The food and faecal samples were dried at 55°C for 48 h and after milled through a 2 mm sieve and packed in to 4 cm × 5 cm F57 Ankom filter bags (20 mg of DM/cm2) that had previously been weighed. The filter bags were incubated for 10 days in the rumen of a fistulated Holstein bull fed a mixed diet of equal parts of forage (corn silage) and concentrate, as used in the treatments (Casali et al., 2008).