The estimates below are an approximation of what changes will occur in PTA due to updating the base from cows born in 1990 to cows born in 1995.
These numbers were derived from the difference between average PTA of cows born in 1995 and those born in 1990. A positive value indicates the PTA of that trait will decrease by that amount due to the base change. This shows that improvement has been made in the three yield traits as well as in productive life.
The table above shows that the PTA for SCS will decrease in all breeds except Milking Shorthorn, but this was primarily due to a change in phenotype. The changes in PTA SCS due to genetics were near zero in all breeds and are shown in the following table. Because low scores are desirable in SCS, a negative value for a breed (for example Guernsey) indicates that genetic progress was made toward lowering SCS.