The mother of a buck actually has more to do with its first rack than does the father so just because a buck has good genetics doesnt mean its offspring necessarily will too. Secondly, just as does produce the highest number of fawns when they are 2.5, 3.5 and 4.5 bucks tend to produce more viable sperm when they are in their prime. Yes the genetics of a buck are the same when they are older but bucks over the age of 7.5 are less likely to successfully breed a doe. Also, older bucks have a much higher chance of dying with each passed year and begin to get pushed around by bucks in their prime which do the most breeding. So it isnt as much that you want to get the genes out of the herd, but more that you want to take that given buck out of the herd because he doesnt have as much of a purpose anymore

Idk what I was thinking earlier when i put that 42% sorry