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FirstCross 2.0 enhancement records successful inbreeding to females


        Breeding methods associated with the duplication of females are, for most breeders, inextricably associated with Leon Rasmussen, who has for many years chronicled the successful runners, stallions, and broodmares with multiple occurrences of a superior female in their ancestries. In recognition of this, Jack Werk coined the term "Rasmussen factor," which has become the popular rubric for methods involving "inbreeding to superior female families through different individuals." In recognition of the popularity of these methods, the Australian Bloodhorse Review has announced that it will publish a book on this subject by Rommy Faversham and Leon Rasmussen. This book will be the first comprehensive account of the Rasmussen factor.
        A great deal of enthusiasm for the Rasmussen factor will have preceded the publication of the book, which is reason enough for the eagerness with which breeders who have used this approach are anticipating its release.
        Unfortunately, many mistakes have been made by breeders in the application of the Rasmussen factor, not realizing that it actually involves many different methods, some of which are favorable and some of which are not. A given method involves essentially three conditions:

  1. The female who is duplicated: Some female ancestors are not of sufficient quality to be combined successfully in pedigrees.
  2. The strains through which she descends to the new individual: Some female ancestors did not produce offspring of sufficient quality or variety to provide branches of descent that would allow for successful duplication. Some strains of a superior ancestor cannot be combined successfully with other strains, and some strains that can otherwise be combined successfully with another strain will not work with one another.
  3. The distance of the inbreeding from the new individual: Strains that cannot be combined successfully at, say, 3x4, might work at the more distant remove of 4x5.

        The Rasmussen factor may indeed have a certain magic all its own, but the same three conditions that apply to methods of inbreeding to males also apply to methods of inbreeding to females.
        The best evidence that a certain method has a chance of success is the record of past success. This is why CompuSire is including a complete analysis of inbreeding to females in its late-February update of the FirstCross 2.0 module. A new database will be extracted from the database of stakes winners included in FirstCross 2.0. It will include an entry for every occurrence of inbreeding to females at all distances that are less than or equal to 5x5 (4x6 included).
        Each entry will contain the name of the stakes winner, the name of the duplicated female, the name of the sire strain, the generational distance of the sire strain, the name of the dam strain, and the generational distance of the dam strain.
        When considering a stallion who would duplicate a female in the pedigree of a given mare, FirstCross 2.0 users will be able to query the database for occurrences of inbreeding to that female and determine whether or not the method that they are considering has been successful in the past, taking all relevant variables into account. This feature will also be useful when researching prospective auction purchases.
        This new feature will not involve any additional cost to FirstCross 2.0 subscribers. It's within our scope to provide it, and we think it's crucial that you have it.

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Copyright © 1998 Roger E. Lyons
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