Researchers tested whether special plant-based additives could help young beef cattle grow better when eating toxic grass. Forty-five heifers were divided into three groups: one got regular supplements, while the other two got supplements mixed with plant compounds called tannins. After 12 weeks, the cattle receiving tannin additives gained weight faster than those on regular supplements alone. However, the additives didn’t affect other health measures like immune response or blood markers. The results are promising but researchers say they need to test more cattle to be sure these additives really work.

The Quick Take

  • What they studied: Whether adding special plant compounds (tannins) to cattle feed could help them grow better and stay healthier when eating toxic grass pastures
  • Who participated: 45 young female beef cattle (about 645 pounds each) grazing on pastures with toxic tall fescue grass, divided into three equal groups
  • Key finding: Cattle that received tannin additives gained about 0.5 pounds per day, compared to only 0.23 pounds per day for cattle on regular supplements—more than double the weight gain in the final month of the study
  • What it means for you: If you raise cattle on problematic pastures, these additives may help your animals grow faster and more profitably. However, this is early-stage research, and farmers should wait for larger studies before making major changes to their feeding programs.

The Research Details

Scientists divided 45 young beef heifers into three groups of 15 animals each. All groups grazed on the same toxic grass pasture for 12 weeks. Group 1 received standard soybean hull supplements. Group 2 received soybean hulls plus a tannin-saponin additive (a plant compound). Group 3 received soybean hulls plus a different tannin-polyphenol additive. The researchers measured how much weight each group gained and tested their blood for signs of health problems and immune response. They analyzed the results by comparing entire pastures rather than individual animals, which is the standard approach for grazing studies.

This research approach is important because it tests additives in real grazing conditions rather than in controlled laboratory settings. By measuring actual weight gain and blood markers, researchers can see if the additives truly help cattle overcome the problems caused by toxic grass. Testing at the pasture level (rather than individual animal level) reflects how farmers actually manage their herds.

This study has some strengths: it used a controlled design with three treatment groups and measured multiple health outcomes. However, there are limitations to consider: only 45 cattle were tested (relatively small), and the weight gain difference was only marginally significant statistically (p=0.07, meaning there’s about a 7% chance the results happened by random chance). The researchers themselves note this is preliminary work needing larger studies to confirm findings.

What the Results Show

The main finding was improved weight gain in cattle receiving tannin additives during the final four weeks of the study (days 56-84). Cattle receiving the ATX additive gained 0.53 kg per day (about 1.17 pounds), and those receiving BX gained 0.49 kg per day (about 1.08 pounds), compared to only 0.23 kg per day (about 0.5 pounds) for cattle on regular supplements. This represents more than a 100% improvement in weight gain rate. However, this difference was only marginally statistically significant, meaning researchers cannot be completely certain the additives caused the improvement rather than random variation. The improvement appeared specifically in the later part of the study period, suggesting the additives may take time to show benefits.

The additives did not significantly affect other important measures. Blood tests showed no meaningful differences between groups in immune response to vaccines (BHV-1 titers), prolactin levels (a hormone related to stress), haptoglobin (a marker of inflammation), or blood urea nitrogen (a measure of protein metabolism). These results suggest the additives may work by improving how cattle digest food rather than by reducing stress or inflammation from the toxic grass.

Previous research has shown that tannins can help protect livestock from toxic plants by binding to harmful compounds in the digestive system. This study provides some field evidence supporting that theory, though the results are less dramatic than some laboratory studies have suggested. The lack of effect on immune markers differs from some earlier research, which may indicate that weight gain improvement is the primary benefit.

The study had several important limitations. First, only 45 cattle were tested across three groups—a relatively small sample size. Second, the weight gain difference was only marginally significant statistically, meaning there’s uncertainty about whether the results are real or due to chance. Third, the study only lasted 12 weeks, so we don’t know if benefits continue longer. Fourth, the researchers tested only two specific tannin products, so results may not apply to other additives. Finally, the study was conducted on one type of toxic grass in one location, so results may differ in other regions or with different grass varieties.

The Bottom Line

Based on this preliminary research, tannin additives show promise for improving weight gain in cattle grazing toxic fescue pastures (moderate confidence level). However, farmers should not make major feeding changes based on this single study. Wait for larger, more definitive studies before investing significantly in these additives. If you do try them, monitor your cattle’s weight gain carefully and compare results to your baseline performance. Consult with your veterinarian or animal nutritionist before implementing changes.

Beef cattle farmers who graze their herds on tall fescue pastures—especially those dealing with toxic, endophyte-infected varieties—should pay attention to this research. The findings may be less relevant to farmers using other grass types or those with access to better-quality pastures. Cattle producers focused on maximizing weight gain and profitability would benefit most from monitoring this research area.

Based on this study, any weight gain improvements appeared to take 4-8 weeks to develop. Farmers should expect a gradual improvement rather than immediate results. Full benefits may take longer than the 12-week study period, so patience is important when evaluating these additives.

Want to Apply This Research?

  • Track weekly weight measurements of your cattle herd and calculate average daily gain (ADG) by dividing total weight gain by number of days. Compare ADG before and after introducing tannin additives, aiming to document improvements of 0.2+ kg per day.
  • If using the app to manage cattle nutrition, log the specific tannin additive product, daily dosage amount, and feeding dates. Create a pasture-level record noting which pastures receive additives and which serve as control groups for comparison.
  • Establish a baseline of your cattle’s normal weight gain on your current pastures over 4-6 weeks before introducing additives. Then implement the additive and continue weekly weighing for at least 8-12 weeks. Use the app to create side-by-side comparisons of weight gain rates before and after treatment to determine if the additive provides value for your operation.

This research summary is for informational purposes only and should not replace professional veterinary or nutritional advice. The study results are preliminary and based on a small sample size with marginal statistical significance. Before making changes to your cattle’s diet or feeding program, consult with your veterinarian, animal nutritionist, or agricultural extension specialist. Individual results may vary based on your specific pastures, cattle genetics, climate, and management practices. Always follow product label instructions and consult with the additive manufacturer regarding proper use and safety.