Pedigree Basics: Terminology
Level: Intermediate
By Valerie Grash, Hello Race Fans Contributing Editor

Of all the angles a handicapper must study, pedigree analysis is perhaps one of the most difficult, but don’t be intimidated. A little basic knowledge can be very effective, particularly when betting on races for 2-year-olds, first-time starters or horses making a surface change.

A good racehorse is as much a product of its breeding as it is of its environment, upbringing and training regimen (not to mention just pure luck). The unique physical features it inherits from its sire (father) and dam (mother) predispose it to run certain distances, over specific surfaces and, most importantly, fast or slow. Training can certainly enhance (or hinder) such predispositions, but it always comes back to breeding.

So, how do you begin studying pedigrees? First, let’s start with the basic terminology, using 2007 Kentucky Oaks and Belmont Stakes winner Rags to Riches as an example.

Rags to Riches Pedigree

Born in 2004, Rags to Riches is the progeny (offspring) of Belmont Stakes and Breeders’ Cup Classic winner A.P. Indy and Grade 1 Acorn Stakes runner-up Better Than Honour. In breeder-speak, a foal is always “by” a stallion and “out” of a mare, thus Rags to Riches is by A.P. Indy out of Better Than Honour. Her dam’s sire (specifically called damsire) is 1981 Canadian Horse of the Year Deputy Minister. The equivalent to the human term “grandmother” is only carried down through the damline, not through her sire, so Blush With Pride (by Blushing Groom out of the Traffic Judge mare Best in Show) would be considered Rags to Riches’ second dam; Best in Show would be her third dam, Stolen Hour would be her fourth dam and so on.

Better Than Honour is a black-type producer, meaning that she has given birth to several stakes winners, including Belmont Stakes winner Jazil, Peter Pan Stakes winner Casino Drive and Breeders’ Cup Marathon winner Man of Iron. Because they share a dam but are by different sires, Jazil and Man of Iron are considered half-brothers to Rags to Riches. Because Casino Drive’s sire Mineshaft is a son of A.P. Indy, he is considered a three-quarter brother to Rags to Riches. Horses that share the same father but different dams are not technically considered siblings, however.

Looking at the pedigree chart above, you’ll notice that the stallions Bold Ruler and Nasrullah appear twice each in Rags to Riches’ bloodline. This is called inbreeding, and so you will hear that Rags to Riches is inbred 5 x 4 to Bold Ruler and 5 x 5 to Nasrullah–the 4’s and 5’s refer to the number of generations back, and should always be read from top to bottom as the pedigree is laid out.

Pedigree Query is the most accessible online source for studying a horse’s pedigree, but it is nowhere near complete since it relies on its users to add and update information on each horse. However, you would be hard pressed to find a more useful source, as you can also view information under “Reports” about a mare’s progeny and their individual race records. In some instances, when a horse has been sold at auction, you can find more comprehensive pedigree records in catalogs on auction websites such as Keeneland, Ocala Breeders’ Sales Company, and Fasig-Tipton. Similar pedigree and racing information can be found for horses racing in Europe at Racing Post and in Australia and New Zealand at Racing and Sports.

So, now that you know the terminology and where to do research, what does it all mean? I thought it would be a good idea to go straight to an expert to find out. Sid Fernando is the president of and Werk Thoroughbred Consultants, Inc., a former bloodstock editor and columnist at the Daily Racing Form who now writes a must-read blog for those interested in international racing and breeding at Sid Fernando + Observations, as well as the pedigree blog Who’s Hot, Who’s Not.

Q: It may sound simplistic, but like human beings, do sires and dams pass down specific genes to their offspring that affect particular areas of physical development such as color, height, bone structure, and muscularity?

A: Sure. The two main colors are bay/brown and chestnut, and chestnut is a recessive gene, which means that you need a recessive chestnut gene from each parent to get a chestnut color. There are stallions, for example, that are dominant bays—they do not carry a chestnut gene—and their offspring are always bays. Seattle Slew and Danzig were examples of dominant bays. Grays, however, are possible at any time when these genes combine.

Size, bone, and muscle mass are all inheritable qualities, as they are in humans.

Q: In general, is there a correlation between the size of horses and how far or fast they can or cannot run? For instance, do taller horses run better than shorter horses over longer distances while shorter horses perform better in sprints? What about big-boned horses over those with more delicate frames?

A: No real correlation between size and speed and distance. However, lighter-made horses do appear to race better on turf and over distances, and sprinters do tend towards more mass, just as in humans.

Q: Is the sire more important than, or equally important to, the dam’s bloodline in considering distance capabilities and how a horse might perform on a particular surface? For example, if the sire excelled at sprinting and the dam’s family is rich in stamina, would the offspring be a sprinter like dad or would the dam’s influence help it stretch out? What about vice versa: If the sire’s a router, but the dam is pure sprint speed? Could the sire’s influence produce a horse with stamina–or is it all a crapshoot?

