Star Milling

Nutrition Fundamental Series: Water

In the horse, as well as companion and zoo industries, it’s not uncommon to observe feeding decisions based on anecdotes, folklore, fables or even human data that are not compatible or skewed from the known fundamentals. There are six major classifications of nutrients and depending on the animal there are approximately 45+ specific nutrients that are required in the diet. In addition there are components of the diet that are not “required nutrients” but are critical considerations in the nutritional management of the horse. The Nutrition Fundamental Series will address the fundamentals of nutrition.


So much nutritional emphasis is placed on protein, fat, minerals, vitamins, and nonstructural carbohydrates that the most essential nutrient, water, is often taken for granted. Water is the vehicle in which all chemical and biological functions take place in the body. Biologically the body is designed to balance water intake with water losses. If the body detects more water is needed there are chemical and biological signals sent to the brain to tell the horse to drink.

Horses are consistent. My routine when feeding horses was to check the water bucket for amounts consumed in addition to checking stall wet spots for urination and of course manure amounts. If the horse’s routine or environment has been the same then expect these daily observations to be the same. The importance of observing water intake cannot be over emphasized.

14 Fundamental Facts about Horses & Drinking Water

  1. If they are on pasture, they drink less water.
  2. If the dry forage source is long stem hay, they drink more water than if on pasture.
  3. If the dry forage source is pellet form, they drink less water than if long-stem hay.
  4. If they consume less fiber than required, they drink less water.
  5. If they consume high protein diets, they consume more water.
  6. If they consume more salt then needed, they consume more water.
  7. If the temperature of the water is too warm or too cold, they drink less water.
  8. During winter cold, they drink less water.
  9. If the day is hot or humid, they drink more water
  10. If they are sick, they drink less water.
  11. If they exercise, they drink more water.
  12. If they are pregnant or lactating, they drink more water.
  13. If they are still growing, they drink more water.
  14. If they are true athletes with a high lean to fat body ratio, they drink more water.

So how much water a horse needs varies. The amount of water consumed depends on their food sources, feed amounts, body weight, body condition score, body muscle to fat ratio, exercise intensity, climate, pregnancy interval, lactation level, overall health, and age. There is a wide range of estimates on how much water a horse will consume. In educational literature estimates include one gallon of water per 100 pounds of body weight. From that estimate then a 1000 lb horse would consume approximately 10 gallons of water each day. However, depending on conditions described in the beginning of this paragraph daily water consumption could actually range from 2 to 15 gallons.

Because of the variations and combinations of influences on water consumption, a table on water consumption estimates is not being provided. However horse owners are encouraged to develop some observation routines. There are techniques that can help one evaluated a horse’s hydration status including the capillary refill test, mucous membrane evaluation, skin pliability, and the “grey hound look”. Ask your vet to go over a couple of these techniques with you.

Most everyone recognizes that in cold weather water intake will reduce and in hot weather water intake increases. During cold weather horse owners need to be concerned with low water consumption because lower water intake is directly correlated with an increase risk of colic. Also be concerned with the temperature of the water. All animals, including horses, are responsive to water temperature. The temperature of the water will influence how much is consume. Ideally the water temperature should be between 45° – 65° F. The only time that water access is limited is immediately after exercise. The horse needs a time period for their heart rate, body temperature, and respiration to return to normal which is the premise of the horse terminology “cooling down”.

Final Thought

Sadly, I continue to hear stories of horse owners limiting water during travel and exercise or even not checking the water source each day. Additionally, one of my least favorite tools for horse management is the automatic water bowl. There are many ways to provide water to your horse, but water buckets are still the most common method used by horse owners and perhaps most preferred by horses as well. I placed a lot of emphasis on developing nutritional management skills and knowing how much a horse is drinking is important. One can never undervalue the importance of clean, fresh, cool and always available water.