Molecular Screening and Prevalence of Inherited Disorders in Indigenous and Crossbred Cattle in India - A Breed-Wise Study

Abstract

This study was aimed to screen the autosomal recessive genetic disorders like Bovine Leukocyte Adhesion Deficiency (BLAD), Bovine  Citrullinemia (BC), Deficiency of Uridine Monophosphate synthase (DUMPS), and Factor XI deficiency (FXI) in cattle that affect the  reproductive health of the cattle population. In the present study, 500 animals of different breeds like Holstein Friesian (n=170), Jersey  (n=75), Kankrej (n=98), Gir (n=100), and Sahiwal (n=57) were screened. Blood samples were collected from different states/areas of  organized farms in India. DNA isolation was carried out by an automated DNA extraction method. The identification of a mutation in the  gene was carried out using a set of published primers by conventional PCR. The PCR product was confirmed on 2% agarose gel. Confirmed  PCR products were digested by restriction enzymes Taq1 for BLAD, AvaII for BC and Ava1 for DUMPS. Restriction digestion followed by 3%  agarose gel electrophoresis to observe the band length, indicates a normal or carrier animal. The specific PCR method was used for FXI  genotype identification. Synthetic genes were synthesized for all four genetic disorders and used as a positive control for the experiment.  In our study, out of 500 cattle tested, only three HF crosses were found to be carriers for BLAD, and none of the animals were found to  be mutants or carriers for BC, DUMPS, and FXI. The results show the prevalence of BLAD as 0.6% in the population and for BC, DUMPS,  and FXI, it was 0%. The prevalence of BLAD carrier animals with heterozygous genotypes was 1.76 % in the HF breed. The genotype  frequency of the BLAD carrier was found to be 0.006. BLAD carrier DNA was confirmed by using Sanger sequencing. Identification of  genetic disorders in the cattle population and eliminating these animals from the breeding program will help in the selection of healthy  animals with desirable traits, which leads to maintaining herd quality, reproductive soundness, and economic viability.