The Suitability of Willow Trees as Animal Forage and their Application in Zoological Institutions

Abstract

In zoos, browse is fed to a range of animals. While browse is quantified by weight, different species select different tree components for food. This study classifies the composition of five Salix cultivars, analyzes leaf, bark, and twig for their nutritional constituents, and uses a rabbit feeding model to assess impact of leaf and bark on physiological responses. Allometric equations quantified cultivar composition using branch diameter and weight measures. Leaf, bark, and twig analysis varied between cultivars in CP, ADF, NDF, Ca, P, Fe, and Zn. Growing New Zealand x Californian male rabbits ate willow leaf and bark well, gaining weight at an acceptable rate (TL: 28 ± 6,TB: 25 ± 6 g/day). Blood markers indicated that willow did not have any negative effects on health, and no significant effect for the inflammatory markers tested. Willow leaf and bark are considered safe and palatable as browse in a rabbit model.