Macro-nutritional balancing in a circumpolar boreal ruminant under winter conditions

Abstract

<ol> <li>Differences in botanical diet compositions among a large number of moose faecal samples collected during winter correlated with the nutritional differences identified in the same samples (Mantel-r = 0.89, p = 0.001), but the nutritional differences were significantly smaller (p < 0.001).</li> <li>Nutritional geometry revealed that moose mixed Scots pine Pinus sylvestris and Vaccinium spp. as nutritionally complementary foods to reach a nutritional target resembling Salix spp. twigs, and selected for Salix spp. browse (Jacob's D > 0).</li> <li>Available protein (AP) and total non-structural carbohydrates (TNC) were significantly correlated in observed diets but not in hypothetical diets based on food availability.</li> <li>The level of Acetoacetate in moose serum (i.e. ‘starvation’) was weakly negatively associated with digestibility of diets (p = 0.08) and unrelated to increasing AP:TNC and AP:NDF ratios in diets (p > 0.1).</li> <li>Our study is the first to demonstrate complementary feeding in free-ranging moose to attain a nutritional target that has previously been suggested in a feeding trial with captive moose. Our results add support to the hypothesis of nutritional balancing as a driver in the nutritional strategy of moose with implications for both the management of moose and food resources.</li> </ol>