Calf Diarhhea-Dealing with Dehydration

  By Heather Smith Thomas

 Diarrhea in calves can be a challenge, and is still the number one killer of calves during the first weeks of life.  It’s generally not a gut infection that actually kills the calf, but dehydration and subsequent imbalances, acidosis, or shock.  Geof Smith, DVM, North Carolina State University, says dehydration, loss of electrolytes and decrease in blood pH (metabolic acidosis) are the three biggest problems.  “Rehydrating those calves is critical,” he says.

George Barrington, DVM, Large Animal Medicine, Washington State University, says supportive treatment with fluid and electrolytes is vital, regardless of the cause of scours--whether bacterial, viral, protozoal or something else.

Derek Foster, DVM, Ruminant Medicine, North Carolina State College of Veterinary Medicine, says that for the vast majority of sick calves, it can be oral fluids.  “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,” he says.

Check Dehydration
IIf we know how dehydrated the calf is, we’ll know if we can turn this around with oral fluids.  “When a calf gets about 5% dehydrated, we notice clinical signs,” Barrington says.  The calf is dull--not as strong and perky—and may not run off as fast when you approach him.
“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,” he says.

In a normal calf the mouth is moist.  “If that moisture becomes tacky/sticky the calf is about 6 to 8% dehydrated.  If it feels really dry the calf is severely dehydrated.  Also, in the dehydrated calf, the eyeball looks like it is sinking back into the head,” says Barrington.  Tissues around the eye are dehydrated.

“The more sunken the eyes look, the more dehydrated the calf is,” says Smith.  “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,” he says.
“We assess the gap between the eyeball and inside corner of the eye,” says Foster.  “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 bigger that gap, the more dehydrated the calf is.”
    
Oral Electrolytes or IV Fluids?
You need to start reversing the problem before he’s severely dehydrated.  “By about 12% dehydration you could lose the calf.  There’s a small window between 5% (when you can tell he’s actually dehydrated), to 10 or 12% when he’s on death’s doorstep,” says Barrington.  You want to intervene well ahead of that point, while he’s still strong, and turn it around quicker.

Ideally, we want to give fluids orally—while he still has a functional gut.  When he gets severely dehydrated, fluids just sit in the stomach and can’t be absorbed because the GI tract has shut down.  If the calf can still stand and walk, even if he’s slightly weak and wobbly, he may not need IV fluids.  

“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,” says Barrington.

Cold extremities (poor blood circulation to legs and feet) usually mean the calf is in shock.  If he has a bacterial infection and sepsis, with bacteria or their toxins getting into the bloodstream, resultant damage may put the calf into shock.  Blood circulation is compromised and shunted to the vital internal organs and is not being sent to the non-essential extremities or peripheral tissues (skin and legs will be cold).  “Shock may accompany dehydration, but not always,” says Smith.

Knowing when a calf is past that window when we can give oral fluids is crucial, to be able to give IV fluids before he goes downhill too far in shock. “Many producers can put in an IV, but if someone doesn’t know how and wants to learn, their veterinarian can show them how, or walk them through it over the phone,” says Barrington.

How Much Fluid?
If the calf is still in the window where we can treat with oral fluids, we need to know how much to give.  “Based on the calf’s weight, we consider three things.  First is what the calf needs for normal maintenance (how much he would normally drink in a day).  Second is the degree of deficit from dehydration. Third, how much is he continuing to lose, via diarrhea?” says Barrington.

“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,” he says.

If a calf has been off feed (not nursing), and scouring, he may be very dehydrated.  “For example, a 150-pound calf would typically need about 4 quarts of fluid per day, just for maintenance, and will likely drink nearly twice that much milk.  If he’s dehydrated just 5%, he’s down about that much already and will need about twice that much in a 24-hour period just to get back to a good level. A 150-pound calf that’s 5% dehydrated is already about 4 quarts in the hole to begin with,” he says.

“During a 24-hour period this calf would need about 8 quarts to satisfy his deficit and maintenance, plus what he’s continuing to lose via diarrhea.  He might need 10 or more quarts of fluid in a day, split into 3 feedings.  One feeding might help, but it’s not enough,” says Barrington.

Also, the younger the calf, the more quickly he’ll dehydrate with scours.  A small young calf has no body reserves; it’s more urgent to give fluids often. If a very young calf gets severe diarrhea (or older calves with severe gut infections) sometimes the only way you can turn it around is to give fluids every 6 to 8 hours, and sometimes even more frequently, depending on the situation.

It’s important to keep administering electrolyte fluid until the calf is no longer scouring.  “A lot of producers ask about this,” says Smith.  “If they give electrolytes and the calf goes back to the cow, should they give electrolytes again?  Calves often have diarrhea for several days.  As long as you can catch them, they probably need to be kept on fluid and electrolytes to make sure they don’t relapse,” he says.
 
