Replacing corn and oat silage with dried stevia plant reduced milk production in dairy cows by approximately 3% while increasing feed intake by 17%, according to a 2026 study of 18 Holstein cows. Gram Research analysis shows that stevia-fed cows had reduced feed digestibility and lower milk protein content, making their overall feed efficiency worse despite eating more. The stevia diets contained more indigestible fiber, which prevented cows from extracting adequate nutrition, ultimately making stevia an impractical replacement for traditional silage in dairy farming.
Researchers tested whether adding dried stevia plant to dairy cow feed could improve milk production and digestion. Eighteen Holstein cows were fed different amounts of stevia mixed with their regular silage over three 21-day periods. According to Gram Research analysis, while cows eating stevia ate more feed overall, they produced less milk and their bodies had a harder time digesting the food. The stevia also changed how much time cows spent chewing and affected the nutrients they absorbed, ultimately making their feed less efficient.
Key Statistics
A 2026 study of 18 Holstein dairy cows found that replacing 40% of corn and oat silage with dried stevia plant reduced milk production from 47.3 kg/day to 45.8 kg/day while increasing feed intake from 25.2 kg/day to 29.5 kg/day.
According to research reviewed by Gram, stevia-containing diets reduced the digestible energy content of feed from 2.71 to 2.28 megacalories per kilogram, a 16% decrease that directly contributed to lower milk production efficiency.
A 2026 dairy cow feeding trial found that milk protein content decreased from 2.97% to 2.74% when stevia replaced 40% of dietary silage, with total milk protein secretion falling from 1.40 kg/day to 1.25 kg/day.
Research shows that cows fed stevia spent 25 minutes more per day eating but 70 minutes less per day ruminating, suggesting the stevia was easier to chew but harder to digest properly.
The Quick Take
- What they studied: Whether replacing regular cow feed (corn and oat silage) with dried stevia plant would improve milk production, digestion, and feeding behavior in dairy cows.
- Who participated: Eighteen Holstein dairy cows that were about 4-5 months into their milk-producing cycle. The study used a rotating design where each cow tried three different diet combinations over 21-day periods.
- Key finding: Cows fed stevia ate 17% more food but produced 3% less milk and had reduced ability to digest their feed, resulting in less efficient milk production overall.
- What it means for you: For dairy farmers, adding stevia to cow feed appears to backfire—while cows eat more, they produce less milk and waste more nutrients. This suggests stevia is not a practical replacement for traditional silage in dairy farming.
The Research Details
This was a controlled feeding experiment using 18 dairy cows. The researchers used a Latin square design, which means each cow received all three different diet treatments in a rotating pattern. This design helps eliminate differences between individual cows. Each diet period lasted 21 days, with measurements taken during the final 6 days when the cows had fully adjusted to the diet. The three diets contained no stevia (control), 25% stevia replacing silage, or 40% stevia replacing silage. Researchers measured everything the cows ate and produced, including milk yield, milk composition, how much they chewed, and what came out in their manure.
The researchers collected detailed information about feeding behavior by watching how long cows spent eating and chewing their food. They also analyzed the digestibility of the feed by measuring the energy content of what the cows ate versus what they excreted. Blood and milk samples were tested to understand how the stevia affected the cows’ metabolism and nutrient absorption.
This type of study design is strong because each cow serves as its own control, reducing the impact of individual differences. However, the study was relatively short-term (21 days per diet), so long-term effects remain unknown.
Understanding how alternative feed ingredients affect dairy cow production is important for farmers looking to reduce costs or find sustainable feed options. Stevia is a plant that grows in some regions and could theoretically be a local feed source. However, this research shows that simply replacing traditional silage with stevia doesn’t work well, which is valuable information for farmers considering this change.
This study has several strengths: it used a rigorous Latin square design that controls for individual cow differences, measurements were precise and standardized, and the sample size was adequate for detecting meaningful differences. The study was published in the Journal of Dairy Science, a respected peer-reviewed journal. However, the study only included 18 cows and lasted 21 days per diet, which is relatively short. The results may not apply to all dairy breeds or management systems. The study also didn’t test whether cows could adapt to stevia over longer periods.
What the Results Show
Cows eating stevia consumed significantly more feed—about 3.3 to 4.3 kg more per day as stevia increased. Despite eating more, milk production actually decreased by about 2.5 kg per day when stevia made up 40% of the diet. The energy content of the feed also dropped substantially, from 2.71 to 2.28 megacalories per kilogram, meaning the stevia-containing diets were less nutrient-dense.
The stevia affected how cows chewed their food in interesting ways. Cows spent more time eating (about 25 minutes more per day at the highest stevia level) and ate larger meals, but they spent significantly less time ruminating (chewing cud), dropping from 586 minutes to 516 minutes per day. This suggests the stevia was easier to chew but harder to digest properly.
Protein production suffered noticeably. Milk protein content dropped from 2.97% to 2.74%, and the amount of protein secreted in milk fell from 1.40 kg to 1.25 kg per day. The cows’ bodies also handled nitrogen (a key component of protein) less efficiently, with more nitrogen ending up in manure rather than being converted to milk protein.
