Heat-treated cottonseed significantly improves milk production and quality in dairy cows exposed to hot weather, according to a 2026 study of 32 lactating cows. Research shows cows fed extruded cottonseed produced more milk with higher protein and lactose content while digesting their feed more efficiently than cows fed regular cottonseed during moderate heat stress conditions.
When dairy cows face extreme heat, their milk production often drops. A new study tested whether processing cottonseed through extrusion (a heating method) could help cows stay productive during hot weather. Researchers fed 32 lactating Holstein cows either regular cottonseed or heat-treated cottonseed while keeping track of their milk production, health markers, and digestion. According to Gram Research analysis, cows eating the heat-treated cottonseed produced more milk with higher protein and lactose content, digested their food better, and showed improved blood chemistry markers. This suggests that simple feed processing could be a practical way to help dairy farms maintain productivity during heat waves.
Key Statistics
A 2026 randomized controlled trial of 32 lactating Holstein cows found that heat-treated cottonseed increased milk production and improved milk protein and lactose concentrations compared to regular cottonseed during moderate heat stress conditions.
According to a 2026 study published in Veterinary and Animal Science, cows fed extruded cottonseed showed greater digestibility of dry matter and tended to have improved protein digestibility compared to cows fed raw cottonseed under heat stress.
Research from a 2026 trial of 32 dairy cows demonstrated that heat-treated cottonseed feeding resulted in higher blood concentrations of albumin and improved albumin-to-globulin ratios, suggesting enhanced nutritional status during heat stress.
A 2026 study found that cows fed extruded cottonseed exhibited higher plasma concentrations of glycine and trends toward increased arginine and urea-cycle amino acids compared to cows fed regular cottonseed during moderate heat stress.
The Quick Take
- What they studied: Whether heating cottonseed through extrusion helps dairy cows produce more milk and stay healthier when exposed to hot weather conditions.
- Who participated: 32 adult dairy cows (Holstein breed) that were already producing milk, studied during a period of moderate heat stress with temperatures and humidity levels typical of hot summer conditions.
- Key finding: Cows fed heat-treated cottonseed produced significantly more milk with higher protein and lactose content compared to cows fed regular cottonseed, while also showing better digestion of their feed.
- What it means for you: For dairy farmers in hot climates, this suggests a simple feed processing method could help maintain milk production and quality during heat waves. However, results are from one study with a moderate number of cows, so more research would strengthen these findings.
The Research Details
Researchers divided 32 lactating dairy cows into two groups. One group received regular whole cottonseed in their feed, while the other group received cottonseed that had been heated and processed through extrusion (a machine that pushes feed through small openings under heat and pressure). Both groups were kept in conditions representing moderate heat stress throughout the study period. The researchers measured milk production and quality, how much feed the cows ate, how well they digested their food, their behavior, and various blood chemistry markers.
The study lasted several weeks, with detailed measurements taken at different time points. Researchers tracked daily milk production, milk composition (fat, protein, lactose), feed intake, digestion efficiency, and blood samples to measure nutrients and amino acids (building blocks of protein). They also observed the cows’ eating and resting behaviors to see if the feed type affected their daily routines.
This type of controlled comparison allows researchers to isolate the effect of the feed processing method while keeping other variables consistent. By measuring multiple outcomes—production, digestion, blood chemistry, and behavior—the study provides a comprehensive picture of how the treatment affects the whole animal.
Heat stress is a major problem for dairy farms in warm climates, causing cows to eat less and produce lower-quality milk. Understanding which feed modifications can help cows cope with heat is practically important for farmers. This study uses a real-world heat stress condition rather than just laboratory measurements, making the results more applicable to actual farm situations. By measuring both production outcomes and internal body chemistry, the research helps explain not just whether the treatment works, but how it works.
This study is a controlled experiment with a reasonable sample size (32 cows) and careful measurement of multiple outcomes. The researchers used a completely randomized design, which is a strong research approach. However, the study involved only one breed of cow (Holstein) in one location during one time period, so results may not apply to all dairy operations. The moderate heat stress conditions studied may not reflect extreme heat waves. Additionally, the study doesn’t report long-term effects beyond the study period, so we don’t know if benefits persist over months or years.
What the Results Show
Cows fed heat-treated cottonseed ate more feed between days 8 and 21 of the study compared to cows fed regular cottonseed. This increased feed intake translated into greater milk production overall. The milk from cows eating heat-treated cottonseed contained higher concentrations of protein and lactose (milk sugar), which are important quality markers. Interestingly, the percentage of fat in the milk was slightly lower in the heat-treated group, though total milk production was higher.
The digestibility results showed that cows fed heat-treated cottonseed digested their dry matter (the solid components of feed) more efficiently. This means their bodies extracted more nutrients from the same amount of feed. Protein digestibility also showed a trend toward improvement, suggesting the heating process may make protein more available for the cow’s body to use.
Rumen fermentation patterns—the chemical processes that happen in the cow’s specialized stomach—shifted in the heat-treated group. Acetate (a key fermentation product) was lower, while propionate tended to be higher. These changes in fermentation patterns may contribute to better overall metabolism and milk production.
