Rumen Health Technical Guide

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Rumen Fermentation

A ruminant animal’s digestive system has evolved to convert feed into energy.

Rumen fermentation is a process that converts ingested feed into energy sources for the host. Fiber scratches the rumen wall to start a series of contractions. These contractions lead to rumination, which is the process that physically breaks down the fiber source. Feed is then regurgitated, chewed and swallowed usually 50 to 70 times during rumination before passing through the next compartment of the stomach.

Microbial populations ferment feed and water into volatile fatty acids (VFA) and gases (methane and carbon dioxide). When fermentable carbohydrate in the diet is digested too rapidly, the bacteria will increase the production of both VFA and lactic acid.12ReferenceView allNocek J. E. 1997.
Bovine Acidosis: Implications on Laminitis. J Dairy Sci 80:1005-1028.
To sustain growth and the activity of fibrolytic microbes, it is crucial to maintain ruminal pH above 5.8, which will prevent the decline of fiber digestion and subsequent problems.13ReferenceView allZebeli Q., Metzler-Zebeli BU. 2012.
Interplay between rumen digestive disorders and diet-induced inflmmation in dairy cattle. Research in Veterinary Science 93(3):1099-1108
Strategies that limit acid load, notably by competing with lactate producing bacteria, help to optimize fiber digestion.14ReferenceView allChaucheyras-Durand F., Chevaux E., Martin C., and Forano E. 2012.
Use of yeast probiotics in ruminants: effects and mechanisms of action on rumen pH, fire degradation, and microbiota according to the diet. In ‘Probiotic in animals’, Ed. E. Rigobelo
Frequent changes in management or diet can alter the balance of the microbes and consequently, the profile of the fermentation end products.


Rumen fermentation pathways