Comparison of Sheep Ruminal Fluid with Sheep and Horse Faeces as Inoculum for In Vitro Gas Production Measurements

A total of 22 ruminant feedstuffs, 14 forages and 8 concentrates, originating from Turkey were used to determine kinetics of in vitro gas production using the Hohenheim gas test (HGT) protocol with multiple readings. Three different inocula sources were ruminal fluid (RF) from fistulated sheep, horse faecal suspension (HFS) and sheep faecal suspension (SFS). Maximum rate of gas production was highest with SFS 2.21 ml/h. The best regression equation for predicting 24 h rumen fluid gas production (ml) was obtained with HFS at 48 h [y = 0.92 +/- 0.03 x + 9.90 +/- 1.17; residual standard deviation, 4.43; coefficient of determination, 0.86]. However, more research is required to standardize and optimize the HFS method.