I understand the Bull Shit that gets splattered once the cow hits the ground can be just a bit overpowering, but do remember that you need to have a cheese farm to be able to even use the cows on the trebuchet.
And even then you're impairing your cheese income by doing it - it's a massive negative :S.
get apples to supply you food instead then build up 300-400 bowmen heheheheh