A fast-paced gallop through the history of the Thoroughbred, from its early origins in 17th century England to present-day concerns about genetic diversity within the breed. The book presents a hypothesis, based on comprehensive pedigree data, and challenges the Thoroughbred industry to engage in a dialogue.

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About the Author

Suzi Prichard-Jones has spent her life immersed in the Thoroughbred industry — owning, training, riding and breeding horses. She has ridden for trainers such as Michael Dickinson, Carl Nafzger and D. Wayne Lukas.

Suzi also founded the Byerley Turk & Godolphin Arabian Conservation Project, which currently has six broodmares. These mares are being bred to the three existing Byerley Turk and Godolphin Arabian line stallions standing in England.

Born and brought up in Ireland, Suzi has experienced racing on five continents while living in Europe, America, the Middle East and Southeast Asia. Today, she spends her time between her homes in Florida, USA and Co. Kildare, Ireland.

Book Summary

The genetic foundation of the Thoroughbred rests upon three direct male tail lines, those of the Byerley Turk, the Darley Arabian and the Godolphin Arabian. Over recent decades, one of the bloodlines of these foundation stallions has begun to dominate the breed, while the other two have receded in particular, the bloodline of the Byerley Turk.

Byerley explores the origins of the Thoroughbred in 17th century England, providing the historical and social context for the emergence of the breed. It traces the bloodlines of the three foundation sires through their progenitors Matchem, Herod and Eclipse to present day racehorses. In doing so, this book presents a new way of looking at Thoroughbred pedigrees by tracing the influence of the three male tail lines.

The author presents a hypothesis that it was the combination of the bloodlines of the three foundation sires that produced a perfect genetic balance 250 years ago, which resulted in the genesis of the Thoroughbred. She believes that the rapidly diminishing influence of the Byerley and Godolphin bloodlines will put the future of the breed at risk.

The book concludes with an overview of emerging science and genetics relating to the pedigree of the Thoroughbred. It raises a red flag for the Thoroughbred industry by asking if the breed faces possible genetic implosion?

Book Contents

A Warning Shot Across the Bow

The disappearance of the Byerley male tail line.

The Foundation Sires

And England’s historical setting as the
Thoroughbred emerged.

Matchem, Herod and Eclipse

The three descendants who ensured the Success of the Thoroughbred.

The Royal Stud Masters

How “God’s Own County” became the birthplace of the Thoroughbred.

People and Pedigrees

The six men who laid the foundations for the breed.

The Byerley Turk Bloodline

Perhaps as simple as an invitation to dinner.

The Remaining Bastions of the Gate

The Byerley Five.

21st Century Science

Current research in the field of equine genetics.

Omne Trium Perfectum

The real meaning of diversity.

Defusing the Bomb

Are we ready?


” In over 1,000 pedigrees analysed, all have provided representation of the bloodlines of the three foundation sires within their first six generations – with the exception of eight pedigrees that demonstrated representation of only two bloodlines (those of the Byerley Turk and the Darley Arabian).

“On the basis of this research, I am willing to offer a free breeding season to either of the Herod line stallions, Pearl Secret or Indian Haven, to the first person who can provide evidence of a racehorse fit for purpose tracing exclusively to the Darley Arabian within its first six generations. “

Suzi Prichard-Jones