Bovine Leukocyte Adhesion Deficiency syndrome (BLAD): A recessive disorder in Holstein Friesian cattle – A review

The present review is to summarize findings on one of the most important recessive hereditary disorder Bovine Leukocyte Adhesion Deficiency Syndrome (BLAD) in cattle. It is a disease of young Holstein calves characterized by recurrent pneumonia, ulcerative and granulomatous stomatitis, periodontitis, delayed wound healing and persistent neutrophilia. The recessive homozygous form is lethal and since carrier animals have viability, BLAD frequency increases by use of carrier bulls in Artificial insemination (AI). The gene CD18 was the suspected culprit and a point mutation was eventually identified within the alleles encoding bovine CD18 in a Holstein calf affected with BLAD. This mutation causes aspartic acid to glycine substitution at the amino acid level. PCR-RFLP, PCR-SSCP, AS-PCR and Tetra-primer ARMS-PCR are certain PCR based techniques which could be used to screen BLAD in cattle. The use of these molecular technologies promises quick detection of carriers enables their culling therefore, controlling and preventing the spread of BLAD in the population.