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 d igest lactose less efficiently than healthy carves, and they are in a catabolic state, which influences plasma glucose concentration after g lucose absorption. Design-Clinical study; 2 treatments with 10 repetit ions/treatment. Animals-20 preruminant Brown Swiss and Simmental Red H olstein calves; 10 calves with mild diarrhea, and 10 age-matched healt hy calves. Procedure-Blood metabolite and hormone concentrations were determined before and after an oral lactose load. Plasma xylose concen tration was determined after an oral xylose load. III calves were test ed 1 day after the onset of diarrhea. Results-Calves with diarrhea (cr yptosporidia, coronavirus) had lower preprandial concentrations of pla sma glucose, insulin-like growth factor I, 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, bloo d 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 bas eline values after lactose ingestion. Conclusions-Lactose digestion is slightly impaired in calves with mild diarrhea. Calves with acute dia rrhea are in a catabolic state and, therefore, respond with a larger i ncrease of plasma glucose concentration to a given amount of absorbed glucose than do healthy calves. Clinical relevance-Plasma glucose conc entration is not a reliable measure for glucose absorption in animals that are in a catabolic state.