I'm pretty sure that, in a situation like this, you actually get to shoot the assistant.. State law, I believe..
Seriously, though, I just can't believe this happened.. I'm really, really sorry to hear it..
I know there are people around here who say that you should walk away and call it even because the guy put a lot of work into the cow, but don't forget that he'd have been right there to collect YOUR money had the cow died naturally... It's not like he was doing this as a favor to you -- this was business..
Honestly, it kinda sounds like the guy might be putting the compensation ball in your court as a tactic, versus an altruistic gesture of goodwill.. I learned a long time ago that one of the most effective ways to deal with a PO'd customer was to ask THEM what you could do to rectify a bad situation.. People are far more likely to accept concrete offers of compensation than they are to ask for something -- no matter how bad things got screwed up.. The more apologetic the management is as they ask what they can do, the worse the customer will feel about demanding what's RIGHT...
That way, management looks good in the eyes of other potential customers, as they so genuinely offered to do whatever it took to set things right, and the customer feels like they were offered compensation but "chose" not to take it -- the proverbial high road, as it were...
All I'm saying is, don't fall for it.. Ask this guy to dismiss his fees and write you a check for $.XX/lb, and see how he reacts.. If he's an honest businessman, he'll get out his checkbook.. If he was playing you to begin with, he'll start trying to negotiate.. Only then will you know what kind of person you're dealing with..
Best of luck, and again, I'm SOOOOO sorry this happened to you!!