Read a pedigree for speed, stamina and class.

Free, plain-English guides to the ideas behind pedigree analysis: what dosage measures and where it goes wrong, why the dam's family matters so much, how family numbers work, and how to read a family's race record for trip.

Start reading →Dosage explained →

Why it's hard

Three things that make pedigrees hard to read.

There's a lot of it

A single sale catalogue can run to hundreds of lots, each with three generations of family history in small print.

Race names don't give distances

A catalogue names the races a family won, but not how far they were. Sprint family or stayer? You have to know the races.

Dosage alone misleads

Classic dosage ignores today's stallions and every mare. On its own it can call a middle-distance family a sprinter.

The guides

Where to start.

Reading a pedigreeBlack type, the dam's produce, the second and third dams: how to read a pedigree and a catalogue page.Read the guide →Dosage explainedReading a racehorse's type from the stallions in its pedigree, and six blind spots to allow for.Read the guide →Why the damWhat a mare passes on that a stallion never does, and why her family's record is the best evidence.Read the guide →Family numbersThe foundation mares, Bruce Lowe's numbers, what 13-e means, and what DNA has shown.Read the guide →The HorseBytes SystemA modern pedigree index, rated 0–100 and tested on what earlier yearlings went on to do.Read the guide →Big missesMulti-million-guinea yearlings that never won or never ran — and what they teach a buyer.Read the guide →Sale resultsBook 1 2026 prices against the HorseBytes System — what it picked, what it missed and why.Read the guide →The salesThe main bloodstock sales in Britain, Ireland and France, and what to look for at each kind of sale.Read the guide →GlossaryPlain-English meanings of the pedigree and sale terms you'll come across.Read the guide →

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