Abstract
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. © 2024 The Authors. This is an open access article under the CC BY-NC-ND 4.0 license (https://creativecommons.org/licenses/by-nc-nd/4.0/deed.en), which allows re-users to copy and distribute the material in any medium or format in unadapted form and for noncommercial purposes, and only so long as attribution is given to the creator.