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07-03-2008
In response to the necessity expressed by a number of persons for a revision of the current indexing system used for Italian breed sires, the Central Technical Commission initiated a study of the matter in June 2007, analyzing the transformations under way in the breeding of Italian beef breeds. Having acknowledged the considerable changes that have taken place and the new needs of the breeders, a project to adjust the selection scheme was undertaken; in particular, the increase in the popularity of open-pasture rearing systems and the indications arriving from the rest of the production chain make it necessary to identify and evaluate new objectives and tools for selection.
Before introducing new genetic indexes for choosing sires, it was considered of primary importance to perfect and consolidate the current Bull Selection Index (BSI) which, in 20 years of activity, has proven its validity, determining a substantial evolution of the beef model of our breeds.
The work done does not entail, for the time being, any change in the selections objectives pursued through the index, which remain the capacity for growth (in terms of average daily gain) and muscle development.
The Genetic Evaluations Office, in collaboration with the University of Padua, made an accurate check of the Performance Index calculation system for the Marchigiana, Chianina, and Romagnola breeds, in order to further improve the reliability of the index currently used.
Over a period of about six months, the BSI was examined and checked; then the calculation methods were simplified and the software procedures for determining it were rewritten. All the origin data recorded from 1988 up to the present at the Genetic Centre were also rechecked, in order to guarantee maximum accuracy and soundness of the starting information.
The inheritability of the traits considered was estimated once again and consequently adopted, using values considered more appropriate. As a result, the index scale was considerably reduced, from the 50-150 interval of the old index to a current one of 65-130. The new system for estimating the genetic value of the sires, while causing ranking changes in the classification of some animals, does not substantially modify the rank of the approved sires.
The Cow Selection Index (CSI), consisting 50% of the BSI and 50% of the Morphology Index, is also affected by the above-said changes, and is lowered proportionally. In any case, it is understood that, on the basis of the regulations in effect, the Bull Dams already approved on the basis of the previous indexes maintain their qualification.
In light of the long, accurate work carried out in collaboration with a group of some of Italy’s most qualified geneticists, we believe that the new system can be more useful in the choosing of the sires and for genetic progress.
The use of the new procedures began on 5 March 2008, and the calves that will be presented in the March auctions have been approved with the new indexes.