Calf diarrhea: What to watch for, how to treat it

Carol Spaeth-Bauer
Wisconsin State Farmer
About 65% of calves die before weaning because of diarrhea and one of the most common mistakes producers make is not catching it soon enough.

With diarrhea being a common reason for death loss in beef and dairy calves, producers need to make sure they recognize it early and get an effective oral electrolyte treatment into the calves right away.  

In the July Hoard's Dairyman webinar, Geoff Smith, North Carolina State University DVM, said about 65% of calves die before weaning because of diarrhea and one of the most common mistakes producers make is not catching it soon enough. 

"If your first sign of diarrhea is the calf didn't drink it's milk today, you're probably too late," Smith said. 

Smith said it's important to teach people working with the calves what to recognize. 

"If you're housing calves on straw, it's easy to miss scours. It'll run right through the straw," said Smith. "Are they drinking their milk aggressively? How is their attitude? Do their eyes look good?"

Smith suggested marking the hutch if the calf is slow drinking its milk and check on it again later. 

"We need to make sure we are training our people how to recognize diarrhea early," said Smith. "If we can catch them early and get them on a good oral electrolyte, most of these calves will get better."

What does diarrhea do to the calf?

When a calf gets dehydrated due to scours, there will be electrolyte abnormalities. The body loses sodium, potassium and chloride that needs to be replaced or the calf can develop metabolic acidosis where the pH level of the blood starts to drop. 

Levels should be between 7.35 - 7.45,  according to Smith. Once the pH level drops to 7.3 - 7.2, the calf will look depressed. By the time it gets to 7.1 "they usually won't want to stand up anymore." At 7.0 "they will be laying on their side and that's about the time they start to die," Smith said.

"So treating this acidosis or correcting the pH of the blood is one of the big things we need to do when treating these calves with diarrhea," said Smith.

Additionally, calves with diarrhea have a negative energy balance. Without a lot of fat reserves, when diarrhea starts and they stop drinking milk, they can starve to death.

"Think about diarrhea, you don’t really die from diarrhea," said Smith. "you die from things associated with diarrhea. Diarrhea itself isn’t that evil."

Farm employees working with calves should be trained to detect diarrhea early when oral treatment will be most effective.

Probably the main reason calves die is from metabolic acidosis when the pH of the blood goes down to the point where life can't be sustained. Some calves may starve to death. Some may get cold, but as long as the metabolic consequences of diarrhea are dealt with, "a lot of times we can get calves through this," said Smith. 

Probably the best thing producers can do for calves with diarrhea is provide a good oral electrolyte. 

"A lot of these calves are not drinking a lot of water. They start scouring. They go off milk — remember milk is 87% water and they are getting most of their fluid volume by drinking their milk," Smith said. "So when they stop drinking their milk and they start having diarrhea real bad they can get dehydrated in a hurry and this is an emergency. So when these calves get diarrhea we need to get aggressive in terms of replacing fluids."  

Recognizing signs of diarrhea

Smith recommends knowing how to assess the situation— how do you know if a calf has diarrhea and the level of severity.

One of the best ways is looking at the position of the calf's eyeball. 

"Studies have shown that the best way in calves to tell if it's dehydrated it to look at it's eyes," Smith explained. "If I take a thumb and roll the eyelid down, I should not see a space or a gap between the eyelid and the eyeball. That’s normal. That’s what these calves should look like."

However, if you roll the eyelid down and see a significant space — the bigger the space the greater the percent of dehydration.

"If you train your feeders to look at the eyes you can quickly pick up if have mild or moderate or severe dehydration," said Smith.

Visual representation of percent dehydration as related to clinical symptoms and health of calves.

Calves with 6% dehydration will look clinically normal and their eyes won't look sunken. Dehydration at 6 - 8%, will have a little bit of sunkenness. At 8 - 10% dehydration, eyes are moderately sunken. Dehydration is severe at 10 - 12%. 

However, catching metabolic acidosis is not as easy as looking at eyeball position.

"There is nothing really on physical exam that will correlate to how low the pH of the blood is or how severe the acidosis is," Smith said. "One thing that does correlate to some degree is how depressed the calf is. When the pH of the blood starts decreasing below normal, that calf will stumble around, kind of look like it was out on the town last night drinking. It will eventually lose it’s suckle reflex and it will go down."

If a calf is still on its feet and drinking, acidosis is probably mild and can be corrected with oral electrolytes. But once the calf goes down, some may respond to electrolytes, some may need intravenous fluids. 

Smith said oral electrolytes "have been the hallmark for treating calves with diarrhea" because its quick, easy to use and fairly cheap at about $2 a dose.

It's important to make sure the electrolyte solution meets the principles of treatment — correct dehydration, replace electrolytes and correct blood pH — and that diarrhea is caught early. By the time the calf isn't drinking its milk or is down, it's probably too late to treat with oral electrolytes.  

If diarrhea is recognized early and treated aggressively with oral electrolytes, "we should be ok with treatment most of the time," said Smith.

