Breeding the Racehorse, by Federico Tesio
As one who has long had an interest in pedigree research, I was glad to discover my local library had a copy of this book, so I could peruse some thoughts a renowned individual had about top racehorses. While the preface said that the book would not provide any insights into some type of formula for producing top-notch racehorses (which, with certain nicks aside, may not be truly possible and is reflected in the adage “Breed the best to the best and hope for the best”), it was still interesting to read Tesio’s observations. He had attempted to investigate Thoroughbred production from a scientific standpoint. Therefore, he considered this book more about heredity’s effects and that the Thoroughbred was a perfect resource for that study, given how meticulously records about the breed have been kept.
The conclusion of his I found most interesting and had not yet considered was that the Thoroughbred can have a variety of colors and even physical appearances (within limits – no draft-horse types!) as far as build and height goes because they are hybrid animals, specifically bred by man, whereas animals who have always lived in the wild will not have such a variety of appearances. His example was brown bears will always be brown and polar bears will always be white.
Tesio also examined how coat color is inherited, assessing which coat color is likely to be dominant and what colors are likely to be seen in horses of two different coat colors. As part of my degree curriculum, I took a course in equine coat color genetics and Tesio’s findings about what the progeny of horses of two different coat colors are likely to produce was in line with what I learned there. He also noted that Thoroughbreds with gray coats are less common than bays and chestnuts since the three foundation sires of the breed were bay and chestnut. He described a gray coat as “not itself a coat, but a pathological discoloration of the only two basic coats which are the bay and chestnut. It is a strange disease of the pigmentation.”
After that, Tesio often referred to a gray horse as one having a disease that resulted in its coat color. I don’t recall in my coat color genetics course what I learned about the likelihood a horse would be gray, as it’s been years since I was in that course, but I found Tesio’s reference to a gray horse’s color being a disease or a horse inheriting the disease of gray coloration an unusual way to describe it. What I have found with a little more research is that gray is definitely a result of the horse gradually losing pigment; but to call it a disease at times I found confusing as it doesn’t seem to fit the definition of a disease. He found that Brownlow Turk and the Alcock Arabian appear to be responsible for the gray color in Thoroughbreds. I have heard that the Alcock Arabian, born in 1722, did introduce that color to the breed.
Regarding markings, Tesio said they are also found in a multitude of combinations since the Thoroughbred is a hybrid largely shaped by people’s choices in breeding. He pointed to penguins as an example of how animals not bred for specific characteristics by humans don’t have this variety – that bird is always black with a white front that is centered.
Tesio went on to discuss nicks he found success with or noted others found success with but also wrote that “generally this is first discovered by chance, then other breeders follow up the initial success until that particular cross becomes the fashion.” Therefore, while he noted he did find success with crosses following that pattern of nicks, his introductory sentence about that quoted above suggests that luck may have a greater role than formula. What he concluded truly led to success in the Thoroughbred as a racehorse was breeders giving more merit to horses that won instead of appearance, retaining only accomplished individuals for breeding.
One other study Tesio wrote about that I found intriguing was about the possibility of success being able to be carried in a male line through generations, seen through the lens of the Epsom Derby. He believed energy (represented by winning this top race) had a limit at which it could be passed on, and that limit seemed to be three generations. While the Epsom Derby has a history tracing back to 1780, it still made me wonder (even with less possibility for three generations to have won), if our country’s own Kentucky Derby would show this theory to be true. But then, there are also so many vagaries of breeding (not the least of which is whims of breeders, which Tesio alluded to when writing of nicks), that maybe some horses never even had a chance to have three generations vie for Derby success, even if it’s not a reflection of them not being capable of three horses from different generations of the same male line being able to win the Derby. And really, it does seem extraordinary if any male line was able to have a winner of the race and sire a winner of it who sired the winner himself, statistically speaking. So maybe that is a real anomaly instead of an example of what energy transmission is possible. Worth a debate!
While some of Tesio’s book was a touch archaic, as may be expected given the time elapsed since it was written, overall I found his insights worth pondering and that they did add to my knowledge of horse heredity. I am glad my library carried this book; I had always wanted to read it someday but thought I’d have to seek out my own copy.