Abstract
Hereditary diseases in cattle lead to economic losses across various breeds worldwide, with arachnomelia syndrome being one such disorder found in Simmental cattle. Arachnomelia results from a recessively inherited loss-of-function variant in the MOCS1 gene detected only in Simmentals. In Türkiye, prior research on hereditary cattle diseases has focused exclusively on dairy breeds, particularly Holstein. This study marks the first investigation in Türkiye of a genetic disease in a dual-purpose breed that is also valued for its beef traits. For this purpose, blood samples were collected from 387 Simmental cattle in Yozgat, Türkiye. The variant MOCS1 allele was analysed, and the results revealed four heterozygous samples carrying the causal two-nucleotide frameshift deletion, as confirmed by Sanger sequencing. This research provides the first detection of arachnomelia in Türkiye, with a prevalence of 1.03% heterozygous carriers in the population studied. To eliminate arachnomelia, screening of Simmental and Simmental-cross cattle is recommended, with the avoidance of carrier matings to prevent the birth of affected calves.