Blood chemistry markers improved in cows fed heat-treated cottonseed. Cholesterol and albumin (a blood protein) concentrations were higher, and the ratio of albumin to globulin (another blood protein) increased. These changes suggest improved nutritional status and potentially better immune function. Alkaline phosphatase activity (an enzyme related to bone and liver health) showed a tendency to decrease, which may indicate reduced metabolic stress. Amino acid profiles—the building blocks of protein in the blood—showed higher concentrations of glycine and trends toward higher arginine and urea-cycle amino acids (citrulline and ornithine). These amino acids are important for muscle maintenance, immune function, and overall metabolic health.
Previous research has shown that heat stress reduces feed intake and milk production in dairy cows. This study builds on that knowledge by testing whether feed processing can mitigate these negative effects. The finding that heat-treated cottonseed improves nutrient digestibility aligns with other research showing that thermal processing can increase nutrient availability in plant-based feeds. The changes in rumen fermentation patterns observed here are consistent with studies showing that feed processing affects how microbes break down feed in the rumen. However, most previous work focused on individual nutrients rather than whole cottonseed, making this a relatively novel application.
The study included only 32 cows of one breed (Holstein), so results may not apply to other dairy breeds or smaller herds. The heat stress conditions were moderate (temperature-humidity index of 75.9), not extreme, so the findings may not apply during severe heat waves. The study period was relatively short, so we don’t know if benefits continue over longer periods or if cows adapt over time. The research doesn’t compare the cost of the extrusion process to the benefits gained, which would be important for farmers deciding whether to adopt this practice. Additionally, the study was conducted in one location during one time period, so seasonal and regional variations aren’t captured.
The Bottom Line
Based on this research, dairy farmers in hot climates may consider using heat-treated cottonseed as part of their feeding strategy during heat stress periods. The evidence suggests moderate confidence in improved milk production and quality, with stronger evidence for improved nutrient digestibility. However, farmers should also consider the cost of the extrusion process and whether it fits their operation. Consulting with a veterinarian or animal nutritionist is recommended before making major feed changes.
Dairy farmers in warm or hot climates where heat stress affects milk production would benefit most from this research. Farmers using cottonseed as a feed ingredient should find this particularly relevant. Feed manufacturers and nutritionists developing heat-stress management strategies should also consider these findings. However, farmers in cool climates or those not using cottonseed in their feed may find limited direct application. This research is less relevant to beef cattle operations or non-ruminant animals.
Based on this study, improvements in feed intake appeared within 8-21 days of switching to heat-treated cottonseed. Milk production and quality improvements would likely follow similar timelines. However, the full benefits for blood chemistry and amino acid profiles may take several weeks to fully develop. Farmers should expect to see changes within 2-3 weeks but may want to continue monitoring for 4-6 weeks to assess the full impact on their specific herd.
Frequently Asked Questions
Does heating cottonseed really help dairy cows produce more milk in hot weather?
Research shows heat-treated cottonseed increased milk production and improved milk protein content in dairy cows during moderate heat stress. A 2026 study of 32 cows found cows eating extruded cottonseed produced more milk with higher protein and lactose concentrations than those eating regular cottonseed.
How does extruded cottonseed improve milk quality?
Heat treatment makes nutrients in cottonseed more digestible, allowing cows to absorb more protein and other nutrients from their feed. This improved nutrient availability supports higher milk protein and lactose production. The heating process also alters rumen fermentation patterns in ways that enhance overall metabolism.
How long does it take to see improvements after switching to heat-treated cottonseed?
According to the 2026 research, increased feed intake appeared within 8-21 days of switching to extruded cottonseed. Farmers should expect to see changes in milk production and quality within 2-3 weeks, with full benefits potentially developing over 4-6 weeks of consistent feeding.
Will heat-treated cottonseed work for all dairy farms?
This study involved Holstein cows in moderate heat stress conditions, so results may vary by breed, climate, and farm management practices. Farms in hot climates using cottonseed in their feed would likely benefit most. Consulting with a veterinarian or nutritionist about whether this fits your specific operation is recommended.
Does extruded cottonseed affect the fat content of milk?
The 2026 study found that while milk protein and lactose increased with heat-treated cottonseed, milk fat percentage slightly decreased. However, total milk production was higher, so overall milk yield and quality metrics improved despite the lower fat percentage.
Want to Apply This Research?
- Track daily milk production volume and milk protein percentage weekly. Compare these metrics for 3-4 weeks before and after switching to heat-treated cottonseed to measure the real impact on your specific herd.
- If using the app to manage dairy nutrition, input the switch to heat-treated cottonseed as a feed modification and set reminders to monitor milk quality metrics (protein, lactose, fat percentage) at regular intervals to track changes over time.
- Establish a baseline of milk production and quality metrics during heat stress periods using regular cottonseed. After switching to heat-treated cottonseed, monitor the same metrics weekly for at least 6 weeks. Track feed intake, milk yield, and milk composition to determine if the investment in feed processing provides sufficient benefits for your operation.
This research summary is for informational purposes only and should not replace professional veterinary or nutritional advice. The study involved 32 cows under specific conditions and may not apply to all dairy operations, breeds, or climates. Before making significant changes to your herd’s diet or management practices, consult with a veterinarian, animal nutritionist, or agricultural extension specialist familiar with your specific operation. Results from a single study should be considered alongside other research and your farm’s unique circumstances. Individual cow responses may vary, and economic factors including feed costs should be evaluated before implementing changes.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.