Water Requirements and Safety for Cattle Following a Disaster

7/6/2017 12:52:53 PM

Although cattle can survive for days without food, a supply of clean, fresh water is essential to keep animals alive following a disaster. Generally, cattle can survive for a few days without water since they store some water in their rumen. But this water will run out quickly and needs to be replaced to keep animals alive and to prevent digestive problems.

Water Requirements

It’s always best to provide free-choice water to cattle, but following a disaster, you may not be able to. Water requirements increase by at least 50 percent in lactating cattle and in hot weather.

Minimum Water Requirements

  • Adult, nonlactating beef and dairy cattle: 10-15 gal/head/day
  • Lactating cows and bulls: 20-25 gal/head/day
  • Young, growing cattle (less than 500 lb): 5-10 gal/head/day

Water Safety

Contamination of water supplies can be common following disasters, particularly following flooding of water wells. Water that is potentially contaminated with bacteria can be treated with 2 gallons of unscented liquid household chlorine bleach (5.25 percent) per 100 gallons of water. To disinfect water wells, pour 4 gallons of a chlorine bleach solution (1 gallon of household bleach and 3 gallons clean water) into the well. Open all faucets and let water run until chlorine is smelled. Then let the system sit for 24 hours. If contamination of water by toxins is possible, it should be avoided until tested.

To Disinfect

Flooding of coastal areas caused by a hurricane storm surge can contaminate water supplies with salt. Calves are more susceptible to salt toxicity. Lactation, hot weather and exertion increase water intake and make adult animals more susceptible to salt toxicity.

Total Soluble Salts Content of Water
(ppm = parts per million)

  • Less than 3,000 ppm = safe for cattle.
  • 3,000-5,000 ppm = Satisfactory, but cattle may be reluctant to drink, and it may cause diarrhea.
  • 5,000-10,000 ppm = Avoid giving to pregnant or lactating cattle, old and young cattle.
  • Greater than 10,000 ppm = Unsafe.

If cattle have been drinking water with dangerous levels of salt, it is best to slowly transition cattle to fresh water. Supplying small amounts frequently is best. Try to ensure that no cows are overdrinking or limiting others access to fresh water.

Conversion factors:

  • 1 ppm = 1 milligram per kilogram (mg/kg) = 1 milligram per liter (mg/L)
  • 1% = 10,000 ppm

Calculating Trough Capacity

Rules of thumb for calculating necessary trough space:

  • 1 gal of water = 8.3 lb
  • 1 cu ft of water = 7.48 gal or 62.3 lb
  • 1 gal of water = 231 cu in

Based on these figures and using some geometric equations, you can closely estimate the amount of water you are providing for livestock.

To figure how much water a trough can hold, use the following examples based on the shape of your water trough:

Circular Trough

In this example, the radius (half the diameter) of the water trough is 48 inches and the depth of the trough is 24 inches. Use this formula:

Circle = π x radius2 x depth = gallons
231

Water trough = 3.14 x (48 x 48) x 24 = 751 gallons
231

You also can calculate the amount of gallons by inch of depth in the tank. For example:
751 gal = 33.3 gallons per inch
24 in

Rectangular Trough

Rectangle = length x width x height = gallons
231

This rectangular water trough is 84 inches long, 36 inches wide and 24 inches deep. Thus, in this example:

Water trough = 84 x 36 x 24 = 314 gallons
231

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