Background: Bovine leukocyte adhesion deficiency (BLAD), deficiency of uridine monophosphate synthase
(DUMPS), complex vertebral malformation (CVM), bovine citrullinaemia (BC) and factor XI deficiency (FXID) are
autosomal recessive hereditary disorders, which have had significant economic impact on dairy cattle breeding
worldwide. In this study, 350 Holstein cows reared in Turkey were screened for BLAD, DUMPS, CVM, BC and FXID
genotypes to obtain an indication on the importance of these defects in Turkish Holsteins.
Methods: Genomic DNA was obtained from blood and the amplicons of BLAD, DUMPS, CVM, BC and FXID were
obtained by using PCR. PCR products were digested with TaqI, AvaI and AvaII restriction enzymes for BLAD,
DUMPS, and BC, respectively. These digested products and PCR product of FXID were analyzed by agarose gel
electrophoresis stained with ethidium bromide. CVM genotypes were detected by DNA sequencing. Additionally,
all genotypes were confirmed by DNA sequencing to determine whether there was a mutant allele or not.
Results: Fourteen BLAD, twelve CVM and four FXID carriers were found among the 350 Holstein cows examined,
while carriers of DUMPS and BC were not detected. The mutant allele frequencies were calculated as 0.02, 0.017,
and 0.006 for BLAD, CVM and FXID, respectively with corresponding carrier prevalence of 4.0% (BLAD), 3.4% (CVM)
and 1.2% (FXID).
Conclusion: This study demonstrates that carriers of BLAD, CVM and FXID are present in the Turkish Holstein
population, although at a low frequency. The actual number of clinical cases is unknown, but sporadic cases may
appear. As artificial insemination is widely used in dairy cattle breeding, carriers of BLAD, CVM and FXID are likely
present within the population of breeding sires. It is recommended to screen breeding sires for these defective
genes in order to avoid an unwanted spread within the population.