Bloat in cattle

Bloat is simply the build up of gas in the rumen. This gas is produced as part of the normal process of digestion, and is normally lost by belching (eructation). Bloat occurs when this loss of gas is prevented. 

There are two sorts of bloat:

1.The least common type is gassy bloat, which occurs when the gullet is obstructed (often by foreign objects such as potatoes) or when the animal can’t burp (such as with milk fever or tetanus). 
2.The second type of bloat is frothy bloat, which happens as the result of a stable foam developing on top of the rumen liquid, which blocks the release of the gas. 
This is by far the most common form of bloat, and unlike gassy bloat, it is highly seasonal with peaks in the spring and autumn. 
This is because the foam is formed by breakdown products from rapidly growing forages (particularly legumes such as clover and alfalfa). 
These increase the viscosity (stickiness) of the rumen fluid and prevent the small bubbles of gas formed by rumen fermentation from coming together to form free gas that can be belched off
 
Distended left abdomen is the most obvious sign.
Usually associated with pain, discomfort, and bellowing.
Death can occur within 15 minutes after the development of bloat.
Gaseous bloat is usually seen in one or two animals. 
Frothy bloat can affect up to 25% of cases.
In some cases sudden death may be the first sign seen by the stockman, although in such cases it is likely that there will be other cattle with bloat that are still alive.

On the clinical signs described above
History of access to lush pasture
Passing a stomach tube will distinguish between gassy and frothy bloat. 
If it’s gassy bloat a stomach tube passed into the rumen will allow the gas build-up to escape through the tube. No such gas is seen in frothy bloat.

ANIMAL’S CONDITION- BLOAT/ RUMINAL TYMPANY

This is a condition which affects the rumen (the first of the four divisions of stomach in ruminants) of ruminants and is characterised by a distended abdomen resulting from an accumulation of gas. 
Microbes resident in the rumen aid in the fermentation of feed eaten by ruminants and this is part of the normal process of digestion. 
As a result of the fermentation process, gas is produced which is normally expelled through the mouth by a process known as eructation or burping. 
Bloat therefore results when there is any form of hindrance to the normal release of gas from the rumen.
  
Based on what is preventing the easy eructation of the gas produced by the fermentation of food, bloat is classified into two main forms: 
1. Gassy Bloat and 
2. Frothy Bloat
 
This is the less common type and it occurs when the oesophagus is blocked normally by a foreign object such as lumps of feed, or when the ruminant cannot burp as a result of weakness especially in conditions such as Hypocalcaemia. 
 :
This is the more common type and it happens as a result of a layer of foam forming on top of the ruminal content thereby preventing the free release of gas. 
This form of bloat is quite seasonal in its occurrence and normally happens at the onset of the raining season. 
This is because the rapidly growing forages (especially legumes) which are highly fed on are rapidly digested leading to the formation of the foam. 
This thickens the ruminal fluid, preventing an easy formation of free gas to  be belched off.

CLINICAL SIGNS

A highly distended left abdomen 
Sudden death, though other animals in the flock may be showing signs of bloat
Death can occur within 15 minutes of bloat as a results of impaired normal respiration. 
History of what ruminants have fed on is key
Auscultation and Palpation
The use of a stomach tube help to distinguish between Gassy and Frothy Bloat. If is Gassy Bloat, the gas will escape through the tube. 
However in Frothy Bloat, no gas will escape.
The passage of a stomach tube is the best treatment for a Gassy Bloat. 
Should a stomach tube fail, a Trochar and Cannula can be used to punch the side of the rumen to allow the gas or the froth out. 
Nevertheless the cause of the obstruction in the case of a Gassy Bloat should always be investigated and treated to prevent reoccurrence.
Antifoaming such as (Polaxolene or Dimethicone) can be used in Frothy Bloat to prevent foam formation. 
However some old methods such as the use of Turpentine and linseed oil have proven to be effective.
Avoid grazing animals on high-risk pastures and also ensure feed or pastures are always free from foreign materials such as plastics and stones.