My niece hit an elk with her GMC heavy half at highway speeds. Even with a grill guard (not sure if it was bolted on or part of the bumper), it did enough damage to move the engine block back and bend the chassis. My point is, despite elk being bigger than deer, damage can still happen even with a grill guard. Beef cows are a danger anywhere in the country so even if the OP doesn't live in elk country, there is still the danger.
Ranch hands are all I am familiar with, but I am sure others are good too.
