Accurate and diverse genetic indexes
The animal’s breeding value

The index scores an animal’s estimated breeding value for a given trait. It is a prediction of the net cumulative effects of the various different genes governing the trait targeted.

Like any other estimate, each index carries with it a degree of accuracy, which is measured by the Coefficient of Determination (CoD). The closer the CoD value gets to one (or 100%), the sharper the estimated breeding value.

An index can only really translate the most probable real genetic value of an animal if it accounts for all the factors that converge to shape a performance (both genetic and non-genetic effects), as in the real world, an animal’s genetic potential will express differently depending on factors like herd management system, for example.

This means that measured performances have to be "corrected" for environmental effects. This correction-adjustment process is done using the animal-model BLUP method, where BLUP stands for Best Linear Unbiased Predictor. This method integrated the performances specific to the animal and its lineage (parents, offspring and collaterals).

Also measured performance (in farm, station, on the animal itself, its offspring), genetic evaluation calculations exploit genealogical information recorded via the national systems of animal identification and genetic information (servicing projection, animal insemination, birthdate, ...).

Controls de parentage by genotyping shall be random in the population, and systematically for the bulls distributed by insemination animal.

Within a given breed, the indexes make it possible to class all evaluated animals on each trait, regardless of their age, gender, herd and home region.

The index gives a relative estimate of a given animal’s breeding value compared to a group of recent-generation cows. Indexes are expressed in terms of deviation from this common reference baseline shared by all the individuals in the same breed, which is re-evaluated annually to account for the genetic progress achieved.

The genetic evaluations led on dairy cattle breed sires and dams in France offer a panel of over 30 indexes on specific criteria. This enables a breeder to make the best-informed choice based on the combination of traits that best fits their performance targets and priorities.

The Institut de l’Elevage is the official authorized publisher of the French genetic merit indexes for cattle, sheep and goat breeds.