IntroductionWheat straw (WS) is one of the major crop residues and valuable feed resources for livestock reared by the resource-poor farmers of many Asian countries. Sugar beet (Beta vulgaris L.) is a cash crop produced all over the world for sugar production by the industries. Strategic supplementation of sugar beet pulp (SBP) to a WS-based diet could modulate rumen fermentation by supplying highly fermentable carbohydrates to rumen microbes, thereby improving utilization of WS. Therefore, the current study aimed to examine the influence of SBP in modulating rumen fermentation kinetics, volatile fatty acid production, enzyme activities, and methanogenesis of WS using rumen liquor of water buffalo.MethodsIn vitro fermentation kinetics was conducted using the automatic gas production system for 72 h at 39 °C with rumen liquor of buffalo.ResultsSupplementing SBP either at 10% or 20% to WS enhanced (p < 0.05) total gas production, potential gas production (b) and rate (per h) of gas production (c). Despite the enhanced (p < 0.05) true degradability of dry matter, organic matter digestibility, and metabolizable energy content of the composite feeds supplemented with SBP, methanogenesis was comparable (p > 0.05) to that in the control. The supplementation of SBP also enhanced (p < 0.05) volatile fatty acid production and fibrolytic enzyme activities (CMCase and xylanase).DiscussionThis study demonstrates that SBP, a widely available by-product of the sugar industry, could be an advisable choice to enhance the utilization of WS, thereby improving livestock productivity.