"Their performance on the race track determines whether they get to come back here and be a brood mare and be in production," Cline says.
As one of three people on the farm who delivers every foal, Cline see many of them in the first few moments of life. The favorite part of the job for Cline is seeing that weak newborn reach its full potential.
"I love seeing a baby that you knew in its first minutes of life win a big race."
It takes only a couple of months before Cline senses whether a horse will ever cross the finish line first.
"The good ones seem to have a lot of class about them and that shows up pretty early."
On the other hand, Cline admits that there are surprises.
"Occasionally, you get one that comes out of left field and you never would have thought that."
As much credit as he gives to the mother's influence, Cline says that stallions' traits do show up. He says one stallion trait is being a tough customer, which Cline defines as a combination of strong will and speed.
"If you have a certain stallion that is known as a tough customer, then certainly their offspring are known as tough customers."
It doesn't take long for Cline to classify a horse's personality. It may be nervous, curious or strong-willed. His preference is for one that's curious with a tough streak.
"When they come out of the starting gate, they're not saying, 'Oh, my gosh, there's 10 other horses.'"
Shawnee Farm, which is owned by Watts Humphrey, usually has a 20-horse racing stable.
The foals are broken for racing at 17 or 18 months old. The process takes about three months, then they're ready to race as 2-year-olds. They may start at the Florida tracks and work up to Keeneland, then Belmont and Saratoga.
Of the many tracks where the horses race, Cline says one of the best places to witness a win is Keeneland in Lexington.
"If you win a race at Keeneland, you can win anywhere," he says.