Ministry of Agriculture, Food and Rural Affairs

Water Requirements for Beef Cattle

It has often been said that water is the most important nutrient. Water is the main component of the animal's body, constituting 50 to 80 per cent of the liveweight, depending on age and amount of body fat. 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.

The four main functions of water in the body are:

• regulating body temperature through evaporation of water from the respiratory tract and from the skin's surface
• helping in the elimination of the waste products of digestion (feces of healthy cattle often contain 75 to 85 per cent water)
• regulating blood osmotic pressure
• a major component of milk and saliva

Water consumption requirements depend on a number of factors including:

• size of animal
• air temperature and relative humidity
• rate and composition of gain
• level of dry matter intake
• moisture content of the ration
• pregnancy
• lactation
• level of activity
• access to shade

Figure 1: Cow at water trough

Table 1 estimates the water requirements of various classes of beef cattle and at different temperatures. The total water requirement includes both water intake from feeds plus that consumed as free water choice.

Rapidly growing cattle consume large amounts of feed. Table 2 estimates the water requirements of cattle based on feed consumption and air temperature.

To ensure optimal performance of cattle, we must make sure their requirements for water are met. The water provided must be clean and fresh to encourage the cattle to drink to fulfill their needs.

Table 1: Approximate Total Daily Water Intake of Beef Cattle in Litres*

Cattle Class	Weight		Air Temperature in °C
	kg	lb	to 4oC	10oC	14oC	21oC	27oC	32oC
Growing Cattle	180	400	15	16	19	22	25	36
	275	600	20	22	25	30	34	48
	365	800	23	26	30	35	40	57
Finishing Cattle	275	600	23	25	28	33	38	54
	365	800	28	30	34	41	47	66
	455	1,000	33	36	41	48	55	78
Wintering Pregnant Cows	410+	900+	25	27	31	37	-	-
Lactating Cows	410+	900+	43	48	55	64	68	61
Mature Bulls	635	1,400	30	33	38	44	51	72
	725	1,600	33	36	41	48	55	78

*Adapted from: Nutrient Requirements of Beef Cattle: Seventh Revised Edition: Update 2000, National Research Council

Table 2: Water Consumption Estimates for Beef Cattle Based on Air Temperature and Dry Matter Intake**

Air Temperature	Water Requirements per kilogram of Dry Matter Intake
25 to 35oC	4 to 10 litres
15 to 25oC	3 to 5 litres Young and lactating animals require 10 to 50% more water.
-5 to 15oC	2 to 4 litres
Below -5oC	2 to 3 litres Increases of 50 to 100% occur with a rise in temperature following a period of very cold temperatures, e.g. a rise from -20o to 0oC.

**Adapted from Effect of Environment on Nutrient Requirements of Domestic Animals, 1981, NRC.

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