Water is essential for horses and livestock. It is needed for almost every function of the body.
Not only is the body composed mostly of water, but one of the primary components of blood is water. Thus, water and water intake are important for circulation and correct function of the heart. Appropriate digestion and urination rely on water as well. In addition to these functions and others, water is needed to replace losses from sweating or other causes. Sweating helps cool the body but leads to loss of fluids and electrolytes. Most large animals need about 1 gallon of water per 100 lbs of body weight each day. This means for a 1,000-pound animal, a minimum of 10 gallons of water each day is needed. For animals that are lactating or exercising (especially in hot, humid weather), water intake needs can double (Meehan et al, 2015).
In light of these facts, it is not surprising that a constant supply of clean, fresh water is important for our horses and livestock. Dehydration can result in problems that threaten both the health and, in severe cases, the life of the animal. Lack of water may also affect the ability or willingness of show animals to perform, grow at optimal rates, (Lardner et al, 2005; McKeever KH; 1998; Amaral-Phillips D, 2010) or even their ability to look their best in the show ring. Decreased milk production and decreased weight gain can be seen in food animal species. For horses, some studies have shown that a decreased amount of water intake or decreased access to water was significantly associated with an increased risk of colic (Kaya et al, 2009; Reeves et al, 1996).
Animals kept on pasture do obtain some moisture from grass, as it contains more water than hay. However, there are times when animals need to be stalled and fed hay during showing, so making sure they drink sufficient amounts of water is especially important. Buckets are often used in stalls, as many do not have automatic waterers. Checking buckets often and maintaining clean buckets with fresh water will help ensure animals are well hydrated.
When horses or livestock lose water due to sweating during hard work, travel, exercise, or a hot environment, a greater demand can be placed on the cardiovascular system (McKeever KH; 1998). In dairy cattle, water intake influences feed intake, and also impacts milk production (Amaral-Phillips D, 2010). In people, studies indicate that optimal fluid balance delays the onset of fatigue (Convertino VA, 1987; Wade et al, 1989; Freund et al, 1998; McKeever KH; 1998). The same appears to be true for large animals, whether they are used for production, pleasure, or showing. Losses can be especially great in the summer. In one study horses exercised in hot, humid environments, had total sweat fluid losses during training that were 2- or 3-fold greater than losses when compared to training in cool, dry environments (McCutcheon LJ, Geor RJ; 1996).
Most animals will rapidly replace any losses by drinking (McKeever KH; 1998), so we can help maintain good health and function by providing drinking water that is palatable and clean at all times.
Key References
Meehan MA, Stokka G, Mostrom M. Livestock water requirements. NDSU Extension Service 2015.
Great and informative info on the importance of water