The Garuda Purana indicates that after death a cow needs to be donated on Vaikunta Samaradhana (11th Day after death). There are 16 cities that one has to pass on the way to Yama’s abode. They are Yamya, Souri, Nagendra, Gandharva, Shailagama, Krouncha, Krura, Vichitra, Vahvapada, Duhkada, Nankranda, Sutapta, Roudra, Payovarshana, Shitadhya & Vahubhiti. In between the cities named Vichitra & Vahvapada, the river Vaitarani which is a terrible river made of blood and guarded by fierce flesh eating birds has to be crossed. By donating a cow a boat will be provided to safely cross this river.
In case a person has no children or if there is any uncertainty if Go Daana will be done by family members a person can donate a cow during his/her lifetime itself. There is no need for family members to do any ceremonies.
The method specified in the scriptures is the Cowherd (Go Paalaka) should hold the tip of the cows tail and the person making the donation will need to keep a thulasi leaf on the hand holding the tail and pour a Udharani of water on the thulasi leaf.