Key points
- A damsire is the sire of a horse's dam, which makes it the horse's maternal grandfather.
- Damsire and broodmare sire refer to the same horse.
- In a pedigree, the damsire follows "out of," on the dam's side of the family.
- Grandsire can mean either grandfather, so use damsire only for the maternal side.
- A damsire is one pedigree input and does not decide a race result.
- Racing Post profiles list the damsire as "Dam's Sire" and include a Damsire progeny tab.
What a damsire is
A damsire is the sire of a horse's dam. In plain terms, it is the horse's maternal grandfather. If a horse's mother has a sire, that sire is the horse's damsire.
The term is most common in thoroughbred racing. Ozrace's glossary of breeding terminology lists "broodmare sire" as the same thing, so you will see both names in pedigree discussions. Damsire is the term to use in most writing, and broodmare sire is the common alternative.
The sire is the horse's father. The dam is the horse's mother. The damsire sits one generation above the dam, so it belongs to the dam's side of the pedigree.
Reading a damsire in a pedigree
Pedigree listings use two phrases to show family lines. A horse is "by" its sire and "out of" its dam. The damsire appears after the dam's name, because it is the dam's sire.
Racing Post uses the field label "Dam's Sire" on its horse profiles. Here is a three-generation example from the Racing Post format for the horse Top Ranked:
Top Ranked
├── Sire: Dark Angel (IRE)
└── Dam: Countess Ferrama (GB)
└── Dam's Sire (damsire): Authorized (IRE)Read the tree from the top. Dark Angel is the horse's sire, so Top Ranked is by Dark Angel. Countess Ferrama is the dam, so Top Ranked is out of Countess Ferrama. Authorized is the damsire because he is the sire of the dam.
The example uses one listing only. It shows where the field sits and does not make any claim about how the horse performed.
Damsire, broodmare sire, and grandsire
Damsire and broodmare sire are interchangeable. Both name the sire of a horse's dam.
Grandsire is a looser term. It can refer to either grandfather, so the word alone does not tell you which side of the pedigree is meant. Use damsire when you mean the maternal grandfather, and reserve grandsire for cases where the source makes the side clear.
The sire's sire is the paternal grandfather. It sits on the father's side, so it is never the damsire. Keep the two apart when you read a pedigree from the top down.
If you want to trace the maternal side further, the dam line entry covers the wider female family, and the sire entry explains the paternal side in the same way.
Why handicappers look at the damsire
Many handicappers check the damsire because it adds a generation of pedigree information. Some people link the damsire line with traits such as stamina, speed, or surface preference. These links are a reason to study the damsire, not a proven effect. The published sources I used for this entry did not confirm those traits, so treat them as working ideas.
Pedigree also plays a role in some handicapping tools. EquinEdge's Genetic Strength Rating (GSR®) evaluates a horse's suitability for a race's distance and surface using pedigree and performance data. It is one example of how pedigree information can enter a handicapping process.
Limits of damsire analysis
A damsire does not decide a race. A horse's form, track conditions, the class of the race, and the other runners all affect the result. The damsire is one piece of the picture.
Sample size is one reason analysts look at the damsire. A single dam may have only a few foals, while her sire may have sired many more runners across several dams. A record built from more runners can be more stable than a record built from one mare. This is a reasoning point, not a rule, and it does not show that a damsire record will predict a winner.
Finding a horse's damsire and its record
To find a horse's damsire, look for the "Dam's Sire" field on the horse's profile. Racing Post profiles show this field in the pedigree section.
Racing Post profiles also include a Damsire progeny tab next to Progeny Statistics. That tab lists results for the damsire's offspring. Use it to see how the damsire's runners have done, but keep in mind that the record includes many horses with different dams, distances, and surfaces.
For more pedigree terms, the EquinEdge glossary lists related breeding and racing words in one place.
Frequently asked questions
Where do I find a horse's damsire?
Check the "Dam's Sire" field on the horse's profile or pedigree listing. On Racing Post, the field appears in the pedigree section, and the Damsire progeny tab shows the damsire's offspring results.
Does a damsire decide how far or on what surface a horse will run well?
No. A damsire can be one input when someone studies a horse's pedigree, but it does not settle how far or on what surface a horse will run well. Form, conditions, and the race itself also matter.