Bloat can kill ruminant animals quickly, sometimes in as little as an hour, says Dr. David Fernandez, Cooperative Extension Program livestock specialist at the University of Arkansas.
Bloat is common when cattle are on lush pastures or eating grain to boost gain. Gasses trapped in the rumen press against the diaphragm, and the animal cannot breathe.
Often, the only sign of bloat is a dead animal in the pasture.
"There are several types of bloat, but most have one thing in common – foam," says Dr. Fernandez. Methane and hydrogen gases are normal byproducts of fermentation in the rumen. Normally, the gas accumulates above the feed and fluids in the rumen and exits when the animal burps.
Under certain conditions, proteins from plants can form tiny bubbles around these gases and trap them in the rumen.
"You can usually see this as swelling on the left side of the animal. If you tap firmly on the swelling, it will sound like a drum," he says.
Types of bloat
Pasture bloat is probably the most common, when livestock are turned out on high protein forages like legumes and clover. Young grain crops and brassicas, such as turnips and rape, can also contribute to bloat.
Grain bloat seems to be caused by a slim-producing bacterium that thrives on high carbohydrate diets and lower pH. The combination of bacterial slime, lower pH and small particle size of grain diets, especially ground corn, creates foam, leading to bloat.
Bloating in the abomasum is usually seen in young, bottle-fed livestock fewer than three weeks old. Infrequent feedings of cool milk that can be consumed rapidly contribute to abomasal bloat, as calves tend to overeat.
When bloating, animals grind their teeth and salivate, appear depressed and refuse to eat. The abomasum swells, and "tinkling" or splashing can be heard if the animal is shaken. Treatment outcomes are usually poor.
The exception to classic bloating is when something blocks the esophagus. The animal may have swallowed something that has lodged in the esophagus and prevents gas from escaping. Animals trapped on their back or side can become bloated when the rumen contents block the esophagus.
"Quickly dislodge the obstruction," advises Fernandez. "Stand clear of the mouth when you do as the gas can escape suddenly and bring some rumen contents with it."
In cattle, a pint to a quart of mineral or vegetable oil can reduce the surface tension of the foam and allow gas to escape. Another option is adding a few ounces of dishwashing soap in water, which will also break down the foam and allow gas to escape, says Fernandez
Old-timers used a bloat needle or even a knife to puncture the rumen and allow gas to escape, but this is dangerous and should only be done if the animal's life is in immediate danger, says Dr. Fernandez. The risk of infection and peritonitis is too high to undertake this step lightly, he advises.
Bloat can be prevented by including ionophores such as lasalocid or monensin to the diet. Be sure to check the label for approved uses and species.
Lasalocid, for example, is toxic to horses, Fernandez warns.
He recommends also to maintain adequate roughage in the diets of animals on high grain diets. Introduce livestock gradually to pasture containing high levels of bloat-promoting forages, and feed grass hay before allowing them to graze for an hour or so, gradually increasing grazing time and reducing hay feeding.
'Increase grass in legume pastures and watch your animals.
Source: University of Arkansas at Pine Bluff