the cbg plant will not feasible for 300 buffalo farm and also 200/250 cow farm. The minimum feasible size of the plant will be 500m3 per day which requires 10 Ton cow dung per day. You can calculate with your number of animal required for the project. The cost of the plant will be Rs. 1.00 Crore and you can get purified biogas of 225 kg per day.