Information on Bloat:
There are two types of bloat: free gas and foamy bloat.
Free-gas bloat is caused by either a blockage of the esophagus, irregular diet, or nerve damage or vagal indigestion (where the vagus nerves connect the rumen to the central nervous system can be inhibited) of the reticulo-rumen, often caused either by injury (i.e., hardware disease), or severe respiratory disease.
Foamy-bloat occurs both on pasture and in the feedlot. Pasture bloat is often caused by alfalfa and clover, and also, but less commonly, high-protein or high-quality grasses (particularly those that are in the vegetative stage). Pasture bloat quite often comes up without warning and symptoms come on very quickly. Feedlot bloat is quite often caused by high-concentrate diet like grain, and especially a concern if an animal has over-done it on the grain, or has been suddenly switched to a high-concentrate diet from a roughage diet, or is on a roughage diet but ate too much high-concentrate feed. Grain silage is not attributed to causing bloat. This type of bloat is caused by tiny grain particles or alfalfa/clover chloroplasts that form a slime that trap these tiny particles and form small gas bubbles. Both grain and bloat-inducing legumes are often digested very quickly, providing for bacterial blooms which produce large quantities of gas and slime.
Symptoms that an animal is bloating are:
1. Distended upper left side (moderate to severe is when the skin over the upper left flank cannot be grasped and lifted)
2. Kicking at the belly
3. Little interest in eating
4. Restlessness
5. Mouth-breathing (panting)
6. Tongue distention
7. Staggering
(Note: the last three symptoms are for severe cases, first four are average ones to look for from mild to moderate or worse case)
Treatment varies depending on the severity of the bloat. If an animal has a mild case of bloat, often just getting it up and moving around will help move the contents in the rumen and free the gas that has built up. However, this may not help either. Mild to moderate cases require tubing with mineral oil or some other anti-foaming agent. Such solutions may not be necessary if the animal has free-gas bloat. Simply putting the tube down into the rumen would be enough to help release the gas that has built up. However, with frothy bloat, the froth will quickly build up in the tube and need to be blown out at the other end by the person handling the tubing operation (sounds gross I know). Thus, an anti-foaming agent is a good method of this.
If bloat is severe or such that tubing is not an option, rumenotomy is necessary to quickly release the contents. A trocar with a canula attached is the best instrument to have for this sort of emergency, since it's much less traumatic for the animal. Make an incision into the skin through the abdominal muscles with a sharp knife about 1 cm (~1/2 inch), then place the trocar into the incision so that it punctures the rumen wall. Remove the trocal and leave the canula in place to allow the gas and froth to escape. A piece of wire may be needed to stir the the froth and allow further release
If no trocar and cannula can be had, then a sharp knife will be needed to release the gas in the rumen. A quick incision into the skin 6 to 12 cm (4 to 6 inches) over the midpoint of the left flank needs to be made, continuing through the abdominal wall to the rumen. Expect an explosive release of gas when this happens. The vet will have to be brought out right away to clean up the wound and sew it up properly to prevent peritonitis.
Prevention:
Most common bloat is on pasture. To prevent pasture bloat, you can do several things:
1. Do not put the animals out on it when they're hungry.
2. Do not allow access to the pasture when alfalfa is in an immature stage
3. Do not allow access to the pasture during early mornings or right after a rain
4. Allow full access to hay when they're out on pasture. Moderate to poor quality hay or straw is great for this.
5. Have them have access to a bloat-prevention block
6. Implement a grass mix in with the alfalfa and clover
With grain, it's best to introduce the ration slowly.
For more information, please see this website:
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6769
