A factorial experiment (5*3) with three replications was conducted to assess the effects of three harvesting intervals on growth, productivity and nutrition of five Cenchrus ciliaris ecotypes. Ecotypes Ologoraing’ok namelock (On), Ologoraing’ok twanga (Ot), Nzingangata (Nz), Orupilipili (Op) and Iramata mtandika (Im) were harvested at 21 (T1), 28 (T2), and 35 (T3) days. Plant height (PH), tiller number (TNT), and leaf area (LA) measured forage growth; herbage was oven dried to determine productivity. In vitro two-stage method was applied to determine dry matter digestibility (IVDMD), Ankom technology to analyse neutral detergent fibre (NDF) and acid detergent fibre (ADF). A combined analysis of variance revealed a significant effect (p<0.05) of harvesting interval on forage growth, productivity, and nutritional attributes. Long harvesting interval reduced nutritional quality but increased PH and LA. Harvesting at T2 had highest productivity. Ecotype with highest PH, LA, and productivity was Op, highest nutritional attributes were recorded on ecotype On. Cumulative productivity ranged from 8251 kgDMha-1 (T1) to 18149 kgDMha-1 (T2). Therefore, it is concluded that long harvesting intervals reduce nutrition but increase growth and productivity attributes of the five ecotypes. From the results, ecotypes Op and On are recommended in areas with similar environmental conditions to Magadu.

Keywords: Cenchrus ciliaris, digestibility, fibre content, management, Tanzania.