WAF, World Ayrshire Federation informerar att det hittats en genetisk defekt hos individer med Peterslund i härstamningen.
Äldre nordiska tjurar med defekten AMC:
| HBNr SWE | CodeNr | Birth country | Name | Sire name | MGS name | Birth date | Bull status | AMC |
| 44607 | 22-4607 | FIN | T Vokke | Ooppium | 29-12-2006 | Dead | Carrier | |
| 92912 | 3-2912 | SWE | VR Leroy | Långbo | Peterslund | 19-10-2007 | Dead | Carrier |
| 99727 | 3-9727 | SWE | VR Lazer | VR Leroy | A Linné | 23-09-2013 | Dead | Carrier |
| 99825 | 3-9825 | SWE | VR Birka | VR Bilbo | Ullimulli | 09-03-2015 | Dead | Carrier |
| 47649 | 22-7649 | FIN | VR Lumia | VR Lazer | A. Andrei | 08-11-2015 | Dead | Carrier |
| 47648 | 22-7648 | FIN | VR Lesley | VR Lazer | R Facet | 24-11-2015 | Dead | Carrier |
| 37858 | 9-6183 | DNK | VR Flores | VR Fabio | VR Leroy | 25-11-2015 | Dead | Carrier |
| 37873 | 9-6182 | DNK | VR Life | VR Lazer | VR Fimbe | 23-02-2016 | Dead | Carrier |
| 37896 | 9-6184 | DNK | VR Luke P | VR Lucky | Nora Prästgård P | 07-05-2016 | Dead | Carrier |
| 48018 | 22-8018 | FIN | VR Lumier | VR Lumia | VR Wand | 12-09-2017 | Dead | Carrier |