DIGESTION OF CORN AND ALFALFA SILAGES IN THE STOMACH AND SMALL INTESTINE OF SHEEP PREPARED WITH TWO RE-ENTRANT CANNULAS

Four wethers, each fitted with a re-entrant cannula in the proximal duodenum and terminal ileum, were used to study digestion of corn and alfalfa silages. The four silages fed were (1) corn silage (2) corn silage with 0.6% urea (fresh weight basis) added at the time of ensiling (3) direct-cut alfalfa silage treated with formic acid (5 g/kg fresh alfalfa) and (4) wilted alfalfa silage. Urea additions to corn silage increased crude protein from 8.1 to 13.2% which resulted in an increase (P < 0.05) in microbial yield from 1.99 to 3.23 g N/100 g organic matter (OM) apparently digested in the stomach. The apparent digestion of OM in the stomach was lower (P < 0.05) with formic-acid-treated alfalfa silage (48.6%) compared to the wilted alfalfa silage (56.1%), but this difference had disappeared at the ileum. The preservation of alfalfa silage with formic acid compared to wilting resulted in a greater (P < 0.05) flow from the stomach and digestion within the small intestine of non-ammonia nitrogen. This effect o...