What to Give
It’s important to use a good electrolyte solution.  “Many stockmen think one product is as good as another, but this is not the case,” says Smith.  “When comparing electrolyte products in terms of rehydration potential, the sodium content is important.  Water by itself will not rehydrate the body.  This is why athletes don’t just drink plain water; they drink Gatorade.  Make sure the sodium concentration of the oral electrolytes you choose is adequate,” he explains.  

Barrington says it’s easier to buy a commercial product than try to mix the ingredients you’d need for reversing electrolyte imbalances.  “It must contain salt (sodium and chloride), potassium, an energy source like glucose, and amino acids like glycine or alanine.  The glucose and amino acids aid in absorption of electrolytes (especially the sodium, which in turn helps the gut absorb fluids).  Oral electrolyte solutions typically have sodium, chloride and potassium (the actual electrolytes) plus an energy source to aid sodium absorption, as well as provide a little energy for the weak calf.” he explains.

“Since most of these calves are acidotic (due to dehydration causing electrolyte imbalance), commercial electrolytes may also contain some kind of buffer.  There are a several different ones, including bicarbonate, acetate, citrate, etc.  All of them have various advantages, depending on the calf’s situation.”  Ask your veterinarians which products might be best for certain cases.

A homemade recipe of salt, Lite salt (to provide potassium), bicarbonate of soda and water can be useful, but lacks the amino acids and energy source for optimum absorption.  Acetate is a better buffer than bicarbonate if the calf is still consuming milk.  Bicarbonate interferes with proper digestion of milk.
        
Giving Oral Fluids
Proactive supportive saves more calves.  Most producers know how to use an esophageal feeder for giving fluids and some use a nasogastric tube.  These are quick and easy ways to get electrolyte fluids into the calf and a safe way to do it if you know how.

“If the calf still has a suckle reflex (able to suck on your finger) we can use the esophageal feeder,” says Smith.  A person just needs to be careful and slow when putting the probe down the throat, making sure it goes down the esophagus and not into the trachea (windpipe).  

Most problems occur when the probe is rammed down quickly.  Because of the ball on the end, the probe is not supposed to be able to go into the trachea, but you should always check by palpating the neck.  “Make sure you can feel two tubes; you should be able to feel the plastic tube separately from the trachea.  Once you get the probe safely down the esophagus you can administer the electrolyte fluid,” Smith says.

Don’t Take the Calf Away from Milk
In years past, veterinarians recommended holding scouring calves off milk for 24 hours, simply feeding electrolyte solutions, but today this is no longer advised.

“The old philosophy was that milk would likely make the diarrhea worse, but more recent research refutes this,” says Foster.  “Milk helps the calf maintain strength and body weight while recovering.  Calves held off milk tend to lose weight.  We prefer to keep them on milk as long as they are up and able to nurse.”

Homemade IV
If you have an IV catheter and tubing, you may be able to save a calf that might not make it if it’s a long trip to the vet.  A gallon of distilled water and some baking soda can turn many of these calves around.    “In the clinic we use isotonic bicarb, but you can also just use 13 grams of baking soda per liter.  We make it up in the pharmacy here, but I’ve used just plain bottled water,” says Barrington.

In regions where ranchers are a long way from a veterinarian, about 20 years ago veterinarians at the Caine Veterinary Teaching and Research Center (University of Idaho), started teaching ranchers how to do this.  Fill a plastic syringe cover (the case for a 20-cc syringe) with baking soda, to put in a gallon of water, warmed to body temperature.  This amount is very close to what you’d weigh with a scale.  A regular rubber IV bottle topper, stretched, will slip over the gallon jug top.  Or, you can insert the IV tube (the sharp tip designed to penetrate an IV bag) into the bottom of the plastic jug.  

Once you get a needle into the jugular vein, let the tubing fill with water, to get all the air out, then attach it to the inserted needle.  You can control the speed of flow with needle size; a small-diameter needle in the vein will keep the flow down to a safe speed.  But for a calf that’s flat out, you can usually run the fluid in faster without problems; these calves have low blood pressure and can take fluid pretty fast.

Most calves will get up after receiving a gallon of this fluid IV.  They may go down again if they are actively scouring, but you can repeat the fluid.  If they don’t get up after the first gallon, however, or don’t look like they are improved, their problem is usually more complex and not just scours.

“We often do the same thing here, using a syringe cover to measure the soda,” says Barrington.  “We just stress that everything should clean, using distilled or bottled water.  Have a plan, and know how much soda to use.  This can be a lifesaver for calves, turning them around to where they become strong enough to take oral fluids.  If you are a long ways from a vet, being able to do this yourself could save a calf’s life,” he says.