Dr. Cook’s book “Specifications for Speed in the Racehorse”
I saw this book when I went to the Keeneland Library with my friend Marilyn. It was available, used, on Amazon.com so I ordered it.
In the book, Dr. Cook (the same Dr. Cook who has patented the bitless bridle) goes into tremendous detail regarding airflow in racehorses. It actually makes a lot of sense to me, and explains why potential winners cannot be determined by conformation. There have been great horses who were less than perfectly conformed, including ones with crooked legs. Dark Mirage was barely 14:3 but won what was called at the time the Filly Triple Crown, and is now called the Triple Tiara. She not only won, she devastated her competition, as can be seen by the photo below.
I was actually aware of her at the time, and photos of her were in the Thoroughbred Record. Not only was she tiny, she was not all that attractive. According to reports, her entrance into the sales ring at Keeneland prompted laughter, and she ended up being the lowest priced horse of the sale at $6,000. However she went on to earn over $362,000 and was Champion 3 year old filly. (Unfortunately, she suffered an injury as a 4 year old and complications ended in euthanasia.)
Dr. Cook’s theory is that airflow is the limiting factor in racing. He goes into great detail and explains using jaw width as a guideline in determining airway size. He states which measurements are average, and which superior. He backs this up with measurements of many champions all of which had larger than average jaw width. According to his research, the “average” TB has a 4-finger jaw width (7.2 cm) or less. Horses who’ve proved superior have from 5-6 finger widths (9 cm and 10.8 respectively).
I feel that his theory is very valid, in part because of something I heard a long time ago – that you should be able to fit your fist between the branches of the jaw at their widest point. Over the years I’ve tried that on a lot of horses (TB’s) and was unable to do it. I tried it on Chance when I first got him, and was happy to see it fit. Not that airflow is the only factor – after all, a horse must be healthy and fit, and I believe a horse can do better barefoot than shod. But if the limiting factor IS airflow – better to have it than not.
Of course I wanted to know immediately how wide Chance’s jaw is. I measured probably 12 times, being sure I did it right. Then I measured my fingers. Turns out his jaw width is 9.5 centimeters. I am happy! Actually, he is bred to run. His sire, Aptitude, won the Jockey Club Gold Cup and the Hollywood Gold Cup, among others, along with finishing second in the Kentucky Derby, and second in the Belmont, and earning over $1.9 million. His dam’s sire, Broad Brush beat Ferdinand, was third in the Derby and the Preakness and earned over $2.6 million.
And of course, I wanted to know how wide Zola’s jaw is. Just about exactly the same. Very cool.
Here are some of the champions Dr. Cook measured. (The book was published in 1993). Northern Dancer 6 fingers, Seattle Slew 5 fingers, Secretariat 5 fingers, John Henry 5 fingers, and Forego 5 fingers.
Now, let’s hope Dr. Cook is right!