Reference for Chullin 205:17

אתי איסור אבר חייל אאיסור טרפה

and the other [R'Simeon B'Lakish] holds that it cannot.<span class="x" onmousemove="('comment',' The prohibition of trefah can only come into force after the animal has been slaughtered when the prohibition of the limb of a living animal has gone.');">⁸</span>

Jastrow