BLAD is a fatal genetic disease involving abnormalities of the immune system in the Holstein-Friesian breed of cattle, Jersey and Simmental. It involves a loss of leukocyte defense function translating into a lack of immunity. The result is recurrent bacterial infections, mouth ulcers, inflammation leading to abnormal development of calves, which die in the first months of life as a result of infections that devastate their bodies.
The basis for the occurrence of BLAD disorder is a mutation occurring within the BTA1 chromosome of the ITGB2 gene, which encodes a subunit of beta-integrin, a membrane glycoprotein. As a result of the mutation, the glycoprotein is not produced, leading to a lack of ability for leukocytes to move to infected tissues, thereby allowing inflammation to spread.
BLAD is a mutation with a recessive basis. Individuals affected by this genetic defect must have the pair of alleles responsible for the mutation. BLAD carriers are characterized by full immune function. They also often show better milk and protein production than individuals fully free of the mutation trait.
| Result | Interpretation |
| BLS | SICK |
| BLC | CARRIER |
| BLF | FREE |
REFERENCES #
- Czarnik U., Grzybowski G., Kamiński S., Prusak B. i Zabolewicz T. Effectiveness of a program aimed at the elimination of BLAD-carrier bulls from Polish Holstein-Friesian cattle. (2007). J Appl Genet 48(4), pp. 375–377.
- Gozdek M., Kolenda M., Kamola D. i Sitkowska B. Report on the incidence of hereditary disorders (BLAD, DUMPS) in the polish population of holstein-friesian cattle. (2020). Acta Sci. Pol. Zootechnica 19(3), 15–22.