The X Factor: What It Is and How to Find It -- by Marianna Haun

The X Factor
What It is and How to Find It
The Relationship Between Inherited Heart Size and Racing Performance

(1997) 6 x 9" laminated softcover, 208 pages, 27 photos,
numerous pedigree charts. Index and Pedigree Index. $29.95

Marianna Haun. former staff writer for the Thoroughbred Times, now author and freelance writer for Associated Press, brings us details of the genetic breakthrough that horsemen and breeders have been waiting for!!

When Secretariat died, an autopsy revealed a 22 lb. heart, nearly three times the size of an average TB heart. After nearly a year of intensive pedigree research, Haun discovered the genetic link from Secretariat's mighty heart to Eclipse's great heart through the mare Pocahontas on the X chromosome trail.

This book explains the X Factor, what it is, how to find it, and the relationship between inherited heart size and racing performance. The author offers lists of stallions and mares who have the large heart, and the 4 most prominent sire lines passing the gene to their daughters. She offers many pedigree charts of champions and great producers, showing how the X-trail zig-zags from one generation to the next, offering insight into the "broodmare sire phenomenon."

There are phenotypical traits linked to the large heart, including a broad flat forehead and small ears, and a characteristic shape of the shoulders and chest. Many photos demonstrate these interesting findings and give credence to the evidence that daughters of large hearted stallions often pass his physical resemblance to their sons and daughters, along with his large heart.

If you are a Thoroughbred or Quarter Horse breeder, "The X Factor" will change the way you think about pedigrees, nicks and matings.

Reviews:

"The X Factor has turned the pedigree page upside down. It also sheds light on the previously inexplicable performance in the breeding shed of some of history's champions."
Penny Chenery ..... Owner-Breeder of Secretariat

"Ms. Haun gives us all new exciting research to contemplate as we plan our matings. Her X Factor theories could genetically explain why some nicks are so much more successful than others."
Pope McLean ..... Crestwood Farm

"The X Factor is a key breakthrough in helping understand genetic influences. Science is rapidly evolving, and such things as gene mapping may not be far away. Breeding will always be somewhat of an art, but this book will prove a valuable aid to breeding better horses."
John C. Harris ..... California Owner-Breeder ..... President, CTBA

"Marianna Haun and the scientists and horsemen she worked with have articulated another piece in the puzzle of genetics which can be used towards making a better animal."
Edward L. Bowen ..... President, Grayson Jockey Club Research Center

"With what we are finding out about the large heart passing from sire to daughter, this helps explain the broodmare sire phenomenon."
Dr. Thomas Swerczek ..... University of Kentucky, Gluck Equine Research Center

"An eye opener for all serious breeders. Anyone who puts any credence in male-line to male-line nicking and males-only dosage, better read this."
Sandy Clark ..... Thoroughbred Consultant-Breeder

ORDER