¹Balıkesir University, Faculty of Veterinary Medicine, Department of Genetics, TR-10145 Balıkesir - TÜRKİYE
²Balıkesir University, Faculty of Veterinary Medicine, Department of Animal Nutrition and Nutritional Diseases, TR-10145 Balıkesir - TÜRKİYE DOI : 10.9775/kvfd.2022.28793 Cholesterol deficiency (CDH) and lethal haplotype 5 (HH5) are autosomal recessive genetic defects of Holstein cattle. HH5 and CDH are associated with embryonic mortality and calf loss, respectively, resulting in severe economic losses in the dairy cattle breeding. The aim of the present study was to investigate the presence of HH5 and CDH haplotypes and to determine the carrier and haplotype frequencies for these haplotypes in Holstein cattle reared in Balıkesir province of Türkiye. Polymerase chain reaction (PCR) was used to detect the deletion of the transcription factor B1 (TFB1M) gene and the retroviral insertion into the apolipoprotein B (APOB) gene, causing CDH and HH5, respectively. A total of 450 Holstein cows born between 2011 and 2018 were screened for causative mutations of both haplotypes. As a result, the carrier frequencies for CDH and HH5 were 4.67% and 7.56% and the haplotype frequencies were 0.023 and 0.038, respectively. 12.22% of the cows were identified to be carriers of at least one genetic defect. This study demonstrated the presence of CDH and HH5 haplotypes in Holstein cattle reared in Türkiye. Keywords : Holstein, Cholesterol deficiency, Lethal haplotype 5, Genetic defects