[Inherited thrombopathia in Simmental cattle]

During the years 2012 to 2014, a total of 5 affected Simmental cattle showing persistent bleeding after minor or unknown trauma, were presented at the Clinic for Ruminants or at the Institute for Genetics of the Vetsuisse-Faculty, University of Berne. The homozygous mutation RASGRP2, initially reported in 2007, was present in all these cases and all available parents were heterozygous carriers thus confirming the recessive mode of inheritance. Three affected animals died as a result of persistent bleeding. One animal was stabilized at the Clinic for Ruminants and was slaughtered one month later. Another case showing persistent bleeding and several hematomas was euthanized after genotyping. A frequency of 10% carriers for the associated mutation was detected in a sample of 145 Simmental sires which were used 2013 for artificial insemination in Switzerland. These bulls are designated as TP carriers and should not be used uncontrolled. Breeding organizations in Switzerland make use of the gene test to select bulls which do not carry the mutation.