Global warming, or agricultural practices?

Mark sent me this; researchers are claiming that global warming will end the practice of eating haggis because warmer temperatures make a better climate for lungworms that effect sheep. Now it may be that warmer weather (not necessarily linked to human action) may make a better climate for lungworms, but there are two big weaknesses with the theory.

First of all, the article concedes that a large contributor to the epidemic of lungworm is the fact that farmers are no longer treating all sheep for this parasite--just as the failure of parents to vaccinate is leading to outbreaks of childhood diseases, the failure of farmers to treat their stock is going to lead to outbreaks, no?

Second, what of the reality that farmers worldwide are trying to squeeze the "last bit of blood out of the turnip"? That is, is this an issue with climate (Scotland has rarely had consistent harsh winters to begin with), or is this an issue with how sheep are raised today?

I'm guessing the latter.