Dr Ashenafi MengistuDr Belete ShenkuteBirhanu Mamo2024-11-062024-11-062024https://etd.aau.edu.et/handle/123456789/3539The study was conducted in the mixed crop-livestock production system of the Arsi zone to investigate major feed resources, feed intake, and digestibility, estimate enteric methane emission, and predict methane and nitrous oxide emissions from livestock manure. Using multistage purposive sampling, 150 households of the three agroecological areas (lowland, midland, and highland) of the Arsi zone were sampled for one year 2021. Data were collected through discussions with key informants and groups, formal surveys, observations, laboratory analysis, and secondary data and analyzed using SPSS and SAS software. The experimental design of the feeding trail was a crossover design with three treatments and three periods. Descriptive statistics, and chisquare, one-way, and two-way ANOVA tests were used to analyze the data. The mean land allocated for cultivation was 82.08%, 88.447%, and 80.97% for lowland, midland, and highland agro-ecologies respectively, while the remaining proportion of lands was uncultivated and used for grazing. The mean total cattle (7.48±0.2) and equine (1.52±0.1) in TLU showed a significant (P<0.001) different between the highland and other agro-ecologies. The mean total goats (0.9±0.1) in TLU was a significant (P<0.01) different between the lowland and other agro-ecologies. The communal grazing land stover crop DM yield was significant (P<0.001) different between the lowland and other agro-ecologies. The fallow land DM yield was significant (P<0.01) different between midland and other agro- ecologies. The Cereal straw DM yield was significant (P<0.01) different between the highland and other agro-ecologies. Cooperatively, straw (cereals and oil), haulms (pulse), stovers (maize and sorghum), and natural pasture DM yields contributed 96.67 % to the total HH annual feed supply. Total dry matter intake (DMI) was higher (P<0.001) for sheep fed in T2 (706.9 g/day) compared to the rest of the treatments, because the presence of s.sesban leaves and NSC increase the intake. The effects of S. sesban leaves decreased the total DMI. The digestibility of DM, OM and CP were significantly (P<0.01) different between T1 and T2, NDF and ADF were significantly (P<0.05) different between T1 and the rest of treatments. The enteric methane emissions factor (4.73kg CH4 head-1 yeay -1 ) and daily methane production (12.69g CH4 head-1 day-1 ) were significant (P<0.01) different between treatments. The enteric methane emissions factor (5.5kg CH4 head-1 yeay -1 and daily methane production (14.6g CH4 head-1 day-1 ) were significant (P<0.01) different between T3 and the rest of treatments. The estimated enteric methane EF (5.2-61.1kg CH4 head-1 yeay -1 ) of different age groups of cattle were significantly (P<0.01) different between cattle subcategories. The estimated enteric CH4 EF (41.7-40.9kg CH4 head-1 year -1 ) of cattle were significant (P<0.001) different between the lowland agro-ecology and other agro-ecologies. The estimated enteric CH4 EFs (3-6.7kg CH4 head-1 yeay -1 ) of different age groups of sheep were significant (P<0.001) different between the sheep categories. The enteric EF (5.3- 5.1kg CH4 head-1 yeay -1 ) of sheep were significantly (P<0.001) different between the lowland agro-ecology and other agro-ecologies. The estimated enteric CH4 FE (2.6- 6.9kg CH4 head-1 yeay -1 ) of different age groups of goats were significant (P<0.001) different between the goats' subcategories. The enteric CH4 EF (5.7-5.5kg CH4 head-1 yeay -1 ) of goats was significantly P<0.001) different between the three agro-ecologies. Cattle contribute 45.76 % followed by horses (20.01 %), donkeys or mules (11.12 %), goats (6.22%), and sheep (5.78%). From the total population in the study area, cattle share (83.88%) the largest EF CH4 followed by donkeys (4.31%), goats (4.19%), sheep (4.11%), and horses (3.23%). From the agro-ecologies point of view per head of animal, the lowland area took the highest share (33.61%), followed by midland (33.23 %) and highland (33.16 %). The shares of agro-ecologies per total population highland area (43.54 %) share the largest emissions, followed by midland (35.23%) and lowland (21.23%). The estimated CH4 (0.74-4.5kg CH4 head-1 yeay -1 ) emissions from manure handling practices in the study area of different age groups of cattle were significant (P<0.001) different between the cattle subcategories. The estimated CH4 (3.17-3.06kg CH4 head-1 yeay -1 ) emissions from the manure of cattle were significant (P<0.001) different between the lowland agro-ecology and other agro-ecologies. The estimated methane emission factors(0.128-0.141kg CH4 head-1 yeay -1 ) from the manure handling practices of different age groups of sheep were significantly (P<0.001) different between the sheep subcategories. The estimated CH4 emission factors (0.137- 0.129kg CH4 head-1 yeay -1 ) from the manure of different categories of sheep were significant (P<0.001) different between the lowland agro-ecology and the other agroecologies. The estimated methane emission factors (0.09-0.177kg CH4 head-1 yeay -1 ) of different age groups of goats were significant (P<0.001) different between the goats' subcategories. The CH4 emission factors (0.154-0.145kg CH4 head-1 yeay -1 ) from the manure handling practices of goats were significantly (P<0.001) different between the three agro-ecologies. The estimated nitrous oxide (1-10.2g CH4 head-1 yeay -1 ) of different age groups of cattle was significantly (P<0.001) different between the cattle subcategories. The estimated nitrous oxide (7.85-7.7g CH4 head-1 yeay -1 ) of dual-purpose cattle was significantly (P<0.001) different between the lowland agro-ecology and other agro-ecologies. The estimated nitrous oxide (1.14-1.32g CH4 head-1 yeay -1 ) of different age groups of sheep were significant (P<0.001) different between the sheep subcategories. The estimated nitrous oxide (1.23-1.19g CH4 head-1 yeay -1 ) was significant (P<0.001) different between the lowland agro-ecology and other agro-ecologies. The estimated nitrous oxide (1.-1.6g CH4 head-1 yeay -1 ) of different age groups of goats were significant (P<0.001) different between goat subcategories. The estimated nitrous oxide(1.4-1.35g CH4 head-1 yeay -1 ) was significant (P<0.001) different between the lowland agro-ecology and other agro-ecologies. Therefore, produce quality feed supply and proper handling husbandry, improved manure management system and promotion of farm level livestock technologies should be exercised astutely to increase productivity and reduce the GHG emission of the livestock sector.en-USAgro-ecologyDigestibilityFeed intakeLivestock productionMethane emissionNitrous oxide emissionSmallholders.Thesis