Bloat in cattle is a different sort of digestive issue than it is in humans. For us, it’s a bit of “tight pant syndrome” or water retention, most of the time due to diet or hormones. Although certainly uncomfortable, it’s typically temporary and not fatal. For cattle, however, bloat can be fatal.
Here’s what you should know about this condition in your animals.
2 Kinds of Bloat in Cattle
To clear up some initial confusion, there are two main types of bloat in cattle: free-gas bloat and frothy bloat.
Free-gas bloat occurs when there is a physical blockage of the esophagus and the animal can’t burp to relieve the constant buildup of gas in the rumen. This can also occur in certain metabolic conditions when the rumen isn’t churning as it should. This is called rumen stasis.
In both scenarios, a large gas bubble builds up inside the rumen which can’t be released, causing distension, pain and death, as the buildup of gas pressure on the diaphragm causes suffocation.
Frothy bloat is slightly different and is the development of a foam (hence the froth) that sits on top of the ingesta in the rumen. This blocks the escape of gas through the esophagus. Both types of bloat involve the blockage of gas from the rumen, just from different causes.
Frothy bloat is sometimes called pasture bloat. This is because it is commonly seen with cattle on certain types of pasture. Legumes such as clover (red, white and sweet clover) and alfalfa are at the highest risk of causing this froth.
But why? Legumes such as clover and alfalfa are high in soluble protein. This can result in the creation of a sort of “slime” that sits on top of the rumen, trapping gas. These grasses also have a highly digestible cell wall that also contributes to the creation of a foamy cap.
How can you tell if an animal is experiencing frothy bloat? Initially, if you look carefully, you may notice that the left side of the animal’s flank is protruding, like a ball filling with air. This is because the rumen lies mostly on the left side of the abdomen.
From the back, the animal will appear uneven. This animal may act uncomfortable, such as repeatedly getting up and then lying down, kicking or looking at its flank, and it may go off feed. These signs may be difficult to observe when the cattle are out on pasture.
As the condition progresses, the left abdominal distension becomes more obvious to the point where the trapped gas puts pressure on the diaphragm and it becomes difficult for the animal to breathe. At this point, the animal may be reluctant to move and be in respiratory distress. If treatment is not implemented at this point, the animal is likely to die from suffocation.
The best way to treat an emergency situation of frothy bloat is to call your veterinarian. She will pass an orogastric (OG) tube—a rubber hose inserted down the throat and into the rumen. This will sometimes allow the release of air from the rumen and offer immediate relief.
However, remember the challenge with frothy bloat is that the froth can block the release of gas via the hose, just as it prevents release naturally through the esophagus. If no gas is released from the OG tube, an anti-foaming agent will be administered. This can be a specific drug like poloxalene, which is a surfactant that breaks down the foam.
It is commonly sold under brand names like Bloat Guard. In a pinch, mineral oil can also be used.
This can all be quite dramatic if an animal is at the point of respiratory distress. So how do you prevent frothy bloat in the first place?
Pasture management is key. Experts recommend avoiding grazing cattle on pastures with more than 50 percent legumes. Dew increases the risk of bloat, so if you are moving cattle to a new pasture that contains legumes, don’t move them until mid-day after the dew has burned off.
Poloxalene is available as a block and feed additive. In high-risk situations, farmers can consider adding this as a daily supplement. Adding hay feeding along with pasture grazing has also been shown to decrease the incidence of bloat.
As with most things, there is not one best method for prevention. Finding a combination of factors that work best for your herd is key.