Effects of feeding systems on rumen environment, degradability and passage kinetics in Ankole × Friesian crossbred steers

Abstract Natural pastures constitute a large proportion of the feed resource base for meat and milk production in Sub-Saharan Africa. However, there is increasing use of agro-industrial by-products, especially those that are cereal-based as supplementary feedstuff to grazing animals and in diets under semi-intensive and intensive production systems. This study evaluated the influence of feeding systems on rumen environment, degradability and passage kinetics. Six Ankole x Friesian F1 crossbred steers weighing 339 ± 29 kg (about two years of age), each fitted with permanent rumen cannula were used in a replicated 3 × 3 Latin square design (n s = 2). Two steers were allocated per period to one of three feeding systems i.e. (1) sole grazing (control), (2) control plus concentrate supplement (composition g/kg DM: 375 maize bran, 559 brewer's spent grain, 62.5 molasses and 3.75 NaCl), and (3) feedlot systems where steers were fed total mixed ration (TMR) comprising g/kg DM: 200 maize stover, 300 maize bran, 447 brewers’ spent grain, 50 molasses and 3 NaCl. Data was collected on rumen pH, ammonia-nitrogen (NH 3 -N), volatile fatty acids (VFA) and degradability of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF). Rumen pH was lowest (P  3 -N ranged between 62.8 and 120 mg/l and was higher (P