Evaluation of the relative feed value of indigenous savanna forage shrub species in Ghana

Abstract

Animal performance mainly depends on the quantity and quality of forage available as feed and animal feed represents one of the major costs in animal production. This research was conducted in the Faculty of Natural Resources and Environment Experimental Field at University for Development Studies, Nyankpala Campus to evaluate the relative feed value of four indigenous savanna forage shrubs. These shrubs were cultivated and their leaves harvested at 7, 10 and 13 weeks after establishment. Harvested leaves were pulverized to determine ash, crude fat, crude fiber, crude protein, neutral detergent fibre (NDF) and acid detergent fibre (ADF). Metabolisable energy, dry matter (DM), digestible dry matter (DDM), dry matter intake (DMI) and relative feed values (RFV) were also estimated. Ash, crude fat, crude fibre, CP, ADF and NDF contents ranged from 7.56 to 11.22%, 1.924 to 2.812%, 9.33 to 16.11%, 4.598 to 4.960%, 20.73 to 27.22% and 33.47 to 53.06%, respectively. The DDM, DMI and RFV ranged from 67.70 to 74.84%, 2.27 to 3.66% and 120.2 to 212.6%, respectively. The NDF, ADF contents of Tephrosia purpurea was significantly higher than those for Cajanus cajan (L), Stylosanthes mucronata and Securinega virosa (P < 0.05). The DDM and RFV of S. virosa and S. mucronata were significantly higher than those for C. cajan and T. purpurea. The DMI in S. virosa and S. mucronata was significantly higher than those for other shrubs. The carbohydrate contents of S. virosa were significantly higher than the other shrubs. In conclusion all the species studied offered considerable potential as high quality forage for ruminants during the acute periods of the year when the quantity and quality of forages are limited.   Key words: Relative feed value, indigenous shrubs, plant maturity, dry matter, livestock.