From Hindupedia, the Hindu Encyclopedia
By Swami Harshananda
Śulagava is a very ancient sacrifice performed to please Rudra/Śiva when cattle were stricken with pests or diseases. It could be performed during the bright half of a month and on an auspicious nakṣatra.
Though an ox is used for sacrifice in the most ancient period, it was substituted by a goat or even cooked food in the later days due to the repugnance of the people against it. The deity was called īśāna. The rite soon went out of vogue.
- The Concise Encyclopedia of Hinduism, Swami Harshananda, Ram Krishna Math, Bangalore