The National Cooperative Dairy Federation of India on Monday bought 900 tonne maize in three lots at 1,765-1,851 rupees per 100 kg through an online auction. The commodity, which is used as cattle feed, was bought on behalf of the Kerala Cooperative Milk Marketing Federation. The federation, which has nearly 200 dairy cooperatives as its members, has developed an online trading platform to purchase feed stock and sell dairy products.