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| Making Your Selection (A Tough Job) by Astrid von Velsen-Zerweck "Once the 1st foals of the year are dropped, a breeder begins again to study stallion directories & numerous glossy brochures from famous stallion stations. He absorbs all of the information, weighs the advantages & disadvantages of his mares & finally selects a stallion that appears to be ideal - a decision that no one else can make for him. The German equestrian Federation, however, gave the breeder an invaluable aid with its 1996 Breeding Yearbook that was published around Christmas. This latest edition of the yearbook has been supplemented in some interesting aspects: For stallions foaled in 1980 or later, in addition to their inspection results & registration of progeny in the performance stud book, the yearbook includes for the 1st time all stallion performance test results. Volume II lists the stallion's get that were successful in the show ring in 1996 & their breeders, and highlights the 50 most successful breeders. This new breeding evaluation of stallions on the BASIS OF SHOW RESULTS OF THEIR GET is always eagerly awaited since it provides more IMPORTANT INFORMATION ABOUT THE GENETIC PROWESS OF A STALLION. The breeding index represents the GENETICALLY ESTABLISHED DIFFERENCE OF AN ANIMAL FROM THE AVERAGE OF ALL ANIMALS OF HIS POPULATION FOR ONE SPECIFIC FEATURE; for the show horse this is the logarithmed amount of prize money won by his get. With this estimated breeding index it is possible to establish the value of a horse for breeding on the bais of the performance of his ancestors, siblings & get, as well as his own performance in the show ring, separated for dressage & jumping. This is what breeders have always done when they looked at the success of a stallion & his ancestors. The complex method of computing the breeding index, however, is able to incorporate all available show results begining with 1976, that is, information about all related animals. The process employs "BLUP Animal Model", a genetic-statistic estimating method which is able to consider environmental influences that affect the performance of a horse together with genetic effects. This is different form a mere listing of the annual sum of prize moneys; the breeding index considers the effect of the rider on the horse's performance, the effect of an individual test, that is the footing & the competition for this test, as well as the age & gender of the show horse. In this way it is possible to filter the actually hereditary portion of a performance, which the horse accomplishes independently of the talent of its rider or the competition, from the plethora of environmental influences. Additionally the sum of prize moneys won is formed only from the get of a stallion, while the BLUP breeding index considers the entire family of a horse, including his ancestors & siblings. Also considered is the mating level which is corrected to the breeding value of a respective partner in the mating. HOW DOES SUCH A BREEDING INDEX COME ABOUT? The younger the stallion, the fewer performance records he himself or his get can provide. The information about the stallion can thus come only from his pedigree, so that his breeding index is initially composed of half of his dam's breeding index & half of his sires & accordingly is still relatively imprecise. But it is possible to compile a breeding pedigree index already for a foal that has not yet been born. With increasing number of get that were pinned in shows, the breeding index becomes ever more precise (accuracy > 60%) & thus more informative. Stallions whose breeding indexes cannot be determined with sufficient precision, because only insufficient performance information is available, do not meet the minimum requirements & NO breeding index is given for them in the Breeding Yearbook. This year (1996) the method of determining a breeding index was adapted, by request of the breed associations, to the newest scientific discoveries. A significant improvement is already the described consideration of the effect of rider & competition. Horses ridden by professionals - riders who get many ribbons in many shows on several different horses - are given a deduction over pinned horses ridden by amateurs. Horses with placings in tests that involve heavy competition are given a bonus. The correction in earlier breeding indexes was made only with respect to the overall show, which was relatively imprecise & led to over- & underevaluation of certain get groups. Moreover, due to the most recent research, heritability of only 10% is used for the logarithmed sum of prize money won. The environmental influences are more significant than had been assumed in the past, with the consequence that more placed get per stallion are now required to produce a sufficiently accurate breeding index. In view of this, the stallions are now grouped into 3 age groups, each being governed by certain minimum requirements. The breeding indexes are relative values (deviation from 100), whose reference basis (100) is the median breeding index of all show horses foaled in 1988. The standard deviation is 20 points. This reflects a standardization method that is different from the past & is comparable to that used in Stallion Performance Tests so that "runnaways", such as DONNERSCHALG last year who had an index of 270, can be avoided. In principle this does not change the ranking of the stallions, the breeding indexes are merely closer to 100. It is thus not possible to directly compare the 1995 breeding indexes with those of today. By changing the procedure & thus improving the breeding indexes, the results of some stallions are changed; some noticeably moved up in rank, for example the Holsteiner stallions CORIANDER & CONTENDER, who are the leaders in jumper producers in the "Older Stallions Group I" others even though notieably more get have been considered, remain unchanged (e.g., the Oldenburger WELTMEYER), while others yet had been overestimated & have now dropped down in ranking - the most prominent example is probably the Hanoverian LANDGRAF, who no longer appears among the top 20 of his group." This article was first published in The American Trakehner (mag), Mare & Foal issue of Fall 1997 |