Food selection by European roe deer (Capreolus capreolus): effects of plant chemistry, and consequences for the nutritional value of their diets

Abstract

With 2 figures in the text)We describe food selection by roe deer (Cuprealus capreolus) in relation to the food quality of the plants available (the concentrations of fibres, sugars, crude protein, and of phenolics and terpenes). Seven tame roe deer feeding in an oak-beech woodland edge used the majority (SO-94%) of the plant species available: they were therefore generalist feeders. However, they preferred only a small number of plant species in the different seasons: ivy (Hederu helix) in winter and autumn, dogwood (Cornus spp.) in summer, hornbeam (Curpinus befulus), hawthorn (Crutuegus spp.) and bluebells (Hyacinthoides non-scriptu) in spring. No preference or avoidance could be demonstrated for 74-85% of the available species, but 7-12 species were avoided according to the season. Though the avoided species were sometimes common, they never comprised an important part of the diet. In contrast, the preferred species made up only 4-13% of the available green matter but composed a large part of the diet (22-49%). Although generalists, the roe deer were therefore also highly selective feeders. The use of the different plant species was influenced by their availability, but to a different extent in the different seasons. Use of the plant species correlated negatively with the fibre content, as predicted from the digestive morphology of this concentrate selector. Preference/avoidance was related to the concentrations of soluble sugars, but not the crude protein content. Contrary to expectation, the roe deer preferred plants with a high concentration of protein-binding phenolics, suggesting that this deer has specific mechanisms for de-activating these compounds. Among the nutritional consequences of the feeding strategy of roe were a 17-35% higher soluble sugar content of the diet compared with the available green plant tissues, and an even greater increase in the phenolics. The crude protein contents and the dry matter digestibility of the diets tended to be slightly higher, and the fibre contents were lower, than those of the available green plant tissues.

Selection for nutrients by red deer hinds feeding on a mixed forest edge

“…The measurements of nutritional characteristics of the available plants that we obtained showed roughly similar patterns between seasons for the diVerent plant categories to those found in a deciduous forest in western France (Tixier et al 1997) and in oak woodland of Northwest Spain (GonzalezHernandez and Silva-Pando 1999). The main particularity of the observed diets in our site was the high quality in winter when deer obtained diets containing 15% DM of crude protein versus only 9.2% DM for the wapiti (Cervus elaphus roosevelti) in Washington State (Leslie et al 1984) and 6.6% DM for red deer in the Nertherlands (Van de Veen 1979).…”

“…This was true across all seasons, suggesting a strong selection for readily digestible soluble sugars. Preferences positively related to soluble sugar concentrations have also been found in another cervid, the roe deer (Capreolus capreolus) in summer and autumn (Tixier et al 1997). Soluble sugars have been shown to be preferred in other herbivores too (grey kangaroo Macropus fuliginosus: Parsons et al 2006;pigtail macaque Macaca nemestrina: Laska 2001).…”

Local habitat and landscape affect Ixodes ricinus tick abundances in forests on poor, sandy soils

“…Although roe deer are considered generalist herbivores, they are highly selective feeders, preferentially feeding on deciduous browse, fruits, and seeds (Tixier and Duncan, 1996). Especially in spring and summer, when female roe deer invest heavily in the care for their offspring (Andersen et al, 1998), coniferous browse is shunned whereas easily digestible forage rich in soluble carbohydrates (e.g., forbs and deciduous browse) is preferred (Cornelis et al, 1999;Tixier et al, 1997). Oak browse is considered highly palatable and acorns can make up a large part of the roe deer diet when they are sufficiently available (e.g., 89 % in a mast year, Maillard and Picard, 1987).…”

Value Addition of Feed and Fodder by Alleviating the Antinutritional Effects of Tannins

“…The addition of maize grain to browse leaves may have increased the weight gain of sheep either by balancing energy and protein requirements or by supplying energy for the detoxification process [219]. This hypothesis is also supported by observations that European roe deer (Capreolus capreolus) selected diets containing high concentrations of low molecular weight phenolics, tannins and soluble sugars [207]. A good source of energy is likely to assist in the detoxification of some tannins, low molecular weight phenolics or their metabolites.…”