Barnyard Basics: Calf diarrhea — dealing with dehydration

“My rule of thumb is that as long as the calf can stand, and still has a suckle reflex, we can administer oral fluids; the calf doesn’t need intravenous fluids,” he said.

His recommendation for a calf with diarrhea is to provide at least 2 quarts of fluids daily, in addition to whatever milk the calf is drinking. Compared to a dairy calf that’s bottle-fed, in a beef operation it’s hard to know exactly how much the calf is actually suckling. If the cow has a full udder, however, you know the calf is either not suckling at all or not enough.

“If the calf is bright and still nursing, 2 quarts of fluid and electrolytes — along with mom’s milk — should correct the dehydration,” he said.

In years past, veterinarians recommended holding calves off milk for 24 hours when calves had diarrhea, simply feeding electrolyte solutions, but this is no longer advised.

The old philosophy was that milk might irritate the damaged gut and make the diarrhea worse, but more recent research disproved that idea. Milk provides nutrients and energy.

“The calves we hold off milk lose weight. We prefer to keep them on milk as long as they are up and able to nurse the cow,” Foster said.

Also, separating the calf from mom is stressful for both the cow and the calf.

Oral electrolyte solutions should contain the necessary electrolytes (sodium, chloride and potassium) in proper balance, plus an alkalizing agent — usually bicarbonate.

“If the calf is on milk we use a different alkalizing agent; bicarbonate interferes with digestion of milk,” Foster said. “We need an alkalizing agent, however, since the blood pH in these calves is often low. Having an appropriate electrolyte that will help correct their blood pH is important.”

Sometimes producers wonder how to tell if a calf needs fluids.

“A simple rule of thumb is that as long as you can still catch the calf, continue giving oral electrolytes,” Foster said. “After the calf is feeling better and hard to catch, it probably no longer needs additional fluids. If it still has diarrhea and is depressed and moving slow, continue with fluids and electrolytes.”

He continued: “For most cases of diarrhea, oral electrolytes once a day in addition to milk they are drinking is enough to keep up with fluid losses. This gives them the electrolytes they need, and helps rehydrate them.”

In serious cases where the calf is weak and not nursing, but not yet to the point of needing IV fluids, electrolytes and oral fluids should be administered every 8 hours. The cow and calf should be in from the pasture and confined where the calf can have more intensive care and shelter. You may need to milk out the cow once or twice until the calf feels well enough to suckle again.

“If the calf is too weak to stand, IV fluids and glucose are necessary because the blood sugar has dropped so low,” Foster said. “Some of those calves also need antibiotics. In general we try to stay away from treating diarrhea with antibiotics because supportive care is often all the calf needs. As long as we can keep them hydrated their immune system can take care of the pathogen — which is often a virus (rotavirus or coronavirus) or a protozoa (cryptosporidium or coccidiosis).”

In these situations antibiotics won’t help; the calf simply needs supportive care.

“We make sure the calf has enough fluid, plus electrolytes, since fluid cannot be absorbed without the proper electrolytes,” Foster said. “Sodium is critical for absorption of water. Amino acids and glucose increase absorption of sodium, which in turn helps increase absorption of water. All these things work together to rehydrate the calf.”

An electrolyte product should be mixed with an appropriate amount of water to ensure the calf gets the right amount of sodium.

“If there is inadequate water the calf ends up with too much sodium and this can also be a problem,” Foster said. “This must be in balance. It’s also important to help correct blood pH if it’s a little acidotic. Unless we are doing bloodwork, we don’t really know how acidotic they are; we are guessing, but most of them are somewhat acidotic and need bicarbonate or acetate.”

The earlier you treat the calf, the quicker he will bounce back.

“If we can reverse dehydration before the calf needs IV fluids, and keep it hydrated until the diarrhea resolves, we can usually avoid having to resort to more intensive treatment,” Foster said.

It pays to closely monitor baby calves, and assess their health.

The calf should be given fluids until it is strong again and no longer dehydrated.

“One way to assess how dehydrated the calf is by checking the eyes,” Foster said. “As a calf gets more dehydrated, the eyes seem to sink back in the head. Assess the gap between the eyeball and inside corner of the eye. In a normal calf, the inside corner, eyelid, third eyelid and eyeball should all be together and touching. As the calf becomes dehydrated the eye starts to recess back into the head (the surrounding tissues are short on fluid) and there’s a gap. The bigger that gap, the more dehydrated the calf is. This rough gauge helps us determine whether it’s a mildly dehydrated calf or a severely dehydrated calf — to decide if we can provide routine treatment with 2 quarts of fluids once a day or if we need to give oral fluids more frequently, or need to give IV fluids.”