According to Gram Research analysis, moist-toasted fava beans improve dairy cow milk production and feed efficiency compared to regular fava beans. A 2026 study of 48 Holstein dairy cows found that feeding moist-toasted fava beans increased milk production by 0.3 kg per day and improved feed efficiency by 3% (from 1.37 to 1.41 kg milk per kg feed), while cows ate the same amount of total feed. This efficiency gain suggests that heating fava beans to 125°C helps cows digest and use the protein more effectively.
Researchers tested whether heating moist fava beans could help dairy cows produce more milk while using nutrients more efficiently. They fed 48 dairy cows different diets—some with regular fava beans and some with heat-treated fava beans—combined with different types of grass and corn silage. The cows eating moist-toasted fava beans produced slightly more milk and used their feed more efficiently, meaning they got more milk production from the same amount of food. This finding could help farmers reduce waste and improve dairy farm sustainability.
Key Statistics
A 2026 research article studying 48 Danish Holstein dairy cows found that moist-toasted fava beans increased energy-corrected milk yield by 0.3 kg per day (30.9 kg/day versus 30.6 kg/day) compared to untoasted fava beans.
According to a 2026 controlled feeding trial with 48 dairy cows, moist-toasted fava beans improved gross feed efficiency by 3% (1.41 kg milk per kg feed versus 1.37 kg/kg), meaning cows produced more milk from the same amount of feed.
A 2026 study of 48 dairy cows found that nitrogen efficiency improved with moist-toasted fava beans (0.296 kg/kg versus 0.292 kg/kg), indicating better protein utilization and potentially less environmental nitrogen loss in manure.
Research published in 2026 involving 48 Holstein cows showed that the benefits of moist-toasting fava beans were consistent across different forage types, working equally well with grass-clover-based or corn silage-based diets.
The Quick Take
- What they studied: Whether heating moist fava beans (a type of legume) in a special way improves how well dairy cows convert feed into milk
- Who participated: 48 Danish Holstein dairy cows (a common dairy breed), split between first-time mothers and experienced mothers, tested over 12 separate groups
- Key finding: Cows fed moist-toasted fava beans produced about 0.3 kg more milk per day and converted their feed to milk about 3% more efficiently than cows fed regular fava beans
- What it means for you: Farmers might be able to improve milk production and reduce feed waste by using a simple heating process on fava beans, though this is most helpful when protein levels in the diet are limited
The Research Details
Scientists conducted a carefully controlled experiment using 48 dairy cows divided into 12 groups. Each group of 4 cows received different feed combinations in a rotating pattern called a Latin square design, where each cow tried all four diet types over four 21-day periods. This design is powerful because each cow serves as its own comparison, reducing the effect of individual differences between animals.
The researchers created four different diets by mixing two variables: fava bean type (regular dried beans versus beans that were rehydrated to mimic fresh harvest moisture, then heated to 125°C for 3 minutes) and forage type (either mostly grass-clover silage with some corn silage, or mostly corn silage with some grass-clover silage). The fava beans made up about 24% of what the cows ate. Cows had unlimited access to feed in automated bins, were milked twice daily, and milk samples were collected weekly.
This research design is important because it controls for individual cow differences—each cow eats all four diet types, so researchers can see exactly what the heating process does without cow-to-cow variation confusing the results. The Latin square design is considered one of the strongest ways to test feed changes in animals. Testing two forage types simultaneously helps determine whether the heating benefit works regardless of what type of grass or silage farmers use.
This study has several strengths: it used a rigorous experimental design, controlled all variables carefully, measured multiple important outcomes (milk production, feed efficiency, and nutrient use), and tested the effect across different forage types to show the results were consistent. The study was published in the Journal of Dairy Science, a respected peer-reviewed journal. However, the study only included one breed of cow (Holstein) and only Danish farms, so results might differ in other regions or breeds. The study lasted 84 days total (four 21-day periods), which is adequate for measuring milk production changes.
What the Results Show
Cows eating moist-toasted fava beans produced 30.9 kg of energy-corrected milk per day compared to 30.6 kg for cows eating regular fava beans—a small but measurable increase of about 0.3 kg per day. This might seem small, but over a year, this equals roughly 110 extra kg of milk per cow annually.
More importantly, the toasted beans improved how efficiently cows converted feed into milk. The gross efficiency (the amount of milk produced per kilogram of feed eaten) was 1.41 kg/kg for moist-toasted beans versus 1.37 kg/kg for regular beans. This means cows eating toasted beans got about 3% more milk from the same amount of feed—a meaningful improvement in farm efficiency.
Nitrogen efficiency (how much of the protein the cow eats ends up in milk) was also better with moist-toasted beans: 0.296 kg/kg compared to 0.292 kg/kg. This suggests the heating process helps cows use protein more effectively, which could reduce environmental pollution from excess nitrogen in manure.
Interestingly, the amount of feed the cows ate didn’t change (about 22 kg per day for both groups), meaning the improvement came from better processing of the same amount of food, not from eating more.
