Construction and operation of an open-circuit indirect calorimetry system for small ruminants

An open-circuit indirect respiration calorimetry system for the collection of long-term metabolic heat production data for medium and small animals is described. The system is designed for use with small ruminants, but it has the capacity for measuring heat production in nonruminant species up to 150 kg. The system consists of an internal climatic control system, air flow control and volume measuring system, and gas analyzers for O2, CO2 and CH4. Carbon dioxide recovery checks of the four chambers produced recovery values ranging from 96.73 to 100.89%. The actual mean fasting heat production measured for 12 wether sheep was 63.13 kcal/kg.75 +/- .83. The total estimated cost of four chambers and the associated instrumentation was less than $17,000 in 1984.