You should've seen Ben and I cracking up over videos yesterday because when we read the options our only two were to walk away or try to kill the cow with a knife (or a rock, but that's not even an option...).

We Googled "killing a cow with a knife" just because we wondered if we could even do it and got lots of advice like needing to have the cow totally restrained and maybe even in some kind of stanchion/sling so it couldn't get away and how big of a blade you'd have to use and we started picturing ourselves trying to tackle this giant longhorn so we could saw at it's tough neck with a 6" knife while it...just sat there and let us?

Seems unlikely to succeed, to put it mildly.