Ruminant Digestive System Ppt Pres 291y51

Ruminant digestive system

What is a ruminant? Ruminants include cows, sheep, goats and deer. They have multiple compartments to their digestive tract which

allows them to eat grass, hay and other cellulose rich foods which most animals cannot digest. This is very useful in agriculture as it allows us to turn un-useful products into meat, wool and milk. The ruminant stomach occupies almost 75 percent of the abdominal cavity, filling nearly all of the left side and extending significantly into the right side. The relative size of the four compartments is as follows: the rumen and reticulum comprise 84 percent of the volume of the total stomach, the omasum 12 percent, and the abomasum 4 percent. The rumen is the largest stomach compartment, holding up to 40 gallons in a mature cow.

Diagram

Where it begins… They produce lots of saliva. Cows are said to produce 100-150

litres of saliva per day! Saliva aids chewing and swallowing, pH levels, and contains enzymes to aid digestion. The animals use their tongues to harvest the grass. They spend 1/3 of their time grazing and 1/3 of their time chewing the cud (ruminating). They lack top incisors, the bottom incisors aid selection of roughage, and the molars and premolars meet to crush and grind food. The food is rolled into a bolus and pushed into the esophagus.

Oesophagus Muscles contract in both directions to allow food to

be brought back up for re-chewing. It has no sphincter valve. It opens into the reticulum and rumen.

Rumen If the food is not sufficiently chewed it will be forced back up by

regurgitation to be re-chewed and mixed with more saliva. The rumen is a large fermentation chamber (in adult cattle its volume is about 125 litres). It contains lots of bacteria and other micro-organisms. It is because the bacteria secrete the enzymes necessary for cellulose degradation that ruminants are able to utilize roughage. The rumen has a textured surface, lined with projections (up to 1 cm long), termed rumen papillae.  The rumen, along with the omasum, absorb the by-products of bacterial fermentation. These by-products are volatile fatty acids (VFAs). The rumen is not functional at birth.

Rumen functions Storage Soaking Physical mixing and breakdown Fermentation

Synthesizes some vitamins  Synthesizes AA and protein  Breaks down fibrous feeds into VFAs 

Reticulum The reticulum is a flask-shaped compartment with a

"honeycomb" appearance. It moves ingested food (ingesta) into the rumen and the omasum. The reticulum also causes the regurgitation of ingesta during rumination, and acts as a collection compartment for foreign objects.

Omasum The omasum, or "manyplies", contains numerous laminae

(tissue leaves) that help grind ingesta. These folds assist in the removal of fluid from the ingesta on their way to the abomasum. The omasum also acts as a type of pump, moving the food from the here to the true stomach, the abomasum, where acid digestion takes place. Functions: Reduce particle size Absorb some water

Abomasum This compartment corresponds to the stomach of the

non-ruminant, and is termed the true stomach. It secretes the gastric juices which aid in digestion. The pH of the abomasum is normally in the range of 2,0 to 2,5. This low pH facilitates initial protein breakdown, and kills the bacteria which have spilled over from the rumen

Differences Ruminants differ from monogastric animals in the following important ways: They have no upper canine teeth, or incisors, and have long, thick and rough tongues. They ruminate. Chewing the cud helps reduce feed particle size, and mixes saliva into the feed. The ruminant digestive system includes a fermentation chamber, called the rumen. The rumen contains micro-organisms which serve some important functions: they make it possible for ruminants to digest fibre (especially those in roughages) and they synthesize nutrients (such as B complex vitamins), and also essential amino acids which become available to the animal when the micro-organisms die, and are digested.