Federico Tesio is renowned for his successful breeding methods. Embracing a holistic approach that combined pedigree analysis with environmental factors, Tesio’s legacy continues to shape the industry. While his principles may seem unspectacular, they light up if the are reframed in the context of “common sense”. Tesio’s approach was founded on rigorous selection, the contradiction between unbiased decisions and intuition based on personal experience and a deep understanding of the complexities of a balanced pedigree. Delving deeper into Tesio’s approach unravels the secrets behind his legendary horses. Let’s look closer into the meaning of “common sense” and embark on a journey of discovery.

The Tesio Method in the light of “common sense”

First and foremost, it must be mentioned that Tesio was a firm believer of a “holistic breeding approach”: pedigree analysis held as much weight to him as training, environmental factors, nutrition, and the proper rearing of foals. “The Tesio Method” refers to the pedigree design he employed to breed such outstanding horses like Nearco, Ribot, Donatello II, Tenerani, and Cavaliere d’Arpino.

An old photo of Federico Tesio.

Federico Tesio.

Who was Federico Tesio (1869 – 1954)?

In a nutshell: one of the most innovative and successful breeders in Thoroughbred racing history. His visionary methods revolutionized mating strategies and continue to influence the industry to this day.

In 1898, he married his wife, known as Donna Lydia, who shared his lifelong passion of raising Thoroughbreds as well as analyzing and designing pedigrees. Also in 1898, he established the Dormello Stud Farm near Stresa on the Lago Maggiore (northern Italy).

He likely was the most successful breeder of Thoroughbreds of all times. While he didn’t admit to have a method, he was happy to share advice (1) and (2):

1) Never remain attached to your female lines.
2) Avoid standing your own stallion.
3) Proven Sires should always be preferred.
4) Always send your best mares to the best stallions.
5) Mating mares is all about constant experimentation.
6) Pay utmost attention to the conformation of the stallion.

These pieces of advice are simply common sense and don’t seem particularly helpful. Have you ever looked up the definition of “common sense”, though? Let’s apply the melting pot of the corresponding definitions to horse breeding:

“Common sense can be located at the intersection of practical reasoning based on experience, involving logical thinking adapted to various circumstances relying on intuition, observation and a basic (or advanced) understanding of how pedigrees work.”

This definition might explain why sometimes “common sense” seems to be so rare – but it is an excellent ground to start exploring Tesio’s advice. Before some common sense is applied to discuss the above points, I would like to introduce two concepts that become obvious when looking at Tesio’s breeding strategy:

The purpose of line-breeding is to concentrate desirable characteristics and traits usually from one (or a very limited number) of successful and influential ancestors. This technique potentially increases the risk of genetic diseases; hence, a healthy balance between concentration and purposeful dilution must be found.

Gender-balance underscores the importance of passing genetic traits through both male and female offspring of a desirable ancestor. The concepts of ‘colt factor’ and ‘filly factor’ further emphasize the significance of gender-balance in breeding programs.

Tesio deemed line-breeding as well as gender-balancing crucial in designing pedigrees: this is very obvious when the pedigrees of his stock is analyzed. Also, he recognized the genetic power of using full siblings to build a strong pedigree. Tesio’s approach went far beyond these concepts and is further discussed below.

But first, let’s apply “common sense” to his advices:

1) Never remain attached to your female lines.

This advice challenges a common sentiment among breeders. Mares, the horses we nurture and care for, often evoke deep emotional attachments. Yet, Tesio’s approach suggests a pragmatic reassessment. He acquired three mares at relatively low prices, likely replacing existing ones in his broodmare band. Did he merely seek cheap stock and chance? Consider Catnip, for instance: Tesio’s undoubtfully arduous journey to England to acquire her contradicts strongly the aspect of lottery. Let’s look at her pedigree:

A pedigree chart.

Figure 1: www.allbreedpedigree.com/catnip

Her pedigree showcases gender-balanced line-breeding to Stockwell and Newminster. But there is one more very important feature in this pedigree that can only be understood in historical context: from 1913 to 1949 the “Jersey Act” (3) was in force that prohibited the import of American Thoroughbreds to Europe. The American lineage on Catnip’s dam side should not be overlooked and can be considered a very “purposeful dilution”! It is notably the cross of Leamington xx Lexington, which also produced Enquirer, an undefeated racehorse of significance. Enquirer became the broodmare sire of Domino that was undefeated in 9 starts as a two-year-old and his earning record stood for 38 years. Two generations later… Catnip became the 2nd dam of Nearco.

The pedigree of Duccia Di Buoninsegna reflects his admiration for St Simon as well as gender-balanced line-breeding. She became the 2nd dam of Donatello II.

A pedigree chart.

