DRY MATTER YIELD AND NUTRITIVE VALUES OF LOCAL GRASSES USED AS LIVESTOCK FEED IN ADOLA REEDDE DISTRICT OF GUJI ZONE, SOUTHERN OROMIA, ETHIOPIA

Abstract

A study was conducted in Adola Reedde district of Guji zone, to asses and identify the major grass species, evaluate their chemical composition, in vitro digestibility, and estimate the biomass yield of the major grass species. A total of 60 key informants taken from the sample kebeles of three agro- ecologies were interviewed to asses and identify common grasses in their vernacular name. Sample collection was done in the mid of September for three consecutive days. A total of 6 rural kebeles were stratified into highland (dega), mid altitude (woina dega) and lowland (kola) agro-ecologies based on the availability, potential and accessibility of local grass species and the specific sampling areas in the kebeles were identified based on slopes of kebeles. The relative feed value (RFV) and dry matter digestibility (DMD) were calculated using NDF and ADF contents. Spearman’s rank correlation was used to examine relationships between laboratory results and farmers perception on grass quality. A total of 15 common grass species were identified and ranked by farmers according to the species’ preferences to cattle. Cynodon dactylon (L.) Pers), Cenchrus ciliaris, Sporobolus pyramidalis P. Beauv, Heteropogon contortus (L.) Roem & Schult and Chrysopogon aucheri were the top five species identified by farmers. The chemical composition of the grasses significantly (P<0.001) varied between agro-ecology and species. The CP values range from 5.65% for lowland to 11.3% for highland agro-ecology. Cynodon dactylon (L.)Pers has the highest while Heteropogon contortus (L.)Roem & Schult exhibited the lowest CP content. An overall mean value of NDF, ADF and ADL were 66.2%, 45.18%, and 11.23%, respectively, and IVDMD, ME, and RFV were 44.65%, 6.69%, and 60.97%, respectively. Total DM yield and DM of individual grass species were significantly (P<0.001) higher in highland than in the low land agro-ecology. Dry matter yield across agro-ecology ranged from 92.47±0.04 g m-2-119.41±0.07g m-2 for highland and lowland agro-ecology, respectively. The effect of intra location transect position was not significantly different (P>0.05) for DM yield. Generally, the potential of the herbaceous species to be used as feed to ruminant livestock, particularly in semi-arid areas is decreasing and it is aggravated by climate change/variability and global warming. Therefore, rangeland improvement has to be made for conservation of key forage species by use of holistic planned grazing, enclosure, and balancing the number of livestock so as to enhance the potential of grassland and dry matter yield of herbaceous species.