Ashvin Krushna Dwadashi (Twelth day of the dark fortnight of the Hindu lunar month of Ashvin)
A legend has it that after samudramanthan (churning of the ocean) five kamadhenus (wish-fulfilling cows) were created from it. This vrat is performed to worship the Divine cow Nanda, one amongst them.
For the fulfillment of wishes in this birth as well as in next several births and to get to live in heaven for as many years as the hair on the body of the worshipped cow.
4. Method of celebration
On this day, married women (also known as soubhagyavatis) partake only one meal and worship a cow which has a calf, either in the morning or evening.