Bovine leukocyte adhesion deficiency / BLAD / HHB (ITGB2-related) - Cattle

BLAD and leukocyte adhesion deficiency in cattle

This DNA test examines the ITGB2 variant c.383A>G that causes bovine leukocyte adhesion deficiency. The condition is also known as BLAD, leukocyte adhesion deficiency type I or Haplotype HHB. ITGB2 encodes CD18, a component of beta-2 integrins on white blood cells.

What does BLAD mean for a calf?

• Immune defect: white blood cells are less able to move from the bloodstream into infected tissue.
• Infection susceptibility: affected calves are highly susceptible to severe and sometimes fatal infections.
• Typical picture: recurrent infections, poor wound healing, reduced growth and persistent high neutrophil counts have been described.

Practical value of this test

The result helps breeders distinguish clear animals, carriers and genetically affected animals. For Holstein-Friesian and other at-risk breeds, carrier detection is valuable for removing BLAD from breeding lines while retaining valuable animals responsibly.

BLAD is inherited as an autosomal recessive disorder.