SYSTEM FOR MEASURING METABOLIC GAS EMISSIONS FROM ANIMALS

摘要

A system is disclosed which measures the flux of metabolic gas emissions from cattle or other animals. The system does not require that the animals be confined to a chamber or stall. An animal whose metabolic gas emissions are to be measured is first fed a permeation tube (a metal tube with a gas-permeable plastic disk in one end). Inside the tube is a tracer that is physiologically inert. The permeation tube is filled with pressurized liquid tracer which slowly permeates (in gaseous form) through the plastic disk. In order to measure rumen-produced metabolic gases, a sample container, such as an evacuated container or an inflatable collar is placed on the animal. A small diameter sample tube is attached from the sample container to a halter and terminates somewhere near the animal's mouth. When the animal breathes, it exhales metabolic gases as well as the tracer. A sample of air containing both the metabolic gases and the tracer gas is then collected through the sample tube. Since the permeation rate of the tracer is known and constant, the ratio of the flux of a given metabolic gas to the flux of the tracer gas is equal to the ratio of the mixing ratios of the respective gases in the air sample that is collected. The rate of flux of metabolic gas from the animal's rumen is thus readily calculated by measuring the metabolic gas and tracer mixing ratios in the sample thus collected.