Thoroughbred birthdays along the Road to the Kentucky Derby…

Oct 20, 2017 Jennifer Caldwell/

…lead through the dark winter months. More specifically, January 1.

Every registered Thoroughbred in the Northern Hemisphere shares that birth day.

The. Same. Exact. Birth. Day.

How is that possible?

Not because every foal is born on the same day, that’s for sure. No, January 1 is the official birthday for all registered Thoroughbreds. Helps keep things simple in determining where and when a horse will race, whether it be against rivals of the same age or older foes.

Unfortunately, that doesn’t exactly mesh with the natural reproductive cycle of the equine. Mares are ready for breeding in late spring/early summer, giving them an entire summer worth of green grass to fuel up and nurture a tiny embryo into a full-fledged foal.

It also means, with their 11-month gestation period, that the foals are born anywhere from May to October. That doesn’t work with the January 1 birthday.

If a foal is born before that day, he is automatically considered a one-year old, even if technically he’s only two days old. Obviously, that puts him way behind his peers.

For farms to get a mare to pop out a foal on or soon after New Year’s Day they must breed her in mid-February or as close to that date as possible.

The problem is that the equine reproductive cycle, in both mares and stallions, is governed by light, and the shorter daylight hours of winter will send it into shutdown mode.

Different methods are used to ramp it back up, but the most popular and widely used practice is artificial light.

The mare is exposed to around 16 hours of artificial light, with the bulbs firing up for about two to three hours after dusk, to get her cycling again. She’s kept under these conditions for 60-90 days, and voila, she’s ready to visit her suitor.

Eleven months later, a future Kentucky Derby winner is born and, only a few hours after birth, is already stretching his legs in preparation for the first Saturday in May three years into the future.

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