The official ranking of animals is based on the PFT index. It refers to the position in the ranking of a specific animal (bull or cow) out of the total indexed population, divided by males and females.
The ranking range goes from 1 to 99, dividing the population in percentiles. There is no n°100 because it represents the perfect animal. Thanks to this ranking, it is possible to define an official limit that allows to establish which animals can be admitted to the artificial insemination. In the case of Italian Holstein Fresian breed the limit is represented by rank 98: the top 2% of the bulls on the list.