Individual Variation of in vitro Dry Matter Digestibility in Moose

Abstract

The in vitro technique for estimating relative digestion rates in ruminants on various forages has created conflicting results in a number of investigations. Some studies show both inter- and intraspecific variation in the ability of inocula to digest the same substrate, while the results of other studies do not verify this potential source of error. This study was designed to compare variation in in vitro dry matter digestibility (IVDMD) using inocula from 8 different moose. Further, samples were taken from 3 different parts of the rumen, cranial sac, ventral sac, and ventral blind sac, in order to look for potential variation in inoculum quality within the rumen. The moose were collected on 3 consecutive days in October 1990. Current year growth of Scots pine (Pinus sylvestris L.) collected immediately before the experiment was used as substrate. The results showed considerable differences between inocula from different animals in digestion of the substrate. Sex or age of inoculum donor did not account for the variability, and site of origin from within the rumen had a significant impact on IVDMD only in 1 animal. A botanical analysis of the rumen contents from the moose showed considerably variation in the proportion of pine and dwarf shrubs (Ericaceae), the main food types consumed. These feeding differences were not reflected in the IVDMD results.