An in vitro rumen gas production technique was employed to determine the methane production and fermentation characteristics
of Leymus chinensis and Medicago ruthenica at differing harvest dates (May 15, May 30, June 30, July 30,
August 30 and September 30), which are sequential phases within a single continuous growth of two 10-year-old pastures.
To quantify the rate of degradation and compare in vitro rumen fermentation characteristic, a logistic-exponential model,
where initial gas volume was zero (LE0), was used to fit gas production and methane output results. Dried, milled forage
samples were incubated in vitro for 72 h at 39°C and gas production was recorded intermittently throughout the incubation
and