Crude fat was determined by hydrochloric acid hydrolysis followed by extraction in petroleum ether according to Stoldt (1952). In vitro OM digestibility was determined by incubating samples
anaerobically in ruminal fluid and a buffer solution for 48 h in glass tubes at 38 1C, followed by incubation in a pepsin HCl solution for additional 48 h at 38 1C according to Tilley and Terry (1963).