[The determination of ammonia in rumen fluid]

The following 3 methods of NH3 determination were compared to each other for accuracy, on the basis of their results: microdiffusion acidimetric NH3 analysis, photometric NH3 analysis, using bivalent potassium tetra-iodomercurate, and steam distillation/acidimetric NH3 analysis. The results obtained from steam distillation at pH 7.6 were found to agree with those recorded from microdiffusion. However, photometric NH3 determination, using Nessler reagent, yielded overestimated values due to interference by other rumen juice substances.