Overeating disease not always caused by overeating | TheFencePost.com

Overeating disease not always caused by overeating

One of the best ways to prevent overeating disease is to keep calves out of muck and away from a concentrated area of other calves who may have scours.
Photo by Savanna Simmons |

Within the menagerie of flora and fauna in a calf’s intestines, the clostridia bacteria are ever-present, awaiting the chance to flare up.

More commonly known as overeating syndrome or purple gut, clostridium can be caused by a factor that upsets the balance of the gut, such as environmental changes like excess precipitation or wet pens, hot milk from the cow or another kind of gastrointestinal upset.

Daniel Harnish, of Harnish Vet Service in Wheatland, Wyo., said overeating syndrome isn’t the best name for what actually happens.

“It was always assumed it was caused by too much food, but that’s not actually the case, though it can happen if the mother gives rich milk,” Harnish said. “Typically it’s the bigger, faster-growing calves that tend to get out and graze earlier and pick up clostridium out of the soil. They’re the ones that are maturing faster, so they’re mouthing the ground and grass a lot earlier than the others will.”

Six strains of clostridia bacteria exist, though usually types C and D are responsible for illnesses in calves, said Jared Sare, of Western Skies Vet in Pinedale, Wyo. Clostridia is in the same family as tetanus.

Young calves that have a distended, swollen hind gut and obvious signs of discomfort and pain, like kicking their belly and colicking, are primary contenders for clostridium.

“If I’m seeing clinical signs of hind gut bloat, full equal low-belly distention, anything like that, and they tend to be painful, I will give banamine, and a clostridial anti-toxin seems to work well. I follow that with penicillin or oxytetracycline or a sulfa bolus,” Sare said. “Once you get it, you’re trying to calm down that bacterial production, the overgrowth. Timing of discovery and/or treatment is the critical crunch window.”

Upon seeing the right symptoms, Harnish assumes clostridium is guilty unless proven otherwise. Ulcers present similar symptoms, but luckily both are treated similarly with penicillin as Harnish’s drug of choice.

He also considers the weather conditions when deciding how to treat bloating and discomfort in young calves. “If we get a big shot of moisture, that’s prime time for clostridium to grow and take off,” Harnish said. “Economically, it’s not feasible to test every case that looks like clostridium, so we treat it presumably. Does that mean for sure they had it? Maybe, maybe not.”


Overconsumption of rich feed by the cow can lead to hot milk, which, in turn, can change the pH level in the calf’s gut. Clostridial bacteria thrives in an acidic environment. In addition to grazing in soil, calves can pick up environmental bacteria from wet and dirty pens. Both Harnish and Sare recommend that pairs be moved out of wet, mucky corrals as soon as possible.

Steps to prevent clostridial bacteria from overpowering the hind gut can be taken, both before the calf is born or when it is first born. Seven- or eight-way vaccinations both contain defense against clostridium, and when given to a cow during preg-checking, antibodies are procured to maintain proper clostridial bacteria levels. A CD/T (Clostridium perfringens types C and D and tetanus) vaccination can also help potentially combat imbalances and develop antibodies in the calf, Sare said.

“A lot of guys do a seven-way when tagging. A lot of experts say it doesn’t work because of the maternal antibodies, but it seems to work,” Harnish said. “You can also give toxoids, which is not a true vaccine and is shorter term than a seven-way, but it tends to help. It’s supposed to help some of the maternal antibodies.”

Harnish recommends administering an anti-toxin prophylactically, which can offer a few weeks of protection, then a seven-way may be administered after maternal antibodies have lessened.

While “overeating disease” is more commonly observed in young calves, a slightly different strain can occur in older calves.

“There’s a different scenario from that week-old calf to six-month weaner,” Sare said. “They tend to be aggressive eaters, so it may start with rumenal acidosis or something like that where the guts are off balance, which allows the clostridia to overtake the gut. If the pH of the gastrointestinal system is off from the feed availability, bacterium propagate and do well in an acidotic animal.”

While vaccination options are available prior to birth, post birth, prophylactically and post flare-up, the best plan of action is to create an environment where clostridial bacteria can’t overtake the gut.

“The best thing for young calves is a balanced diet, a clean water source, a clean pen and get young calves and heavies out on fresh grass or pens,” Sare said. “Decrease environmental exposure; keep their noses and mouths out of the muck. You can minimize exposure that way, and keep them healthy otherwise, and keep their guts happy.” ❖


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