Addah, W., Baah, J., Okine, E. K. and McAllister, T. A. 2012. Use of thermal imaging and the in situ technique to assess the impact of an inoculant with feruloyl esterase activity on the aerobic stability and digestibility of barley silage. Can. J. Anim. Sci. 92: 381-394. Feruloyl esters limit the digestibility of forages, a constraint that may be overcome if additives with feruloyl esterase (FE) activity are applied to forage. This study determined if a FE-producing strain of Lactobacillus buchneri LN4017 in combination with Lactobacillus plantarum LP7109 and Lactobacillus casei LC3200 improves fermentation, aerobic stability and in situ fibre disappearance of whole-crop barley silage. Barley forage (350 g kg^-1 DM) was either uninoculated (UN) or inoculated (1.3×10⁵ CFU g^-1 fresh forage; IN) and ensiled in Ag-Bag^® silos. Bags were opened after 90 d of ensiling. Samples were collected on day 95, 123 and 175 for determination of fermentation characteristics. Surface temperature of the face of each bag was measured over 3 d using a thermal infrared camera. Ruminal in situ DM and NDF disappearance (aNDFD) of silage and rumen fermentation patterns were measured using three ruminally cannulated heifers. The L. buchneri-treated silage possessed a higher acetic acid concentration than UN (48.8 vs.18.4 g kg^-1 DM). The temperature at the face of IN was lower than UN immediately upon exposure and after 3 d of aerobic exposure. Inoculation increased (P=0.01) 24-h and 48-h aNDFD with a trend towards a glucogenic pattern of ruminal fermentation in heifer compared with UN silage. There was evidence that the FE-producing inoculant improved aerobic stability and aNDFD of whole-crop barley silage.