OK now that I have your attention, I'll explain in gristly graphic detail what a Derby is:
A Derby is a mid to late springtime thing. The gestation period for a horse is about eleven months. It's best to have a horse mate and foal in mid to late spring. So that is why a Derby is held in mid to late spring.
People would bring their female horses, they wanted to breed with a prized stallion to a Derby. A stallion is prized most at three years of age. A race would be held to see who's stallion would be prized, more or less.
And after the race a bowler would be prepared for the winners. Here's one being prepared:
Here's one being used:Get your semen here! Get it while it's steaming hot! Get it on a stick!
Gold would be exchanged with the owner of the winner for one of those sticks, a stick with a swab at one end soaked in prized steaming seamen.
Remember the part where I said people do bring a female horse to a derby, this is part where the female horses who were brought to the derby in the first place, begin to be addressed.
In the olden days the semen really did need to be administered while still steaming hot. Now days they use liquid Nitrogen to cryopreserve the semen, to allow for a more genteel setting on the day of the race.
So people don't need to bring their female horses to see the race anymore. But don't you worry about it none, those female horses are still going to get to meet their prized steaming seaman.
The owners of winning stallions are banking on it. So you see a Derby isn't so much race, as it is a stock exchange.