Forage Focus: Summer water requirements for cattle

While we often talk a lot about nutrition, forage quality, and mineral needs during the summer grazing season, water is sometimes taken for granted, almost overlooked. Yet water is the most essential nutrient for livestock production

While we often talk a lot about nutrition, forage quality, and mineral needs during the summer grazing season, water is sometimes taken for granted, almost overlooked. Yet water is the most essential nutrient for livestock production. Cattle can survive for a number of days, even up to weeks without food, but will die within a few days without water. Assuming that the goal of most cattle producers is more than just cattle survival, it is important that cattle receive a sufficient quantity of water each day to maximize feed intake, produce milk for the calf, and maintain a healthy reproductive cycle.

Research has shown that without a sufficient quantity of water, dry matter intake of cattle is reduced. This reduction in dry matter intake affects production, whether that is gain, growth, lactation or reproduction. The quantity of water needed by cattle is influenced by air temperature, activity level of the animal, lactation, and type of feed. As air temperature, activity level and lactation level increase so does the requirement for water. A ration low in moisture, compared to a pasture ration of young vegetative grass will require more water. The following chart provides an estimate of the gallons of water needed per day for various classes of beef cattle under varying summer temperatures:

Daily water intake (Gallons)1

Cattle Class

70 F

80 F

90 F

500 lb calf




800 lb growing heifer/steer




800 lb finishing cattle




750 lb pregnant heifer




Dry pregnant cow




Lactating cow




Mature bull




1. Compiled from 1996 NRC Requirements for Beef Cattle and Winchester and Morris, 1956. Water Intake Rates of cattle. Journal of Animal Science, 15:722.

Recognize that these figures are estimates. They take into account air temperature, and, to some degree, the production level of the animal, but activity level, humidity and, for pastured animals, moisture content of the pasture can all affect these numbers. I have seen tables that put the requirement for a lactating beef cow in 90-degree heat at 25 plus gallons of water per day. Still, the chart provides a starting point for the cattle producer to determine the water needs of his/her animals.
How this quantity of water will be delivered to the herd is an important consideration. Smaller paddock sizes with a water source in each paddock is the ideal because it minimizes animal energy expended walking to a water source and allows animals to come to the water source on an individual basis. In practical terms this means that the water system can be designed with lower flow rates and smaller water tanks. As a guideline, provide a tank that allows two to four percent of the animals to drink at one time and a flow rate that provides the total daily need in four hours. Larger paddocks, where a trip to the water source involves traveling out of sight of herd mates, generally means cattle will come to water as a herd. The result is that the water system must be designed to provide a larger quantity of water within a shorter time frame. The rule of thumb for this situation is to provide enough tank space for 10 percent of the cattle to drink at one time and a flow rate adequate to insure that all the cattle can drink in about 20 minutes.

While the quantity of water supplied is critical, the quality of that water is an important consideration as well. Poor and/or contaminated water supplies decrease cattle consumption of water, which affects dry matter intake and decreases animal performance. Additionally, certain contaminants can directly impact upon the health of cattle, and, in extreme cases, result in death.

Water quality for livestock can be evaluated in terms of salt concentration, nitrate levels, sulfates and sediment. Salt concentration is determined by the amount of dissolved inorganic salts such as calcium chloride, sodium chloride, magnesium chloride, sulfates and bicarbonates contained in the water. Generally a level of 3000 milligrams per liter (mg/l) or parts per million (ppm) or lower is the limit for a cattle water source. The nitrate level in water should be under 300 mg/l or 300 ppm. Sulfates in the water source are a concern because sulfur can tie up dietary copper, zinc and manganese. A general recommendation is that water sulfate concentrations not exceed 1000 mg/l or ppm. There are a number of labs around the state that can do a water quality analysis for livestock.

As a side note, any producer feeding supplemental grains or by-product feeds should be aware of the sulfur concentration of those feeds plus what the water source may contain. High sulfur levels in the total ration can lead to reduced gain, and, in extreme cases, result in sulfur induced polioencephalomalacia (PEM), a central nervous system disease that causes cattle fatality.