Heat Wave Changes Cattle Water Needs

Low Water Intake Can Cause Health Issues for Cattle During Heat Wave

Jennifer Carrico
By  Jennifer Carrico , Senior Livestock Editor
Ensuring feedlot cattle have access to enough water during a heat wave event can help prevent health problems. (Photo courtesy of Kansas State University)

REDFIELD, Iowa (DTN) -- The late-summer weather outlook for much of the Midwest and Great Plains includes high temperatures and humidity. These heat waves can stress livestock housed outside and change their water consumption.

The need for additional water consumption by beef cattle, especially, can lead livestock to experience water deprivation and salt toxicity, according to Steve Ensley, Kansas State University veterinary toxicologist.

"On hot days, animals will hover around a watering device. If there is only one in a pen or limited flow, and they cannot consume water for even two hours, water deprivation can become an issue," he said.

The problem of water deprivation can happen at the same time as a condition called salt toxicity. Ensley explained that when an animal dehydrates, its body will pull fluid out of its brain. Then, sodium stored there gets trapped. The animal's inability to disperse this sodium outside the brain can create a toxic level of sodium. According to a North Dakota State University news release (https://www.ag.ndsu.edu/…), symptoms of salt toxicity in cattle can include salivation, increased thirst, abdominal pain and diarrhea followed by wobbling, circling, blindness, seizures and partial paralysis. "Sometimes the cattle become belligerent. Other central nervous signs include dragging a hind limb or knuckling of the fetlock joint," the release stated.

WATER INTAKE INCREASES IN HEAT

Alfredo DiCostanzo, a University of Nebraska Extension educator, said various factors affect water intake. Temperature, humidity and feed intake are the main drivers that affect how much water is needed.

"A quick reference to keep in mind as heat and humidity approach heat stress levels is the requirement of 1 gallon of water per pound of dry matter consumed," DiCostanzo said. "With warm nights and hot days, cattle are consuming 25 to 30 pounds of dry matter and will need to have access to 25 to 30 gallons of water daily."

According to DiCostanzo, cattle under heat stress will need the water they require for a 24-hour period to be available more quickly during periods of high heat. Feedlot managers should have water available sooner than usual with water flowing at a minimum of 8 to 10 gallons per minute to meet the needs of the cattle. At an expected water drinking rate of 1.1 to 3.7 gallons per minute, every animal must spend 7 to 22 minutes daily at the water trough.

"Adding extra water tanks to increase water access in 'problem' pens can help reduce heat loads caused by crowded water tanks, poor air movement, or lack of shade," he added.

EXTRA WATER ACCESS CAN HELP

Ensley said a feed bunk can be used to help with adding water for animals.

"Plug up a pen's feed bunk, fill it with water and sort half the animals out of the pen," Ensley said. "Allow them to drink for five minutes, and then rotate the other half back in. Do that every hour for 10 to 12 hours or until the animals are not rushing to water."

If animals are already dehydrated and suffering from salt toxicity, allowing them to drink their fill of water too quickly can cause water intoxication, and they will display clinical signs quite quickly. Within 60 minutes of drinking too much, their brain will swell, and they can have seizures, collapse and not be able to get up. Some animals will get aggressive because of the damage to the neurons in the brain. If the condition progresses rapidly, it can lead to death.

Dehydrated animals suffering from salt toxicity should drink water in small amounts at frequent intervals, according to the NDSU news release. Severely affected animals may need to be given water by a stomach tube.

There is no antidote or specific treatment for water deprivation salt toxicity, so preventing dehydration by ensuring animals always have access to fresh water is critical, according to the NDSU news release.

Ensley advises installing a monitoring device on water distribution systems before extremely hot temperatures to ensure the pens are getting an adequate amount of water with good water flow.

"Livestock that have recovered from salt toxicity/water deprivation may have long-term effects," Ensley said. "They could go partially blind, but there are no food safety concerns," he said. "They should get up to the bunk and eat and drink. Producers should allow them to finish the feeding period."

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

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Jennifer Carrico