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April 2018: Guernsey evaluations

Issues affecting Guernsey evaluations in April 2018


Guernsey unknown parent groups in April 2018
During the April 2018 run, the program used to create the unknown parent groups (UPG) for the breeds during the traditional evaluation had an unintended behavior for Guernsey. When breeds have too few unknown parents in the last 15 years, the UPG for the breed are suppressed and Holstein UPG are used instead. In April, Guernsey dropped below that threshold and lost all Guernsey UPG, defaulting into using Holstein UPGs instead. This behavior was not intended for genomic breeds and is not due to any new policy or software, but a long existing default value.
We identified the problem during the run, but recoding an exception requires extensive time and testing, which was incompatible with publication deadlines. Therefore, we decided to apply an emergency correction on the genomic side, which benefited most genotyped animals. Although this problem affects mostly not genotyped animals with incomplete pedigree (both males and females), we identified a handful of cases where genotyped cows and bulls in special circumstances had their PTA inflated by the larger Holstein UPG solutions.
For example, on the list of top 50 NM$ genotyped bulls published in December 2017 and April 2018, the top 3 bulls in April 2018 are affected, because all three of them have about 50% unknown pedigree. Please note that two of these bulls were already in the top 10 list in 1712.

We encourage breeders to verify the pedigree completeness % of the bulls (on our bull evaluation query: on the top right, next to birth date) and cows ( to identify the animals mostly affected. The lower that value is, the more inflation derived from using HO UPG is expected.

We plan to correct the default behavior of the program for all breeds involved in the CDCB genomic evaluation in August to prevent this unintended switch ever occur again.

About pre-released file
A new was placed today in the public FTP ( We discovered that the file we posted on Friday was faulty. We kindly ask all users that have already downloaded the file, to redo the download discarding the previous version.

We apologize for the inconvenience.