Which bacterium is typically found in the rumen of cattle?

Methanobacterium

The correct answer is Option (3)-Methanobacterium.

The rumen is the largest compartment of the cow's stomach and is responsible for the initial digestion of plant-based feed. It is a specialized fermentation chamber where complex carbohydrates, such as cellulose and hemicellulose, are broken down by microbial activity.

Methanobacterium is a type of methanogenic archaea that resides in the rumen. It plays a crucial role in the rumen ecosystem by producing methane gas through a process called methanogenesis. Methane is a byproduct of microbial fermentation and is released through belching by the cattle.

The presence of Methanobacterium in the rumen is significant because it contributes to the overall fermentation process and energy metabolism of the cow. However, methane emissions from ruminant animals, including cattle, are also considered a significant source of greenhouse gases and contribute to global warming.

It's important to note that while Methanobacterium is a common bacterium found in the rumen of cattle, other bacteria, protozoa, and fungi also play essential roles in rumen digestion and the breakdown of complex plant materials into simpler compounds that can be absorbed and utilized by the cow.