Bovine lymphocyte intestinal retention defect / BLIRD (ITGB7-related) - Cattle

BLIRD in Holstein-Friesian cattle

This DNA test examines the ITGB7 variant p.(G302S) with genomic notation g.26807079G>A. The variant belongs to Bovine lymphocyte intestinal retention defect, abbreviated BLIRD. BLIRD is an inherited immune and intestinal disorder in Holstein cattle in which the normal presence and distribution of specific T cells in the intestine is disrupted.

What does BLIRD mean?

• Reduced growth: genetically affected animals show clearly lower average growth than clear animals.
• Immune profile: the disorder is associated with abnormal white blood cell and lymphocyte counts.
• Intestinal function: the involved T cells play a role in immune control and regulation of the intestinal lining.

Practical value of this test

The result helps Holstein breeders distinguish clear animals, carriers and genetically affected animals. Identifying carriers allows risk pairings to be avoided and supports targeted management of BLIRD in breeding lines where this variant occurs.

BLIRD is inherited as an autosomal recessive disorder.