Concurrent studies of the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves

Abstract

I . The effect of age on the flow of duodenal digesta and of pancreatic secretion was studied in preruminant calves fitted with duodenal re-entrant and pancreatic sac cannulas. In Expt I a comparison was made at 7, 24 and 63 d of age of Ayrshire calves given whole milk, and in Expt 2 Friesian calves given milk-substitute diets were studied during the period 16-37 d of age.2. For the Ayrshire calves, nd lib. whole-milk intake increased with age, but whole-milk intake on a per kg metabolic body-weight (Wo.'s) basis did not alter. As the intake increased with age, the whey fluids were passed out of the abomasum more rapidly.3. As judged by the mean duodenal pH values and the values for 'chloride ion minus sodium ion' concentration in the digesta, and for apparent secretions (total quantity recovered at duodenal cannula during 12 h after feeding minus intake) the duodenal digesta became more acid as the Ayrshire calves became older. There was no change with age in the extent of degradation of the milk proteins as indicated by the protein-nitrogen:total N values for duodenal digesta. 6 . The extent of the increase in secretion of pancreatic enzymes during the first hour after the Friesian calves were fed milk-substitute diets differed between enzymes.7. The changes in the quantities of pancreatic enzymes secreted are discussed in relation to the changes in the digestibility of milk-substitute diets.

The effect of stabilized rumen extract on growth and development of calves: 3. Digestion in the small intestine

“…The differences between groups were most pronounced 3 h after feeding reflecting probably the difference in peak microbial activity in the rumen of 2 h after feeding. A similar decrease of the p H value of duodenal digesta was reported by TERNOUTH et al (1976).…”

“…In calves 30 to 42 days of age fed on reconstituted milk (i. e. heat-treated skimmed milk + fat) protein N was 43 to 49% of total N while with whole milk this proportion was 22 to 33% (TERNOUTH and ROY 1978). When calves at the age of 7,24 and 60 days were fed on the same kind of milk the protein N :total N ratio did not change significantly (TERNOUTH et al 1976).…”