ABSTRACT
The fermentation of carbohydrates in the rumen of sheep is known to lead to the formation of large amounts of the lower fatty acids. The important part that these acids assume in the metabolism of ruminants has been remarked upon (Marston, 1939, 1946). While it is believed that acetic, propionic and butyric acids are the main fatty acid products of the fermentation, there is no certain knowledge of the proportions and quantities in which they are formed.
Experiments conducted since this was written have shown that propionic acid is absorbed preferentially from very dilute solutions containing no phosphate and adjusted to pH 6-5 before they were introduced into the rumen. Little if any preferential absorption of propionic acid was observed when more concentrated solutions were introduced at the pH used in trial 1 even if phosphate were present. Further work is proceeding to determine the influence of pH on the absorption of fatty acids from the rumen.
