Horse Breeding Lingo: Pedigree Terminology

Horse Breeding Lingo: Pedigree Terminology

When you’re talkin’ bloodstock pedigrees, there’s a high-falutin’ lingo you should use. Here's how to talk the talk and read pedigree charts.

red roan broodmare and foal in a pasture with mountains in the background (Credit: Briana Malmquist/@pipers_zoo)

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Every part of our horse industry has its own way of talking. A “leg-yield” in English circles is more often called a “two-track” or a “half-pass” in the western arena. “Chute fees” and “farm fees” on a stallion contract might mean the same thing, or two very different things, depending on the breeding farm.

It’s true in pedigree circles, too. Those folks who make their living studying equine bloodlines, building sale catalog pages or offering breeding consulting services have a distinct way of talking about pedigrees.

The Journal dug up the definitions for and the proper use of some basic words that crop up when you’re talking about equine ancestry. You probably know some of them, but you’ll be surprised at others.

Sire and dam: A sire is a horse’s father, a dam its mother. 

To produce and to sire: A mare produces foals; stallions sire foals; stallions do not produce foals.

Out of and by: A horse is always out of a mare and by a stallion. For example, Hollywood Dun It is by Hollywood Jac 86 (his sire) and out of Blossom Berry (his dam) by Dun Berry (her sire).

Half-sister or half-brother: Only refers to horses that are out of the same dam. Horses by the same sire and out of different dams are not referred to as half-siblings.

Brother or sister: Horses that have the same sire and dam. In a pedigree, simply saying “sister” or “brother” always indicates the horses are full siblings in blood. For example, saying “Dry Doc, brother to Doc O’Lena,” means that Dry Doc is a full brother to Doc O’Lena.

Broodmare sire or dam’s sire: The sire of a horse’s dam, the horse’s maternal grandfather.

Tail male line: The listing of a horse’s male ancestry through its sire. For example, Hollywood Dun It is by Hollywood Jac 86, by Easter King, by King, by Zantanon, by Little Joe, by Traveler.

Tail female line: The listing of a horse’s female ancestry through its dam. For example, Hollywood Dun It is out of Blossom Berry, out of Regina Bella, out of Tina Regina, out of Little Dunny 2, out of Anna’s Little Dunny, out of Anna Wilkens.

First dam, second dam, third dam, etc.: The first dam is a horse’s mother. The second dam is its dam’s mother. The third dam is its dam’s maternal grandmother, and so on. It always refers to the tail female line.

Top side: Slang for the sire’s side of a pedigree page.

Bottom side: Slang for the dam’s side of a pedigree page.

Blue hen: A mare that has had a remarkable and lasting, multigenerational influence on a breed, typically through male and female descendants. Some Quarter Horse examples would be Royal Blue Boon in cutting circles or Do Good in the racing world.

Inbreeding: Breeding closely related individuals.

Inbreeding quotient: Numbers that indicate how often a horse traces back to the same horse. In a genetic pedigree, the first generation is considered the horse’s sire and dam, not the horse itself. For example, if you say, “Leo is 2x2 to Joe Reed,” Joe Reed P-3 appears twice in Leo’s pedigree in the second generation.

  • Leo is by Joe Reed II by Joe Reed P-3.
  • Leo is out of Little Fanny by Joe Reed P-3.
  • Joe Reed II and Little Fanny are Leo’s first generation (parents); Joe Reed P-3 is in Leo’s second generation (grandparents), twice.

Linebreeding: Breeding individuals that are distantly related, typically further back than the fourth generation. Learn more about linebreeding here.

Outcross: Breeding two unrelated individuals, or individuals that, if they do have the same ancestor, that ancestor is significantly far back in the two horses’ pedigrees. Learn more about outcrosses and hybrid vigor here.

Nick: Bloodlines that work noticeably well when crossed together, repeatedly producing outstanding performers. Nicks often remain true through several generations, a stallion’s sons and grandsons working well on another stallion’s daughters and granddaughters, etc. Learn more about nicking here.

How to Read a Horse's Pedigree

Often you'll see pedigrees written like “Freightrain B-Sinuous by Mr Jess Perry.” This indicates the sire (Freighttrain B), dam (Sinuous) and dam sire (Mr Jess Perry). A horse is “by” a sire and “out of” a dam.

When reading Quarter Horse pedigrees, remember that the sire will be on top, and the dam will be on the bottom. The tree reads from left to right, with each successive generation branching out. The dam’s mother is known as the second dam, and her mother is the third dam, etc.

Whistle Stop Cafe pedigree

Pedigree Reports From AQHA and QData

The American Quarter Horse Association offers free pedigree records, as well as pedigree research reports from QData.