Water: The Essential Nutrient

Marcia Shannon
State Swine Nutrition Specialist
University of Missouri
Phone: (573) 882-7859


Water is the single most important nutrient of life. Without water, no metabolic and physiological processes within the body can occur. Water is necessary for the movement of nutrients to the cells, removal of waste products from these cells, mineral or acid/base balance, protection of nervous system, lubrication of joints and body temperature control. Other signs of water being essential are that water is required in amounts larger than any other nutrient and represents approximately 50 to 80 % of body weight depending on age and fat content.

So, what is normal water consumption for pigs? Typically, pigs will consume 2 to 3 lbs of water for every pound of feed consumed per day. At any time, if adequate water is not provided to the pig, feed intake and subsequent growth performance will be reduced. Some signs of inadequate water intake include very dry feces, hollow eyes, and dehydrated skin. Table 1 reports some suggested daily water intake and flow rates for several stages of swine production. However, it is not just the supply of adequate water, but also the supply of quality water. The quality of water refers to the salt, calcium, magnesium, iron, manganese, nitrate, sulphate and total dissolved solids content. All water supplies should be tested routinely and the recommended limits to their content in water are provided in Table 2.

Table 1. Suggested Daily Water Intake and Flow Rates
Stage of Production Intake, L/dFlow rate, L/min
Table 2. Recommended Water Quality Guidelines
CharacteristicMax. Concentration, ppm
Total dissolved solids< 5000

Water Requirement

Many factors influence the amount of water intake by a pig. These factors can be body weight, water quality (total dissolved solids), water salinity, water temperature, environmental temperature (season), relative humidity, moisture content of feed, feed intake, protein content of the diet, salt content of the diet, fiber content of the diet, health status of the pig, drinker design, and drinker placement.

The most critical stages of production to ensure water intake is not restricted or limited are at weaning and during lactation. After weaning, the pig often becomes dehydrated due to the change from a liquid-based diet (milk) to a dry grain-based feed and this affects feed intake and growth performance. A common practice of offering fresh water daily in small bowls on the floor or cup waters for the first week post-weaning has been shown to provide benefits.

Similarly, the lack of water intake of the lactating sow will, not only limit feed intake, but also milk yield since milk consists of 80 % water. Ultimately, the reduction in milk yield will slow growth and development of the suckling pig. Table 3 reports performance data from a cooperative study involving 6 universities and 236 crossbred litters evaluating nipple drinker water flow rates during the winter and summer on performance of lactating sows and their litters (Leibbrandt et al., 2001). This data shows that restricted water intake (70 mL/min) and summer season reduced feed of the sow and resulted in greater weigh loss during lactation, but had only slight affects on litter performance.


The supply of adequate water is essential for body functions and lack of water will result in poor pig performance. All pigs are affected, but the newly weaned pig and lactating sow are especially sensitive to low water intake, which could affect subsequent performance (growth and increase weaning to estrus interval). Water intake will vary greatly between pigs, so the best bet is to ensure that all pigs are receiving a fresh supply of quality water at all times.

Table 3. Effects of season and drinker flow rate on sow and litter performance
Winter (Nov.-Feb.)Summer (June-Aug.)
Water Flow, mL/min
Sow Performance
Sow wt., lb d 109 477481480.3490.2
Sow wt. Change, lb/d 0 to 21 d -0.55-1.47-1.45-2.2
Feed Intake, lb/d    
0 to 7 d 9.378.217.76.84
8 to 14 d 11.739.818.877.99
15 to 21 d 12.679.9710.169.26
0 to 21 d11.269.338.918.03
Litter Performance
Pigs/litter 21 d9.
Litter wt., lb    
0 d 15.315.314.514.9
7 d 2626.224.825
14 d
21 d 53.752.749.350

Leibbrandt, V.D., L.J. Johnston, G.C. Shurson, J.D. Crenshaw, G.W. Libal, and R.D. Arthur. 2001. Effect of nipple drinker water flow rate and season on performance of lactating swine. J. Anim. Sci. 79:2770-2775.