Well I have to say it's an interesting idea. A domestic animal would really work well with the slavery idea, especially if they're driven to find an 'owner'.
The mental transformation does raise concern though, maybe just bringing a few more instincts to notice and a few urges rather than a full 50/50 shift? Oh wait, I just reread and noticed it's only when the collar is worn. The idea of having bit of a furry 'sub mind' is still interesting though.
And I'd gladly pay for it if it was appealing enough to me.