Nutrition in ruminants

• Some plant-eating animals like cows, goats, sheeps, etc. swallow large amount of food at a time.
• They quickly swallow the grass and store it in a separate part of the stomach called rumen.

• Here the food gets partially digested and is called cud.
• But, later the cud returns to the mouth in small lumps and the animal chews it.
• This process is called rumination and these animals are called ruminants.

Ingestion:

• The food is taken into the mouth with the help of tongue.
• As the food is being chewed, it is also mixed with saliva.
• Since grass is difficult to digest, ruminants have big chewing teeth with powerful jaw muscles.

Digestion:

• After the initial chewing, the food passes down the 2 to 3 feet long oesophagus.
• The oesophagus leads into the stomach, which in ruminants is four chambered.

1. Rumen:  This is the first and the largest chamber of the stomach.
2. Reticulum: This is the second chamber of the stomach.
3. Omasum: This is the third and the smallest chamber of the stomach.
4. Abomasum: This is the last chamber of the stomach.

Rumen:

• The rumen helps in storing the large quantities of food that has been quickly consumed.
• The food is partially digested here and is now called the cud.
• The rumen also has billions of bacteria and protozoa which breakdown the fibre called cellulose found in hay and grass.

Reticulum:

• The reticulum helps in moving the swallowed food back into the mouth for thorough chewing.

Omasum:

• Its main function is to absorb excess water and reduce the particle size further.

Abomasum:

• The walls of the abomasums secrete digestive juices that help in digestion.

Absorption:

• Absorption begins in the four-chambered stomach itself but the main absorptive organs are the intestines.
• The food from the abomasum passes into the small intestine, where it mixes with secretions from the pancreas and liver.
• Most of the digestion of carbohydrates, proteins, and fats takes place here.
• Several villi are present here, which help in increasing the surface area for absorption.
• The small intestine leads into the large intestine.