I noticed that Rav Kapach Tz"l (in his mishna torah) interpreted tzizito in R' Yirmiya's question (ho bfnim ve tzizito bhutz?) as referring to the cohen's long (curly) peios, since, otherwise it's forbidden for cohanim to serve if the hair on their head is long.
Do you think this is the pshat? Or are there any other explanations?
Thanks very much.
It is an interesting suggestion, although it is not necessary. Firstly, the Gemara in Ta'anis 17b tells us that serving in the Mikdash with long hair bears the death penalty, it is not Mechalel Avodah (see commentaries on the first Tosfos in our Perek). Slaughtering while standing outside of the Azarah, on the other hand, is Mechalel Avodah. The Gemara is therefore justified in asking whether the long hair that sticks out of the Azarah disqualifies the Korban in this case. (I later found that the MIKDASH DAVID 2:36:1 makes a similar suggestion.)
Secondly, some people's hair can grow very fast. Although it might be a very uncommon situation, Tosfos in Kesuvos 4b DH Ad proves at length that the Gemara often will address extremely uncommon situations in order to prove a theoretical point.
Note that a similar question to yours may be asked on the Gemara on 19a, "Yatza Sa'aro b'Vigdo," see Rashi and Shitah Mekubetzes #17 there. (The word "Tzitziso" that is used in our Gemara does not lend itself to the interpretation of the Shitah, though.)
Did the Kohanim in fact wear Tzitzis while doing the Avodah? Wouldn't the Tzitzis be an extra Beged? (I am assuming that the Kesones didn't have Tzitzis because it did not have 4 corners, although the Me'eil did (but did not have Tzitzis), but it is a little Dachuk to say that the Gemorah was talking about the Kohen Gadol...)
Excellent point; a Talis Katan would indeed be an extra Beged and it would be prohibited for a Kohen to wear it during Shechitah.
The Acharonim indeed discuss whether or not the Me'il had four corners. The MINCHAS CHINUCH (99:4) points out that according to RASHI on the Torah and the RA'AVAD (Hilchos Klei ha'MIkdash 9:3), it was simply a shirt, but according to the RAMBAM (ibid.) and RAMBAN (Shemos 28:31) it seems to have had four corners. The Minchas Chinuch asks why we do not find it recorded anywhere that it had Tzitzis. He answers that the Bigdei Kehunah did not belong to the Kohanim since they were Hekdesh, and a Beged that does not belong to its wearer it Patur from Tzitzis.
If shechita is keshera be'zar, then would a kohen necessarily have to be wearing bigdei kehuna to do it?
You are indeed correct; it would be permitted for either a Kohen or a Zar to perform Shechitah without Bigdei Kehunah (and with Yitur Begadim). Thanks for the correction!