Direct and indirect calorimetry of medium sized animals

Direct and indirect calorimetry of medium sized animals is described and in its technique compared with calorimetry of small animals and with whole-body calorimetry in man. Among the indirect methods discussed are: determination of oxygen consumption/carbon dioxid production in open and closed systems, isotope dilution techniques, combustion calorimetry and estimation of metabolism from heart rate. The group of medium sized experimental animals used in the direct calorimetric measurements included rats, rabbits, skipmunks, Chinese hamsters and dogs. Most instruments for medium sized animals apply the gradient layer principle proposed by Benzinger and Kitzinger (ref.1).