During hot weather, water is important to minimize effects of heat stress. Cattle use body water evaporation for cooling--via sweating and respiration. Robert Collier of the University of Arizona says, "Cattle increase evaporative heat loss by increasing their respiration rate and exchange of air through respiratory passages, which increases evaporation in the air passages. This is an indirect type of cooling. Cattle have limited ability to sweat, so they increase their respiration rate. They are also more prone to build up body temperatures during periods of heat stress," says Collier.

Dr. Tom Welsh of Texas A & M says that when an animal gets hot, blood vessels dilate to get more blood to the surface to exchange more heat with the environment to cool off. "They drink more, and also try to conserve water if there's not enough available. There are hormonal changes that take place to conserve water in the body--less sweating, urination, salivation, etc. If cattle have water available, however, they can exchange heat through urination, salivation, and sweat. If they can keep replenishing the water loss, everything they can get rid of takes heat with it," says Welsh.

Don Spiers of the University of Columbia, Missouri, says that air movement between animals is important, and one way to avoid heat stress is to minimize overcrowding and bunching together. "If there are only a few water troughs and the animals are crowded around them trying to get to the water, they reduce any beneficial effects of a breeze. Recommendations for water troughs are for three inches of linear water space per head. During hot periods the dominant animals stay by the troughs and the others can't get to the water. If you have only one trough per pen, this can become a serious problem. The more watering area you can provide, the better--with fresh, clean water," says Spiers.

Welsh recommends providing at least two gallons per 100 pounds of body weight if the temperature is 70 degrees, but if it goes up to 95 degrees, that intake may double. "If you are watering a lot of animals, you need a good water flow, and if it's an automated system you must make sure it is delivering the water," says Welsh.

Water Trough Designs
Shawn Reece, at Superior Livestock Waterers in Hereford, Texas, says most waterers are put in the fencelines, to service adjacent pens, and tanks are usually put on several sides of a pen, to give more access. Water pressure is important.

Volume and water pressure are critical; if there are a lot of cattle drinking, you need quick recovery on the tanks. Most yards run four to six inch lines to the pens, reducing it down as it goes in the tank--but the volume is there. If cattle stand around waiting for water, there's a lot of pushing and shoving. The stress and crowding can seriously contribute to heat stress.

Where to place a water tank is always a question--whether it's best in the middle of the pen or in the fenceline, how close to the feed bunk, etc. "We're seeing water tanks closer to feed bunks, so cattle don't have to walk as far when they turn around and leave the feed. They can get the water pretty quickly. The first group will hit the water and go lie down, then the next set hits, and it seems to get them all watered quicker. They have a pecking order and get used to the routine," says Reece. But in hot weather some of the dominant ones will stay by the water and won't let the subordinant ones come to the water trough.

"There's not a lot you can do about this problem except put in more water tanks, and most feedlots aren't willing to spend the money. I have seen people, in extreme situations like a serious heat wave, quickly bring in a temporary round tank, to set beside the other water tank, plumbed to it, to give more drinking space. Come winter, it can easily be removed," says Reece.

Carter Thomson, at Miraco recommends multiple watering areas in each pen. "Most people put waterers in a fenceline so each pen has two tanks. A lot of our yards put one large waterer in the middle of a pen. It holds 60 gallons, and has a fast recovery. These are eight feet long and can go in the fenceline or out in the open. When Garden City Feedyard expanded, they used our ball waterers because of concern about the Ogallala aqui fer going down. There may come a day when they'll say people can no longer use constant flow, and they wanted to be prepared for that with our energy-free waterer."

"Water is critical in summer, so scaling it to number of head per waterer is important. There should never be more than 150 head on the eight foot waterer. Distance from the bunk is also critical unless someone cleans the tanks every day. Cattle will carry the feed in their mouth and on their muzzle and drop it in the water. You usually want the tank 30 to 40 feet away from the feed bunk."

Keeping Water Cool
Shaded water stays cooler. Dairies figured out years ago shaded water increased milk production, but feedlots are just starting to realize what this can mean to them in dollars.

Thomson says, "A five year study with beef cattle in California (Imperial Valley Experiment Station) compared use of spray, cold drinking water, and shade. The cattle given cold water to drink did better than the other two groups. Body temperature stayed lower in the cold water group, and they ate better." Cooling the water to 65 degrees (from 80 degrees) for feeder cattle boosted daily gains by 0.32 pounds. The cattle did not drink more water; the value of cooled water was due to direct transfer of heat from the animal to the water rather than to greater evaporative water loss.

Research at Texas A & M showed that cooling the drinking water has an advantage over other cooling methods because it is not dependent on relative humidity. Evaporative cooling does not work if humidity is high. Thus cold drinking water can be an effective method in areas plagued by high temperatures and high humidity. Cattle don't like cold water, but even though they drank less of it, its cooling effect on their bodies was greater, because it absorbed more body heat (718 kilocalories compared to 341 with warm water).

The results of this study suggest that cattlemen who have cold well water should not put it in a large open tank where it will warm up. Instead, they should use waterers that hold a small amount and are shaded or insulated (designed to prevent freezing in cold weather). Drinking cold water can help cattle rid themselves of the large heat load they produce from digestion and hot weather.

Energy free waterers, such as these, keep the water cooler in the summer and from freezing in the winter.