According to Gram Research analysis, sheep can eat plenty of very wet plants without losing weight, and the water in these plants dramatically increases urine production and dilutes nitrogen waste. A research article found that urine production was strongly linked to water intake (r² = 0.90), with sheep consuming over 30 grams of high-water forage per kilogram of body weight. This diluted urine reduces nitrogen pollution in groundwater, offering farmers an environmental solution without harming animal growth.
Researchers studied what happens when sheep eat very wet, watery plants instead of dry hay. They found that sheep can actually eat plenty of these wet plants without losing weight, and the extra water makes their urine much more diluted. This matters because diluted urine means less nitrogen pollution in the environment. The study shows that the water in the plants—not special chemicals some plants contain—is what increases urine production. While there are some costs to consider, like losing more minerals, wet plants could be a smart way to reduce farming’s environmental impact.
Key Statistics
A 2026 research article in the Journal of Animal Science found that sheep eating very wet plants (8.5-13.3% dry matter) consumed over 30 grams per kilogram of body weight in eight out of ten diet treatments without reduced intake.
Research showed a strong positive relationship between water intake and urine production in sheep (r² = 0.90, P<0.001), demonstrating that plant water content—not special plant chemicals—drives increased urination.
Plantain-based diets produced significantly lower nitrogen concentrations in sheep urine compared to chicory and ryegrass diets, reducing potential groundwater pollution while maintaining adequate animal intake.
The Quick Take
- What they studied: Whether young sheep can eat enough wet, watery plants (like plantain and chicory) to stay healthy, and how this affects their urine and nitrogen waste.
- Who participated: Young growing sheep fed different types of low-dry-matter plants in controlled pen feeding experiments with long adaptation periods to allow the animals to adjust to the new diets.
- Key finding: Sheep ate plenty of very wet plants without problems, and their urine volume increased strongly with water intake. The water in the plants—not special plant chemicals—caused the increased urination.
- What it means for you: Farmers could use wet plants to reduce nitrogen pollution from sheep farming without hurting animal growth, though they should monitor mineral and energy losses in the animals’ diet.
The Research Details
Researchers conducted pen feeding experiments where young sheep were given different types of low-dry-matter forages (plants with very high water content). The plants tested included plantain, chicory, and ryegrass varieties with water content ranging from 84-91.5%. The sheep were allowed long adaptation periods—meaning they had plenty of time to get used to eating these unusual plants before measurements began. This is important because animals often need time to adjust to new foods.
The researchers measured how much the sheep ate and drank, collected their urine and feces, and analyzed the plants for compounds that might act as diuretics (substances that make you pee more). They also measured nitrogen levels in the urine and other waste products. This careful measurement approach allowed them to understand exactly what was causing the changes in urine production.
This research design matters because previous studies had shown that high-water plants might reduce how much animals eat, which could hurt their growth. By using long adaptation periods and measuring everything carefully, this study could show whether that concern was real. The findings suggest that with proper adaptation time, sheep can thrive on these wet plants, which opens the door to using them as an environmental solution.
The study used controlled pen feeding experiments with careful measurement of intake, urine output, and plant chemistry. The long adaptation periods strengthen the findings because they show real-world conditions where animals have time to adjust. However, the sample size is not specified in the available information, which makes it harder to assess statistical power. The research was published in the Journal of Animal Science, a peer-reviewed scientific journal, which indicates it met professional standards for publication.
What the Results Show
Sheep ate high amounts of very wet plants—over 30 grams per kilogram of body weight in eight out of ten diet treatments—even when the plants were extremely watery (8.5-13.3% dry matter). This shows that concerns about reduced intake were unfounded when sheep had time to adapt.
Urine production was strongly linked to water intake from the plants (r² = 0.90, P<0.001), meaning the more water the sheep drank from the plants, the more they urinated. This relationship was very strong and statistically significant. Importantly, plant compounds previously thought to act as diuretics showed no real effect on urine production—the water content was what mattered.
The urine became much more diluted, which means nitrogen was spread out in larger volumes of liquid. This is environmentally important because concentrated nitrogen in urine can pollute groundwater, while diluted urine poses less risk. Plantain-based diets produced the most diluted urine with the lowest nitrogen concentration.
