Originally Posted by Thoroughbred Fan

Obviously there is a large number of factors which go into this statistic. Some of them include: quality of breeding/boarding farm care, mare's reproductive current health, mare's reproductive history, mare's age, luck, etc...

With the better stallions, the farm can be a little bit more selective about the mares their stallion covers. For instance, I would expect Kingmambo to have a rather high rate of live foal from upcoming crops becasue he has the neck issues and can't cover as many mares. The farm will make sure each cover has the highest possibility of producing a live foal.

Conversely, many regional stallion might be bred to mares that just aren't reproductively healthy or might be older and need more intensive care, which unfortunately they don't get.

Bottom line, is I'm not real sure you can compare apples and oranges. Obviously, the higher the percentage the better.