Forage value of Mediterranean deciduous woody fodder species and its implication to management of silvo-pastoral systems for goats

Abstract

Forage value of 10 deciduous woody fodder species during six stages of maturity as well as their acceptance by goats in July and August were studied in Macedonia, northern Greece. The fodder species studies wereAmorpha fruticosa L.,Carpinus orientalis Mill.,Colutea arborescens L.,Corylus avellana L.,Fraxinus ornus L.,Ostrya carpinifolia Scop.,Pyrus amygdaliformis Vill.,Quercus pubescens Willd.,Quercus sessiliflora Salich, andRobinia pseudoacacia L. with two accessions, common and spineless. All these species are integral components of the mediterranean silvo-pastoral systems. Monthly forage samples were collected throughout their growing period (May to November), which coincides with the long dry summer when herbaceous plants are dormant, and analyzed for crude protein content, neutral detergent fiber (NDF), lignin and in vitro organic matter digestibility (IVOMD). Comparing the leguminous species (Robinia pseudoacacia, Amorpha fruticosa, Colutea arborescens) with the remaining species, the leguminous one had on average a higher (P≤0.05) content of crude protein (21.1%, 21.0% and 17.1% vs. 10.5–13.3%, respectively) and higher (P≤0.05) IVOMD values (58.4%, 56.0% and 60.0% vs. 47.3–52.8, respectively). Moreover, the leguminous species were among species with lower NDF (42.3%, 45.0% and 35.2% vs. 36.0–48.9%, respectively) and lignin content (7.1%, 8.3% and 9.1% vs. 7.6–10.9%). All species showed a significant increase in crude protein when new leaves appeared (May). Most of the fodder species had digestibilities in the higher range (>55% IVOMD) and low NDF content (<53.5%) during the growing season (first five stages). Lignin contents ranged from 5.9% (A. fruticosa, May) to 16.0% (O. carpinifolia, Nov.).Robinia pseudoacacia had the highest relative acceptance index whileAmorpha fruticosa, Colutea arborescens andCorylus avellana the lowest. It is concluded that deciduous woody fodder species may play a significant role as sources of nutrients in the mediterranean silvo-pastoral systems during the summer period of seasonal nutritional shortage.