Biomass, Botanical Composition and Nutritive Value of Mixed Herbaceous Species of Range Land Co-grazed by Sheep, Goats, Cattle and Camels at Fafen Livestock and Forage Research Station, Somali Region, Ethiopia

Abstract

A study was conducted at Fafen Livestock and Forage Research Station of Somali Region Pastoral and Agro-pastoral Research Institute, Ethiopia to determine forage mass, botanical composition and nutritive value of herbaceous vegetation of a range co-grazed by sheep, goats, cattle and camels. The area is located at an altitude of 1600 m and has an average rain fall of 660 mm. Grazing experiment was conducted on 6 ha of land co-grazed by sheep, goats, cattle and camels. Grazing lasted 16 weeks (November 2019 to February 2020) using 6 growing animals from each species. The range was dominated by species of grasses such as Chloris radiata, Eragrostis ciliaris and Panicum atrosanguineum; forbs such as Asystasia schimperi, Acanthospermum hispidum and Solanum somalensis; and browses such as Lantana camara and Acacia spp. Four enclosures (E) each 25 m2 were made to serve as control. Forage measures were performed from fives areas of grazing and the four enclosures at the start, middle and end of the grazing period. Botanical composition was assessed as the contribution of dominant grass (Chloris radiata), other grasses and forbs. The result of the study revealed that forage mass at the start (2085 vs 2001 kg/ha; SEM= 99.9) and middle (2352 vs 2115 kg/ha; SEM = 80.5) was similar (P > 0.05) between grazing and enclosure areas, while values for grazing area was lower (P < 0.05) at the end (1496 vs 1918 kg/ha; SEM=68.8) of the grazing period. Forage mass at the end of the grazing compared to the start was reduced by 28 and 3% for grazing and enclosure area, respectively. The contribution of Chloris radiata, other grasses and forbs for enclosure area were 44.2, 20.4 and 35.4%, respectively, with no impact of the grazing period (P > 0.05). For grazing area, the contribution of other grasses was unaffected (P > 0.05), while the percentage of forbs decreased by 37% (from 40.5 to 25.5%) and Chloris radiata increased by 31% (from 32.9 to 43.1%) at the end compared to the start (P < 0.05). The chemical composition of herbaceous forages did not differ much between grazing and enclosure area, reflecting less impact of co-grazing on nutritive value. The CP content (9.0, 6.2 and 4.5 % DM; SEM = 0.43) and IVDMD (58, 50, and 47%; SEM = 1.68 for start, middle and end, respectively) decreased (P < 0.05) with advance in grazing period; while the opposite trend was noted for fiber content of forages. The impact of co-grazing on biomass and chemical composition in this study appears to be of not high magnitude. However, the poor chemical composition of the range, coupled with selective feeding of forbs reflects the need for range improvement measures and/or supplementation strategies for improved livestock productivity.