A plant-based supplement containing tannins and spices increased milk production by 3.8% in dairy cows when given at 10-20 grams per day, according to a 2026 study published in the Journal of Dairy Science. Gram Research analysis shows that medium doses of this supplement worked better than high doses, improving both milk yield and protein content while allowing farmers to use lower-protein feed. The supplement also changed the bacteria in the cows’ stomachs, creating a more efficient microbial community, though results were from a small study of eight cows.
Researchers tested a natural supplement made from plant compounds and spices on dairy cows eating a lower-protein diet. The supplement, given at different amounts, improved milk production and changed the bacteria living in the cows’ stomachs. According to Gram Research analysis, the best results came at medium doses of the supplement, increasing milk yield by about 3.8% compared to cows receiving no supplement. The study shows that natural plant-based products can help dairy farms produce more milk while using less protein in their feed, which could reduce costs and environmental impact.
Key Statistics
A 2026 study of eight dairy cows found that 20 grams per day of a plant-based supplement containing tannins and spices increased milk production from 37.1 kg to 37.7 kg daily and boosted milk protein yield from 1.22 to 1.26 kg per day.
According to research reviewed by Gram, the optimal dose of the plant supplement was 10-20 grams per day, with higher doses of 30 grams actually reducing milk production back to 36.3 kg per day, demonstrating a quadratic dose-response relationship.
A 2026 Journal of Dairy Science study found that the plant-based supplement changed the rumen microbiome by reducing bacterial diversity and identifying 26 species with significant changes, some directly correlated with improved milk production and feed efficiency.
The Quick Take
- What they studied: Whether a natural supplement made from plant tannins and spices could improve milk production and change stomach bacteria in dairy cows eating a diet with less protein than normal.
- Who participated: Eight Holstein Friesian dairy cows (a common dairy breed) that were mid-lactation, producing about 39 kg of milk per day at the start of the study.
- Key finding: Medium doses of the plant supplement (10-20 grams per day) increased milk production by 3.8% and improved milk protein content compared to cows receiving no supplement, with the best results at 20 grams per day.
- What it means for you: If you consume dairy products, this research suggests farms may be able to produce milk more efficiently using natural supplements instead of higher protein feeds, potentially reducing costs and environmental impact. However, this was a small study in controlled conditions, so results may differ on real farms.
The Research Details
Scientists conducted a carefully controlled experiment using eight dairy cows over 16 weeks. Each cow received four different treatments in rotation, with each treatment lasting 4 weeks. The treatments were: no supplement (control), 10 grams per day of the plant supplement, 20 grams per day, and 30 grams per day. The cows ate the same base diet of grass and corn silage with reduced protein levels throughout the study.
The researchers measured milk production daily, collected milk samples to check quality, and took samples from inside the cows’ stomachs to study the bacteria living there. They used advanced genetic testing (called shotgun metagenomics) to identify which bacteria were present and how the supplement affected the bacterial community.
This type of study design, called a Latin Square, is considered very reliable because each cow serves as its own control, reducing the effect of individual differences between animals.
Understanding how natural supplements affect both milk production and the bacteria in a cow’s stomach is important because it helps farmers make better feeding decisions. The rumen (cow stomach) bacteria are crucial for digesting food and producing nutrients, so changes in these bacteria can affect overall health and productivity. Testing different doses helps identify the sweet spot where benefits are maximized without wasting money or causing problems.
This study has several strengths: it used a rigorous experimental design, measured multiple important outcomes, and used advanced genetic technology to study the microbiome. However, the sample size was very small (only 8 cows), which limits how much we can generalize the findings to all dairy farms. The study was conducted in controlled laboratory conditions, which may not reflect real farm environments. The researchers were transparent about their methods and used appropriate statistical analysis.
What the Results Show
The plant supplement had a dose-dependent effect on milk production, meaning that moderate amounts worked better than very high amounts. At 10 grams per day, milk production increased from 37.1 kg to 38.5 kg per day (a 3.8% increase). At 20 grams per day, production was 37.7 kg per day. However, at the highest dose of 30 grams per day, production dropped to 36.3 kg per day, suggesting that more isn’t always better.
Milk protein content improved with the supplement, increasing from 1.22 kg per day at the control level to 1.27 kg per day at 20 grams per day. This is important because milk with higher protein content is more valuable to dairy processors. The supplement also appeared to improve the quality of fatty acids in the milk, particularly at the 20-gram dose.
The supplement changed the bacteria living in the cows’ stomachs, making the bacterial community leaner and more focused (less diverse) at higher doses. The researchers identified 26 bacterial species that changed significantly with the supplement, and some of these bacteria were linked to better digestion and milk production.
