Here is an example of direct updating of an index for milk yield, based on father’s, offspring’s, mother’s and own yield.
An applet in which the three-part indecies are calculated is applied.
The father’s index is symbolized by F BV, and is calculated on the basis of 20 offspring with an average yield of 7400 kg milk.
The mother’s index is based on two lactations with a yield of 7500 kg milk on average.
Own index is based on one lactation with an average yield of 7200 kg milk.
The population average is 7000 kg milk, the heritability is 25% and the coefficient of repeatability is 30 %.
In the last two lines of the applet the combination index is calculated. First the combination of the two parents’ index, and finally the combination of the parent index and own index.
The combination index is 7299.48 kg milk, with a squared accuracy of 0.392.
