This research aims to evaluate small local prototype forage chopper machine performance during chopping fodder beet tubers. The independent variables including, four levels of fodder beet tubers moisture content of 81.6, 74.4, 66.2 and 57.9 % (w. b), four levels of cutter head speeds namely 18.8, 21.2, 23.50 and 25.8 m/s, and four levels of feed mechanism speeds of 0.41, 0.79, 1.13 and 1.45 m/min. During the execution of the present experiment the blade holders are inclined at 129° resulting in a cutting angle of the knives of 22°. The test results for modified forage chopper performance found that, the highest percentage of chopping length suitable silage (category of 3 - 6 cm) obtained at cutter head speed of 25.8m/s, feed mechanism speed of 0.41m/min and moisture content of 66.2%. The highest of actual capacity, machine efficiency recorded were 3.512Mg/h and 90.74, respectively. Also, experiment recorded minimum of total losses, unit energy required and total losses cost of 7.65%, 0.849kW.h/Mg and 35.97L.E/h, respectively. Too, minimum of criterion function cost was 140.44L.E/h. Silage was made from the results suit chopping length, it found that the percentage of ammonia does not exceed 8%, the degree of PH was less than three. Also, silage was kept with leaves and legs in good condition. And the most suitable moisture content in the material used to be preserved is 65 - 70% (w. b). Moisture and all these indicators are proof that the silage is good and the interactions are done in a good way.