Yisehak K., Janssens G.P.J.
Evaluation of nutritive value of leaves of tropical tanniferous trees and shrubs
Livestock Research for Rural Development
Department of Animal Sciences, College of Agriculture and Veterinary Medicine, Jimma University, P. O. Box 307, Jimma, Ethiopia; Laboratory of Animal Nutrition, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium
Yisehak, K., Department of Animal Sciences, College of Agriculture and Veterinary Medicine, Jimma University, P. O. Box 307, Jimma, Ethiopia; Janssens, G.P.J., Laboratory of Animal Nutrition, Faculty of Veterinary Medicine, Ghent University, Heidestraat 19, 9820 Merelbeke, Belgium
This study was conducted to compare the nutritive value of indigenous fodder trees and shrubs (IFTS) and assess the relationship between farmers' IFTS preference, the perception of their characteristics, and analyzed nutritional value at two distinct altitudes within the same area (high altitude and low altitude). Results were based on laboratory analyses of plant samples and a diagnostic survey of randomly selected 360 livestock farmers. Fifty IFTS were identified and examined for proximate and fibre components, in vitro digestibility, digestible nutrients, energy and condensed tannins (CT). Farmers scored the identified IFTS on a scale of 1 to 4 on nutritive value, growth rate, biomass, compatibility and multifunctionality. Nutritive value ranged widely among IFTS from 66 to 242 g CP/kg dry matter (DM), 185 to 502 g neutral detergent fibre (NDF)/kg DM, 0.1 to 228 g CT/kg DM, 478 to 745 g total carbohydrate (CHO)/kg DM, 332 to 963 g total digestible nutrients (TDN)/kg DM and 5 to 15 MJ ME/kg DM. Trees showed higher CP contents than shrubs though CHO was higher for shrubs, especially at high altitude (P<0.05). Farmers' scores for nutritive value were positively correlated with CP content of IFTS (r = 0.36; P<0.05). Even though the association was negative for CHO content (P<0.01; r = -0.32), these scores were higher at high altitude (P<0.05). A negative relationship was observed between CT and TA, CP, DMD, OMD, ME and TDN (P<0.05). It was concluded that although variation within shrubs and within trees was high - CP was higher in trees than in shrubs and lower CHO in trees than shrubs, therefore warranting further research in the added value for ranging ruminants' nutritional status of providing fodder tree material instead of only access to pasture and shrubs. Farmers' perception of nutritive value of IFTS was partly associated with protein content, but other unidentified factors were contributing to their preference. Geographical differences exert shifts in the perceived and analyzed nutritive value of IFTS, thus care should be taken when developing recommendations for the use of IFTS in an entire region.
Fodder trees and shrubs; In vitro digestibility; Nutritive value; Tannin; Total digestible nutrients