Measurement of Methane Production Rate in the Rumen Using Isotopic Tracers

Methane production by ruminants has been estimated by isotope dilution... As with any technique of this type, its accuracy depends on the efficient mixing of the labelled material (tracer) within the pool that is to be measured (tracee),... in the rumen. The solubility... is low and its diffusibility is high, so these properties cause difficulties not encountered with non-gaseous solutes. However, with care these problems can be minimized, and the continuous infusion...into the rumen can yield valuable measurements of methane production. The technique can be used to estimate production in the rumen by sampling the gas phase in the dorsal rumen, or alternatively total tract... production (less a small correction for methane lost from the anus) if total expired gases are collected.