In reply to fmck:
> So if you run into one when its dark and the mist seriously reduces your visibility will your insurance have to pay for running into them?
A good test here might be to replace "cow" with "small child". If you ran in to a small child because it was dark and there was poor visibility, it might be suggested that you were running/cycling/driving to fast.
Many hazards - potholes, children, adults, cars etc are smaller than a highland cow. If a cow catches you by surprise you are going far to fast for other hazards.
You don't move faster than you can see.