As the drought continues and temperatures remain above normal, cattle water is becoming a greater concern, says Ted McCollum, Texas AgriLife Extension beef cattle specialist.

“Because little or no forage growth has occurred this year, the forage contains very low amounts of water,” says McCollum. “Anaverage cow grazing green forage normally consumes about 30-70 lbs of water daily, or about 3.5-8.4 gallons, from the forage she grazes. This year, as a result of no forage growth and a relatively low intake of dry forage, daily water consumption from grazed forage is probably around 3-5 lbs or 0.4-0.6 gallon.”

Couple low water intake from forage with the higher, stressful temperatures this summer, McCollum says, and intake of water from drinking sources takes on greater importance than in normal years or years with high temperatures but with green forage.

“The lack of water from forage is more important than we credit. How many people would think of going out to work for a few hours without a jug of water to drink from periodically? The water in the grazed forage is the cow’s ‘jug of water’ that rehydrates her while she is out on the range or pasture.”

High temperatures alone may not a problem, but hot temperatures in combination with lack of green grass as is the case this year, is a problem, McCollum says.

“The risk of heat stress is greater because we have high ambient temperatures combined with dry, dead forage. The cow’s ‘jug of water’ is relatively empty this year, and the risk of heat stress and water-related problems is greater.”

He says water deprivation, water intoxication and water quality can all play roles. The three may act independently, but often are interrelated.

Water deprivation, when cattle cannot consume adequate amounts of water, can be fatal or lead to circumstances that can be fatal. It can happen when a well can’t pump enough water to keep up with livestock needs or a pond or creek dries up. But water deprivation also can occur in circumstances when it is perceived there is an adequate amount of water available.

Cattle behavior may lead to water deprivation becausethey develop preferences for grazing sites and loafing areas. If more than one watering point is available, they may develop a preferred watering location in a pasture. So a grazing area with multiple watering points may appear to have an adequate supply of water. But if cattle have a preferred site and that site breaks down, dries up or the water quality declines and reduces consumption, then water deprivation may occur.

Cattle with no familiarity of a grazing area also can suffer deprivation, says McCollum.
“Do not assume cattle will find water. When cattle are moved to new pastures, take them to water and observe their consumption to determine if they are willing to consume the water,” he advises.

Water intoxication occurs when cattle overconsume water. It usually occurs following a period of reduced water consumption or increased water loss from the body. Electrolyte balance in the body is disrupted and water intoxication occurs, which can be fatal.

In cases of acute water intoxication, dead cattle will be found near the watering site. Water intoxication typically follows water deprivation, so a key to avoiding it is avoiding water deprivation.

Limiting water intake when cattle are moved to a new water source may be next to impossible, McCollum says. If cattle are dehydrated, it may be worth the effort to allow them to drink, but find a way to limit the amount immediately consumed.

With the water quality concern, the supply of water may be adequate but the cattle are deprived because they cannot or will not consume enough of it. Total dissolved solids and total soluble salts are two water quality measures that can lead to poor performance and possibly death.

As the concentrations increase, water intake is reduced. Also, high consumption of sodium, calcium, magnesium salts and sulfates can lead to failure to thrive, and in some cases, can be fatal. Nitrates in the water may also be of concern.

“Coupled with reduced water intake, these issues can become even more of a concern,” he says. “Water quality can indirectly affect performance and health by reducing water consumption, which exacerbates heat stress and can lead to water intoxication once cattle locate or can access palatable water.”

Another problem McCollum points out is that hot, sunny days and warm, stagnant water may lead to blue-green algae blooms. Some species of blue-green algae are toxic, so consumption of the algae or the toxins from it can be fatal.

Oftentimes, algae is concentrated on the downwind side of the pond as a result of wave action, he says. Dead rodents, birds or fish along the downwind side of the pond may indicate the presence of blue-green algae. Limiting access to the downwind side of the pond by cattle may reduce risk of toxicity.

Copper sulfate can be used to limit algae growth, but caution must be exercised because excess copper sulfate can lead to stream pollution and harm fish and plant life.

“Also, don’t rule out toxic plants that may be present around watering locations. The immediate area around ponds and tank overflows is disturbed, and the moisture profile in the soil is better than out in the pasture,” says McCollum.

“Even though drought conditions exist, disturbance and moisture are conducive to weed growth. Pigweed, kochia, Russian thistle, dock, buffalo burrs, etc. can grow in these areas, and they are green and may be attractive to cattle. If cattle deaths are occurring, see what has been grazed off around the watering area.”

For more information, read Water quality: Its relationship to livestock.