Effect of supplementing napier grass (Pennisetum purpureum) with poultry litter and sunflower meal based concentrates on feed intake and rumen fermentation in Friesian steers

Abstract Intake of nutrients and rumen fermentation values were determined in a 4×4 Latin square design using four rumen fistulated Friesian steers. In Trial 1, steers were fed medium (MNG) or old (ONG) maturity napier grass ( Pennisetum purpureum ) supplemented with 3.65 kg of DM of sunflower seed meal based concentrate (SFBC) or poultry litter based concentrate (PLBC) while in Trial 2, steers were fed MNG only or MNG supplemented with 0.91, 3.65 or 6.35 kg of DM of the PLBC. In Trial 1, intakes of crude protein (CP) (15.3 vs 11.1 g kg −1  W 0.75 ) and organic matter (OM) (127.1 vs 124.7 g kg −1  W 0.75 ) were higher on MNG vs ONG diets while intakes of CP and OM were 3% higher on SFBC vs PLBC diets. Rumen pH was higher (7.1 vs 6.7) on ONG vs MNG ( P P >0.05). Concentrations of ammonia (NH 3 -N) were higher on MNG vs ONG (101.0 vs 51.2 mg l −1 ) but 12.5% lower on SFBC vs PLBC diets while concentrations of VFA were higher on MNG vs ONG (123.8 vs 101.8 mmol l −1 ) and 2.5% higher on SFBC vs PLBC diets ( P P −1  W 0.75 while intakes of CP were 10.6, 12.2, 15.6 and 17.5 g kg −1  W 0.75 for treatments 0, 0.91, 3.65 and 6.35 kg/day of PLBC, respectively, ( P 3 -N increased to 6.35 kg/day of PLBC ( P