Analysis of ruminal fluids with the ammonia electrode.

Abstract

The ammonia concentration of samples collected from the rumen of beef steers was determined by both the Conway and ammonia electrode procedures. Rumen fluid had to be centrifuged and diluted for the electrode procedure to function properly. When only one animal was used as a source of rumen fluid and multiple determinations were made on each sample, the mean ammonia concentration was significantly lower for the electrode procedure than the Conway procedure. The correlation between the two procedures was greater than 0.8 in 78% of the comparisons. In 44% of the comparisons with a concentration range of 3–117 mg/100 ml, the electrode procedure yielded a higher concentration value than the Conway procedure. Two methods of employing the electrode were also compared. Although the known addition method yielded significantly lower ammonia concentration than the direct method, these differences were less than 5% of the mean and probably reflect the sensitivity of the electrode to generate a low standard error.