Measuring ventilation using carbon dioxide balances: Evolution of CO_2 production from litter in two broiler cycles

摘要

The carbon dioxide (CO_2) balance used to determine ventilation rates needs accurate emission values from animals and their manure. The objective of this work was to quantify the amount and evolution of CO_2 produced by broiler litter in two 42-day growing cycles, and its contribution to total CO_2 emission in the farm. The effect of litter aeration on CO_2 production was also investigated. In each studied growing cycle, three groups of 800 male broilers were kept in three 13m x 6m broiler rooms using new wood shavings as bedding material. In two of them, the litter was aerated weekly from day 19 to the end of the growing period (treatment A) with a broiler litter mixer and the other remained as control (treatment C). Litter properties were analyzedweekly for dry matter, ash, nitrogen content and pH. The CO_2 concentrations and emissions of each room were continuously monitored. Emissions from the litter were quantified on days 14, 21, 28, 35 and 42 of the growing cycle, using two 0.15 m~2 staticchambers. CO_2 emission from litter was negligible from the beginning of the cycle until day 28. The maximum emission was found at day 42, being on average 7.97 ± 0.32 g CO_2/m~2/h (average ± S.E.) for C and 9.09 ± 0.23 CO_2/m~2/h for A. CO_2 emissions from litter were affected by litter treatment and animal age. The litter CO_2 emissions were not constant in absolute or relative terms during broiler growing cycle, and depend on litter properties, particularly dry matter content. At the end of the cycle, litter contributed to the total CO_2 emission from 8 to 16%.