Rumen degradation and estimation of microbial protein yield and intestinal digestion of napier grass (Pennisetum purpureum) and various concentrates

Abstract A study was conducted in a repeated measure arrangement using four rumen fistulated steers to determine degradation of napier grass ( Pennisetum purpureum ), protein ingredients and concentrates. Cotton seed cake (CSC), poultry litter (PL), soyabean meal (SBM), and sunflower seed meal (SFM) were used in Trial 1. In Trial 2, a commercial concentrate, a PL-based concentrate, a SFM-based concentrate and two napier grass cuts; medium (MNG) and old (ONG) were used. Rumen degradation data was used to estimate yields of rumen microbial protein (RMP) and total protein digestion in the intestines (TPDI). The estimated yields of RMP and TPDI values were comparable to determined values in other studies. The protein ingredients had highest (37–88 g N kg −1 fermentable organic matter (FOM)), concentrates moderate (26–27 g N kg −1 FOM) and napier grass lowest (10–19 g N kg −1 FOM) efficiency of RMP synthesis. The yields of RMP (44–52 g kg −1 DM) and TPDI (49–79 g kg −1 DM) were lower in ONG than MNG ( P −1 DM) and TPDI (89–219 g kg −1 DM) were lowest in PL and highest in SBM ( P −1 DM) and TPDI (96–118 g kg −1 DM) ( P −1 DM more TPDI than animals fed MNG.