The Council on Dairy Cattle Breeding (CDCB) will be changing the phenotypic base used in the
expression of the PTAs for the calving traits in August 2020. This will result in a decrease in the
mean and standard deviations, especially for Calving Ease. However, the ranking of the bulls
will remain quite stable.
As, Daughter Calving Ease (DCE) and Daughter Stillbirth (DSB) are two components of the TPI formula, we will need to make an appropriate adjustment to the TPI formula. Only the Calving Traits will be adjusted, all other traits will be remaining unchanged. CLICK HERE for the full release from Holstein Association USA