Detection of bovine leukocyte adhesion deficiency (BLAD) in Turkish native and Holstein cattle

Induced pluripotent stem cells from domesticated ruminants and their potential for enhancing livestock production

Ruminant livestock, including cattle, sheep, goat, and buffalo, are essential for global food security and serve valuable roles in sustainable agricultural systems. With the limited availability of embryonic stem cells (ESCs) from these species, ruminant induced pluripotent stem cells (iPSCs) and iPSC-like cells provide a valuable research tool for agricultural, veterinary, biomedical, and pharmaceutical applications, as well as for the prospect of translation to human medicine. iPSCs are generated by reprogramming of adult or fetal cells to an ESC-like state by ectopic expression of defined transcription factors. Despite the slow pace the field has evolved in livestock species compared to mice and humans, significant progress has been made over the past 15 years in using different cell sources and reprogramming protocols to generate iPSCs/iPSC-like cells from ruminants. This mini review summarizes the current literature related to the derivation of iPSCs/iPSC-like cells from domesticated ruminants with a focus on reprogramming protocols, characterization, associated limitations, and potential applications in ruminant basic science research and production.

Screening for bovine leukocyte adhesion deficiency, deficiency of uridine monophosphate synthase, complex vertebral malformation, bovine citrullinaemia, and factor XI deficiency in Holstein cows reared in Turkey

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.

Implication of complex vertebral malformation and bovine leukocyte adhesion deficiency DNA-based testing on disease frequency in the Holstein population

Two inherited lethal disorders, bovine leukocyte adhesion deficiency (BLAD) and complex vertebral malformation (CVM), play a major role in breeding of Holstein cattle. Both inherited diseases are based on single nucleotide polymorphisms that have been known for 12 and 7 yr, respectively. A total of 25,753 cattle were genotyped for BLAD (18,200 tests) and CVM (14,493 tests) in our laboratory since the beginning of the genotyping programs for these diseases. Based on founder effects, the CVM mutation is thought to be linked to milk production. The BLAD was genotyped using RFLP until 2001; then a fluorescence resonance energy transfer assay on a LightCycler was used, as for CVM genotyping. By using single nucleotide polymorphism-aided breeding, the allelic frequency of the BLAD and CVM mutations in the active sire population was reduced from 9.4% in 1997 to 0.3% in 2007 (BLAD) and from 8.3% in 2002 to 2.3% in 2007 (CVM), with calculated half-life of the mutant allele of 2.1 yr for BLAD and 3.6 yr for CVM. An observed increase of BLAD frequency in 1999 could be attributed to the massive use of a BLAD-positive sire tested falsely negative in another laboratory. These data show that marker-assisted selection is capable of substantially reducing the frequency of a mutation within a period of not more than 5 yr. The different selection strategies against the lethal recessive allele in CVM and BLAD are reflected in the different reduction rates of the specific allele frequencies.