Getting Ahead of Cattle Bloat


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Paying attention to pastures, rations and bunk management will help keep cattle digestion on track. 

Indigestion for ruminant animals can be a bigger problem than in humans. In cattle, bloat is marked by excessive accumulation of gas in the rumen. Most gases are eliminated by belching, but sometimes this normal process can be interrupted.

Bloated cattle typically show a distended left abdomen, and the pressure in the rumen causes animals to quit eating while appearing distressed and struggling to breathe. Expansion of the rumen can inhibit breathing. In fact, bloat can be a cause of sudden death in feedlot cattle. Both pasture and feedlot cattle can experience bloat after eating certain plants or high-quality forages, said Josh Stroh, beef nutritionist, Hubbard Feeds.

Protecting against pasture bloat

Pasture, or frothy, bloat can be caused by rapid ingestion of legume or legume-dominant pastures like alfalfa, ladino, and red and white clovers. These crops have a higher percentage of protein and are digested more quickly. This type of bloat is typically seen when cattle are released to graze during the vegetative or early bud stages.

“With these crops like clovers and winter wheat, cattle can’t belch the gas out. That just creates a frothy environment in the rumen where the gas is trapped in this foam,” Stroh said.

Sound grazing management and poloxalene supplements can help eliminate the risk of frothy bloat. Poloxalene is a non-ionic surfactant that lowers the surface tension of the frothy mass so the bubble film is weakened and can no longer contain the gas. Producers can simply set out poloxalene blocks for easy administration.

Fending off feedlot bloat

Feedlot, or dry, bloat can be caused by a sudden change in diet. The rumen environment has microbes that assist in digestion. The microbes are adjusted to a certain diet, and major changes can result in acidosis. Most cases of bloat at the feedlot level are related to acidosis.

“You want to make incremental, small changes to the ration so you can adapt the rumen microbes to those ingredients,” Stroh said.

New calves arriving at the feedlot can be at higher risk of bloat as they adjust to new surroundings and learn to eat from bunks. Consistent dry matter intake is hard to achieve with the natural eating variation that occurs during this period of adjustment, which invites digestive issues, Stroh said.

Achieving consistent intake is helped with bunk management, careful feed mixing and uniform feed delivery. Overconsumption of grain or fines, as well as sorting, increases the risk of acidosis and bloat. The goal is to reduce variability from one meal to the next, and make gradual, consistent changes when transitioning diets, Stroh said.

“Corn is very starchy. In too dry a ration, corn will sift or fall out, and cattle can cherry-pick it out and create inconsistency that creates a bloat risk,” Stroh said.

Additives like monensin and lasalocid can help improve average daily gain while reducing bloat risk. However, organic or natural operations may not be able to use them.

Treating bloat

If identified early, cattle experiencing bloat can be relieved of the trapped gas using a stomach tube or rubber hose. Mineral oil or an approved defoaming agent can be used to break up the stable foam in the rumen. This allows the gas in the foam to be released.

Other cases may require the use of a trochar and cannula punched through the side of the animal into the rumen to relieve the gas. However, the trochar can be a source of infection. Consult with a veterinarian for training on bloat interventions.

Persistent risks

Even operations managing their pasture and rations well can be at risk, Stroh warned.

“I live in Montana, and if we have a blizzard or a nasty day, I can be sure I’ll get phone calls about bloated calves,” he said. “Even if you are paying attention to it – setting yourself up for success – you can still have issues with bloat. Anything you can do to get consistent intake is going to be the game changer, and anything outside of that is a risk.”


1 Rasby, RJ, Anderson, BE, Randle, RF. Bloat Prevention and Treatment in Cattle. University of Nebraska–Lincoln Extension Publications. May 2010.


Bloat Following Grub Treatment 1

Bloat may occur 10 to 24 hours following grub treatment with organophosphate grubicide. If used late in the season, the treatment kills migrating grubs in the area of the esophagus and can result in swelling that prevents the animal from belching or swallowing normally.

If bloat occurs, do not feed the animal for a few hours and walk it slowly until the bloat goes down. If the animal is having trouble breathing, relieve the bloat with a trocar or large bloat needle. Do not pass a stomach tube in animals that bloat following grub treatment. The esophagus may be damaged and permanent injury may result. Antihistamines and corticosteriods should be administered under a veterinarian’s direction.


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