This is an interesting article.

http://www.healthytheory.com/corn-fed-vs-grass-fed-beef

Basically, cows are obviously naturally built to eat a grass diet. A corn diet is not natural and causes health problems, which leads to lower quality meat. The same old problem of intensive farming, unfortunately.

Slightly off topic, but what an animal eats really affects the flavour. The best lamb I've ever eaten was Libyan lamb, which grazed on open hillsides covered with wild herbs and the flavour was superb.

Yes it can. I had some basil fed snails the other year and they were very tasty.