I'm just not sure how relevant all of this is, but part of the Kentucky Derby pre race speculation seems to always include when the various horses were actually born, as opposed to their attributed birthday of January 1st. For what it's worth…
Only one of the top 20 contenders for the May 7 Kentucky Derby Presented by Yum! Brands (gr. I) was a January foal, that distinction belonging to Tampa Bay Derby (gr. II) winner Watch Me Go. This year’s Derby elder was foaled in Florida Jan. 23, 2008. Only four of the contenders are February foals. Three of the last seven Derby winners were foaled in February: 2004 winner Smarty Jones
Last year’s winner, WinStar Farm’s homebred Super Saver was foaled March 8.
Of this year’s contenders, two will not have reached their actual third birthday by Derby day. Twice the Appeal was a foaled May 10, 2008 and Mucho Macho Man is the baby of the bunch being a June 15 foal. Mine That Bird, the 50-1 upset winner of the 2009 Derby was not yet 3 when he won, being a May 10 foal.