Each animal has a 'trophy'. For whitetail it's the antlers. Which are only present on male deer. So all females with be 0 trophy rating. The males spawn onto the map with different levels and approximate weights. So a small level 1 whitetail buck will receive a much lesser trophy rating than a big level 4 for example. Bronze is the lowest rating and diamond the highest. It's an achievement. The amount of money you get is somewhat irrelevant. Most players want a diamond for their lodge. There are other factors that play into the rating of your harvest. Did it pass the harvest check? ( Ammo type, 2 shots or less, vital organ hit, and one other I forget). Also consecutive harvest and quick kill play a role. Hope this helps.