The 2018 Kentucky Derby field by foal date and dosage index

by Dick Powell

Since the last time I looked at prospective Kentucky Derby (G1) starters, 11 of them have defected for one reason or another. So, with the Derby fast approaching and the field of 20 starting to solidify, it’s time to take another look at the field.

For historical purposes, here are the last 20 runnings of the Kentucky Derby listed by year, winner, foaling date and dosage index:

FOALING DOSAGE

Clearly, MINE THAT BIRD is the outlier with a May foaling date and high dosage index. The other winners that had Dosage Indexes above 4.00 all had relatively early foal dates.

This year’s field of 21 most logical qualifiers, in alphabetical order, are as follows:

FOALING DOSAGE

When I sort them by foaling date, a different picture appears:

FOALING DOSAGE

So, five of the 21 leading contenders for the Kentucky Derby were born in May while history shows only one winner in the last 20 years was born in May. Another way of looking at foaling dates is that four of the past five Derby winners were foaled in February and the other one was March 10.

PROMISES FULFILLED, with a May 11 foaling date and a Dosage Index of 9.00, looks like this year’s version of MINE THAT BIRD. And like MINE THAT BIRD, you better get 50-1 odds if you bet PROMISES FULFILLED.

MAGNUM MOON has a May 9 foaling date and did not begin his career until four months ago.

MENDELSSOHN has a May 17 foaling date and will not even become a three until Preakness Stakes (G1) Day, but he started five times last year and his seven career starts are at least more than 15 other prospective starters.

AUDIBLE has a high dosage index of 5.00 but, like the last three Derby winners that also did, he has a relatively early foaling date.

I didn’t bother sorting by Dosage Index since only AUDIBLE, PROMISES FULFILLED and FIRENZE FIRE are above 4.00. Since five of the last 20 Kentucky Derby winners had dosage indexes above 4.00, it’s not the definitive cut-off that it used to be and the last three winners were over 4.00. It is still a good barometer of speed versus stamina in a horse’s pedigree but not as reliable as it once was for this specific race.