A continuous approach to assess methane production rate in ruminants using respiration chambers

摘要

The methane production from ruminants is one of the most discussed topics in animal production since it has been identified as a key problem regarding world climate change. Methane production can be quantified with open-circuit respiration chambers. Usually, the calculation of total methane production is the mean concentration measured along the trial multiplied by the total volume of air exchanged (1/period), resulting in an average value that does not contemplate the production rates variation of methane due to the pattern of ruminal fermentation (Dauncey et al., 1978; Aguilera and Prieto, 1986; Rodriguez et al, 2007). Other authors (Brown et al, 1984) have provided a different approach for gas production calculations in which they included a differential term that is more appropriate for detecting rapid changes in metabolic rate, such as the result of physical activity. However, for continuous modeling processes, such as methane production, that approach might not be suitable. This work evaluates the methane production along the measurement time by modeling the cumulative gas curve to generate gas production rates that can be used to compare factors, such period within a day.