An adult horse will drink between 15 and 35 litres of water per day – the exact amount depends on the temperature, how much work they are doing, what feed they are eating, etc. Research shows that horses drink significantly more water when they have access to an open water surface (such as a trough) than a small water cup. Horses need to consume much more water than feed each day. Wild horses eat food that is made up of about 80% water. Hay and oats contain only about 15% water, which means that domesticated horses get the majority of their water intake from a trough or a cup for large periods of the year.
Early signs of too little water intake include refusing to eat and urinating less. After a time of this, performance can be affected, and this can also lead to illnesses such as colic. In the winter, horses prefer warm water to ice cold water – the best temperature is about 18°C. Horses like to drink at the same time as they eat, which is an important point to consider when horses are fed outside in the paddock. According to the Society of the Protection of Animals, horses should always have access to water.
It’s no surprise that the temperature of the water in the winter is also important. In a study researching cows drinking water ranging in temperature from 3°C to 24°C, they drank the largest volumes at 17°C. The majority of water was drunk when they were fed, and the speed that they drank was also found to be connected to how much they drank. Free-range cows, sheep and goats should always have access to water.
Veterinarian Sara Nyman has researched a lot in the area of horses and water. See what she thinks about the subject in this film.