The study used programming methods to assess the farm-level impact of incorporating forages, including dual purpose Cajanus cajan (C. cajan), into the crop-livestock system in the Coastal Savannah Zone of Ghana. The system was modeled in GAMS and solved using linear programming. The optimal enterprise mixes and their resultant net revenues with and without the interventions and therefore the change in net revenue were obtained. The intervention was to grow forages as part of the crop-livestock system and feed them to milking cows and their calves for increased milk production and growth. The grain of the forage was used as food by the farmers, and manure from the animals was also used for crop production. The effect of policy options like educating farmers to accept and use C. cajan grain as food and thereby increase its production was analysed. The change in net revenue with incorporation of C. cajan into the system was 50 percent. A 5 percentage points change in the inclusion level of C. cajan grain in farmers’ diet and subsequent increase in its cultivation precipitated a 4 percent change in net revenue. C. cajan was not produced beyond the level required for household consumption and its main attraction seemed to be its food value. The addition of C. cajan into the crop-livestock system of the area improved farmers’ incomes. Increased cultivation of C. cajan may be dependent on the food value of the crop for the household.