Effects of oral lactose and xylose loads on blood glucose, galactose, xylose, and insulin values in healthy calves and calves with diarrhea.

OBJECTIVE

2 hypotheses were tested: calves with acute, mild diarrhea digest lactose less efficiently than healthy calves, and they are in a catabolic state, which influences plasma glucose concentration after glucose absorption.

DESIGN

Clinical study; 2 treatments with 10 repetitions/treatment.

ANIMALS

20 preruminant Brown Swiss and Simmental Red Holstein calves; 10 calves with mild diarrhea, and 10 age-matched healthy calves.

PROCEDURE

Blood metabolite and hormone concentrations were determined before and after an oral lactose load. Plasma xylose concentration was determined after an oral xylose load. III calves were tested 1 day after the onset of diarrhea.

RESULTS

Calves with diarrhea (cryptosporidia, coronavirus) had lower preprandial concentrations of plasma glucose, insulin-like growth factor 1, and 3,5,3-triiodothyronine (P < 0.01) and a higher concentration of free fatty acids (P < 0.03) than did healthy calves. After the oral lactose and xylose loads, blood galactose and plasma xylose concentrations were lower in ill calves (P = 0.10 and P = 0.07, respectively). In calves with diarrhea, there was a larger increase of plasma glucose concentration (P = 0.12) and a smaller increase of plasma insulin concentration (P = 0.04) above baseline values after lactose ingestion.

CONCLUSIONS

Lactose digestion is slightly impaired in calves with mild diarrhea. Calves with acute diarrhea are in a catabolic state and, therefore, respond with a larger increase of plasma glucose concentration to a given amount of absorbed glucose than do healthy calves. CLINICAL-RELEVANCE: Plasma glucose concentration is not a reliable measure for glucose absorption in animals that are in a catabolic state.