Figure 2: www.allbreedpedigree.com/duccia+di+buoninsegna

Tofanella, another acquisition, became the dam of Tenerani. This mare’s pedigree again reflects Tesio’s preference for St Simon and gender-balanced line-breeding. This pedigree features the full siblings Floriezel and Persimmon: genetically an extremely strong combination as the genetic lineage of the sibling’s sire and dam are beautifully emphasized through Cyllene and Hampton. This pedigree is a great example of building up incredible background strength with extremely focused line-breeding.

A pedigree chart.

Figure 3: www.allbreedpedigree.com/tofanella

Reflecting on these pedigrees, it becomes obvious that his advice to not remain attached to your mares could be reframed to: “If you can enhance your broodmare band by recognizing genetic potential and without risking bankruptcy, it might be wise to do so.” The selection of these mares shows that it’s worth to give luck a chance!

2) Avoid standing your own stallion.

This advice prompts reflection on the concept of bias, that resonates deeply with this rule. Your stallion, akin to a cherished child or beloved pet, always embodies the epitome of excellence. Even if he truly is a remarkably successful and beautiful animal, objective assessment is imperative: he might not be the right fit for your mares – if viewed impartially.

3) Proven Sires should always be preferred.

Tesio also said to always breed to the finest offspring of a stallion that you can afford to breed to. If you apply “common sense” again and reframe this rule, this advice reveals the statistical nature of genetics. There are numerous examples of full siblings that exhibit very different traits. Selecting the sibling with demonstrated racing ability becomes paramount—an endeavor aimed at always selecting desirable traits. Tesio, in essence, advocates for the application of evolutionary pressure and meticulous selection to optimize breeding outcomes.

4) Always send your best mares to the best stallions.

This echoes the old saying of “breed the best to the best and hope for the best”. That this doesn’t work is not a secret – but then “hope dies last” (Pandoras Box). While hope may endure, it rarely covers the cost of hay. Applying “common sense” offers a slightly different approach: always send your best mare to the best possible stallion. How do you select your best mare? Beyond pedigree, temperament and conformation are similar important for producing a champion. To be familiar with her abilities as a broodmare is key. The broodmare that consistently foals high quality offspring regardless of the stallion might be the “best mare”. For such a promising or proven producer, the optimal stud might not be the most renowned one, but rather the one that complements her attributes best. Investing more in the ideal stallion for your “best mare” proves most likely wiser than spending a fortune on a stud fee for a maiden mare.

5) Mating mares is all about constant experimentation.

This maxim rings very true to seasoned breeders. However, when viewed through the lens of “common sense”, a nuanced interpretation emerges: once you have adjusted the statistics (by determine the optimal pedigree pattern) that success becomes slightly more likely than failure, the quest for the ideal stallion begins. While multiple pairings may yield similar patterns, discerning which stallion complements the mare best becomes the core of the experiment. Through iterative refinement, breeders gradually are able to figure out the best match for each individual mare.

6) Pay utmost attention to the conformation of the stallion.

This underscores an often-overlooked aspect of breeding: the stallion’s reputation may overshadow his conformation. Tesio was a master of observation and knew about its importance; conformation though sometimes gets overlooked by pedigree geeks. Applying common sense yields the saying: “you ride the horse, not the paper”. The stallion’s conformation must harmonize with the mare’s and vice versa, underscoring the importance of meticulous evaluation beyond pedigree and reputation.


Was all that Tesio did merely applying “common sense”? Likely so. However, what constituted “common sense” for him may not have been readily apparent to others. The very common issue that “common sense” is known to have, is that “common sense” often is not that common.

Further analysis of pedigrees led to intriguing conclusions, detailed in my 2019 book, “Pedigree Patterns of Thoroughbred and the Theory Behind” (4). Tesio’s approach extended way beyond gender-balanced line-breeding and the use of siblings; he intricately wove patterns into his pedigrees. The success of these patterns lies in their alignment with nature’s gender-specific selection of traits. Delving into the theory behind these fascinating patterns unveils an even deeper understanding of pedigrees, making it a captivating exploration.

For those intrigued by the theory behind pedigree patterns, I invite you to explore more at www.magicmatchgenetics.com.


1. Tesio, Federico. Tesio – In His Own Words.
The Russell Meerdink Company Ltd., 2005. ISBN: 978-0-929346-76-2.
2. Morris, Tony. World Of Breeding: Tesio – the Einstein of the breeding world.
www.thefreelibrary.com. [Online] 2004.
3. Wikipedia. Jersey Act. www.wikipedia.org. [Online] https://en.wikipedia.org/wiki/Jersey_Act.
4. Spleiss, Chantal. Pedigree Patterns of Thoroughbreds and The Theory Behind.
Rocking Wolf Technologies GmbH, 2019. ISBN: 978-3-9525051-0-6.