Parashas Vayikra · Aliyah 1 · Passuk 5
Chabad.org — English translation + Rashi
Torah Temima points to Yoma 27a and the related discussion on Chullin 10b (verified; slaughter by a non-Kohen is valid; from receiving the blood onward is the Kohen’s domain).
E-Daf — Yoma 27a ·
E-Daf — Chullin 10b
Shas PDF Yoma 27a
English: “And he shall slaughter the young of the herd before Hashem, and the sons of Aharon the Kohanim shall bring the blood…” — from the receiving [of the blood] onward is the mitzvah of the priesthood; this teaches that slaughter is valid when performed by a non-Kohen (zar).
Custom (change of subject / grammatical shift) — the switch from singular “he shall slaughter” to plural “the sons of Aharon… shall bring” marks the boundary: slaughter may be done by a non-Kohen; from kabbalah of the blood onward is reserved for Kohanim.
Shechita of a sacrificial animal need not be performed by a Kohen. From the moment the blood is received in a vessel, the avodah belongs to the Kohanim.