Effect of Maturity at Harvest on Chemical Composition, Tannin Concentration, Digestibility and Yield of Velvetbean (Mucuna pruriens)

Velvetbean is a relatively cheap source of supplemental protein for ruminants fed low quality forages. However, there is little published information on the maturity stages at which the nutritive value of velvetbean is optimized. This study evaluated the chemical composition, tannin concentration and digestibility of velvetbean harvested at 77, 90, 110, and 123 DAP at the BRU. Dry matter, NDF, ADF, and lignin concentration increased (P<0.001) with maturity but CP concentration did not. The CP concentration of velvetbean ranged from 13 to 16% and that of leaves was 9 to 26%, stems 8 to 13% and pods 10 to 20%. Total tannin concentration was highest (P<0.001) at 110 DAP (6%) followed by 123 DAP, and samples harvested at 90 DAP had the lowest concentration (3%). Pods had the highest tannin concentration (9%). In conclusion, velvetbean should be harvested at approximately110 DAP to optimize nutritive value and yield.