Question

In ruminants, bacterial action occurs in
A) Reticulum
B) Omasum
C) Abomasum
D) rumen

Answer 1

Hint: Ruminants are herbivorous mammals that are of the suborder Ruminantia that can acquire nutrients from plant-based food by the process of fermenting it in a specialized stomach before digestion, through microbial actions. The process of rechewing the cud to disintegrate the plant matter and thereby helping in digestion is called rumination.

Complete answer:
The stomach of a cow is a fermentation chamber in which the bacteria digests the cellulose which is present in grasses and feeds, thereby converting them to fatty acids and amino acids, which are the fundamental nutrients that are used by the cow and also the basis for the production of milk.

The rumen is the largest stomach compartment in ruminants and also the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favouring environment helps it to serve as the main site for microbial fermentation of ingested feed.

The reticulum is considered to be the second chamber in the alimentary canal of a ruminant animal while rumen is the first compartment in the stomach of a ruminant, that gets food or cud from the oesophagus, digests it partly with the help of bacteria, and passes it to the reticulum.

The omasum which is also known as the bible is the third compartment of the stomach in ruminants. The omasum is before the abomasum and after the rumen and reticulum. Different ruminants have different omasum structures and also function depending on how they developed through evolution and the food they eat.

The abomasum, also known as the maw, is the fourth and final compartment in the stomach of ruminants. It secretes rennet, which is used in cheese creation.

Therefore, the correct answer is option ‘D’ i.e, rumen.

Note: Rumination takes place in the front part of the digestive system and hence is called foregut fermentation, typically requires the fermented ingesta (known as cud) to be regurgitated and chewed again. The rumen is also known as a paunch and it is the larger part of the reticulorumen. It comprises several muscular sacs like the cranial sac, ventral sac, ventral blinds, and reticulum.