A comparison of pH determination methods in food animal practice

The accuracy of a portable pH meter in measuring blood pH in neonatal calves, urine pH, and ruminal fluid pH in cows has been assessed. Thirty-five diarrheic and 15 healthy beef calves were used for blood gas analysis; 57 healthy dairy cows provided voided urine samples; and ruminal fluid samples were obtained from 10 dairy cows with ruminal fistulas on 4 separate days. Measurements of blood pH were obtained from an automated blood gas analyzer and the portable pH meter. Measurements of urine and ruminal fluid pH were determined with the benchtop pH meter, urinalysis strips, narrow range pH paper, and the portable pH meter. The portable pH meter was more accurate in measuring urine pH and ruminal fluid pH in cows than blood pH in neonatal calves. The urinalysis strips and the narrow range pH paper were found adequate to evaluate urine and ruminal pH.