Ruminant Animals Essay

986 Words 4 Pages
Ruminant species, such as cows, deer, and sheep, have multi-compartmented stomachs. The digestive system starts at the mouth which breaks down the food mechanically. Cows spend around one third of their day grazing and then one third of their day ruminating. The teeth grind the food and saliva is produced to help the food travel down the oesophagus. The saliva contains salivary lipase to break down fat. It also contains the enzyme salivary amylase to break down starch. A bolus is formed when the saliva, containing potassium, sodium, bicarbonate and phosphate is mixed with the food. The bolus then enters the rumen via the oesophagus, which pushes the bolus down using muscle contractions. Ruminants barely chew their food, hence why they have …show more content…
The food is then mixed with saliva and is swallowed again. The regurgitated food is then transported to the first chamber of the stomach. The repetitive process of chewing is called chewing the cud. The first chamber of the stomach is the rumen, which consists of papillae (short projections on the wall of the rumen) for absorption and regular contractions (one to three per minute) to mix the food around. The rumen is a large, anaerobic vat (a large container which holds liquid), where fermentation takes place. A cow’s rumen can accommodate 113 to 275 litres and contains the two microorganism’s protozoa (100,000 per gram of rumen fluid) and bacteria/fungi (100 million per gram of rumen fluid). The two microorganisms digest roughages, like plant fibre, to make volatile fatty acids (VFA’s). VFA’s provide over 70% of the ruminant’s energy supply. They also make microbial protein and vitamins K and B-complex. The plant fibre is broken down by bacteria (which is a source of protein and is later digested in the abomasum), making it easier to digest. The rumen also absorbs the majority of volatile fatty acids and protein synthesis takes …show more content…
Fermentation is continued in the reticulum, decreasing the size of the foodstuffs. Heavy objects (nails, wire etc.) are trapped and collected by the reticulum. They have to be removed by a rumen magnet or by surgery as the sharp objects could pierce the wall of the reticulum. The reticulum contains bacteria, anaerobic fungi and protozoans which produce enzymes. The smaller foodstuffs are then transported into the omasum, along with microbe-laden liquid. The omasum is spherical which contains many folds (leaves). It also has a large surface area, which increases the amount of absorption able to take place. Salts and water (30%-60% of the water intake) are absorbed and acid digestion proceeds. Nutrients, such as sodium and potassium are also absorbed. It is also believed to produce a grinding action on foodstuffs and it may absorb residual VFA’s and bicarbonate. The digestion and absorption is then continued in the abomasum, the true, glandular stomach, where gastric juices are produced. The enzyme lysozyme is produced to break down bacterial cell walls and the large quantities of bacteria that pass from the rumen. The abomasum wall produces cells which release digestive enzymes and hydrochloric acid, such as pepsin, to chemically break down proteins by an addition of a water molecule (hydrolysis). The proteins are broken down into dipeptides and amino acids (sub-units), preparing

Related Documents