Abstract. The use of specialized meat breeds in cattle breeding
programs is considered very promising for improving herds'
productivity. However, in animal genotype, along with genes that positively
affect the productivity signs, there are genes whose mutations, known as
genetic defects, negatively affect the health of animals. The aim of the
study was the screening of the Russian populations of Aberdeen Angus,
Hereford and Belgian Blue cattle on gene mutations associated with the
genetic defects of arthrogryposis multiplex (AM), osteopetrosis (OS),
developmental duplication (DD), double muscling (M1), hypotrichosis (HY) and
maple syrup urine disease (MSUD) as well as the F94L polymorphism of myostatin
gene (MSTN) linked with the gene responsible for less fat content in the carcass by means of DNA
analysis. In the article, test systems based on the polymerase chain reaction method are presented. The analysis of the Aberdeen Angus (n=4480)
population has revealed 0.19 ± 0.09 % animal M1 carriers,
0.53 ± 0.03 % OS carriers, 1.92 ± 0.09 % AM carriers and
9.00 ± 0.20 % DD carriers. The genotyping of Hereford cattle of
Russian populations (n=525) has not revealed any individual carriers of
MSUD or HY genetic defects. All of the Belgian Blue population (n=92)
animals were heterozygous M1 carriers. The study of the F94L MSTN polymorphism has demonstrated extremely
high frequencies of the desirable A allele (0.93 and 0.90) in two Aberdeen Angus populations with an average
mean of 0.63 ± 0.08, which was 32 % higher compared to the Belgian Blue
population. The results suggest the high genetic potential of the Aberdeen
Angus and Belgian Blue cattle, but the existence in the genotypes of the mutant
alleles associated with hereditary diseases indicates the risk of
uncontrolled use of these breeds.