Complacent About The Rasmussen Factor?

We’d have to admit, we’ve never taken too seriously the idea that the “The Rasmussen Factor” – inbreeding to superior females within five generation through different individuals – was a direct causal influence for upgrading racing performance. In fact at the generational distances usually found in thoroughbred pedigrees, it’s unlikely that inbreeding to any single individual in isolation, whether male or female, will have a significant impact.

We can imagine, however, that many of our friends in Australia might be tempted to think differently. The definitive tome on the subject “Inbreeding to superior females: Using the Rasmussen Factor to produce better racehorses” authored by Rommy Faversham and the late Leon Rasmussen, was published by The Australian Bloodhorse Review (now Bluebloods), and for many breeders, the greatest stallion of their time was the mighty Danehill (inbred 3 x 3 to Northern Dancer’s dam, Natalma).

So it may be that in Australia, deliberate inbreeding to females has been practiced more often than in many other parts of the world, and of course we know all the expression “practice makes perfect.” If that’s so, taken at face value, the events of the weekend in Australia suggest that some Australian breeders have perfected the technique.

We can start with a look at Complacent, who vaulted to favoritism for the Victoria Derby (gr. I) with a win in the Gloaming Stakes (gr. III). He is by one Epsom Derby (gr. I) winner, Authorized (by Montjeu), and his dam is by another, Quest for Fame. Authorized is out of Funsie, who in turn is by Saumarez, a son of Rainbow Quest (sire of Quest for Fame), and his dam is out of a daughter of the important mare, Green Valley II, who also appears as dam of Quest for Fame’s broodmare sire, Green Dancer (a three-quarters brother to the dam of Funsie).

Street Sense’s daughter, Champagne Cath, gained a first black-type victory in the Reginald Allen Stakes. Her dam is by El Moxie (by Conquistador Cielo, a son of Mr. Prospector, out of Raise the Standard, a half-sister to Northern Dancer). Street Sense’s grandsire, Machiavellian, is by Mr. Prospector, out of a daughter of Raise the Standard, and so very closely related to El Moxie.

The Best in Show family has been a prominent one in Australia, and is carried through two particularly influential stallions, Redoute’s Choice (whose fourth dam is Best in Show) and Last Tycoon (by Try My Best, a grandson of Best in Show.  Redoute’s Choice and sons have sired at least 16 stakes winners out of mares carrying Last Tycoon, eight graded, and three grade one. The latest of these, Sharnie Rose, by Redoute’s Choice’s son Nadeem, with a second dam by Last Tycoon, captured the Golden Pendant (gr. II) on September 28. A different version of the Best in Show duplication appears in Australian Saturday stakes winner, Crafty Cruiser, who is by Good Journey (by Nureyev) out of a mare by Last Tycoon’s son, O’Reilly. Incidentally, Good Journey, Last Tycoon, Redoute’s Choice and the granddam of Redoute’s Choice, are not only all from the Best in Show family, but also from the same sire line (Northern Dancer).

We’ll also mention that Redoute’s Choice appears as Stratum, whose son, Divine Calling, took another Saturday black-type event, the Bill Stutt Stakes (gr. II). Stratum carries Australian Champion Sire, Bletchingly (by Star Kingdom’s son, Biscay out of the mare, Coogee), and Divine Calling’s fourth dam, Manila, is by Star Kingdom out of Coogee.

Sharp-eyed readers will have noticed by now, that the horses mentioned above not only have notable females duplicated in their pedigrees, but that those duplications are arriving via similarly-bred individuals (we’ve tended to call them “genetic relatives” an admittedly somewhat loose term, but one that seems to reasonably describe horses who have a similar pedigree background, but are not always relatives in terms that would formally describe them, such as “brother” , “sister”, “half-brother”, “half-sister” and so on. The result is that the duplicated females are part of a grouping of similar ancestors, focused through individuals closer up in the pedigree. With this method of breeding – if through superior individuals – there are more chances of either reinforcing positive genetic variants, or combining compatible variants – than with a more outcrossed individual.

Happily, to demonstrate that principal, the weekend in Australia also threw up a couple of notable examples that don’t rely on duplicating females. The Moir Stakes (gr. I) winner, Samaready, is by More Than Ready, out of a mare by Secret Savings (himself inbred to the mare Broadway). More Than Ready’s dam, is by Woodman, who is three-quarters related to Seeking the Gold, the sire of Secret Savings. Rain Drum, winner of the Shannon Stakes (gr. II) is by Fastnet Rock (dam by the Nijinsky II horse, Royal Academy) is out a mare by Thunder Gulch, a horse whose dam is by Storm Bird, who in turn has a similar pedigree to Nijinsky II.  We’ll leave by mentioning that Royal Academy is also closely related to Storm Bird’s son, Storm Cat, as Royal Academy is a half-brother to Storm Cat’s dam. The cross of Fastnet Rock with Storm Cat line mares, has already produced grade one winners Foxwedge and Irish Lights.


6 Comments on "Complacent About The Rasmussen Factor?"

  1. Ann Ferland says:

    I had hoped to exploit the close genetic relationship of my mare’s second dam with Deputy Minister, but, alas it was not to be; she died foaling last spring. Her half-sister has produced a SW by Dehere, the only foal of racing age with Deputy Minister on the sire’s side, so it was something I felt encouraged about.

  2. Rommy Faversham says:

    Hi Alan,

    I’m confused.

    Does this mean we should take the Rasmussen Factor seriously?

    Since we live in a democracy, I think if most people think it’s hogwash
    then we should really go with the majority.

    It’s all hocus pocus, anyway – at least, that’s what I’ve read.

    • Alan Porter says:

      Hi Rommy,

      Thanks for the comment. My take would be that there is a tendency for the Rasmussen factor to be associated with the type of matings that upgrade pedigrees. I am not convinced that the duplication of a single mare at, say, five generations, is in an of itself going to make a lot of difference to most matings. However, because mares and their daughters frequently get bred in similar ways, so creating these genetic relatives that are discussed in the article.

      I think the “Rasmussen Factor” was a useful talking point in the evolving debate, but I think it’s easy to confuse what is causal and what is associative (I’ve done it myself), so I wouldn’t necessarily plan a mating on the basis of an RF pattern, but will frequently make matings that do have an RF present.

  3. Rommy Faversham says:


    Please correct me, but it would seem your second and third sentences are
    at least partially contradictory.

    You have indeed become the planet’s leading pedigree professional, but honestly
    dude, does female family inbreeding improve a pedigree or not?

    The Rasmussen Factor is nothing more than a unit of its measure.

    It is not a ‘talking point’ or any other marketing strategy.

    There are others who continue to master that art.

  4. Julian Montes says:


    About 40 years ago I began to thirst for every piece of information on available on pedigree I taught myself, I begun to purchase books about pedigree and breeding of thoroughbreds. I consider myself an expert on the subject. I read, researched, and analyzed the genotype of these hybrid animals and the genetic traits that makes them a winner. I am just beginning to explore my options to use my knowledge to assist people in racing, making selections for breeding and/or purchasing excellent runners . About your article, the Rasmussen is one of MANY factors that goes into breeding a winner.

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