See how to spot and fix dehydration in calves, especially important during dry seasons and drought.


A Southeast FarmPress article starts out with a trick question: True or False? The leading killer of calves in the first weeks of life is a gut infection. The answer, is both true and false because, it’s true that gut infections cause dehydration in many calves during the first week of their lives, but it’s false because it’s the ensuing scours and dehydration that actually kills the calf, not the infection itself. Dehydration of calves due to scours is a big concern for all ranchers, but it’s especially important when the weather is hot and dry. See the recommendations the article gives for heading off dehydration in calves with scours, below, and lose fewer to gut infections and other dehydration-causing factors.

Spotting Dehydration in Calves


Spotting dehydrated calves quickly is important as there is usually a “point of no return.” According to George Barrington, professor of large-animal medicine at the Washington State University College of Veterinary Medicine, “There’s a small window between 5% [when you can tell it’s actually dehydrated], to 10% or 12%, when he’s on death’s doorstep… By about 12% dehydration, you could lose the calf.” He was joined in the article by Geof Smith, a large-animal veterinarian with the College of Veterinary Medicine at North Carolina State University, on detecting and treating dehydration.

Barrington said in the article, “When a calf gets about 5% dehydrated, we notice clinical signs.” Signs include:

  • Dulled Reactions. The calf not as strong and perky and may not run off as fast.
  • Pinched Skin. “If you pinch the upper eyelid or the neck or wherever the skin is thin and can be pinched [skin tenting], and see how fast it sinks back into place, this gives a clue. If the calf is less than 5% dehydrated, it goes back into place quickly. At 5% or more, the skin stays tented a few seconds. The more dehydrated the calf, the longer the skin stays tented,” Barrington said.
  • A Dry Mouth. “If that moisture becomes tacky or sticky, the calf is about 6% to 8% dehydrated. If it feels really dry, the calf is severely dehydrated,” Barrington said.
  • Sunken Eyes. “In the dehydrated calf, the eyeball looks like it is sinking back into the head,” Barrington said. “The more sunken the eyes look, the more dehydrated the calf is,” Smith said. “If the eye is right there under the eyelid, hydration is fairly normal. If you roll down the lower lid and see a big space there, this indicates dehydration.”

Treating Dehydrated Calves


Scours can be caused by something bacterial, viral, protozoal or other, but the treatment is the same. First, you need to determine if they can take fluids orally. “My rule of thumb is that as long as the calf can get up and stand and still has a suckle reflex, we can give oral fluids, and the calf doesn’t need IVs,” said Derek Foster, professor of ruminant medicine, North Carolina State University College of Veterinary Medicine.

However, the calf can go into shock, and the GI tract will shut down, meaning fluids just stay in the gut rather than being distributed throughout the body. “If the calf is down, however, and can’t get up without assistance, he may be too far past the point for oral fluids. Muscles become flaccid and weak, ears and inside of the mouth will be cold, body temperature low, and the mouth dry. If he gets so dehydrated he becomes shocky, he needs intravenous fluids as soon as possible,” Barrington said.

His advice for administering a good electrolyte solution until it is no longer scouring. “Based on the calf’s weight, we consider three things. First is what the calf needs for normal maintenance [how much it would normally drink in a day]. Second is the degree of deficit from dehydration. Third, how much is he continuing to lose via diarrhea. Sometimes people are surprised by the volume needed. If the calf is 5% or more dehydrated, you can estimate the amount of fluid needed by estimating how much the calf weighs. A gallon of water weighs 8 pounds,” Barrington said.

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