Effect of feeding differently processed sweet sorghum (Sorghum bicolor L. Moench) bagasse based complete diet on nutrient utilization and microbial N supply in growing ram lambs

Abstract

This study was carried out to identify appropriate processing method for efficient utilization of sweet sorghum bagasse (SSB), an agro-industrial by product of ethanol industry after blending with concentrate. SSB based complete diet with roughage to concentrate ratio of 50:50 was processed into mash (SSBM), expander extruded pellet (SSBP), chop form (SSBC) and evaluated in comparison to sorghum stover based complete diet in mash form (SSM). Twenty-four Nellore×Deccani ram lambs (9 months age; 21.1±0.57kg body weight) were randomly divided into four groups of six animals each and the experimental complete diets were allotted at random to each group and evaluated for their intake, nutrient utilization and microbial N supply. Among all the groups, the average dry matter (DM) intake (g/kg w0.75), digested DM, organic matter and crude protein were higher (P<0.01) in lambs fed SSBP diet. The cellulose digestibility was higher (P<0.05) in lambs fed SSBP diet than those fed SSM and SSBC diets. Intake of digestible crude protein (DCP, g/d) and metabolizable energy (MJ/d) were higher (P<0.01) in lambs fed SSBP diet. The SSBP diet had higher (P<0.01) DCP and N (P<0.05) balance compared to other three diets. Increased (P<0.01) purine derivatives and microbial N supply was observed in processed diets. Expander extrusion of SSB based complete diet resulted in improved (P<0.01) efficiency of microbial protein synthesis. It is concluded that, when SSB was processed into complete diets, in terms of nutrient utilization and microbial N supply, the expander extruded pellet diet was better utilized than chopped or mash form by the growing ram lambs.