The digestibility of the feed declined across the board. The stevia diets contained more indigestible fiber and fewer large feed particles, which meant cows couldn’t extract as much nutrition from what they ate. This reduced digestible energy availability, which directly explains why milk production fell despite higher feed intake.
Several secondary changes occurred with stevia feeding. Free fatty acids in the blood increased, suggesting the cows’ bodies were mobilizing fat stores, possibly because they weren’t getting enough energy from their feed. Milk urea nitrogen (a marker of protein metabolism) decreased, indicating altered protein processing. The composition of milk fat changed slightly, with more pre-formed fatty acids appearing in milk. Fecal output increased substantially, with nitrogen excretion in manure rising from 266 to 417 grams per day, indicating poor nutrient retention.
Limited research exists on stevia as a dairy cow feed ingredient, making direct comparisons difficult. However, this study aligns with general principles of ruminant nutrition: feeds with high indigestible fiber and poor nutrient density typically reduce milk production. The findings contradict the hypothesis that stevia might be a beneficial feed additive, suggesting that while stevia has interesting properties in human nutrition, it doesn’t translate well to dairy cow feeding.
The study lasted only 21 days per diet, which is relatively short for assessing long-term adaptation. With only 18 cows, results may not apply to all dairy operations or breeds. The study didn’t test intermediate stevia levels or examine whether cows might adapt better over longer periods. Seasonal variation in stevia quality wasn’t examined. The study also didn’t evaluate economic costs or environmental impacts of stevia production compared to traditional silage. Finally, the mechanism explaining why stevia reduced digestibility wasn’t fully explored—the researchers observed that stevia diets had more indigestible fiber, but didn’t determine whether this was inherent to stevia or resulted from how it was processed.
The Bottom Line
Based on this research, dairy farmers should not replace corn and oat silage with dried stevia plant. The evidence is strong (confidence level: high) that this substitution reduces milk production and feed efficiency. If farmers are interested in alternative feeds, they should consult with nutritionists and conduct small-scale trials before making large changes. For those specifically interested in stevia, future research might explore whether fresh stevia, different processing methods, or very small inclusion rates could work better.
Dairy farmers considering feed cost reduction or sustainability improvements should pay attention to this research. Agricultural researchers and nutritionists developing alternative feed strategies should note that stevia doesn’t work as a silage replacement. However, this study doesn’t affect consumers or people interested in stevia as a human food supplement—the research only addresses stevia as livestock feed. Farmers in regions where stevia grows locally might have been hoping for a cost-effective feed source, but this research suggests that hope is unfounded.
The negative effects on milk production appeared within the 21-day study period, suggesting these are not delayed effects that might improve with time. Farmers implementing stevia feeding would likely see reduced milk production within 2-3 weeks. However, it’s unknown whether cows might partially adapt over months or years, though the fundamental digestibility issues suggest long-term adaptation is unlikely.
Frequently Asked Questions
Can stevia be used as a feed ingredient for dairy cows?
While stevia can be physically added to cow feed, a 2026 study found it reduces milk production and feed efficiency. Cows eating 40% stevia produced 3% less milk despite eating 17% more feed, making it impractical for dairy farming.
Does stevia improve digestion in dairy cows?
No. Research shows stevia actually reduces digestibility. Stevia-containing diets had 16% less digestible energy and higher indigestible fiber content, preventing cows from extracting adequate nutrition from their feed.
What happens to milk protein when cows eat stevia?
Milk protein content decreases. A 2026 study found milk protein dropped from 2.97% to 2.74% when stevia made up 40% of the diet, with total protein secretion falling from 1.40 kg/day to 1.25 kg/day.
Why do cows eat more when fed stevia if it reduces milk production?
Stevia-containing diets have lower energy density, so cows must eat more to try to meet their energy needs. However, the poor digestibility of stevia prevents them from extracting enough energy, resulting in less milk despite higher feed intake.
Is stevia a cost-effective alternative to traditional silage?
No. While stevia might seem economical, the 3% reduction in milk production and 17% increase in feed intake make it economically inefficient. Farmers would spend more on feed while producing less milk, resulting in significant financial losses.
Want to Apply This Research?
- If a user is a dairy farmer considering feed changes, track daily milk production (kg/day), feed intake (kg/day), and feed efficiency ratio (milk produced per kg of feed consumed) for 2-3 weeks before and after any feed modifications. This allows direct comparison to baseline and early detection of production losses.
- Users managing dairy operations should use the app to log feed ingredient changes and set alerts to monitor milk production metrics weekly. If considering alternative feeds, document the specific ingredient, inclusion rate, and production outcomes to build a personal database of what works on their farm.
- Establish a baseline of current milk production and feed efficiency. If testing any new feed ingredient, maintain detailed records for at least 3-4 weeks to allow cows to adjust while capturing early performance changes. Compare metrics to baseline using the app’s tracking features to make data-driven decisions about feed changes.
This research applies specifically to dairy cow feeding and does not reflect stevia’s safety or efficacy for human consumption. The study was conducted over a short 21-day period and involved 18 cows; results may not apply to all dairy operations, breeds, or management systems. Farmers considering any significant feed changes should consult with a veterinarian or dairy nutritionist before implementation. This article summarizes research findings and should not be considered veterinary or agricultural advice. Individual farm results may vary based on local conditions, cow genetics, and management practices.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.