Prof. Berhan TamirDr. Getu KitawKedir Mohammed2023-12-122023-12-122021http://etd.aau.edu.et/handle/123456789/772The study was carried out at Holetta Agricultural Research Center to evaluate the effects of urea-molasses, urea-lime and effective micro-organisms treatments on wheat straw quality parameters, and feed intake and apparent digestibility, growth performance and total feed cost of crossbred calves (3/4 Friesian X Borana). A completely randomized design was used for the laboratory trial. The randomized complete block design was employed to conduct the feeding and digestibility trial for over a total period of 104 experimental days. The dietary treatments were: - untreated wheat straw (T1), wheat straw treated with urea-molasses (T2), Urea-lime (T3) and activated effective micro-organism (T4). The result from the laboratory trial indicated that treatment options affected (P<0.05) the proximate, detergent and in vitro digestibility fractions with the highest crude protein (CP%) content being recorded for (T2 = 6.31%) followed by (T3 =4.88%). The values of NDF and ADF were reduced by effective microbial and urea-molasses treatment options. The highest (P<0.001) daily DM intake were recorded for calves that were receiving dietary T3 (3.7 kg/head) and T4 (3.5 kg/head) than those receiving T2 (3.1 kg/head) and the control diet T1 (3.02 kg/head). Apparent dry matter and nutrient digestibility of the experimental calves fed treated straw were found to be highest (P<0.01) when compared to calves that were maintained on the control diet. Average daily gain of calves was significantly highest (p<0.001) for calves in T3 (422.7 g/d) and T4 (391 g/d) groups than those in T2 (281.7 g/d) and T1 (204.3 g/d) groups. Feed conversion ratios was observed to be higher (P<0.01) for calves in T3 (8.8 g feed/ each g gained) and T4 (9.4 g feed /each g gained) groups than those on the control diets (15.1 g feed /each g gained). The total feed cost of calves maintained on the treated straw-based diets was significantly (p<0.001) higher than those on the control diet. The ratio of total feed cost to the live weight gain of calves were significant (P<0.05) higher for T1 (110.8 birr/each kg gained) and T2 (109.6 birr/each kg gained) as compared to T4 (82.5 birr/each kg gained) and T3 (76.7 birr/each kg gained). Hence, it could be concluded that treating wheat straw using urea-molasses, urea-lime and EM could improve its nutritional values, improve growth performance cost-effectively when fed to crossbreed calves with concentrate supplemented at the rate of 1.2% of the calves’ fortnightly weight changes. However, to draw valid conclusion further research needs to conduct to identify the optimum level of lime in the urea-lime combinations used for the crop residues treatment.enCrossbred calvesstraw treatmentfeed intakeapparent digestibilityWheat strawlive weightThesis