Key points
- A broodmare sire is the father of a horse's dam, also called the damsire or maternal grandsire.
- In "by Stallion A out of Mare B, by Stallion C," Stallion C is the broodmare sire.
- The broodmare sire passes roughly 25% of a horse's genetics through the dam.
- Handicappers read broodmare sire data for stamina, distance, and surface clues on the maternal side.
- A broodmare sire is not the horse's own sire, and it is not the same thing as a stallion's broodmare sire record.
- EquinEdge folds pedigree signals like this into Genetic Strength Rating (GSR®) and its AI-powered handicapping.
What a broodmare sire is
A broodmare sire is the father of a horse's dam. The dam is the horse's mother, and the broodmare sire is her father. That makes the broodmare sire the horse's maternal grandfather. Handicappers and bloodstock writers also call this horse the damsire.
The term shows up most often on catalog pages, in stallion profiles, and in past performance lines. When a racehorse is described as "by Tapit out of a mare by A.P. Indy," A.P. Indy is the broodmare sire. Tapit is the horse's own sire, and the unnamed mare is the dam.
The word "broodmare" tells you the dam has a breeding role. A broodmare is a female horse used to produce foals. Add "sire" to it, and you name the stallion who produced that broodmare. The broodmare sire is one generation further back than the horse's own sire, but he still matters to the horse in front of you.
Where the broodmare sire sits in a pedigree
Pedigrees read from left to right, starting with the horse and moving back through the generations. The broodmare sire sits on the bottom half of the pedigree, because he comes through the dam's side.
Here is a simple three-generation view in words:
- Generation one: the racehorse.
- Generation two: the sire (father) and the dam (mother).
- Generation three: the sire's sire, the sire's dam, the broodmare sire, and the dam's dam.
The broodmare sire is the dam's father, so he appears in generation three on the maternal side. The dam's dam, sometimes called the second dam, sits beside him in that same generation.
A concrete example makes the position easier to follow. Take a horse described as "by Curlin out of a mare by Medaglia d'Oro." Curlin is the sire. The dam is a mare whose own sire is Medaglia d'Oro. Medaglia d'Oro is the broodmare sire. The horse carries Curlin on the top line and Medaglia d'Oro one step back on the bottom line.
Quick-reference table
| Term | What it names | Position in the pedigree |
|---|---|---|
| Sire | The horse's father | Generation two, top half |
| Dam | The horse's mother | Generation two, bottom half |
| Broodmare sire (damsire) | The dam's father | Generation three, bottom half |
| Dam's dam (second dam) | The dam's mother | Generation three, bottom half |
| Sire's sire | The sire's father | Generation three, top half |
Why the maternal side matters for handicapping
Most casual fans learn the sire's name first, because stallions get the headlines. The broodmare sire works more quietly, but he carries real predictive value for a handicapper.
A horse receives roughly half its genetics from the sire and half from the dam. The broodmare sire contributes about 25% of the horse's genetics, because he passes genes to the dam, who then passes half of her genes to the foal. That is a meaningful share, and it often shows up in the traits handicappers care about most.
The maternal side frequently influences stamina and distance ability. A broodmare sire known for producing stayers can hint that a horse will handle longer routes. A broodmare sire with a sprint-heavy record can point the other way. Surface preference runs through the dam's side too. A broodmare sire whose offspring win on turf often suggests the horse may improve when it switches to grass.
This is why serious handicappers do not stop at the sire's name. They read the bottom half of the pedigree to find the broodmare sire and ask what that stallion tends to pass along. The answer helps them judge whether a horse will handle today's distance and surface.
How broodmare sire data shows up in past performances
Past performance lines and pedigree views list the sire and dam together, usually in a compact line near the horse's name. The broodmare sire appears right after the dam, often introduced by the word "by."
A line might read: "Curlin - Mare by Medaglia d'Oro." The first name is the sire. The second name, after "by," is the broodmare sire. Once you know how to read that line, you can scan a full field and compare the maternal side of every contender in seconds.
Some handicappers keep a short mental note on the broodmare sires they see most often in a given meet or circuit. If a particular broodmare sire keeps showing up in the winners at a certain distance or surface, that pattern is worth tracking. It is the same habit as following a hot jockey or trainer, applied to pedigree.
How EquinEdge surfaces pedigree signals
EquinEdge analyzes past performance data on every horse in North America in real time, and pedigree is part of that picture. The platform reads the sire and broodmare sire data behind each runner and folds it into the metrics you see on a race card.
The clearest place this shows up is Genetic Strength Rating (GSR®). GSR® weighs the genetic and pedigree signals behind a horse, including the influence of the sire and the maternal side, to produce a strength score you can compare across the field. Instead of reading a raw pedigree line and guessing, you get a rating that already accounts for the broodmare sire's contribution.
That matters for bettors who want to move from memorizing names to making decisions. You can still read the "by X out of a mare by Y" line yourself, but EquinEdge turns that same information into a metric you can weigh against pace, class, and form.
Common mistakes to avoid
Confusing the broodmare sire with the horse's own sire. The sire is the father. The broodmare sire is the dam's father, one generation further back. They are different horses, and they sit on different halves of the pedigree.
Assuming the broodmare sire contributes half the genetics. He contributes about 25%, through the dam. The sire and the dam each contribute about half, and the broodmare sire's influence flows through the dam's half.
Confusing a single horse's broodmare sire with a stallion's broodmare sire record. A stallion can be a broodmare sire many times over, across many foals and many dams. When someone says a stallion is a "leading broodmare sire," they mean his daughters are producing successful runners. That is a different claim from naming one horse's damsire.
Reading the broodmare sire in isolation. The broodmare sire is one signal among several. His influence shows up alongside the dam's own racing record, the sire's profile, and the horse's form and pace figures. Use him as a clue, not a verdict.
Frequently asked questions
What is the difference between a sire and a broodmare sire?
The sire is the horse's father. The broodmare sire is the father of the horse's dam, which makes him the maternal grandfather. The sire sits in generation two, and the broodmare sire sits in generation three.
Why is the broodmare sire also called the damsire?
"Damsire" is a shortened way of saying "the dam's sire." Both terms name the same horse. You will see "broodmare sire" more often in breeding and catalog writing, and "damsire" more often in casual handicapping talk.
How much of a horse's genetics come from the broodmare sire?
About 25%. The broodmare sire passes genes to the dam, and the dam passes roughly half of her genes to the foal. That leaves the broodmare sire with about a quarter of the horse's genetic makeup.
Does the broodmare sire matter for betting?
Yes. The maternal side often carries signals about stamina, distance, and surface preference. A broodmare sire with a strong record at a certain distance or surface can help you judge whether a horse will handle today's race conditions.
Where do I find the broodmare sire on a race card?
Look for the sire and dam line near the horse's name. The name after "by" in the dam's portion of the line is the broodmare sire. For example, in "Curlin - Mare by Medaglia d'Oro," Medaglia d'Oro is the broodmare sire.
Learn the pedigree terms that matter
If you want to go deeper, start with the basics. Our glossary entry on what a broodmare is explains the dam's breeding role, and the piece on what a sire is covers the top half of the pedigree. For the full picture of how bloodlines shape performance, read our horse pedigree and breeding guide.
When you are ready to see pedigree data turned into a usable rating, EquinEdge analyzes past performance and pedigree signals on every horse in North America in real time. Start your trial at dashboard.equinedge.com/signup-plans and see how Genetic Strength Rating (GSR®) reads the broodmare sire's influence for you.