The purpose of this study was to assess the effect of harvest interval on the production and composition of a local variety of cassava, managed as a semi-perennial forage. The experiment, which was conducted in Salao village located approximately 10 km from Pakse. the capital of Champasack province, Lao PDR, started in January and finished in August 2016. Treatments were different harvest intervals (45, 55, 65, 75 and 85 days) arranged in a randomized complete block design (RCBD) with 4 replications. Two harvests were taken for each interval. Content of DM, crude protein (CP) and ash, and protein solubility, were higher in leaves than in petioles of the cassava foliage. Overall, the nutritional value of cassava foliage was increased with increasing harvesting interval. Predicted annual yield of DM and CP increased with a positive curvilinear trend as harvest interval was increased from 45 to 85 days. For the 85 day interval the predicted annual yields of fresh biomass, DM and CP were 43.8, 10.3 and 1.86 t/ha/year, respectively.