Effects of season and agro-ecology on nutritional quality of foliages of multipurpose trees and shrubs: perceptions and measurements for global importance

The productivity of livestock in Ethiopia is low due to scarcity and fluctuating quantity and quality of feed resources. Identify and use of new potential feed resources such as indigenous fodder trees and shrubs (IFTS) could bridge the gap.  The present study was aimed to identify and evaluate agro-ecological and seasonal variations of nutrients as well as to estimate potential biomass yield of IFTS collected from low and mid altitude of Gambella region, south-western of Ethiopia. Lare district was selected from the low altitude area (450-700 metres above sea level, masl) where as Godere was selected for the mid altitude area (800-1500 masl). A cross-sectional study was conducted in three Farmers administrations of each district assumed to represent the existing livestock production system purposely. The potential fodder yield productivity of identified shrubs and trees’ was estimated by measuring stem circumference using measuring tape. The samples of foliages were collected at dry and wet season and analyzed for their nutritional content. All the surveyed data were analyzed using SPSS version 19 and SAS version 9.2.In the mid altitude region, the contribution of IFTS as livestock feed was found to be 23.33 %, cutting and carrying were the existing practice of feeding animals under various productive status. Agro pastoralists of the lower altitude region were persuasively using the foliages of IFTS during the flooding of the grazing lands in rainy season as well as during prolonged drought periods. As perception of all respondents fluctuation of body conditions of animals indicates the feed shortage in seasons. Flooding for lowland and shortage of grazing land for mid altitude were the main cause of feed shortage during wet season. Twenty seven potential IFTS were identified with variant nutrient content and biomass productivity. Trees have high biomass productivity compared to shrubs across seasons and agro-ecologies (P<0.05).The biomass productivity of browses was higher at mid altitude compared to low altitude (P<0.05). Ficus sur and Vernonia amygdalina had the highest biomass yield over trees and shrubs (P<0.05). Higher protein content was observed in fodder trees compared to shrubs (P<0.05). It's revealed in the present study that the browse species had NDF of < 45 % and ADF< 35%, these values are indicating high fodder value of IFTS for supplementing livestock. This study also confirms browse plants have significant potential for complementing the dry and wet season feed shortage.