FAQ Horse Care

Breeding Basics: Understanding the Equine Pedigree

horse pedigree
Written by Natalie Gasper

Determining Your Horse’s Lineage

If you’ve ever looked into buying a horse, you’ve probably seen sellers mention “an excellent pedigree,” or name the horse’s sire and dam. Not sure what those words mean? We’ve got you covered.

A pedigree is a way to record and trace a horse’s lineage. Knowing the history of your horse’s bloodline can help you determine their potential personality traits or training issues. Pedigrees are important when it comes to breeding and deciding which type of horse you hope to have. There are lots of terms related to pedigrees, like dam, sire, and stallion, which refer to the way one horse is related to another horse. A pedigree also determines which, if any, breed registries your horse qualifies for.

What is A Pedigree?

A pedigree is a fancy term for a horse’s lineage, aka his family tree. It traces a horse’s bloodline back through many generations.

Stallions fighting

Photo Cred: Canva

Pedigree Basics


A horse’s father. Any horse who is a sire is a stallion (or was at the time they were bred).


A horse’s mother.


Any uncastrated (or intact) male horse under the age of four.


Any female horse less than four years old.


Any horse, male or female, less than one year of age.

Mare and foal

Mare and Foal. Photo Cred: Canva


The first year of a foal’s life can be divided into two parts. If he’s referred to as a suckling, it means he is still drinking his mother’s milk.


The second part of a foal’s first year comes at around three months of age when he is weaned from his mother.


Male and female horses are called yearlings when they are between one and two years of age.


Any female horse over the age of four.


Any castrated (can’t reproduce) male.

Male horses can be castrated as early as six months, and once they are, they are referred to as geldings, regardless of their age (though you can still call them weanlings or yearlings, if applicable).


Any uncastrated (can reproduce) male horse over the age of four.

How Do You Read a Pedigree?

When a horse is “by” someone, that’s his sire. “Out of” = the dam (or mom). So this horse: Chuckles, by Laughs, means Laughs is Chuckles sire. Oreo, out of Cookies, means Cookies is Oreo’s dam.

Take a look at this sample pedigree.

When reading a pedigree, you typically read from left to right. For example, the far left would be the horse the pedigree is for. Immediately to the right would be that horse’s parents, with the sire listed on the top and the dam on the bottom.

The pedigree branches out from there, typically going back several generations. For Thoroughbreds, there would be five columns, so five generations represented on the pedigree.

Appendix Quarter Horse pedigree (half Thoroughbred):

Appendix horse registration

Photo Cred: Susanna W.

Read more about the history of the Appendix Quarter Horse

Top Side

A fancy term for the sire’s portion of the pedigree, which is on top (and usually blue).

Bottom Side

Refers to the dam’s portion of the pedigree, which is on the bottom (and usually pink).


Inbreeding happens when two closely related horses are bred.

Breeding stock

Breeding stock. Photo Cred: Canva


Linebreeding is breeding two horses that are distantly related. Typically, this means going back further than the fourth generation (or that the common ancestor is at least in the fourth generation or higher).


An outcross is breeding two unrelated horses. There’s a possibility they share an ancestor, but it would be pretty far back in both pedigrees.

If you crossed a Thoroughbred with a Dutch Warmblood, this would be an example of an outcross breeding, as it’s very unlikely the two share a common ancestor.


Stallion. Photo Cred: Canva

Breed Registries

A breed registry, sometimes also called a stud book, is an official list of horses within a certain breed whose parents are documented.

Take AQHA, for example, which is a registry for American Quarter Horses.

What are some of the most common breed registries in the US?

There are many more, but here are a few of the most well-known:

  • American Warmblood Registry
  • Clydesdale Breeders of the USA
  • Dutch Warmblood Studbook in North America
  • American Hanoverian Society
  • American Miniature Horse Association
  • American Paint Horse Association
  • American Quarter Horse Association
  • Performance Horse Registry
  • The Jockey Club (for Thoroughbreds)

How do breed registries validate parentage?

Many breed registries require genetic verification of parentage to be included on their list, so if your horse is an AQHA member, you can be very sure his listed parents are his parents.

How do you register a foal?

The process can vary from registry to registry, but generally, you have to complete and submit a registration application form.


Genetics has come a long way and can tell us much about horses and their potential traits.

How are white markings determined?

This comes down to a horse’s genes. Some horses, like chestnuts, are more prone to having white markings than black horses.

How is coat color determined?

Horses have two basic colors: red and black. Which pigments they can reproduce and in which quantities depends on their genes.

How do you decide which stallion to breed your mare to?

Research the pedigrees of both your mare and any stallions you’re considering. You want horses who have good temperaments and will complement each other.

Does a particular stallion have a line that’s known to be difficult to train? Better not choose him for your strong-willed mare.

Wild horses

Photo Cred: Canva

Frequently Asked Questions

Q: What do you call a horse’s parents?

A horse’s parents are called his dam (mom) and sire (dad).

Q: What is a grandsire horse?

A grandsire is a horse’s grandfather. This term can be used for either the sire’s father or the dam’s father.

Q: What does horse pedigree mean?

A horse pedigree traces a horse’s ancestors and can give you an idea of what the horse’s temperament will be like or in what disciplines he may excel.

Parting Thought

Learning how to read and interpret a pedigree takes time, but it’s a great way to help you find your next partner or simply learn more about equine genetics.

P.S. Enjoy this article? Trot on over to: 


Directory of Horse Breed Associations – Horse Illustrated

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About the author


Natalie Gasper

Nancy loves retraining off the track Thoroughbreds and working with her dogs!