On Tuesday, December 2, genetic evaluations for cows and bulls will be released to the entire industry. While some shifting in predicted transmitting abilities (PTA) and indexes occurs at each run, this December's third set of evaluations for the year will have larger-than-normal adjustments. That's because the genetic base is being ratcheted down for the first time in five years to compensate for genetic progress. At the same time, the breeding goals are shifting in the industry, and that is being reflected in updates to genetic indexes. Here is the lowdown:
Progress on genetics for all breeds:
- PTA Milk - will be reduced from 52 pounds (Milking Shorthorn) to 191 pounds (Holstein).
- PTA Fat - downward shifts of 6 pounds (Brown Swiss and Guernsey) to 19 pounds (Jersey)
- PTA Protein - reduced 3 pounds (Guernsey) to 12 pounds (Holstein and Jersey)
- PTA Type - type values will fall 0.24 (Ayrshire) to 0.99 (Holstein).
- Net Merit (NM$) - Less emphasis on productive life (PL) and somatic cell count (SCC). Both traits are reduced 3 percent. The extra weight will go on fat and protein yield. Total emphasis on production is 43 percent; 41 percent, health; and 16 percent, type.
- Holstein Total Performance Index (TPI) - Added a fertility index consisting of 13 percent of the TPI formula and a feed efficiency index at 3 percent. To make room, some emphasis was shifted away from type, udder composite and productive life.
- Jersey Performance Index (JPI) - Heifer and cow conception rate (HCR and CCR) each received a 2 percent rank, while protein moved up 1 percent to 43 percent of the JPI formula. To compensate, daughter pregnancy rate and productive life each received less weight.
- Brown Swiss Progressive Performance Ranking (PPR) - Beefed up daughter pregnancy rate from 4 to 10 percent. To clear space, SCC was reduced from 8 to 4 percent, while PL went from 12 to 10 percent.
In the meantime, if you would like to learn more about the changes to the Net Merit formula, go to: http://aipl.arsusda.gov/reference/nmcalc-2014.htm.
For more on TPI, go to: http://www.holsteinusa.com/genetic_evaluations/ss_tpi_formula.html.
There doesn't appear to be online explanations for the other indexes. However, you can check out Chad Dechow's column in our December issue of Hoard's Dairyman to get the full details.
