Water is the main constituent of the animal’s body,constituting 50 to 80 percent of the live weight,depending on age and degree of fatness. An animal can lose almost all of its fat and about 50 per cent of its body protein and survive. However, the loss of 10 per cent of its body water can be fatal. Therefore, a successful livestock enterprise requires a good water supply. A good water supply is defined both in terms of quantity and quality of the water. A good water supply is important to the livestock manager because total water intakes are positively related to feed dry matter (DM) intakes.