Feeding value of sweet sorghum bagasse and leaf residues after juice extraction for bio-ethanol production fed to sheep as complete rations in diverse physical forms.

Abstract

The fodder value of sweet sorghum bagasse with leaf residues (SSBLR) remaining after juice extraction for bio-ethanol production as major diet ingredient was assessed in male growing sheep measuring intake, digestibility and growth rates. The SSBLR contributed about 450 g/kg in total mixed rations and was offered as mash (8 mm), pellets (16 mm) and feed block (SSBLR chopped). Chaffed SSBLR supplemented with the remaining concentrate components of the total mixed ration-offered for 2 h before the chaffed SSBLR-served as a control. Six sheep were randomly allocated to each treatment, balancing the group weight. Intake of all SSBLR based rations was generally very high exceeding 42 g/kg of sheep live weight in the control and feed block ration and intake was further increased to 52 and 56 g/kg in the mash and pellets rations, respectively. Observed live weight gain in sheep fed mash and pellets were 133 g/d and 130 g/d, respectively, compared to 90 g/d and 81 g/d observed in the feed block and control group, respectively. Organic matter digestibility was 0.59 and 0.58 in the mash and pellet group compared to 0.62 and 0.61 in the feed block and control group, respectively. All comparisons in mash and pellet versus feed block and control group were different (P<0.05). SSBLR can be utilized as major ration component thereby mitigating fodder shortages likely to arise from using sweet sorghum stalks for juice extraction for bio-ethanol production. Use of SSBLR as ration component for will also add to the economic viability of sweet sorghum ethanol value chains. In decentralized systems where juice is extracted from sweet sorghum stalks in the villages and options of processing SSBLR are limited, SSBLR can be used in chopped form with similar efficiency than as component of processed feed block. In centralized system, generating large quantities of SSBLR, processing feed into mash and pellets would be advantageous for supporting higher livestock productivity and lower feed transport costs.