Hot Water in Feed
Ing Lucie Humeni
In winter, many horse owners feel that by preparing a mash or other feed with hot water, they are pleasing their horse and at the same time “warming” them up a little. It’s a nice idea, because people are used to the fact that a warm cup of tea or soup lifts both mood and body temperature. The idea of adding warm water, making a mash, and giving the horse something that feels pleasant in cold weather and intuitively natural from a human perspective is understandable.
However, a horse is not a human, and its digestion and thermoregulation do not work the same way as ours. The horse’s organism did not evolve to consume hot liquids. In some cases, warm feed can indeed help increase fluid intake, but there are also situations where higher temperatures bring more risks than benefits.
Hot Water and the Horse — Against Nature
Try to imagine a horse in the wild. In winter, it drinks from a stream or a trough covered with a layer of ice. Nothing even remotely resembling the temperature of warm tea. The horse’s body is adapted to drinking cool to lukewarm water. Hot liquids can be unpleasant for some horses and may even reduce their willingness to drink—which is the last thing you want in winter.
In natural conditions, horses commonly drink water whose temperature ranges, depending on the season, from approximately 2–18 °C. Several studies show that horses prefer water at around 15–20 °C. Yes, if water is too cold, horses may drink less—but if it is too warm, the result is exactly the same.
What Do Scientific Studies Show?
- Horses prefer cool to mildly lukewarm water; extremely cold water can reduce drinking.
- Excessively warm to hot water can also lead to reduced fluid intake.
- Disrupted hydration in winter increases the risk of colic.
It is therefore true that protection from overly cold water (for example, warming water to a pleasant, non-icy temperature) can be beneficial. At the same time, hot water is unnatural for horses and may cause them to drink less or even refuse feed.
Why a Hot Mash Does Not Warm the Horse
A widespread myth claims that warm mash “heats the horse from the inside.” This assumption, however, does not reflect how a horse actually maintains its body temperature.
A horse generates heat primarily through:
- digestion of fiber — fermentation in the cecum,
- natural physical activity,
- thermoregulatory mechanisms (coat, blood circulation).
Consuming hot feed has only a very short-term and negligible effect on overall body temperature. The organism quickly equalizes the temperature of ingested feed. For a horse, a far more effective “source of heat” is hay, because fiber fermentation is a process that naturally produces a significant amount of heat—and this is what helps keep horses thermally comfortable in winter.
In practice, this means that if an owner wants to keep a horse warm, the most effective measures are:
- ad libitum access to hay,
- protection from wind and moisture,
- and, if necessary, an appropriate blanket, depending on the horse’s health status or condition.
A warm “mash” cannot replace these effects.
Warm Water and Probiotics
Probiotics are not just another “ingredient” in feed. They are living microorganisms whose effectiveness depends on remaining viable until they reach the horse’s digestive tract. The stability of these organisms is highly sensitive to temperature conditions.
Scientific studies consistently show that:
- most commonly used probiotic cultures lose vitality at temperatures above 40–50 °C,
- some yeasts have higher tolerance, but still react sensitively to prolonged heat exposure,
- bacteria such as Lactobacillus or Bifidobacterium are particularly susceptible to high temperatures,
- beneficial microorganisms used in feed mixtures are not technologically treated to withstand being poured over with hot water.
For these reasons, products containing probiotics are generally recommended to be mixed with cold or lukewarm water. This recommendation is not a formality or excessive caution—it is a necessary condition for probiotics to be effective.
This applies specifically to the Energys Mash mix, where this recommendation is stated precisely to protect microbial cultures.
When feed is mixed with hot water, probiotics may be partially or completely deactivated. The result? The horse receives a palatable feed, but without the expected functional effect.
Even though it may be tempting to pour hot water over feed, doing so often reduces its benefits. Horses are best kept warm in a natural way—through high-quality fiber-based feed and sufficient access to hay, which we must not forget.
Sources
- Morán, M. E. et al., 2025. Evaluating the Impact of Temperatures and Exposure Times on Probiotics Viability Under Pre- and Post-Technological Processes. Online. SSRN / ScienceDirect. Accessed: 18 Nov 2025.
- Chelliah, R., Kim, E.-J. et al., 2021. In Vitro Probiotic Evaluation of Saccharomyces boulardii. Online. Foods. MDPI. Accessed: 18 Nov 2025.
- Jafari, M., Jafari, N., 2016. Influence of Heat Shock Temperatures and Fast Freezing on Viability of Probiotic Sporeformers. Online. Nutrition & Food Sciences Research. Accessed: 18 Nov 2025.
- Kristula, H. M. Horse Hydration: Your Questions Answered. Online. TheHorse.com. Accessed: 18 Nov 2025.
- Horse Journals. Winter Water for Horses. Online. HorseJournals.com. Accessed: 18 Nov 2025.
