The only bad thing about buying yearling semen is that it is a gamble as to whether the buck will turn out to be big or not. A lot of nice yearlings never turn out to be much better at 2 or 3 years of age. Sure the pedigree is the same, but what are they wearing on their head, and no one knows if they will really produce.
I used to speculate on yearlings every year, but now the semen prices have gotten to high for the gamble any more. Then you end up with semen that really isn't good enough to use and it just sits there. So I have decided to wait and only buy a buck that has turned out and then just pay the extra cost.
Gene Flees says he doesn't think buying a buck younger than 3 is a good idea. He would rather wait until you see what the buck looks like by age 3.
I don't post all this to start a big debate, just some thoughts.