Breed: Holstein-Friesian

BLAD (Bovine Leukocyte Adhesion Deficiency) is a fatal immune defect resulting in reduced power of resistance, retarded physical growth, and frequent infections. The calves are born with serious infections, they are very thin and if not stillborn, they die shortly after birth. The defect is caused by a mutation in a single leukocyte surface molecule (CD18) resulting in a malfunctioning of the granulocytes (a part of the white blood cells). The mutation prevents the granulocytes from attacking bacteria, and wounds thus heal very slowly.

The defect is inherited recessively, i.e. a sick calf must inherit the defect from both parents. Carriers of BLAD are healthy, but can be identified by a DNA analysis. The defect is only seen in Holstein-Friesian cattle.

Osborndale Ivanhoe (US 1189870) was identified as the first ancestor to carry the defect and several well-known and much used bulls sired by Osborndale, i.a. Penstate Ivanhoe Star (US 1441440) and Carlin-M Ivanhoe Bell (US 1667366) are carriers of BLAD. The test only requires a sample of the animal itself, and there is no need to test the parents.

Results for BLAD tests:

• TL (normal - the animal has not inherited the defect from its parents)
• carrier (the animal has inherited the defect from one of its parents)

Information about multiple birth