1. On Bava Kama 24B: the person attacked by a man's dog which was encited by another person may say to the owner of the dog: "You know your dog is encitable! You should not have left him."
How is the owner to know his dog is encitable? It must be a MUAD Dog! But in other cases the owner pays half the damages? - or no damages at all, as he can say "What have I done to you"?
2. Secondly: If we compare the dog to a bull - why is this not to be compared to the Shor HaItstadyon, [Chapter 4 Mishna 4] which was provoked, but in this case NOT with the owner's consent, and therefore the owner should be exempt! [It would seem there that the bull is exempt from death but not the owner from damages - if it was done with his consent - but without the owner's consent why should the owner be liable?]
3. Third: the claim of the victim is quoted as ["Lo Ibaya Lach L'ashuyei" - which probably means "left him alive", in other words this is in accordance with Rabbi Eliezer who says there is no guarding a MUAD except by slaughtering it!
So is this the Halacha - according to Rabbi Eliezer?
1. An excitable dog is not a Mu'ad, for he generally does not attack. However, the owner still knows that his dog gets upset under certain specific circumstances.
2. See Tosefos. There is provocation and there is PROVOCATION.
3. "L'Ashuyei" means left alone, not left alive.