Comparison of ruminal and post-ruminal digestion of a concentrate feed in the young calf.

Pre-ruminant calves were pair-fed a concentrate feed in either liquid form (LC) from a nipple bottle or in dry form (DC). We then studied the effects of these two forms of feed on body weight gain, feed utilization, digestibility, digestive enzyme secretion and volatile fatty acids in the rumen liquor. The live weight gain of calves receiving the liquid concentrate was depressed by 34 p. 100. The digestibility of total dry matter, protein, starch and energy was lower in the LC than in the DC group. The daily amounts of trypsin, chymotrypsin and amylase excreted in the faeces were similar in both groups. Lipase secretion was significantly increased in the LC group. Due to a 2.7-fold increase in the amount of faeces excreted, faecal digestive enzyme concentration was depressed in the LC group. Feeding dry concentrate to young calves reduced the pH in the rumen liquor and markedly increased the concentration of volatile fatty acids, especially C2, C3 and C4. The processes occurring in the rumen increased the digestibility of the concentrate protein by about 60 p. 100 and that of starch by 20 p. 100.