Researchers studied 36 beef cows to understand how some cows can eat less food while staying just as healthy and productive as others. They measured how much food the cows ate, how much milk they produced, and even tracked gases the cows released. The study found that cows that were naturally more efficient at using their food ate significantly less, but this didn’t hurt their health, weight gain, or ability to have healthy calves. Interestingly, a cow’s efficiency could change depending on whether it was pregnant or nursing, suggesting that efficiency isn’t a fixed trait. These findings could help farmers choose cows that eat less food while maintaining good productivity.
The Quick Take
- What they studied: Whether cows that naturally eat less food while maintaining their health and productivity could be identified and selected for breeding purposes
- Who participated: 36 adult female beef cows (crossbred Angus) that had given birth before, monitored during pregnancy and nursing periods while eating grass-based diets
- Key finding: Cows classified as efficient eaters consumed 15-20% less food than inefficient eaters during pregnancy and 10-15% less during nursing, without any negative effects on their health, weight gain, or calf production
- What it means for you: If you raise beef cattle, selecting for feed-efficient cows could reduce feed costs significantly. However, efficiency ratings may change as cows move through different life stages, so farmers should monitor cows regularly rather than assuming one measurement predicts long-term efficiency.
The Research Details
Researchers followed 36 beef cows over two major life stages: pregnancy and nursing. They used automated systems to precisely measure how much food each cow ate, tracked their weight and body condition, measured milk production, and even captured the gases cows released (like methane and carbon dioxide). The cows were divided into three efficiency groups—efficient, moderate, and inefficient—based on how much food they needed compared to what scientists expected. This allowed researchers to compare how these different efficiency groups performed across all the measurements they tracked.
The study used two different ways to measure efficiency: one based on how much extra food a cow ate beyond what was expected (called RFI), and another based on how much energy a cow recovered from its food (called RNE). By using both measurements, researchers could see if they were measuring the same thing or if they revealed different information about cow efficiency.
Understanding which cows naturally eat less food is valuable because feed is typically the biggest expense in raising beef cattle. If farmers can identify and breed cows that are naturally efficient eaters, they could reduce costs without sacrificing the health of the cows or the quality of their products. This study is important because it shows that efficiency can be measured reliably and that selecting for it doesn’t harm other important traits like milk production or calf development.
This study has several strengths: it used automated systems to measure feed intake and gas emissions, which are more accurate than manual measurements; it followed cows through multiple life stages; and it used two different efficiency measures to get a complete picture. However, the study only included 36 cows, which is a relatively small group, so results may not apply to all beef cattle populations. The study also only looked at one type of diet (grass-based), so results might differ with other feeding systems. The findings were published in a peer-reviewed scientific journal, which means other experts reviewed the work before publication.
What the Results Show
Efficient cows ate significantly less food than inefficient cows—about 15-20% less during pregnancy and 10-15% less while nursing—without any negative effects on their health or body condition. This is the most important finding because it shows that efficiency differences are real and measurable. Interestingly, efficient cows didn’t gain weight any differently than inefficient cows, and their calves were born healthy and normal.
When researchers looked at how cows used the energy from their food, they found that inefficient cows wasted more energy on basic body maintenance (like keeping warm and running their organs), while efficient cows used their food more effectively. This suggests that some cows are simply better at converting food into useful energy.
Milk production was similar across all efficiency groups, with one small exception: the most efficient cows (by one measure) produced milk with slightly higher lactose (milk sugar) content. This is a minor difference that wouldn’t significantly affect milk quality or usefulness. The study also measured methane emissions (a greenhouse gas cows release), and found that efficient cows actually released slightly more methane per unit of food eaten, though the total amount was still lower because they ate less overall.
An important secondary finding was that a cow’s efficiency rating wasn’t stable over time. A cow that was efficient during pregnancy might be moderate during nursing, or vice versa. This suggests that efficiency is influenced by the cow’s current life stage and needs, not just by fixed biological traits. Additionally, the two efficiency measures (RFI and RNE) showed only weak to moderate correlation with each other, meaning they capture somewhat different aspects of how efficiently a cow uses food. This suggests that farmers might want to consider both measures rather than relying on just one.
This research builds on previous studies showing that feed efficiency varies among cattle and can be measured reliably. However, this study is unique because it tracked the same cows through multiple life stages and used two different efficiency measures simultaneously. Previous research in dairy cattle suggested that efficiency might change with life stage, and this beef cattle study confirms that pattern. The finding that efficiency measures aren’t perfectly correlated with each other is also relatively new and suggests that scientists may need to refine how they define and measure efficiency in cattle.
The study included only 36 cows, which is a small number for drawing broad conclusions about all beef cattle. All cows were the same breed type (Angus-cross) and ate the same diet (grass-based), so results might not apply to other breeds or feeding systems. The study was conducted at one location, so environmental factors specific to that location might have influenced results. Additionally, the study only followed cows for one production cycle (one pregnancy and nursing period), so it’s unclear if efficiency patterns would remain consistent over multiple years. Finally, while the study measured many variables, it didn’t investigate the genetic basis of efficiency, so it’s unclear how heritable these traits are or how quickly they could be improved through selective breeding.
The Bottom Line
For beef cattle farmers: Consider using feed efficiency measurements when selecting breeding animals, as this could reduce feed costs by 10-20% without harming productivity. However, recognize that efficiency may vary across seasons and life stages, so periodic reassessment is important. For researchers: Continue investigating why efficiency changes across life stages and develop better methods to predict long-term efficiency. For consumers: This research supports sustainable farming practices by identifying ways to reduce feed waste and environmental impact in beef production.
Beef cattle farmers and ranchers should care most about these findings, as they directly impact feed costs and profitability. Agricultural researchers and breeding programs should use this information to develop better selection strategies. Environmental advocates may be interested in the efficiency-methane relationship. This research is less relevant to dairy farmers (though some principles may apply) and not directly applicable to people who don’t raise cattle.
If a farmer began selecting for feed-efficient cows today, they would see immediate benefits in reduced feed costs for the selected animals. However, genetic improvements in a herd would take 3-5 years to become apparent, as it takes multiple generations of selective breeding to shift herd-wide traits. Individual cows’ efficiency might change within a single year as they move through different life stages, so monitoring should occur at least seasonally.
Want to Apply This Research?
- Track daily feed intake per cow and body weight weekly, then calculate feed efficiency monthly (pounds of feed eaten per pound of weight gained). Compare this metric across seasons to identify which cows consistently perform well and which ones vary significantly.
- Set a goal to measure and record feed intake for at least 10-15 cows in your herd over a full year cycle. Use this data to identify your most efficient animals and prioritize them for breeding. Adjust feeding strategies based on life stage (pregnancy vs. nursing) since efficiency changes across these periods.
- Establish a baseline efficiency measurement for your herd, then reassess every 3-4 months as cows move through different production stages. Track not just total feed intake, but also body condition and milk production to ensure you’re not sacrificing productivity while selecting for efficiency. Keep records across multiple years to identify which animals maintain consistent efficiency and which ones vary significantly.
This research describes scientific findings about cattle feed efficiency and should not be interpreted as veterinary or agricultural advice. Individual farm conditions, cattle genetics, and management practices vary significantly, so results may not apply to all operations. Farmers considering changes to breeding programs or feeding strategies should consult with their veterinarian, agricultural extension office, or livestock nutritionist to determine what’s appropriate for their specific situation. This study was conducted on a small number of cows under specific conditions and may not represent all cattle populations or production systems. Always work with qualified professionals before making significant changes to your livestock management practices.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.