Effect of dietary inclusion of Pennisetum purpureum (Napier) grass on growth performance, rumen fermentation and meat quality of feedlot sussex red steers

Abstract

The aim of this study was to evaluate the growth performance, fermentation indices and meat quality of Sussex steers fed totally mixed rations that composed of graded inclusion levels of Napier grass (NP). Three experimental diets designated as diet 1 (0.0 g kg–1 NP: Control), diet 2 (300 g kg–1 NP grass) and diet 3 (600 g kg–1 NP) were formulated. Twenty-four male steers aged 8 months with an average body weight of 185.0 ± 30 kg were used. In a completely randomized design, the animals were allocated to the diets and fed for 120 days. Dietary NP inclusion reduced (P < 0.05) the animals’ average daily gain and increased the feed efficiency. The steers’ daily feed intake and final body weight decreased (P < 0.05) with a 600 g kg–1 inclusion level. The fermentation indices were not affected (P > 0.05) by the inclusion. While the inclusion reduced (P < 0.05) warm muscle temperature, it had no effect (P > 0.05) on carcass dressing percentage, warm and cold initial and ultimate pH. However, 600 g kg–1 inclusion level reduced (P > 0.05) warm and cold carcass weights. Meat physical attributes, moisture characteristics and tenderness were not affected (P > 0.05) by dietary treatments, except for the 7-days aged meat thaw loss, which increased at 600 g kg–1 inclusion level. Inclusion of 300 g kg–1 increased meat protein and fat, but dry and organic matter contents decreased with increasing inclusion levels. Dietary inclusion of NP grass up to 300 g kg–1 in steers’ diets improved feed intake, carcass traits and yielded meat high in protein and fat.