What helps the digestion of cellulose in cattle?

There are many factors that aids in the fermentation of cellulose and other plant matter in the cow's digestive tract. One is the microflora of the reticulo-rumen, which is comprised of a large population of bacteria and protozoa. These microbes have co-evolved in the cow's digestive system to obtain as much energy and protein as possible from the material consumed by the cow, while at the same time aiding the animal by breaking down the material (cellulose, hemi-cellulose, fibre and lignin) so the cow herself can obtain the nutrients she needs to live and function normally.

The second factor is the environment of the rumen. The rumen itself is an environment where no oxygen is available or can be made available, thus enabling fermentation to take place. The microflora in the cow's rumen are adapted to live and function in such an anaerobic environment, further enabling the fermentation process in the cow's rumen.

The third factor is the ability of the reticulo-rumen to mix the various matter that exists in these two chambers: gas, liquid and solid matter. Smooth muscle contractions force the liquid that is found on the middle layer of matter in the rumen (the top layer is gaseous material) to mix with the solid matter that has sunk to the bottom of the rumen, enabling further digestion and fermentation of the plant matter that was just consumed. These contractions also help in moving foreign objects such as pieces of metal, nails and stones to the reticulum so that they do not impede on the proper digestion process nor puncture the rumen wall.

Thus, it is a combination of the presence of microflora, the anaerobic environment and the smooth muscle contractions of the reticulo-rumen that help in fermentation of cellulose in the cow's digestive system.