It doesn’t take long for a dairy calf to go from healthy to unwell when faced with a bout of diarrhea. Very quickly, the young animal can become dehydrated, creating further problems within the calf.

“There are millions of reactions happening in the body,” said veterinarian Amelia Woolums during an episode of the Hoard’s Dairyman “Herd It Here” podcast. “Those reactions don’t work well when there is a deficit of water or electrolytes.”

She said the two most obvious signs of dehydration are sunken eyes and skin that is less pliable.

Talking first about the eyes, Woolums said, “When doing a physical examination on calves, always look at the eye.” The Mississippi State University professor explained that there is usually no gap between the edge of the eyelid and the eyeball. When calves start to become dehydrated, a little gap will be visible, and the more dehydrated the calf, the deeper the gap will be.

To test the skin’s pliability, Woolums said to pinch skin on the neck of the calf, turn it 90 degrees, and then release. “It should go flat immediately,” Woolums shared. “If it doesn’t, this can signify dehydration.”

She noted that these same signs can be visible in a calf that is too thin, with not enough body fat. The difference, though, is that it takes many days for a calf to become emaciated enough to display these signs. Dehydration signals, on the other hand, can appear in just hours.

To tackle dehydration in calves, Woolums said it is best to work with the veterinarian who knows your herd best to get advice on identification and treatment.

As for recognizing signs of dehydration, she said it is a matter of practice and experience. “Once you see a calf with a sunken eye, you’ll know it,” she said. She recommends caretakers try the skin test on healthy calves, so that when they do the test on a dehydrated calf, the difference will be more obvious.

To learn about methods for administering fluids to calves, listen to the podcast, “Advice for rehydrating dehydrated calves.” This episode was sponsored by Boehringer Ingelheim Animal Health.