Choosing an electrolyte solution

However, producers need to put some thought into which electrolyte solution they choose. 

The ideal properties to look for in oral electrolytes are having sodium in the appropriate concentration to correct dehydration, about 90-130 mM/L as shown by studies, and an ingredient to help the intestine absorb the sodium. Products with sodium concentration less than 90 mM/L are not recommended. 

"Sodium can’t just swim across the gut wall, it has to be carried across," said Smith. 

One of those pathways is glucose, which many oral electrolytes contain. But typically, either a neutral amino acid, like glycine, or volatile fatty acid, like acette, or sometimes both, are also pathways to help facilitate the absorption of sodium in the intestine.  Most of the better products will contain glycine, Smith said. It's one of the more expensive ingredients so cheaper products will cut out glycine.

An alkalinizing agent like acetate, propionate or bicarbonate will help increase the pH level in the blood. Additionally, there should be some energy fuels for the calf, like glucose, "particularly if withholding milk for any length of time," said Smith. 

"Lastly you want to make sure the oral electrolyte certainly isn’t doing anything to encourage diarrhea," said Smith. "You want to make sure its facilitating that healthy gastrointestinal environment."

Smith recommends potassium ranges between 10-30 M/L and chloride ranges between 40-80 mM/L.

One of the best ways to detect diarrhea in calves is looking at the position of the calf's eyeball. There should not be a gap between the eye and the eyelid.

"Almost every product that I know of is probably going to meet those recommendations," said Smith. 

It's also important to stay away from products with high osmolality, which refers to how concentrated the product is. The higher the osmolality the more sugar there is in the product. If osmolality is pushed too high Smith said there is a risk of having more severe scours and abomasal bloat. Smith recommends avoiding anything above 500 - 600 mOsm/L.

"More sugar is better. We need to get energy in these calves, but we need a limit as to how much we’re pushing into these calves at one time and get away without producing some other problems as well," said Smith.

Alkalizing agents like bicarbonate, acetate and propionate, increase the pH level of the blood. In the U.S., primarily bicarbonate-based products are used, but Smith said there are some acetate-based products out now also. 

While bicarbonate works, Smith said there are several advantages to acetate or propionate, which produce energy when metabolized whereas bicarbonate does not. Also, acetate helps with sodium absorption. Using bicarbonate products day after day could increase the pH of the stomach and promote bacterial growth in the stomach. 

"I’m not saying bicarbonate products are evil, but there are some advantages to acetate," Smith said. "If I had a choice to use an acetate or a propionate product, I probably would choose that."

How much electrolyte solution?

Smith recommends feeding oral electrolytes at least once a day as an extra meal for dairy calves, twice if scouring is bad. Additionally, milk should not be withheld for prolonged periods. 

Oral electrolyte solutions with high bicarbonate should be avoided for beef cattle 

Bicarbonate-based products should not be mixed with milk because it will interfere with digestion of the milk. A two-hour separation between milk feeding and using a bicarbonate-based product is recommended. 

If feeding calves an acetate product with moderate osmolality and feeding whole milk or something with low osmolality, the two could be mixed together, said Smith. 

Using milk replacer, which probably already has a high osmolality and adding an oral electrolyte could be "very, very dangerous," Smith pointed out. 

Common mistakes

While failing to catch diarrhea in its early stage is one of the most common mistakes made on farms, not giving enough fluids is another. 

"I see a lot of people giving one or two liters of IV or subcutaneous (under the skin) fluid to the calves; that just isn’t enough," stressed Smith. "If you detect dehydration at 6%, a calf needs at least three liters to correct the deficit. A couple of pints of oral electrolyte solution isn’t enough. You probably need four to five liters of fluids"

Another mistake is giving oral fluids to a calf that needs intravenous fluids. When a calf is down and has no suckle reflex, oral fluids won't be effective, Smith said. It's important to know when to call a veterinarian or to have an intravenous therapy protocol. 

Withholding milk for more than 24 hours is another mistake producers make. Diarrhea can last five to seven days, if milk is withheld, "those calves will starve to death," said Smith. While oral electrolytes will correct acidosis and rehydrate the calf, "getting them back on milk is what's going to get energy into that calf," Smith said. 

Oral electrolyte solutions don't have enough energy to sustain calves, so they need milk. 

"There is no proven benefit to withholding milk. It only makes a negative energy balance worse," said Smith. "It's ok to skip one feeding if a calf is depressed and refuses to nurse, however, milk should be resumed within 12 hours."

Small volumes of milk more frequently is probably the best thing for calves with diarrhea, but labor situations might not allow treating sick calves differently than healthy ones, Smith added.

When dealing with diarrhea, Smith said, "We need to make sure we are recognizing it early, using an effective oral electrolyte product on our farm and getting that into these calves right away."

Carol Spaeth-Bauer at 262-875-9490 or Follow her on Twitter at cspaethbauer or Facebook at