The study did not track meat quality or consumer outcomes beyond carcass data. Some statistics in the abstract are incomplete, so the full paper is needed for precise details.
The Bottom Line
Feedlot managers considering lubabegron should treat these findings as promising but preliminary. The emissions reduction is the most established point, since it is the basis of the FDA approval. Confidence is moderate that the additive does not reduce growth in this setting. Confidence is low to moderate for the muscle, urine, and carcass benefits, which need confirmation in larger, more varied herds before they should guide routine decisions.
Beef producers, feedlot managers, animal nutritionists, and researchers studying livestock emissions should pay attention. Consumers can read this for context but cannot act on it directly. The study does not address dairy cattle, cattle raised on pasture, or other livestock species.
Effects in this trial appeared during the 91-day feeding period, and urine, emissions, and carcass results were measured at the end of that window. On a farm, changes in emissions or carcass traits would likely show up within one feeding cycle. Proof of animal health benefits or consumer-level benefits would require longer and larger studies.
Frequently Asked Questions
What is lubabegron used for in beef cattle?
Lubabegron, sold as Experior, is an FDA-approved feed additive that reduces ammonia gas emissions per kilogram of live weight and hot carcass weight in beef steers and heifers fed in confinement for slaughter. It works by altering how the animal’s body uses energy and protein during the final feeding period.
Does lubabegron change how fast cattle gain weight?
In a 2026 study of 16 Angus steers, lubabegron did not change starting or final body weight, feed intake, average daily gain, or feed efficiency compared with control steers. Its measured effects were lower muscle protein breakdown, reduced urine output, and a 9.21% drop in calculated ammonia emissions.
Does lubabegron affect blood sugar control in steers?
Blood sugar control appeared unchanged. In a glucose tolerance test on 16 Angus steers in a 2026 study, glucose and insulin responses did not differ between steers fed lubabegron and untreated controls. Because the sample was small, larger trials are needed to confirm this for other cattle.
Is lubabegron safe for beef cattle and consumers?
The product is FDA-approved for reducing ammonia emissions in confined beef steers and heifers. This 2026 study measured muscle, urine, and carcass outcomes but was not designed to evaluate long-term effects on human health. Anyone with questions about meat safety should consult USDA guidance or a veterinarian.
Want to Apply This Research?
- For users managing a farm or following livestock nutrition data, log the start and stop dates of any feed additive, daily feed intake, and weigh-ins to calculate average daily gain. Track each 91-day feeding window and compare it against a control group raised under the same conditions.
- Consumers who buy beef can ask suppliers about feed programs and emissions efforts. Anyone raising cattle at home should consult a veterinarian or animal nutrition professional before adding any feed additive.
- Review feed, weight gain, and carcass records at the end of each feeding cycle and compare them with multi-year averages. Share the data with a nutritionist to see whether emissions or muscle outcomes shift over time, while watching for changes in feed efficiency or animal health.
This article summarizes a single small animal study and is for general information only. It is not veterinary, farm management, or medical advice. Results from 16 steers may not apply to other cattle, diets, or conditions. Consult a veterinarian or animal nutrition professional before changing any feed program.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.