German Shepherd dog

I understand that progeny groups allow prospective stud users to see the ability of a dog to produce “itself” & prove their worth through their progeny.

However, exactly how are these abilities measured? By this I mean, is it known what percentage of a stud’s total progeny is on show i.e. a dog may have produced 1000 progeny with 20 good ones on show or produced 100 progeny with 20 excellent ones on show.

Also is the bitch of the progeny taken into account? From my, admittedly pretty basic knowledge of genetics & breeding, do not half the genes come from the bitch?

And as a final question for how long can a stud maintain his ability to produce to type, his whole life?

All are pretty big generic questions I’m afraid but these are the sort of things I always think about when taking the hound for a walk & have nobody knowledgeable enough around to ask!

Cheers,

AandA