Samyutta Nikaya: Lakkhanasamyutta (II-19)
1: Although Theravada Buddhism may not be officially vegetarian, this sutta showing the torment of a being who was formerly a cattle butcher, certain points in that direction. The occupation of butcher was considered “wrong livelihodd” and thus the profession was not at all conducive to the path. One could opine that the being would come to liberation many lifetimes later, once the karma had eventually played out. It does seem a bit sophistic, however.
Other professions besides butcher are mentioned:
Torturer
Horse-trainer
Slanderer
Corrupt magistrate
Adulterer
Hostile Brahmin
Adultress
Fortune-teller
Jealous spouse
Executioner
Evil bhikkhu
Evil bhikkhuni
Novice evil monk
Novice evil nun
[NOTE: some of these aren’t necessarily professions, but just characteristics of individual human beings.]