Disorders of the Digestive System on the farm

Cause: Ruminants produce a large volume of gas mainly carbon dioxide and methane through the action of the microbial population in the rumen, with adult cattle producing up to 800 litres daily. Under normal circumstances, the rumen contracts and forces the gas out in a process known as eructation or belching. Pasture bloat is plant-induced, with the gas in the rumen being trapped in foam which cannot be eructated. Legumes and the young, leafy phase of grass have the most potential to cause bloat of this kind. Acute bloat results when the gases of rumen fermentation are trapped due to an obstruction in the oesophagus.

Symptoms: Distension of the abdomen which if left untreated may cause suffocation of the animal, due to pressure on the heart and lungs.

Treatment: Anti-foaming agents can be introduced into the rumen to break up the froth causing the blockage. Common household agents used include vegetable oil and turpentine should commercial treatments be unavailable. Should the bloat be caused by a blockage, then a trocar and cannula are used to release the gas.

Prevention: Roughage such as dry hay should be included in the diet while the animal is grazing on a high legume pasture. The dry nature of hay for example stimulates the production of saliva which helps prevent bloat. Should an animal suffer a consistent pattern in relation to the illness, a TB test should be considered as TB can be the fundamental cause of recurrent bloat.

ACIDOSIS

Cause: The number and types of micro-organisms such as bacteria and protozoans in the rumen depends primarily on the foodstuffs fed to the animal. Some microorganisms have the ability to digest cellulose but not starch, others can digest starch but not cellulose, while some can digest both. Changing rapidly from a roughage to a grain ration results in a more acidic environment in the rumen due to the production of excess lactic acid. If excess amounts accumulate in the rumen, they will be eventually absorbed via the rumen wall into the bloodstream.

Symptoms: Increased respiratory and heart rate, loss of appetite and condition and weight loss.

Treatment: Veterinary assistance should be sought.

Prevention: Efficient management in relation to feeding is essential from the gradual introduction of concentrates into the diet, to monitoring ration size.