Researchers tested a feed additive called narasin on beef cattle to see if it helps them grow better and produce higher-quality meat. They studied 128 young bulls over four months, giving some cattle different amounts of the additive while others got none. The additive worked best in the first month, helping cattle gain weight faster and use their food more efficiently. The cattle that received a medium dose also developed better fat coverage on their meat, which is important for meat quality. While the benefits didn’t last the entire feeding period, the results suggest this additive could be useful for cattle farmers.
The Quick Take
- What they studied: Whether adding a substance called narasin to cattle feed helps them grow faster, eat better, and produce better quality meat
- Who participated: 128 young Nellore bulls (a type of beef cattle) that weighed about 865 pounds at the start, divided into 32 groups of 4 cattle each
- Key finding: Cattle given narasin gained weight faster in the first month (about 2% better), and those getting a medium dose had better feed efficiency and improved meat quality with better fat coverage
- What it means for you: If you eat beef, this research suggests farmers may be able to raise cattle more efficiently using this additive, potentially affecting meat availability and cost. However, the benefits were temporary, so it’s not a complete solution to cattle farming challenges
The Research Details
Scientists divided 128 young cattle into four equal groups. One group received no additive (the control group), while the other three groups received different amounts of narasin mixed into their feed. All cattle ate the same high-grain diet for about three and a half months. The researchers measured how much weight the cattle gained, how much food they ate, how they behaved while eating, and examined their meat quality after slaughter. They also looked at changes inside the cattle’s digestive systems.
The study was carefully designed by grouping cattle by starting weight first, then randomly assigning groups to different treatment levels. This helps ensure fair comparisons. The cattle were watched for 14 days to adjust to their new diet before the actual study began, and the additive was stopped three days before slaughter to follow safety rules.
This type of study is called a controlled experiment because researchers controlled which cattle got which treatment and kept other conditions the same. This design helps prove whether the additive actually caused any changes observed.
This research matters because the cattle industry is always looking for ways to help animals grow faster and use feed more efficiently. If a simple feed additive can improve these things, it could help farmers produce more meat with less feed, which saves money and resources. Understanding how much of the additive works best is important for practical use on farms.
This study has several strengths: it used a large number of cattle (128), divided them fairly into groups, and measured many different outcomes. The research was published in a respected scientific journal (PLoS ONE), which means other scientists reviewed it before publication. However, the study only tested one breed of cattle (Nellore), so results might differ with other cattle types. The study was conducted in controlled feedlot conditions, which may not reflect all real-world farming situations.
What the Results Show
During the first 28 days, cattle receiving narasin gained weight about 2% faster than cattle without it, and this difference was statistically significant (meaning it wasn’t due to chance). Cattle receiving the medium dose (20 ppm) showed the best feed efficiency, meaning they gained more weight per pound of food eaten compared to other groups.
Interestingly, these early benefits didn’t continue throughout the entire 111-day study period. By the end, the differences in weight gain and feed efficiency disappeared. This suggests the additive’s effects are strongest when cattle first enter the feedlot and may wear off over time.
For meat quality, cattle receiving the medium dose developed better fat coverage at the 12th rib (a standard measurement point for meat quality). This is important because proper fat coverage affects both meat flavor and market value. The additive didn’t reduce how much food the cattle ate overall, which is good because it means the additive helped without causing cattle to eat less.
Cattle receiving the medium dose ate for longer periods during meals on day 70 of the study. The lowest dose of additive increased the size of small finger-like structures in the cattle’s rumen (the first stomach chamber), which could help with food digestion. However, higher doses reduced certain types of cells in the cecum (part of the large intestine), which might affect digestion in that area. These changes suggest the additive affects how cattle digest food in different ways depending on the dose.
Previous research has shown that ionophores (the class of chemicals narasin belongs to) generally improve feed efficiency in cattle. This study confirms that finding but adds important details: the benefits are strongest early in the feeding period, and there’s an optimal dose (20 ppm) that works better than higher amounts. This is consistent with other research showing that more of a substance isn’t always better.
The study only tested one breed of cattle (Nellore), so results might be different for other beef cattle breeds. All cattle were young males, so the results may not apply to female cattle or older animals. The study was conducted in a controlled feedlot setting, which may not reflect how cattle perform on pasture or in different climates. The benefits observed in the first month didn’t continue, so farmers would need to understand why the effects fade. Finally, the study didn’t examine long-term health effects or whether the additive affects the nutritional quality of the meat produced.
The Bottom Line
Based on this research, narasin at a dose of 20 ppm appears to be the most effective level for improving early cattle growth and meat quality (moderate confidence). The additive can be safely used at doses between 13-27 ppm without reducing food intake (moderate-to-high confidence). However, farmers should understand that benefits are strongest in the first month and may decrease over time (moderate confidence). This additive should only be used as part of a complete cattle nutrition strategy, not as a replacement for good feeding practices.
Cattle farmers and ranchers should care about this research, particularly those raising beef cattle in feedlots. Meat processors and retailers interested in improving meat quality may find this relevant. Consumers interested in how their beef is produced might want to know about this practice. People with concerns about animal agriculture efficiency should be aware of these tools. However, this research is specific to beef cattle and doesn’t apply to dairy cattle, poultry, or other animals.
The benefits appear within the first month of feeding the additive, with improved weight gain visible within 28 days. However, these early benefits fade over the remaining three months of the feeding period. Farmers should expect the most dramatic improvements in the first month, with diminishing returns afterward. The meat quality improvements (better fat coverage) were observed at slaughter after the full feeding period.
Want to Apply This Research?
- If you’re tracking beef consumption or interested in how your food is produced, note the dates you purchase beef and track any perceived differences in quality or taste. You could rate meat quality on a scale of 1-10 and note whether the producer used growth-promoting additives (often listed on packaging or available from the retailer).
- Use the app to set a reminder to research the farming practices of your regular beef suppliers. You could create a ‘beef quality tracker’ to note which sources produce meat you prefer, then investigate whether they use additives like narasin. This helps you make informed choices about the beef you purchase.
- Over several months, track your beef purchases and any information available about production methods. Create a simple rating system for meat quality and compare it to production practices. This long-term tracking helps you understand whether production methods affect the meat quality you experience as a consumer.
This research describes a feed additive used in cattle farming and does not provide medical advice for humans. The study was conducted on animals in controlled conditions and results may not apply to all farming situations or cattle breeds. Narasin use in livestock feed is regulated by agricultural authorities in different countries—farmers should follow local regulations and consult with veterinarians or animal nutritionists before implementing any changes to cattle feed. This information is for educational purposes and should not replace professional agricultural or veterinary guidance. Always consult qualified professionals before making decisions about livestock management or feed additives.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.