Rumen gas kinetics

Gas production from thirty samples of feedstuffs (10 samples of corn silage, grass silage, and grass hay, respectively) was assessed in vitro using two methods: the Hohenheim gas test (HGT) and the ANKOM RF Gas Production System (ANKOM). Samples were incubated in buffered rumen fluid. Gas kinetic parameters were calculated using the Gompertz model. Results revealed significantly lower gas production with the ANKOM compared to the HGT. Significant differences were observed between the HGT and ANKOM in the specific gas production rate (parameter C), maximum fermentation rate (MFR) and gas produced after 24 h of incubation (Gas24) for each feed group. High coefficients of determination (R2) were calculated between the methods for the gas kinetic parameters MFR, Gas24, total potential gas production (parameter B), decrease in the specific gas production rate (parameter A), moderate R2 for C, and low R2 for time of maximum fermentation rate (TMFR). Despite the lower quantities of gas generated with the ANKOM, there are strong correlations in the parameters of gas kinetics that promise the possibility of developing correction models. Future development of such models could position the ANKOM as a viable alternative to HGT, particularly for calculating metabolizable energy and net energy for lactation in feedstuffs.