According to Gram Research analysis, soybean hulls significantly improved milk production in postpartum dairy cows. A 2026 study of 20 Holstein cows found that replacing traditional long-fiber feed with soybean hulls (7.8% of diet) increased milk yield, milk quality, and digestive efficiency during the critical first three weeks after birth. The cows eating soybean hulls produced more lactose-rich milk and showed healthier rumen fermentation with elevated beneficial fatty acids, suggesting this industrial byproduct could serve as a sustainable alternative feed for dairy operations.
Researchers tested whether soybean hulls, a leftover product from processing soybeans, could improve milk production in dairy cows right after they give birth. Twenty cows were fed either a traditional diet or one that included soybean hulls for three weeks. The cows eating soybean hulls produced more milk, had better milk quality, and showed healthier digestive systems. This finding suggests soybean hulls could be a sustainable and affordable alternative feed that helps both the cows and dairy farmers.
Key Statistics
A 2026 research article of 20 postpartum Holstein dairy cows found that soybean hulls significantly increased milk yield, energy-corrected milk production, and milk lactose content compared to traditional long-fiber diets during the first 21 days after birth.
According to a 2026 study published in the Journal of Dairy Science, cows fed soybean hulls showed significantly higher concentrations of volatile fatty acids in the rumen, including acetic acid, butyric acid, and pentanoic acid, indicating improved digestive fermentation.
A 2026 dairy cow study of 20 animals found that soybean hull supplementation increased nutrient digestibility and elevated pancreatic glucagon concentrations in blood serum, suggesting enhanced energy metabolism during the postpartum period.
Research from 2026 involving 20 postpartum cows demonstrated that soybean hulls altered rumen microbiota composition, increasing beneficial bacteria like Roseburia and Coprococcus while reducing other bacterial groups, supporting improved milk production.
The Quick Take
- What they studied: Whether replacing regular hay with soybean hulls in a dairy cow’s diet after giving birth would improve milk production and the cow’s health.
- Who participated: Twenty adult Holstein dairy cows (the most common dairy breed) during their first three weeks after giving birth, which is a critical time for milk production.
- Key finding: Cows fed soybean hulls produced significantly more milk and higher quality milk compared to cows on a traditional diet. Their digestive systems also worked better, producing more beneficial acids that help cows stay healthy.
- What it means for you: If you buy dairy products, this research suggests farmers may be able to use cheaper, more sustainable feed ingredients without sacrificing milk quality. However, this study was small and only looked at three weeks, so more research is needed before widespread adoption.
The Research Details
Researchers divided twenty dairy cows into two groups right after they gave birth. One group ate a traditional long-fiber diet (regular hay and similar feeds), while the other group ate a diet where about 7.8% of their food was replaced with soybean hulls, which are the outer shells left over after soybeans are processed for oil and meal. The researchers measured milk production, milk quality, what the cows ate, how well they digested their food, and changes in their blood and digestive system over 21 days.
Soybean hulls are interesting because they contain lots of complex carbohydrates and fiber, similar to traditional hay, but they come from an industrial waste stream. This makes them potentially cheaper and more sustainable than conventional feeds. The researchers wanted to see if this byproduct could work just as well or better than traditional fiber sources, especially during the critical postpartum period when cows need to recover and start producing milk.
The study measured multiple outcomes including how much milk the cows produced, the composition of that milk (fat, protein, lactose), how efficiently they digested nutrients, and even changes in the bacteria living in their stomachs and the chemical signals in their blood.
The postpartum period is crucial for dairy cows because they need to recover from pregnancy and birth while also producing large amounts of milk. During this time, cows are under significant metabolic stress. Finding feeds that improve both milk production and the cow’s health during this vulnerable period could improve animal welfare and farm sustainability. Additionally, using industrial byproducts as animal feed reduces waste and creates a circular economy in agriculture.
This study was published in the Journal of Dairy Science, a well-respected peer-reviewed journal in animal nutrition. The researchers used a randomized design, meaning cows were randomly assigned to each diet group, which helps reduce bias. However, the study included only 20 cows and lasted only 21 days, which are relatively small scope and short duration. The findings would be stronger if confirmed in larger studies over longer periods and across different farms and cow breeds.
What the Results Show
Cows fed soybean hulls ate more food overall and digested their nutrients more efficiently than cows on the traditional diet. This led to significantly higher milk production: the soybean hull group produced more total milk, more energy-corrected milk (a measure that accounts for milk composition), and more fat-corrected milk. The milk from cows eating soybean hulls also contained more lactose, a natural sugar in milk.
The digestive benefits were substantial. In the rumen, the part of a cow’s stomach where fermentation happens, cows eating soybean hulls produced significantly higher levels of volatile fatty acids. These are short-chain fatty acids that serve as the cow’s primary energy source and are signs of healthy digestion. Specifically, acetic acid, butyric acid, and several other beneficial acids were all elevated in the soybean hull group.
Blood tests revealed that cows eating soybean hulls had significantly higher levels of glucagon, a hormone that helps regulate blood sugar and energy metabolism. This suggests their bodies were processing energy more efficiently. The researchers also found that soybean hulls triggered changes in liver metabolism, activating pathways involved in protein processing and fat metabolism, which are important for milk production and overall health.
