Comparison of the chemical composition of major feed resources between the midland and lowland agro-ecological zones in the Majang zone of southwest Ethiopia

Abstract

Evaluation of feed chemical composition is essential for predicting nutrient deficiencies and improving feed for optimal livestock productivity. However, variation in agro-ecological zones (AEZs) might affect the chemical composition of feeds. The main objective of this study was to evaluate and compare the chemical composition of major feed resources in the midland and lowland AEZs of the Majang zone in southwest Ethiopia. A total of eight representative samples of feed resources were collected from lowland (Godere district) AEZ (500–1500 m above sea level) and midland (Mangashi district) AEZ (1501–2300 m above sea level). The samples were analysed for dry matter (DM), ash, crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL). The result revealed significant differences (p < 0.05) in the chemical composition traits between the two AEZs in the study area. For example, the DM, ash and NDF contents of C. dactylon were higher (P < 0.05) in the lowland AEZ, while the ADF and ADL contents were higher in the midland; D. abyssinica had higher (P < 0.05) ADF content in the lowland, while Z. mays stover had higher (P < 0.05) DM, ash and ADF contents in the lowland. S. bicolor stover showed higher (P < 0.05) DM, ash, ADF and ADL contents in the lowland, while C. gayana had higher (P < 0.05) ash and CP contents in the lowland and higher (P < 0.05) ADF and ADL contents in the midland AEZ; Atella (a traditional alcohol byproduct) had greater (P < 0.05) ash and ADF contents in the lowland. Regardless of the AEZs, the DM, ash, NDF, ADF, EE, CP and ADL contents of the feed samples varied from 89.97 ± 0.33 % in P. purpureum to 92.50 ± 0.01 in Sorghum bicolor stover, 4.27 ± 0.19 in Atella to 12.37 ± 0.42 in elephant grass, 51.66 ± 0.38 in Atella to 66.10 ± 0.25 in D. abyssinica, 32.21 ± 0.29 in D. abyssinica to 42.58 ± 0.44 in D. abyssinica, 0.63 ± 0.15 in Atella to 2.55 ± 0.03 in C. dactylon, 4.77 ± 0.01 in Zea mays stover to 11.83 ± 0.02 in V. unguiculata and 10.31 ± 0.07 in Z. mays stover to 19.41 ± 0.07 % DM in C. dactylon, respectively. From this study it was concluded that variation in AEZ has a significant effect on chemical composition traits of the feeds in the study area. The results of the study revealed that V. unguiculata stands out as a valuable protein source, while crop residues may require additional protein supplementation to meet livestock requirements in the study area.