DOI: 10.5061/dryad.9zw3r22fh
title: Macronutritional composition of Swedish moose rumen samples collected 2014/15

description: At northern latitudes, large spatial and temporal variation in the
 nutritional composition of available foods poses challenges to wild
 herbivores trying to satisfy their nutrient requirements. Studies
 conducted in mostly captive settings have shown that animals from a
 variety of taxonomic groups deal with this challenge by adjusting the
 amounts and proportions of available food combinations to achieve a target
 nutrient balance. In this study, we used proportions-based nutritional
 geometry to analyse the nutritional composition of rumen samples collected
 in winter from 481 moose (Alces alces) in southern Sweden and examine
 whether free-ranging moose show comparable patterns of nutrient balancing.
 Our main hypothesis was that wild moose actively regulate their rumen
 nutrient composition to offset ecologically imposed variation in the
 nutritional composition of available foods. To test this, we assessed the
 macronutritional composition (protein, carbohydrates, and lipids) of rumen
 contents and commonly eaten foods, including supplementary feed, across
 populations with contrasting winter diets, spanning an area of
 approximately 10 000 km2. Our results suggest that moose balanced the
 macronutrient composition of their rumen, with the rumen contents having
 consistently similar proportional relationship between protein and
 non-structural carbohydrates, despite differences in available (and eaten)
 foods. Furthermore, we found that rumen macronutrient balance was tightly
 related to ingested levels of dietary fiber (cellulose and hemicellulose),
 such that the greater the fiber content, the less protein was present in
 the rumen compared to non-structural carbohydrates. Our results also
 suggest that moose benefit from access to a greater variety of trees,
 shrubs, herbs and grasses, which provides them with a larger nutritional
 space to manoeuvre within. Our findings provide novel theoretical insights
 into a model species for ungulate nutritional ecology, while also
 generating data of direct relevance to wildlife and forest management,
 such as silvicultural or supplementary feeding practices.
description: To obtain information about
 the nutritional composition of foods eaten, fresh rumen samples were
 collected immediately after harvest by filling a 1 litre plastic airtight
 container with rumen content. Hunters were instructed to mix contents and
 take material from throughout the rumen and to remove excess rumen liquid
 by squeezing each handful. Rumen samples were frozen shortly after
 sampling (normally 0.5-1 hour) and stored at -20 ˚C. Rumen samples were
 dried at 60 °C until the samples came to a constant mass, and then ground
 using a hammer mill (KAMAS<sup>©</sup> Slagy 200B; 1 mm
 sieve).   We obtained 481 rumen samples
 (collected between 13-Oct-2014 and 22-Feb-2015), all of which were used in
 our sample-based nutritional analyses (wet chemistry, near infrared
 spectroscopy (NIRS) and right-angle mixture triangles). We used NIRS to
 estimate the concentrations of nutritional constituents of rumen samples,
 with a subset of representative samples also analysed using wet chemistry
 for calibration purposes. For more information about field and laboratory
 procedures, please see the associated article.
description: The Excel file contains one work sheet, on which you find data
 regarding the nutritional composition (and metadata) of moose rumen
 samples (n=481), used in the Right-angled Mixture Triangle in the article.
 The units are displayed in each column heading, as are explanations of
 abbreviations.