Evaluation of the Total Carbon Dioxide Apparatus and pH Meter for the Determination of Acid-Base Status in Diarrheic and Healthy Calves.

Three simple tests of acid-base status were evaluated for field use. Blood samples were collected from 20 diarrheic and 24 healthy calves less than six weeks of age. One sample was collected anaerobically and immediately analyzed on a blood gas analyzer. The other samples were used for measurement of blood and serum pH using a pH meter and pH paper, and for serum total carbon dioxide (TCO(2)) using a TCO(2) apparatus. The TCO(2) apparatus gave the best results and would be useful in the field. TCO(2) apparatus measurements had a high correlation, r=0.91, with blood gas analyzer blood bicarbonate values. Healthy calves have a serum TCO(2) content of 30 mmol/L and bicarbonate requirements for correcting metabolic acidosis in diarrheic calves can be calculated:Bicarbonate required (mmol) = (30-TCO(2)) x Body Weight x 0.6 This can be converted to grams of sodium bicarbonate by dividing by 12.