The supplement did not affect overall milk fat content or the amount of nitrogen (protein building blocks) that the cows used efficiently. Rumen pH, which indicates stomach acid levels, remained stable across all treatments, suggesting the supplement didn’t cause digestive upset. Interestingly, the bacteria changes only appeared in the solid part of the rumen contents, not in the liquid part, suggesting the supplement primarily affected bacteria that live on feed particles.
This research builds on previous studies showing that plant-based compounds can improve rumen function. The finding that moderate doses work better than high doses aligns with other research on phytogenic (plant-based) products, suggesting there’s an optimal range for effectiveness. The study adds new information by showing exactly how these supplements change the bacterial community and which bacteria species are most affected.
The study used only 8 cows, which is a very small number. Results from small studies can be unreliable and may not apply to larger herds or different farm conditions. The experiment was conducted in a controlled research setting, not on a working farm, so real-world results might differ. The study lasted only 16 weeks total, so we don’t know if the benefits would continue long-term or if cows would adapt to the supplement over time. The supplement was tested only with a specific low-protein diet, so results might be different with other feed types.
The Bottom Line
Based on this research, dairy farmers interested in using plant-based supplements should consider doses between 10-20 grams per day, as this range showed the best results in this study. However, because this is a small, controlled study, farmers should start with lower doses and monitor their own cows’ response before committing to large-scale use. Confidence in these recommendations is moderate—the study shows promise but needs confirmation in larger, real-farm settings.
Dairy farmers looking to reduce protein costs in their feed should pay attention to this research. Consumers interested in sustainable dairy production may care about findings showing that natural supplements could reduce the need for high-protein feeds. Veterinarians and animal nutritionists should consider this as one tool among many for optimizing dairy cow diets. People with allergies to specific plants or spices should be aware if these supplements enter the food chain.
Based on this study, improvements in milk production appeared within the first few weeks of supplementation. The changes in rumen bacteria likely occurred gradually over the 4-week treatment periods. On a real farm, you might expect to see production changes within 2-4 weeks, though individual cows may respond differently.
Frequently Asked Questions
Can natural plant supplements really improve milk production in dairy cows?
Research shows that plant-based supplements containing tannins and spices can increase milk production by 3-4% when given at optimal doses (10-20 grams daily). The supplements work by changing the bacteria in the cow’s stomach, improving digestion and nutrient use. However, more research on larger farms is needed to confirm these results.
What’s the best dose of plant supplement for dairy cows?
This study found that 10-20 grams per day produced the best results, with 20 grams showing the highest milk protein content. Doses of 30 grams per day actually reduced milk production, suggesting there’s an optimal range. Individual farms may need to adjust based on their specific conditions.
How do plant supplements change the bacteria in a cow’s stomach?
The plant compounds in the supplement promote a leaner, more efficient bacterial community by reducing overall diversity while increasing beneficial bacteria species. This creates a more focused microbial ecosystem better suited for digestion and milk production, similar to how probiotics work in humans.
Can farmers use plant supplements instead of high-protein feed?
This study suggests plant supplements may allow farmers to use lower-protein diets without losing milk production, potentially reducing feed costs. However, this was a small controlled study, so farmers should test supplements on their own herds gradually before making major feed changes.
How long does it take to see results from plant supplements in dairy cows?
Based on this research, changes in milk production appeared within the first few weeks of supplementation. The bacteria in the cow’s stomach likely changed gradually over 2-4 weeks. Individual cows may respond at different rates depending on their health and diet.
Want to Apply This Research?
- Track daily milk production volume and milk protein percentage weekly. Record the exact dose of supplement given each day and note any changes in milk quality metrics. Compare these metrics to baseline measurements from before starting supplementation.
- If using this supplement on a farm, implement a gradual introduction protocol: start at 10 grams per day for one week, monitor milk production and cow behavior, then increase to 20 grams per day if results are positive. Document all changes in feed composition and supplement dosing in the app.
- Set up weekly reminders to record milk production, milk composition (fat and protein %), and any visible changes in cow health or behavior. Create alerts if milk production drops more than 5% from baseline, which might indicate the dose is too high or the supplement isn’t working for your herd. Track costs of the supplement versus savings from reduced protein feed.
This research describes results from a small, controlled laboratory study with eight dairy cows and should not be considered definitive guidance for farm management. Individual farm results may vary significantly based on herd genetics, existing diet, farm conditions, and management practices. Farmers considering implementing plant-based supplements should consult with a veterinarian or animal nutritionist before making changes to their feeding program. This summary is for informational purposes only and does not constitute veterinary or nutritional advice. Always work with qualified professionals when making changes to animal feed or management practices.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.