A: It really depends on the stallions and mares in question. There are certain sires, Dynaformer, for example, that sire distance horses, usually on turf; and there are mares from families that have been cultivated for classic distances, such as the mares in the Aga Khan broodmare band. Then there are stallions, such as Carson City , who were better suited for speed on dirt, and there are mares and families that are more speed-oriented. Usually, breeders tend to breed like to like, or in gentle deviations, instead of sprinter to extreme stayer, or vice versa. When they do, it’s called “fish and fowl” mating. In a fish and fowl mating, it’s difficult to predict what you might get. However, take a look at the most famous example of combining Dynaformer with a Carson City mare—the tragic Derby hero Barbaro. He was promising on turf, was switched to dirt and won the Derby . His Carson City dam is a full sister to the stakes-winning sprinter Lucky Lavendar Gal—who won each of her seven races at sprint distances like a typical Carson City . But Barbaro’s dam, the sister to Lucky Lavendar Gal named La Ville Rouge, was a winner at sprints on dirt, won on turf over a route and also was Grade 1-placed in a turf race over a distance of ground. She proved to be a perfect mate for Dynaformer.

Q: How far back into a horse’s pedigree should one study in order to better understand whether or not the horse can perform on certain surfaces or at various distances? Do certain genetic traits change or die out after the passing of so many generations?

A: Four or five generations is sufficient.

Q: When you hear the term “back class” in a pedigree, what exactly does that mean?

A: That refers to stakes producers in the direct line of female descent a few generations back from the horse in question.

Q: Could you recommend any good books that are must-reads for anyone just beginning to explore pedigrees and bloodlines? What are the classic sources, and which ones present more recent ground-breaking theories?

A: Frank Mitchell’s book on breeding theories, Racehorse Breeding Theories is a good starting point. Another great book with historical background is Abe Hewitt’s The great breeders and their methods.

Q: Do you have any other advice for people just starting with pedigree handicapping?

A: Watch for sires whose progeny perform well on turf and off-tracks. Also look for speed sires and early 2-year-old sires when handicapping early maiden races, and look for turf and distance sires, for example, when looking at distance races on the turf.

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  • RAGS TO RICHES (USA) ch. M, 2004 {8-f} DP = 8-11-19-0-0 (38) DI = 3.00 CD = 0.71 – 7 Starts, 5 Wins, 1 Places, 0 Shows Career Earnings: $1,342,528

    In the example above, could you tell me what the [8-f] after 2004 stands for and I have another example that has [5-h] in the same area, what would that stand for?

    Thanks in advance

  • Great question, Jim! These number-letter combinations refer to the family from which the horse is genetically descended through their damline. I’m not sure I can define it any better than they do here:

    The relevant passage:
    “Female family numbers are calculated by looking down the tail female pedigree (dam’s, dam, dam, etc) as far back as it goes. Most modern thoroughbred can trace tail female to one of 43 mares that founded the breed. At the end of the 19th century, a man named Bruce Lowe categorized each of these families and gave the one that produced the most stakes winners the number 1, second most stakes winning family got the number 2, etc. Research later extended this to 73 families and in the 1950’s Bobinski updated the family tables and separated each of Bruce Lowe’s families into sub categories (family 1 was splint into 1-a, 1-b, etc). There are roughly 200 branches or sub families that are recognized today.”

    “Family numbers are used mostly today to check the accuracy of pedigrees and to classify particularly strong female influences. Some people consider some families to be “sire” families and others to be “broodmare” families. For instance, family 8 is a sire family responsible for producing a lot of good sires and male race horses and they’d like to see colts produced from that family rather than fillies. For instance, a mare tracing to family 1-x will always be tail female to La Troienne which is a really good female family in racehorses. Family 9-c will often go through Lady Josephine and there are other famous mares that pop up in pedigrees all the time.”

    This page ( explains to whom the numbers belong. For example, Rags to Riches’ 8-f belongs to the English mare called Remembrancer Mare (b. 1807): The 5-h belongs to another English founding mare, Ann of the Forest (b. 1790):

  • i am looking for service that has an ‘ongoing’ updated list of sires/mares whose progeny excel on ‘off-track’ surfaces. (e.g. mudders, slop, etc.) any recommendations? i’ve googled about but haven’t really found anything specific.

  • Hi Alex – off the top of my head I can’t think of anything that is specific to off-track sires/mares (but sounds like a great product for someone to develop if it doesn’t already exist!). We’re planning on doing an post on off-track sires/mares in near the future but we’ll look around to see if anyone offers a product. Thanks for stopping by!

