Comparison of the effects of an isosmolar and hyperosmolar oral rehydrating solution on the hydration status, glycemia and ileal content composition of healthy neonatal calves

Isosmolar oral rehydrating solutions (ORS) used to treat diarrheic calves are low in energy. In contrast, hyperosmolar ORS may have a dehydrating effect. This study was designed to compare the net water and glucose absorption from the small intestine of normal calves given isosmolar or hyperosmolar ORS. Six calves were used for the experiment. A reentrant ileal cannula was implanted surgically. Each calf was fed with either the isosmolar or the hyperosmolar solution. The next day, the second solution was given. Both contained chromium EDTA as a nonabsorbable marker. Changes in the hematocrit, total plasma protein, plasma osmolality, plasma glucose concentration, and ileal volume, osmolality, glucose content, and chromium concentration were monitored for 10 hours. The only statistically significant difference was in the post-feeding plasma glucose level: it peaked at the higher level (p less than 0.05) in calves fed the hyperosmolar solution. In normal calves, the hyperosmolar ORS had no effect on the hydration or on the small intestinal fluid composition.