From Prof DN Jha’s ‘The Myth of the Holy Cow’, “...later Vedic texts provide detailed descriptions of sacrifices and frequently refer to ritual cattle slaughter. The Gopatha Brahmana alone mentions twenty one yajnas, though all of them may not have involved animal killing. A bull (vrshabha) was sacrificed to Indra, a dappled cow to the Maruts and a copper coloured cow to the Asvins. A cow was also sacrificed to Mitra and Varuna. In most public sacrifices, (the asvamedha, rajasuya, and vajapeya) flesh of various types of animals, especially that of the cow/ox/bull, was required…The agnyadheya, which was a preparatory rite preceding all public sacrifices, required a cow to be killed and the adhvaryu priest is said to have ‘put apart... on the red hide of a bull... four dishfuls of rice’. In the ashvamedha (horse sacrifice) the most important of the Vedic public sacrifices, first referred to in the Rigveda, and discussed in the Brahmanas, more than 600 animals (including wild boars) and birds were killed and its finale was marked by the sacrifice of 21 sterile cows, though the Taittirya Samhita (V.6 11-20) enumerates 180 animals, including horses, bulls, cows, deer and nilgai to be killed. The gosava (cow sacrifice), was an important component of the rajasuya and vajapeya sacrifices. In the latter, the Satapatha Brahmana tells us, a sterile spotted cow was offered to the Maruts. Similarly, in the agnistoma, a sterile cow was sacrificed. According to the Taittiriya Brahmana, an important element in the panchasaradiyasava (darsapunamasa) was the ‘immolation’ of seventeen ‘dwarf heifers under three’ and on the day preceding the sacrifice, the sacrificer was himself required to eat forest plants or fruits. The killing of animals, including cattle (pasu) figures in several other yajnas including chaturmasya, sautramani and independent cattle sacrifice called pasubandha or nirudhapasubandha, which also an important component of many sacrifices.”