A comparison of pH determination methods in food animal practice

The accuracy of a portable pH meter in measuring blood pH in neonatal calve s, urine pH, and ruminal fluid pH in cows has been assessed. Thirty-five di arrheic and 15 healthy beef calves were used for blood gas analysis; 57 hea lthy dairy cows provided voided urine samples; and ruminal fluid samples we re obtained from 10 dairy cows with ruminal fistulas on 4 separate days. Me asurements of blood pH were obtained from an automated blood gas analyzer a nd the portable pH meter. Measurements of urine and ruminal fluid pH were d etermined with the benchtop pH meter, urinalysis strips, narrow range pH pa per, 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 c alves. The urinalysis strips and the narrow range pH paper were found adequ ate to evaluate urine and ruminal pH.