The composition of bacteria living in the cows’ digestive systems changed significantly between the two groups. Cows on the traditional diet had higher amounts of certain bacteria like Ruminococcus and Lachnobacterium. Cows eating soybean hulls had higher amounts of different bacteria including Roseburia, Coprococcus, and Eubacterium nodatum group. These bacterial changes suggest the soybean hulls created a different digestive environment, one that appears to support better milk production and nutrient processing. The genetic activity in the cows’ livers also shifted, with increased activity in pathways related to fat metabolism and energy processing.
Previous research has shown that the type and length of fiber in a cow’s diet affects both milk production and digestive health. This study adds to that knowledge by showing that soybean hulls, an industrial byproduct, can actually outperform traditional long-fiber feeds in the critical postpartum period. Most prior studies focused on mature, established lactation, so this research fills a gap by specifically examining the immediate postpartum phase when cows are most vulnerable and when feed quality has the biggest impact on long-term productivity.
The study included only 20 cows, which is a relatively small number for drawing broad conclusions. All cows were Holstein breed, so results may not apply to other dairy breeds. The study lasted only 21 days, covering only the immediate postpartum period, so we don’t know if benefits continue over a full lactation cycle. The research was conducted in a controlled research setting, not on commercial farms, so real-world results might differ. Additionally, the study didn’t measure economic costs or long-term effects on cow health beyond the three-week period.
The Bottom Line
Based on this research, soybean hulls appear to be a promising alternative feed for postpartum dairy cows, with moderate to strong evidence for improving milk production and quality during the first three weeks after birth. However, farmers should consider this as a potential option rather than a definite recommendation until larger, longer-term studies confirm these findings. Any diet changes should be made gradually and under guidance from a veterinarian or animal nutritionist, as sudden feed changes can upset a cow’s digestive system.
Dairy farmers and agricultural operations would benefit most from this research, as it offers a potential way to improve milk production while using a sustainable, lower-cost feed ingredient. Consumers interested in sustainable agriculture and animal welfare should care because this research supports more environmentally friendly farming practices. However, individual consumers don’t need to change their behavior based on this single study. Researchers in animal nutrition and sustainable agriculture should pay attention as this work opens doors for further investigation.
Based on this study, improvements in milk production and digestive health appeared within the first three weeks of feeding soybean hulls. However, we don’t know how long these benefits last or whether they continue throughout the entire lactation period (typically 10 months). Farmers considering this feed would likely see changes within 2 to 4 weeks, but longer-term monitoring would be needed to assess sustainability of benefits.
Frequently Asked Questions
Can soybean hulls improve milk production in dairy cows?
Yes, a 2026 study of 20 postpartum cows found that soybean hulls increased milk yield, milk quality, and digestive efficiency compared to traditional feeds during the first three weeks after birth. However, this was a small, short-term study, so larger research is needed to confirm long-term benefits.
What are soybean hulls and why use them as cow feed?
Soybean hulls are the outer shells left over after soybeans are processed for oil and meal. They contain beneficial fiber and carbohydrates similar to traditional hay but come from industrial waste, making them cheaper and more sustainable while potentially improving milk production.
How do soybean hulls affect a cow’s digestive system?
Soybean hulls increase the production of beneficial volatile fatty acids in the rumen and alter the bacteria living in the digestive system. A 2026 study found they increased acetic acid, butyric acid, and other short-chain fatty acids that serve as the cow’s primary energy source.
Is it safe to switch a dairy cow to soybean hull feed?
The 2026 study showed positive results, but any diet change should be gradual and supervised by a veterinarian or animal nutritionist. Sudden feed changes can upset a cow’s digestive system, so introduce soybean hulls slowly over 7 to 10 days.
How long does it take to see milk production improvements from soybean hulls?
In the 2026 study, improvements in milk production and digestive health appeared within the first three weeks of feeding soybean hulls. However, the study didn’t measure effects beyond 21 days, so longer-term benefits remain unknown.
Want to Apply This Research?
- For dairy farmers using a nutrition tracking app, measure and log daily milk production volume and milk composition (fat and protein percentages) weekly when introducing soybean hulls to the diet. Compare these metrics to baseline measurements from the two weeks before the diet change.
- A farmer could use the app to set a reminder to gradually introduce soybean hulls over 7 to 10 days (replacing 1 to 2% of the diet every few days) rather than making an abrupt change. The app could track the percentage of soybean hulls in the diet and flag any digestive issues or production drops that might indicate the transition is too rapid.
- Set up weekly check-ins in the app to record milk yield, milk composition, and any observations about cow health or behavior. Create a comparison dashboard showing metrics from before and after the diet change, with alerts if production drops below baseline or if digestive issues appear. Continue monitoring for at least 8 to 12 weeks to assess whether benefits from the initial three-week period persist.
This research describes findings from a single 21-day study involving 20 cows in a controlled research setting. Results may not apply to all dairy operations, breeds, or longer time periods. Before making any changes to dairy cow diets, consult with a veterinarian or animal nutritionist, as individual cow health, farm conditions, and local feed availability vary. This article is for informational purposes and should not replace professional agricultural or veterinary advice. Soybean hull feed quality and safety should be verified through proper sourcing and testing before use.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.