Ruminants differ significantly from other mammals in that much of their feed undergoes microbial predigesting in the forestomaches, chiefly in the rumen and reticulum. There is also post gastric fermentation in the cecum and colon

Ruminoreticular motility or fermentation is depressed in many conditions, including improper feeding (overload or deficiency of specific nutrients), lack of water, infectious diseases, intoxications, lesions of any part of the upper GI tract, metabolic states (eg, hypocalcemia), or reduced flow of alkaline saliva that allows pH to fall and the microbial population to be altered to an extent that is harmful to the animal