The sacred Mantras, Svaha and Vashat, are always established upon kine. Kine are the chief conductresses of Sacrifices. They form the mouth of Sacrifice.
स्वाहाकारवषट्कारौ गोषु नित्यं प्रतिष्ठितौ। गावो यज्ञस्य नेत्र्यो वै तथा यज्ञस्य ता मुखम्॥