Dear Gowrish,
Your wish to start a dairy farm is appreciable. Mr Ashwini has correctly suggested to surf on NABARD Site where you will find project report on various subject including dairy. Why you are worried if somebody says you are getting only 15% return? How much return do you want? When you are into dairy business, the logic is simple and clear that You are having live stock which needs fodder, water, medicine, attendance etc which is not free. I want to explain very simply that one cow milching duration is 300 days approx. If one cow cost Rs 30,000/- and it gives 10 Ltrs a day and the milk cost per litre is Rs 20/- then for 300 days milk cost is Rs 60,000/-. Deduct amount from this towards attendant, medicine, fodder etc. Your profit for the first year will be helfers of the cow which will become cow after two year. You will be saving approx Rs 10000/- from each cow in a milching period. I hope you have understood the basics now.
Yours sincerely
Kamal Prasad