Prevalence of carriers of cholesterol defiiciency-associated APOB mutation in some native, Holstein and Simmental cattle breeds in Trkiye

Genetic diseases play an increasingly important role in cattle breeding as breeding technologies such as artificial insemination has an inborn risk of disseminating deleterious genes, especially from high merit breeding sires. Cholesterol deficiency (CD) is a metabolic disorder first recognized in Holstein cattle in 2015. The condition is characterized by chronic diarrhea and unthriftiness in calves being homozygous for the defective allele. The prevalence of carriers of CD in Turkish cattle is at present unknown and therefore 700 heifers and cows of different breeds, including 300 Holsteins were genotyped. Of the tested Holsteins, 2.0% turned out to be carriers of CD thus showing that the defective allele for CD is actually present in Turkish Holstein cattle. The carrier prevalence was between 0% and 4.0% in 4 different Holstein herds. Carriers were not found in other breeds tested, which included native Turkish cattle breeds. To avoid the birth of Holstein calves that will develop clinical signs of CD, sires should be tested for CD, and only homozygous normal individuals should be used for breeding.