Muscle Weakness – new genetic defect transmitted to Polish Holstein-Friesian cattle

The aim of the study was to find out whether carriers of new genetic defect Muscle Weakness (MW) occur in the population of Polish Holstein-Friesian bulls. Fifty bulls were included in the analysis. Bulls were selected as having in the pedigree known carrier of MW. All bulls were diagnosed by DNA sequencing of CACNA1S gene containing single nucleotide substitution (rs3423414874) responsible for 97% of MW cases. Among 50 bulls, 19 MW carriers were found. Our results show that causal mutation for MW is already transmitted to Polish Holstein-Friesian cattle which is sufficient ground to take practical action in order to avoid further spreading of mutation causing MW.