Nutritional quality of Calobota sericea fodders harvested at different phenological stages – opportunities for inclusion in fodder flow programs for extensive livestock farmers

Abstract

Calobota sericea (Thunb.) Boatwr. & B.-E.van Wyk (Fabaceae) is a native legume from the semi-arid rangelands of South Africa. The species has been prioritised as a forage for water-limited agro-ecological areas. No information regarding the nutritional quality of C. sericea forage harvested at different phenological stages is currently available, limiting our knowledge as to the best time to harvest the forage. The aim of this study was to determine the nutritional quality of C. sericea forage harvested at five phenological stages. Results from the study show that crude protein, fibre, energy and digestibility of the forage decreased with plant maturity, but not all mineral nutrients showed the same trend. In general, C. sericea forage harvested at non-reproductive, early flower bud and full flower stages could provide sufficient energy and protein to maintain livestock condition. At these stages, the neutral detergent fibre and digestibility of the harvested materials are also good, indicating that intake and processing of these forage would not be a problem for the livestock. At these phenological stages most of the mineral nutrients were also sufficiently high to meet the minimum requirements of small stock. Thus, C. sericea forage harvested at the appropriate phenological stages could provide a useful source of forage for resource poor farmers.