Fermentation in the Rumen of the Sheep

Abstract

1. When wheaten hay and lucerne hay were fermented by organisms from the rumen of the sheep it was necessary to employ a large inoculum of rumen fluid in order to reproduce the rumen fermentation in vitro. With a small inoculum the fermentation did not conform to the known characteristics of the natural process. 2. Products per kilogram of wheaten hay fermented in vitro were: fatty acids 200-250 g.--acetic acid 41%, propionic acid 43% and butyric acid 16% (by weight); methane 15 l. Products per kilogram of lucerne hay were: fatty acids 250-300 g.--acetic acid 53%, propionic acid 29% and butyric acid 18% (by weight); methane 20 l. 3. The findings support the view that, owing to the more rapid absorption of propionic than of the other acids from the rumen, the proportion of this acid remaining in the rumen fluid is considerably less than the proportion actually formed in the fermentation.