"Be thou increased by this offering" It is said through sacrifice, life is returned to it's divine source regenerating the power or life of their source life is fade by life.
Sacrifice offering of animal is practiced in different religion around the world differently according to their religion and tribe celebrated in a communal way or individual through their own distinct method as ritual. In Hinduism individually as the 'Vakal' for tribute to merci of god or tribal celebration for making happy to their 'Kula Devata' (tribal god) for cleanness of sin, good health, prosperity and peace. They offer blood and beheaded head to deity and take rest to share as Prasad. Behind all the myth fallowed by taboo each time innocent animal get beheaded mercilessly one way or other. Mass slaughter of animal is barbaric and inhuman. And condemned.