  • I have been running pedigrees of the 2017 classic preps thru SA Derby. after going back 6 generations on There is under the pedigree male-tail/female-tail chart statistics about number of foals,etc.etc. Question: there is a bold face type of two letters…BW. I thought this stood for the Sire’s “black type” but the percentage% numbers do not make sense. Like Tiznow,who I believe is 20 years old was sire of Irap in Blue Grass on 4-8-17 and had only
    7 BW’s next to his stats with over 1300 foals. So,BW,must stand for some other pedigree stat.
    Please help with answer. Really like your scholarship. Ken Kolb in New Orleans. Will be sorting out Arkansas Derby tonight for 4-15-17 Oaklawn Park. Can you give me what BW stands for in foal stats and nicking? Thank you.

  • Hi Kenneth! Also good to hear from another pedigree enthusiast :-)

    According to Directory of Reference, “BW” does refer to Black-Type Winners:

    In Tiznow’s stallion register, the 7% is referring to percentage of black-type winners, not the actual number overall, and they are calculating that out of just the number of starters, not overall foals.

    Hope that helps! I’m planning on tackling the Arkansas Derby myself later this evening. Would love to hear your thoughts!

  • What are the initials DP, DI, and CD stand for along the top of the pedigree charts. I understand they help with the nicking process. I am just getting into the TB race scene and find it so very interesting. I want to know how to do nicking as I want to breed to 2 well placed stallions in Kentucky, so I want to have the best mares to suit these stallions. Thank you for your time

  • Hi Lawrence,

    DP stands for Dosage Profile
    DI stands for Dosage Index
    CD stands for Center of Distribution (higher numbers indicate tendency to perform best over shorter distances, while low numbers indicate longer races preferred)

    All three statistics derive from Dr. Steve Roman’s Dosage system (developed in the early 1980s) which seeks to assess a horse’s distance capability. While his website ( is no longer available, you can download a free .pdf copy of Roman’s book Dosage: Pedigree & Performance (2016) at this website: It’s a daunting read, but well worth it for a complete understanding of Roman’s method, including how he arrived at the Dosage Profile (DP) centered on certain influential sires (“chefs-de-race”). By considering the first four generations of a horse, these five numbers represent the distance performance of chefs-de-race’s progeny, placing each in a category: Brilliant, Intermediate, Classic, Solid, and Professional. “Brilliant” represents sprinting races, while “Professional” would be extreme (in North America) distance events.

    For example, Breeders’ Cup Classic winner Gun Runner’s pedigree numbers read:
    DP = 1-2-14-1-0 (18)
    DI = 1.25
    CD = 0.17

    Since the median DI in North American thoroughbreds is roughly 2.40 and the average CD is 0.70, Gun Runner’s pedigree clearly indicates the ability to get longer distances.

  • Hi, Can you remind me of what the color is for in the pedigree? I see red here with Bold Ruler, and I have also seen blue and yellow added.

  • My OTTB has 6 ancestors 4- and 5-generations back in his pedigree with = before their names. 5 are from either FR or GB, so I thought it might denote a foreign horse, but one does not state a country so I assume it’s American. So I can’t figure out what the = means. Can you help?

  • Can you give me an example of one of the horses with the = in front of their name? I’m wondering if became they are 4- and 5-generations back there might be a question as to whether they are pure-bred thoroughbreds? I’ll know better when I see an example :-)

  • Scrub that idea about whether they are pure-breds; I see now examples of Nearco, Mumtaz Mahal and Blandford in Foolish Pleasure’s pedigree with the = in front of the name. I hope to have an answer for you soon :-)

  • I went straight to THE pedigree expert, Sid Fernando. He said that = does signify that the horse is foreign-born but did not breed in the US (if they were imported to this country and were bred here to other horses then they would have an * in front of their name). It’s an old designation that isn’t used any more; foreign-born horses just have their country noted. Hope this helps!

  • I hope that you can help me interpret a pedigree record that I found in The American Race-turf Register, Sportsman’s Herald, and General Stud Book; Patrick Nisbett Edgar, 1833, p. 267 (found on My transcription of that record is:

    R. mare–
    Got by the C. A. H. Symme’s Old Wildair — Batt’s & Maclin’s Fearnought — Rockingham
    Va. 1827. JONAS SILLS

    From the book’s introduction, I believe the letter codes included therein are:
    R = race horse
    C = celebrated
    A = American
    H = horse

    What I am not clear on is if the listed names are the stallions in reverse chronological order. That is, Isabella is of Old Wildair, who was of Fearnought, who was of Rockingham.

    What do you think?

    Thank you for any help you might be able to provide!

  • I see an * on several of the Dam’s names. What does that mean?

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