Successful sheep production requires a continual supply of clean, fresh water at a temperature that will optimize intake. Water has three important roles in the sheep’s body: (1) to serve as a coolant; (2) to transport nutrients and wastes; and (3) to provide a medium for chemical reactions.

Generally, if the water source is high quality, intake will increase as dry matter intake increases. Daily water consumption should be two to four times that of dry matter intake. On the average, sheep drink about 1.0 to 1.5 gallons of water for each 4.0 pounds of dry matter consumed. However, this ratio may be narrower for ewes in late gestation and lactation. These ewes should have an unlimited water supply and be allowed to drink frequently. On the other hand, excessive water in feedstuffs, like silage and succulent forage, may reduce water intake from other sources. Insufficient dry matter consumption from high moisture feedstuffs, especially by lambs, may keep them from gaining or even maintaining body weight. The dry matter portion of the feedstuff may be so diluted that consumption of other nutrients (protein, energy, minerals, and vitamins) falls below the minimum requirements for gain or even maintenance of body weight.

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. Water needs increase when environmental temperatures rise above 70°F. On the other hand, significant decreases in water intake occur when the environmental temperature drops below 20°F. 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. Ideal water temperature is between 45° and 55°F. 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. Continuous flow sources are excellent, but consumption of extremely cold water requires extra feed to maintain body temperature. If only ice water is available to sheep consuming large amounts of roughage in winter, they may not consume enough water to efficiently digest high roughage diets. In turn, feed intake decreases and total productivity decreases. Also, sheep will not consume adequate amounts of water if it is stagnant, hot, or has an objectional odor.

Rain, dew, or snow will influence water intake. Ewes and lambs maintained on green, succulent pastures, where rain showers occur frequently and a heavy dew is a daily occurrence, may require very little additional water. In areas where snow continually covers the ground, much or all of the daily requirements for water can be met from the consumption of snow. Still, a continual, fresh water source is preferred.

Development of new water sources has improved range use in fenced pastures and on summer and winter ranges where sheep are herded. Stream water is a superb source for sheep, but use of areas along the stream should be varied to prevent erosion and decreased water quality. Reservoirs and ground tanks have been used effectively on summer and winter ranges. However, tank water can become brackish and contaminated. Clean, fresh water should be hauled rather than trying to force consumption of poor quality water. If hauling water becomes a necessity, sheep should be watered at least daily in troughs with adequate space for all animals to drink.

A clean, cool, and continual water supply is essential for feedlot lambs. Those that drink frequently and consume more water have fewer digestive problems and a lower incidence of urinary calculi; they also achieve more efficient use of diets than lambs watered only once or twice daily.

Energy

Dietary carbohydrates, lipids, and excess protein all contribute toward fulfilling the energy requirements of sheep. Carbohydrates are the major source of energy. Concentrates (grains) contain starch, a rich source of energy. Roughages (hay, grazed forages) contain fiber (cellulose) and are not as rich in energy as concentrates, but can be used for energy via the unique, ruminal-reticular, microbial fermentation process.

Quantitatively, energy is the most important item in the sheep’s diet. Major sources of energy for sheep are grazed forages, hay, silage, and grains. Optimum energy intakes from these sources result in efficient reproduction, growth, lactation, reproduction, and wool production. However, excessive energy consumption can lead to decreased efficiency because of excessive fattening, which can reduce growth rate, lower milk production, increase reproductive failure, and decrease efficiency of wool growth.

Energy is the most common limiting nutrient encountered in sheep production, especially for ewes. This usually arises from an inadequate amount of feed resulting from drought, snow cover, low, dry-matter intake of green pasture or silage, consumption of low-quality feedstuffs, or long-term access to unpalatable feedstuffs. Inadequate energy intake causes slow growth, weight loss, reproductive failure, decreased milk production, lowered resistance to diseases and parasites, and increased mortality.

Only that portion of the daily ration that is actually digested and absorbed from the gastrointestinal tract benefits the animal. Therefore, digestible energy (DE) and net energy (NE) are more important in determining optimum feeding levels than is total feed consumed. Grains and protein supplements contain relatively large amounts of DE and NE, hay is intermediate, and silage and fresh forage are low when expressed on an “as-fed” basis. On a “dry matter” basis, silage and fresh forage are equivalent to high-quality hay. But, if these feedstuffs are fed as the complete diet, excess water content sometimes causes an energy deficiency because sheep simply cannot consume enough dry matter for their productive functions.

Energy requirements vary dramatically through the annual production cycle of ewes. Maximum energy intakes are required by ewes during late gestation and lactation. Environmental stress alters the energy requirements of all classes of sheep.