Sheep and Goat Metabolism Unit for the Collection of Excreta and Expired C14O2

Abstract

A sheep and goat metabolism unit for the collection of excreta and expired C14O2 is described. The animal is confined in a metabolism crate with its head placed into a plexiglas box which is ventilated with a vacuum pump at a rate of 70 1. per minute. The exhaust gas stream of the vacuum pump is split, and a fraction (0.5%) is bubbled through a trap containing 12.5% of ethanolamine in ethylene glycol monomethyl ether. Two gas meters are used: one for measuring the gas passing through the trap, and the other for determining the volume of gas which is exhausted. An 8 ml. portion of the trapping solution is counted in a liquid scintillation counter for determining C14O2. This system offers the following features: (1) The apparatus can be put into operation within 15 min.; (2) Small amounts of expired C14O2 can be rapidly and accurately determined; (3) An animal can be maintained in the system for 72 hr., if necessary.