With the official April 2019 proof release, Germany has made some important improvements in its breeding value estimation system. This includes a change in the RZM formula with more weight on fat, taking in to account that (a) there is no longer a quota on fat in Germany and (b) the significant change in the price ratio on the world market between butterfat and protein.
Another significant development in the German genomic evaluation system is a major adjustment to a mixed reference population featuring bulls and cows.
As cows better represent the entire genetic range across all Holsteins, the additional production data added from 130,000 genotyped cows through KuhVision (the whole herd genotyping project) means a huge increase in the quality of the overall reference population.
Some expected changes in the gEBV’s have also been observed.
Through KuhVision, Germany has collected a large amount of standardised data on dairy cow health. And by using this data from the reference cow population alongside herd hoof trimming data, 13 new health traits have been added to the German genetic evaluation.
By combining the relative traits, breeders from April 2019, can use 5 new selection traits for cow health. This includes the 4 main indices for udder health (RZudderfit), hoof health (RZhoof), cow reproduction (RZrepro) and metabolism stability (RZmetabol). These 4 sub-indices are then combined into a Total health index (RZhealth) according to their economic importance.
The new German breeding value for resistance to digital dermatitis (Mortellaro), “DD control”, introduced in August 2018, is part of the new hoof health index but will also be published separately. The elite 10% of bulls which transmit a high resistance to the digital dermatitis disease, will continue to carry the highest label “DD premium” while the 25% best bulls will carry the label “DD control”.
All of the new German health traits will be expressed as usual on a relative scale with a mean of 100 and a genetic standard deviation of 12 points. Higher EBV’s are more desirable, indicating that daughters are less affected by the identified diseases. Our global clients can now enhance their selection criteria by focusing on all areas of animal health but need to be aware that at this stage, the new health traits are not included in the Total Merit Index RZG.
Finally, the April Sire Summary has seen the regular annual base change in Germany of -2.6 RZG (Total Merit) points, -1.4 RZM (Production) points and -2.0 RZE (Type) points on
average for each Black & White Holstein bull. All improvements and amendments need to be considered when comparing the German April 2019 with the December 2018 figures