Pakistan Journal of Nutrition 10 (11): 1013-1021, 2011 ISBN 1680-5194 © Asian Network for Scientific Information, 2011 Corresponding Author: Takele Feyera, Department of Animal Science, Ambo University, P.O. Box 19, Ambo, Ethiopia 1013 Digestion, Intake and Live Weight Changes of Horro Lambs Fed Vetch (Lathyrus sativus) Haulm Basal Diet Supplemented with Sole Wheat Bran, Acacia albida Leaf Meal or Their Mixture Takele Feyera and Getachew Animut 1 2 Department of Animal Science, Ambo University, P.O. Box 19, Ambo, Ethiopia 1 Haramaya Univesrity, School of Animal and Range Science, P.O. Box 138, Dire Dawa, Ethiopia 2 Abstract: Twenty five yearling male Horro lambs with initial body weights (IBW) of 23.14±2.45 kg (mean±SD) were used to determine effect of supplementation of wheat bran (WB), Acacia albida leaf meal (AA) or their mixture on nutrient digestibility, feed intake and growth performance of yearling Horro lambs fed a basal diet of vetch (Lathyrus sativus) haulm (VH). Animals were blocked into 5 based on IBW and were randomly assigned to treatments. Treatments were ad libitum feeding of VH either without supplement (T1) or with daily supplement of 300 g DM of sole WB (T2), sole AA (T5), or mixture of the two at 2:1 (T3) or 1:2 (T4) ratios of WB:AA. The study had 7 days digestibility and 84 days feeding trial. The VH, WB and AA had crude protein (CP) contents of 6.5, 16.0 and 19.5%, respectively. Supplementation did not impact (P > 0.05) dry matter (DM), neutral detergent fiber and acid detergent fiber digestibility but significant increased (P < 0.05) organic matter and CP digestibility. Intake of the basal diet DM was not affected by supplementation. Intake of total DM and nutrients increased by supplementations. Supplementation also increased average daily gain (ADG), and animals on sole VH diet lost weights of 40.95 g daily while gains of 39.52, 52.86, 42.38 and 28.09 g/day were recorded for T2, T3, T4 and T5, respectively. Among the supplemented treatments, T3 showed higher final weight, total gain and ADG (P < 0.05) than T5, but means for other supplemented groups were similar (P > 0.05). Positive and significant (r=0.82, P < 0.05) correlation was observed between ADG and CP digestibility. This relationship might have caused growth performance differences among treatments. Key words: Acacia albida, digestibility, growth performance, Horro lamb INTRODUCTION In areas where livestock are closely integrated with crop production, crop residues are considered as valuable sources of ruminant feeds. The tendency of increased acreage of cropping land is always at the expenses of decreased available grazing lands, thus boost the importance of straws as animal feed resources. However, crop residues are of generally low in nutritive value and are fibrous having low digestible (<500 g digestible organic matter per kg Dry Matter (DM)) and low Crude Protein (CP) content (<50 g/kg DM) (Emyr, 1994). Nevertheless, pulse crop resides/haulms have relatively better nutritive value than cereal straws but hardly supply animals’ maintenance requirements (De Leeuw, 1997). Thus, supplementation of crop residues with agro- industrial by-products and/or plant protein sources will alleviate CP deficiency in fibrous feeds (Solomon, 2001). FAO (2002) suggested that the urgent need of the farmers for high quality feed for ruminants in developing countries can be achievable through intensive utilization of multipurpose trees and shrubs as they have better nutritional quality nearly equivalent to that of grain based concentrates. According to Shayo (1998), leaves of multipurpose trees are highly digestible; contain high area were 12 and 26 C, respectively. concentration of CP and minerals and low cell wall contents. Among the well known multipurpose tree in Ethiopia, Acacia albida is one potential multipurpose tree capable of producing leaves and pods of high nutritive value. According to Hassan et al. (2007) and NFTA (1997) A. albida is known to produce leaves and pods during dry season when most trees shade their leaves. This important characteristic of the plant is a key attribute that makes A. albida worthy of investigation as feed for ruminants. Therefore, this study was carried out with the objective of investigating the effect of supplemental wheat bran, A. albida leaf meal and their mixtures on digestibility, feed intake and weight gain yearling Horro lambs fed L. sativus haulm basal diet. MATERIALS AND METHODS Study site, feeds, feed preparation and feeding: The study was conducted at Ambo University, Ambo Woreda, Oromia Region, Ethiopia which is located at 115 km West of Addis Ababa. The site is situated at 8 17’N- o 9 56’N latitude and 37 1’E-38 45’E longitude and at mid o o o altitude that ranges from 1,380 to 3,300 meter above sea level. The mean annual rainfall was 1079 mm and the mean minimum and maximum daily temperatures of the o