Introduction Water is the single nutrient required in the greatest quantity by animals. Pigs require water for a variety of reasons, including most metabolic functions, adjustment of body temperature, movement of nutrients into the body tissues, removal of metabolic waste, production of milk, and for growth and reproduction. An animal can lose practically all its fat and over half of its protein and yet live, while a loss of one-tenth of its water results in death.
Pigs consume the majority of their water by drinking.
However, some water is ingested in feed and metabolism also generates water. The pig loses body water via urine, feces, respiration and from the skin. The balance between water intake and water loss is affected by numerous factors including health status, nutrition and the environment. Surprisingly, few studies have directly addressed the question and many investigations erroneously equate water use or water consumption with water requirements. The primary aims of this paper are to provide useful guidelines for water delivery and to illustrate the importance of management to adapt water delivery to the specific and changing needs of the pig.