An Open-Circuit Indirect Calorimetry Head Hood System for Measuring Methane Emission and Energy Metabolism in Small Ruminants

摘要

Simple SummaryAn open-circuit indirect calorimetry system for small ruminants was updated. Calibration factors for CH4, CO2 and O2 close to 1 confirmed the absence of leaks in the indirect calorimetry system and the accurate performance of this device. An experimental test quantified the gas exchange and the repeatability for CH4 and heat production measurements, which were 79% and 61%, respectively. The heat production obtained by indirect calorimetry was close to the heat production obtained by carbon and nitrogen balance. Discrepancies between the two methods averaged 1.92% when expressed as a percentage of the intake of metabolizable energy, a rather satisfactory value considering the substantial amount of technical and analytical work involved. The close agreement found between them can be considered as an indicative of the absence of systematic error. When diets with different forages were compared, the daily CH4 production was 1.54 and 1.25 L/h for diets-based in alfalfa hay and alfalfa silage, respectively.