Excessive intakes of protein nitrogen or nonprotein nitrogen will significantly increase water intake due to extra water required for urinary elimination of the excess nitrogen. Likewise, excessive mineral consumption, especially salt, will increase water requirements. Although sheep can tolerate water containing 1.0 to 1.3 percent salt over a relatively long period of time, they cannot tolerate more than 1.5 percent salt in water. Furthermore, diets containing .5 to 1.0 percent of the dry matter as salt can be tolerated if clean, fresh water is continually available. Greater than 1.0 percent salt in the diet should be avoided because of reduced dry matter intake.
Body temperature is controlled by the latent heat of evaporation of water from the lungs.
This can be particularly important for lactating ewes, because much of the water they consume leaves the body through milk. If water intake is reduced, significant reductions in milk production can result. The factor that governs water consumption more than any other is the temperature of the water itself. The water supply should be located in the shade during the summer. Heaters can be used in winter to keep the water as close to the ideal temperature as possible.