Kentucky Derby field foaling date and Dosage Index

Last year’s Kentucky Derby (G1) winner, JUSTIFY, who went on to sweep the Triple Crown, fell right in line with a Dosage Index of 3.00 and a foaling date of 3/28. For years, most Derby winners had a Dosage Index below 4.00 as a ratio of speed to stamina in their first four generations of pedigree. This year’s Derby will be run on May 4, so having a foaling date before then means that he is a three-year-old chronologically and a following date after means that he is chronologically a two-year-old. Here are the last 21 winners of the Kentucky Derby listed by year, foaling date and Dosage Index:

YEAR	WINNER	FOAL DATE	DOSAGE INDEX
2018	JUSTIFY	3/28	3.00
2017	ALWAYS DREAMING	2/25	5.00
2016	NYQUIST	3/10	7.00
2015	AMERICAN PHAROAH	2/2	4.33
2014	CALIFORNIA CHROME	2/18	3.29
2013	ORB	2/24	3.21
2012	I'LL HAVE ANOTHER	4/1	2.11
2011	ANIMAL KINGDOM	3/20	1.67
2010	SUPER SAVER	3/18	3.00
2009	MINE THAT BIRD	5/10	4.33
2008	BIG BROWN	4/10	1.67
2007	STREET SENSE	2/23	2.14
2006	BARBARO	4/29	2.41
2005	GIACOMO	2/16	4.33
2004	SMARTY JONES	2/28	3.29
2003	FUNNY CIDE	4/20	1.53
2002	WAR EMBLEM	2/20	3.40
2001	MONARCHOS	2/9	1.40
2000	FUSAICHI PEGASUS	4/12	3.67
1999	CHARISMATIC	3/13	5.22
1998	REAL QUIET	3/7	5.33

As you can see, seven of the 21 winners had Dosage Indexes above 4.00, so that angle seems to be losing relevance. MINE THAT BIRD is the only winner who was foaled in May and he also had a Dosage Index of 4.33. The lesson to be learned here is that if you are going to be an outlier in both categories, make sure you get a big price. This year’s field of 21 with the highest Kentucky Derby eligibility points, in alphabetical order, are as follows:

HORSE	FOAL DATE	DOSAGE INDEX
TACITUS	2/21	3.31
OMAHA BEACH	4/24	2.69
VEKOMA	5/22	2.56
PLUS QUE PARFAIT	3/31	2.47
ROADSTER	4/23	2.60
BY MY STANDARDS	3/22	3.00
MAXIMUM SECURITY	5/14	3.00
GAME WINNER	3/6	2.33
CODE OF HONOR	5/23	0.76
HAIKAL	3/23	3.00
IMPROBABLE	2/11	4.23
WAR OF WILL	4/17	1.72
LONG RANGE TODDY	4/12	4.33
TAX	4/20	1.56
CUTTING HUMOR	4/7	2.11
WIN WIN WIN	3/20	4.50
COUNTRY HOUSE	5/8	2.69
GRAY MAGICIAN	2/16	5.00
SPINOFF	2/18	2.78
MASTER FENCER	2/21	2.50
SIGNALMAN	3/21	3.80

Here, we have three of the top nine horses, and four overall, based on points with foaling dates in May and VEKOMA will still be a two-year-old when the Preakness Stakes (G1) is run on May 18. Four of the 21 contenders have a Dosage Index above 4.00, which is in line with recent pedigree profiles. The top 21 contenders sorted by foal date:

HORSE	FOAL DATE	DOSAGE INDEX
IMPROBABLE	2/11	4.23
GRAY MAGICIAN	2/16	5.00
SPINOFF	2/18	2.78
TACITUS	2/21	3.31
MASTER FENCER	2/21	2.50
GAME WINNER	3/6	2.33
WIN WIN WIN	3/20	4.50
SIGNALMAN	3/21	3.80
BY MY STANDARDS	3/22	3.00
HAIKAL	3/23	3.00
PLUS QUE PARFAIT	3/31	2.47
CUTTING HUMOR	4/7	2.11
LONG RANGE TODDY	4/12	4.33
WAR OF WILL	4/17	1.72
TAX	4/20	1.56
ROADSTER	4/23	2.60
OMAHA BEACH	4/24	2.69
COUNTRY HOUSE	5/8	2.69
MAXIMUM SECURITY	5/14	3.00
VEKOMA	5/22	2.56
CODE OF HONOR	5/23	0.76

Only one winner in the past 21 runnings of the Derby had a May foaling date but this year, we have four with VEKOMA and CODE OF HONOR being highly rated. Of the four contenders who have a high Dosage Index, at least IMPROBABLE and GRAY MAGICIAN were February foals. So if a contender does not have enough stamina in the first four generations of their pedigree, an early foaling date might help them physically develop earlier than normal. PHOTO: Justify wins the 144th Kentucky Derby (G1) at Churchill Downs (c) Coady Photography/Churchill Downs