The genetic base cow – the genetic reference point for all dairy cattle in New Zealand – has been updated this month to become younger, moving from a 2000 to a 2005 born base cow.
The genetic base is updated every five years by New Zealand Animal Evaluation Limited (NZAEL).
In a media release, NZAEL manager Jeremy Bryant said the base cow update reflected genetic progress and prevented the gap between today’s animals and the genetic base becoming too large, thereby keeping the scale of genetic predictions relevant.
“Every year, there is genetic improvement in the national herd, which leads to each group of heifers coming through having a higher breeding worth (BW) than the cows before them,” said Bryant.
The genetic base update means all animals are compared with a more recent cow population – in this case, the average of a group of well-recorded 2005-born cows.
BW will be scaled back by about $50 as a result of the update. The drop in BW will be identical across all animals and herds.
As a result of the base cow change, the median BW in the New Zealand herd changes from 107 to 68.
Like BW, CRV Ambreed’s New Zealand Merit Index (NZMI) is also scaled back as a result of the base cow change, dropping overall by 49 points.
For example, if an animal or herd has a NZMI of 0, this indicates that its genetic merit is very similar to the genetic base cow. If an animal has a NZMI of 150 points, this indicates that the animal has the ability to breed replacements that will be 150 points higher than the genetic base cow, making the progeny more efficient and easy to manage.
CRV Ambreed product development team leader Erin O’Connor said this change would affect everyone and all farmers would see a noticeable change when they look at both their herd records and the sires they can select from.
“Farmers shouldn’t be concerned of the index drops as a result of the update. This change does not cause any re-ranking among bulls or herds or change the genetic merit of animals, nor is it an indication of a change in the value of an animal,” she said.
“CRV Ambreed’s sires remain strong and robust and we are confident that they will continue to breed progeny that will be healthy, productive, fertile, efficient and last in the herd for years to come.”
Want to know more?
More information is available on DairyNZ’s website at http://www.dairynz.co.nz/animal/animal-evaluation/interpreting-the-info/genetic-base-cow/.
Your local sales consultant is also happy to talk through the changes with you directly.