Disclosed is an apparatus for monitoring methane emissions from a ruminant animal such as a cow. The apparatus includes means to entice a ruminant to voluntarily place its nose and mouth in a position that facilitates measurement of exhaled breath, such as a feed dispenser. The apparatus also includes a gas collection manifold with an inlet near the nose and mouth position in the ruminant enticement means to draw a flow of air into the inlet. The apparatus also includes a methane monitoring device monitoring methane in the gas collection manifold including methane concentrations in exhaled breath of the ruminant and optionally also in air in the absence of the ruminant. The apparatus also includes a data analysing station that processes the monitored methane concentrations to determine methane emitted by the ruminant from rumen metabolism. The determined methane emitted by the ruminant is a measure of a flux of methane in the exhaled breath, the measured flux being determined based on total air flow in the gas collection manifold. The apparatus may also measure flux of carbon dioxide from the total airflow in the manifold, and levels of a tracer substance in the breath of the ruminant animal. The apparatus may further dispense a dietary supplement to the ruminant animal based on the measured methane and/or carbon dioxide fluxes.
