Feeding of untreated (T2) and 2% urea treated SBS (T3) was evaluated to calculate the feed conversion efficiencies and economics of milk production in cows, in reference to Jowar straw diet (T1). The feed conversion efficiency was found as 46.67, 55.84 and 61.04 % in T1, T2 and T3 groups, respectively. Gross protein efficiency was found comparatively more in T3 group's cows as compared to T1 and T2 groups cows, the values being 32.88, 34.33 and 35.97% and on the other hand net protein efficiency was worked out as 57.65, 59.86 and 60.70% in cows maintained on T1, T2 and T3 groups, respectively. This means, the availability of protein for milk protein secretion was more in T3 group and thereby more protein content in milk. The daily cost of feeding/cow was ` 49.83/-, 37.26/- and 33.19/- under T1, T2 and T3 groups, respectively. However it appears that one could reduce the expenditure on feeding of the cows to the extent of 48.83 and 12.33% by offering 2% urea treated SBS diet over feeding of Jowar straw and untreated SBS diet to cows.