Abstract Broiler litter, consisting of bedding material (chopped wheat straw or rice hulls), excreta, wasted feed and feathers was ensiled at 40 or 50% moisture for 42 days. Cheddar cheese whey was added to adjust the moisture level in some of the silage. The dry matter digestibility in vitro (IVDMD), after 21 days of ensiling was greater for silage containing the wheat straw base than for that with the rice hull base. Whey improved the IVDMD of the wheat straw base silage but not that of the rice hull base silage. Moisture levels did not influence the IVDMD. In a second trial, broiler litter consisting of chopped wheat straw bedding, excreta, wasted feed and feathers was ensiled for 28 days at approximately 45% dry matter. The litter was ensiled as: (1) litter alone; (2) litter plus Irish potato cannery waste (IPW); (3) litter plus ground maize, and (4) litter plus ground grain sorghum. The materials added supplied 33% of the dry matter of the silages. The pH of the silages 1 and 4 weeks after ensiling was (1) 6.00, 5.83; (2) 5.00, 4.56; (3) 4.96, 4.80; and (4) 4.92, 4.78. Total faecal and urine collection trials were conducted using 12 Holstein steers having an average body weight of 200 kg. Dry matter digestibility was greater ( P < 0.01) for silages 2, 3 and 4. Digestible energy and protein were 61.2, 70.6; 65.3, 74.6; 65.2, 71.2; and 68.2, 76.4% for silages 1 through 4.