Nehro, runner up in the 2011 Kentucky Derby, died of colic Saturday morning.

A 5-year-old son of Mineshaft, Nehro had been showing signs of discomfort in his stall at Churchill Downs earlier in the morning, and his condition “spiraled badly” according to trainer Steve Asmussen. Nehro died en route to a nearby clinic.

“I am deeply saddened,” said owner Ahmed Zayat. “Nehro was my favorite horse whom I had a deep bond with. Everyone who came in contact with this horse loved him. He cannot be replaced, and I’m devastated.”

Joy Gilbert photo courtesy of Spendthrift FarmMalibu Moon

Sitting in the interview room at Churchill Downs on Saturday evening, Ogden Mills "Dinny" Phipps averted his gaze to watch a nearby replay of the 139th Kentucky Derby over and over. Each time, the result was the same—Orb, the homebred colt he owns in partnership with his cousin, Stuart S. Janney III, splashing home in the mud to overpower a strong field of 3-year-olds in America's most famed race.

The replay wasn't getting old, though.

A full field of 20, headed by favored Orb and unbeaten Verrazano, will contest the Grade 1, $2 million Kentucky Derby Saturday at Churchill Downs.

Below is a closer look at the individual pedigrees and backgrounds of this year's entrants, in post position order.

The Kentucky Derby will be the first start at a mile and a quarter for each of the 20 horses expected to enter the gate for Saturday’s race.

With no previous form at the classic distance on which to base an opinion when analyzing the Derby horses, one of the most important factors will be their pedigrees, which can be a telling indicator of who might succeed when stretched out to ten furlongs.

The Kentucky Derby carries a purse of $2 million, but America’s most famous race can pay further dividends for the connections of the winner’s sire.

The stallions represented by Kentucky Derby winners – particularly those early in their stud careers – typically see significant fee increases the following season and can also garner larger books filled with higher-quality mares.

Princess of Sylmar, who ran down last year’s champion juvenile filly Beholder in the final sixteenth to score a 38.80-to-1 upset win in the 139th running of the Kentucky Oaks, is the first Grade 1 winner for second-crop sire Majestic Warrior, an 8-year-old son of A.P. Indy who stands at Coolmore’s Ashford Stud in Versailles, Ky.

Sometimes in horse racing, it's better to be lucky than good.

In the spring of 2009, owner-breeder Ed Stanco's mare Storm Dixie, a winning daughter of Catienus who had been retired the fall before, was on her way to be bred for the first time. After extensive analysis and consulting bloodstock experts, Stanco had selected Grand Slam at Coolmore's Ashford Stud in Versailles, Ky., for Storm Dixie’s first mating. However, with one phone call his plans changed abruptly.

Princess of Sylmar’s upset victory in the Kentucky Oaks added yet another feather to the cap of the Pennsylvania-bred program on a national stage.

The Majestic Warrior filly became the second Pennsylvania-bred to win the Oaks in the past three years, following in the footsteps of Plum Pretty in 2011. Princess of Sylmar is the fourth Oaks winner in the race’s 139-year history to hail from the Keystone State, also joining 1922 winner Startle, and Cream in 1913.

The horses in this year’s Kentucky Derby will be racing for more than just the purse money and a gold trophy. They’ll also be racing to build résumés for their stallion careers and add to the legacies of their sire lines.