I have been getting numerous calls about the safety of putting cattle and sheep on alfalfa or clover fields and the risk of bloat. The true frothy bloat comes from consumption of legumes and certain conditions can increase the risk of occurrence.
First we should define what bloat is.The fermentation that takes place in the rumen produces a large volume of gas continuously. This gas must be belched out as it accumulates to prevent distention of the rumen wall. The gas that normally is produced is in a free form, meaning that it can form a large “ bubble” of gas that can easily be passed.
Bloating is simply the accumulation of gas with the inability to pass it out, leading to stretching the rumen wall as pressure builds. Initially the distention is seen on the animals left side with the rumen protruding above the level of the backbone. This is seen in the paralumbar fossa, which is the triangular region just back of the ribs. As pressure increases the enlargement is evident on the right side as well. Between the pressure and the physiological changes that occur the animals show signs of great distress. Signs include restlessness, frequent attempts to pass manure, labored breathing, grunting with exhalation and ultimately being unable to stand.
There are two types of bloat. One is simply caused by the inability to properly belch because of a physical obstruction in the lower esophagus, irritation or inflammation in the region of the sphincter at the entrance of the rumen, or laying down on their side and unable to sit up.We won’t go into detail on this type now.
The more serious type is the frothy bloat which occurs after consuming a large amount of a legume. The gas in a frothy bloat is contained in tiny bubbles and in that form they cannot be belched up.
Treatment for this requires a surfactant to transform the tiny bubbles into large pockets of free air that can be successfully belched. This commonly is a type of oil given as a drench or via a stomach hose. I will use 12 ounces of a liquid vegetable oil but you can use something like butter. There are commercially available bloat treatments available that contain DSS, which is an excellent surfactant.
After administration the animal may start belching on its own. If not a stomach tube may be inserted to find the gas pockets that are forming to relieve some pressure. This may need to be done several times to get sufficient reduction in rumen pressure.
A note of caution handle these animals gently as the added stress of handling can cause them to die while you are working with them.
In severe cases where the animals are down and breathing is very labored, the bloat can be relieved by inserting a knife into the rumen. This needs to be done only on the left side (facing the back end of the animal) and only in the triangle behind the ribs. Because of the infection this causes in the abdomen this method should only be used in emergency situations.
Animals recovering from bloat should be pulled off of the legume pasture and fed dry hay. Supplemental Vitamin B Complex such as Dr. Paul’s B-Well Capsule helps recovery. Also, a source of probiotics, such as the Bovine Boost Paste, helps re-establish the gut flora.
Prevention of legume bloat is the key. Here are some guidelines to consider.
1) Never put animals on lush legume unless they are full- allow access to dry hay or silage to ensure they are not hungry plus empty going onto the new pasture or field
2) Introduce to pasture when plants are not wet from dew or rain
3) Never introduce animals if frost is on the plants
4) Use caution for a week after the first hard frost
5) Feeding Farmatan prior to turning animals out. Contact Doc Tom for recommendations and supply options to obtain Farmatan. The Farmatan is allowed for organic production
6) Bloat blocks containing Poloxalene are available to be fed as a preventative. These are not allowed in organic production.
Following these guidelines should prevent the losses that can occur from legume bloat. Be sure to observe your animals closely when they go on the new pastures. Animals that are very full but comfortable, chewing their cut, and belching are not bloated. This commonly is seen after they have access to lush green legume pastures.