The aim of the study was to investigate the influence of
oral rehydration solutions (
ORS) on milk clotting, abomasal pH,
electrolyte concentrations, and osmolality, as well as on the
acid-base status in blood of suckling calves, as treatment with
ORS is the most common
therapy of
diarrhea in calves to correct
dehydration and
metabolic acidosis.
Oral rehydration solutions are suspected to inhibit abomasal clotting of milk; however, it is recommended to continue feeding cow's milk or milk replacer (MR) to diarrheic calves to prevent
body weight losses. Three calves with abomasal cannulas were fed MR, MR-
ORS mixtures, or water-
ORS mixtures, respectively. Samples of abomasal fluid were taken before and after feeding at various time points, and pH,
electrolyte concentrations, and osmolality were measured. The interference of
ORS with milk clotting was examined in vivo and in vitro. To evaluate the effects of
ORS on systemic
acid-base status, the Stewart variables strong ion difference ([
SID]),
acid total ([A(tot)]), and partial pressure of CO2 (pCO2) were quantified in venous blood samples drawn before and after feeding. Calves reached higher abomasal pH values when fed with MR-
ORS mixtures than when fed MR. Preprandial pH values were re-established after 4 to 6 h.
Oral rehydration solutions prepared in water increased the abomasal fluid pH only for 1 to 2 h.
Oral rehydration solutions with high [
SID(3)] ([Na(+)] + [K(+)] - [Cl(-)]) values produced significantly higher abomasal pH values and area under the curve data of the pH time course.
Caseinomacropeptide, an
indicator of successful enzymatic milk clotting, could be identified in every sample of abomasal fluid after feeding MR-
ORS mixtures. The MR-
ORS mixtures with [
SID(3)] values > or =92 mmol/L increased serum [
SID(3)] but did not change venous blood pH.
Oral rehydration solutions do not interfere with milk clotting in the abomasum and can, therefore, be administered with milk. In this study, MR-
ORS mixtures with high [
SID(3)] values caused an increase of serum [
SID(3)] in healthy suckling calves and may be an effective treatment for
metabolic acidosis in calves suffering from
diarrhea.