Different plant types produced different results. Plantain diets led to lower proportions of nitrogen in urine compared to chicory and ryegrass diets. Ryegrass produced the highest concentration of nitrogen in urine. The total amount of nitrogen excreted was higher in plantain treatments, but because the urine was so diluted, the concentration was lower. The study also found that high urine volumes meant higher losses of energy and minerals from the animals’ bodies, which could be a concern for long-term animal health and productivity.
Previous research had suggested that high-water plants might reduce how much animals eat, potentially hurting their growth and milk production. This study contradicts that concern, showing that with proper adaptation time, intake remains high. The finding that water content—not plant chemicals—drives urine production also challenges earlier assumptions that certain plants like plantain contained special diuretic compounds. This research aligns with growing interest in using high-water forages as an environmental solution in temperate grazing systems.
The study does not specify the exact number of sheep used, making it difficult to assess how confident we should be in the results. The research was conducted in controlled pen settings, which may not perfectly reflect how sheep behave when grazing in pastures. The study focused on young, growing sheep, so results may not apply to adult sheep or dairy animals. The increased loss of minerals and energy in urine could have long-term health consequences that weren’t fully explored. Additionally, the practical costs of implementing these wet-plant systems on farms weren’t evaluated.
The Bottom Line
Farmers interested in reducing environmental nitrogen pollution can consider using high-water-content plants like plantain and chicory in sheep diets. The evidence is strong (based on controlled research) that sheep will eat adequate amounts of these plants with proper adaptation time. However, farmers should monitor animal health for mineral and energy deficiencies, and consult with veterinarians about long-term impacts. This approach works best for young, growing sheep rather than adult animals.
Sheep farmers concerned about environmental impact should pay attention to these findings. Environmental regulators and agricultural extension services promoting sustainable farming should consider this research. Farmers in temperate regions with access to plantain and chicory varieties are the best candidates for this approach. This may be less relevant for farmers in very dry climates or those raising dairy sheep, where milk production concerns might outweigh environmental benefits.
Sheep need several weeks to adapt to high-water plants before reaching normal intake levels. Once adapted, the dilution effect on urine happens immediately with each feeding. Environmental benefits from reduced nitrogen concentration would accumulate over months as the practice continues. However, any negative effects on mineral status or energy balance would likely take weeks to months to become apparent.
Frequently Asked Questions
Can sheep eat very wet plants without losing weight?
Yes. Research shows sheep consumed over 30 grams per kilogram of body weight of high-water plants (8.5-13.3% dry matter) with proper adaptation time, indicating intake remains adequate even with extremely wet forages.
What causes sheep to produce more urine on wet plant diets?
The water content in the plants themselves drives increased urine production, not special plant chemicals. Studies found a strong relationship (r² = 0.90) between water intake and urine volume, with plant compounds previously thought to be diuretics showing no real effect.
How does diluted urine help the environment?
Diluted urine contains lower concentrations of nitrogen, reducing groundwater pollution. When nitrogen is spread across larger urine volumes, it poses less environmental risk than concentrated urine from animals eating dry feed.
Which plants work best for reducing nitrogen pollution in sheep farming?
Plantain varieties produced the most diluted urine with lowest nitrogen concentration in research trials. Chicory and ryegrass also work but produce higher nitrogen concentrations. All require 2-3 weeks adaptation time for sheep to reach normal intake levels.
Are there downsides to feeding sheep very wet plants?
Yes. High urine volumes increase mineral and energy losses from animals’ bodies, which could affect long-term health and productivity. Farmers should monitor mineral status and consult veterinarians about supplementation needs.
Want to Apply This Research?
- Track daily forage water content percentage and corresponding urine output volume in your sheep herd. Record this weekly to identify patterns between plant moisture levels and urination frequency.
- If using high-water plants, gradually introduce them over 2-3 weeks while monitoring individual sheep intake and body condition. Use the app to set reminders for weekly mineral supplementation checks and urine pH monitoring.
- Create a monthly dashboard tracking: (1) forage water content %, (2) average daily intake per animal, (3) estimated urine output, and (4) body weight changes. Compare these metrics across different plant varieties to optimize your environmental impact while maintaining animal health.
This research describes feeding practices for sheep in controlled experimental settings. Before implementing high-water plant diets on your farm, consult with a veterinarian or animal nutritionist to ensure the approach is appropriate for your specific animals, climate, and management system. The study focused on young, growing sheep and may not apply to adult animals or dairy sheep. Monitor animals closely for signs of mineral deficiency or energy imbalance. This information is for educational purposes and should not replace professional agricultural or veterinary advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.