Technical Note: Effect of substrate drying method on in vitro dry matter disappearance in moose

Abstract

One identified potential source of error in nutritional evaluations using the in vitro technique is the drying method used on test substrates. This study was conducted to determine what effect, if any, different drying methods have on the dry matter disappearance of 4 browse species in moose (Alces alces L.) inoculum. Browse species were Scots pine (Pinus sylvestris L.), birch (Betula pendula Roth, Betula pubescens Ehrh.), willow (Salix spp.), and sweetgale (Myrica gale L.). In addition, we determined the effects of drying method on neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) concentration of the browse species. Each species was either freeze-dried (-40 degrees C) or oven-dried at 35 degrees, 60 degrees and 105 degrees C, respectively. High drying temperatures significantly depressed (P<0.0001) in vitro dry matter disappearance (WDMD) in all browse species tested except of Scats pine. High temperatures also reduced NDF (P<0.05) in all the species, while ADF and ADL were elevated (P<0.05) in all specks except Scats pine. We conclude that freeze-drying is the most preferable method to be used on forage and browse samples being evaluated for nutritional quality.