The type of forage (grass-clover silage versus corn silage) affected nitrogen efficiency—cows fed more corn silage used protein more efficiently than those fed more grass-clover silage. However, this forage effect didn’t change the benefit of moist-toasting, meaning the heating process worked equally well regardless of which silage type farmers used. Milk protein percentage was slightly lower with moist-toasted beans (3.73% versus 3.78%), but total milk protein production didn’t differ because the milk volume was higher.
This research builds on earlier studies showing that processing legume seeds can improve their nutritional value for livestock. The moist-toasting process appears to work similarly to other heat treatments that improve protein digestibility in beans. The finding that efficiency improves without increasing feed intake suggests the heating changes how the cow’s digestive system breaks down and uses the beans, rather than making them more palatable. This aligns with previous research on heat-treated legumes in ruminant nutrition.
The study only tested one breed of dairy cow (Holstein) in one country (Denmark), so results might differ for other breeds or in different climates. The experiment lasted 84 days total, which is long enough to measure milk production changes but relatively short for assessing long-term sustainability. The study didn’t measure costs of the moist-toasting process, so farmers would need separate economic analysis to determine if the milk production gains justify the heating equipment investment. The study also only tested one specific heating temperature and time (125°C for 3 minutes), so different heating conditions might produce different results.
The Bottom Line
For dairy farmers with limited dietary protein availability, moist-toasting fava beans appears to be a worthwhile processing method with moderate confidence. The improvement in feed efficiency (3%) and milk production (about 1% increase) are real but modest. Farmers should consider this approach if they already grow or source fava beans and have access to toasting equipment. The method works equally well with different forage types, making it adaptable to various farm systems. However, conduct a cost-benefit analysis specific to your operation before investing in toasting equipment.
Dairy farmers who use fava beans as a protein source in their feed programs should pay attention to this research, especially those managing protein levels carefully. Farmers in regions where fava beans are readily available (particularly Europe) may find this most practical. This is less relevant for farmers who don’t currently use fava beans or who have abundant protein sources available. Nutritionists formulating dairy cow diets should consider this finding when recommending legume inclusion.
Changes in milk production and feed efficiency should be measurable within 2-3 weeks of switching to moist-toasted fava beans, based on this study’s 21-day measurement periods. Maximum benefits would likely be seen after 4-6 weeks as cows fully adapt to the new feed. The improvement is modest (about 1% more milk), so farmers should not expect dramatic changes but rather consistent, incremental gains.
Frequently Asked Questions
Do toasted fava beans really help dairy cows produce more milk?
Yes, moist-toasted fava beans increase milk production by about 0.3 kg per day per cow and improve feed efficiency by 3%, meaning cows get more milk from the same amount of feed. The effect is modest but consistent across different farm conditions.
How much more milk can I expect if I switch to toasted fava beans?
A single cow would produce roughly 0.3 kg more milk daily, which equals about 110 extra kg annually per cow. On a 100-cow farm, this could mean 11,000 kg (11 metric tons) additional milk per year, though actual results depend on your specific situation.
Does the type of grass or silage I use affect whether toasted fava beans work?
No, the research shows moist-toasted fava beans improve efficiency equally well whether you use mostly grass-clover silage or mostly corn silage. The benefit is independent of your forage choice, making it adaptable to different farm systems.
What temperature and time are needed to toast fava beans properly?
The study used 125°C for 3 minutes in a flame tumble toaster, applied to beans rehydrated to about 207 g/kg moisture content. However, the study only tested this one condition, so other heating parameters might work differently.
Is moist-toasting fava beans better for the environment than regular drying?
Moist-toasting improves nitrogen efficiency in milk production, meaning less excess nitrogen in manure, which could reduce environmental pollution. However, the study didn’t measure the energy cost of the toasting process itself, so a full environmental comparison requires additional analysis.
Want to Apply This Research?
- Track daily milk production (kg/day) and feed intake (kg/day) for each cow or group, then calculate feed efficiency weekly (milk ÷ feed). Compare these metrics for 3 weeks before and 4 weeks after switching to moist-toasted fava beans to measure the actual improvement on your farm.
- If you currently feed fava beans, work with your feed supplier to source moist-toasted fava beans instead of regular dried beans. If you don’t currently use fava beans, consider adding them to your feed program at 20-25% of the diet dry matter, using the moist-toasted version. Track the cost difference and compare it against the milk production gains.
- Establish a baseline of your current milk production and feed efficiency metrics. After implementing moist-toasted fava beans, measure these same metrics weekly for 8 weeks. Use the app to log milk production, feed intake, and calculate efficiency ratios. Set a target of 1-3% improvement in feed efficiency and monitor whether you achieve it. If you don’t see improvement after 6 weeks, consult a nutritionist about other diet factors that might be limiting.
This research describes results from a controlled study in Danish Holstein dairy cows and may not apply to all dairy operations, breeds, or geographic regions. The study measured short-term effects (84 days) and did not assess long-term health outcomes or economic viability. Farmers should consult with a veterinarian or dairy nutritionist before making significant changes to their feeding program. This information is for educational purposes and should not replace professional agricultural advice. Individual results will vary based on farm management, cow genetics, and local feed availability.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.