The update was originally scheduled for June of this year; however, the decision has been made to delay the change by 12 months. This delay will allow for the Animal Evaluation Unit (AEU) and DairyNZ subsidiary, NZ Animal Evaluation Limited (NZAEL), to complete the transition of the animal evaluation system, which is scheduled to be operating wholly out of DairyNZ in early 2016.
In general, the genetic base cow is lifted every five years. Lifting the genetic base cow will cause an identical drop in Breeding Worth (BW) across all animals and herds. This drop does not cause any re-ranking among bulls or herds, equally it is not an indication of a change in the value of an animal, but rather a smaller difference between the animal/herd and the genetic base cow.
Breeding Worth (BW) represents the genetic merit of an animal, compared to the ‘genetic base cow’. If an animal or herd has a BW of 0, this tells you that their genetic merit is very similar to the genetic base cow.
Every year we see genetic improvement in the national herd; which leads to each group of heifers coming through having a higher BW than those cows before them. A genetic base cow update prevents the gap between the today’s animals, and the genetic base becoming too large, and keeps the scale of our genetic predictions relevant.
While it is important that the base cow is routinely updated, the specific timing of a base cow lift is of very small consequence. Herd and animal genetic evaluations will be unaffected by this 12 month delay.
For more information on the current 2000 born ‘base cow’ click here