Reference for Chullin 63:3

פשיטא

according to the Rabbis, the Red Cow is valid<span class="x" onmousemove="('comment',' The Rabbis hold that whatever is done unintentionally or accidentally whilst slaughtering the Red Cow will not affect the validity of the Red Cow, for the slaughterer's mind will not have been taken away from the Red Cow.');">³</span>

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