Bovine Leukocyte Adhesion Deficiency | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Overview of Bovine Leukocyte Adhesion Deficiency (BLAD)

• BLAD is a fatal autosomal disease affecting Holstein. Friesian cattle, resembling common calf diseases such as pneumonia and diarrhea, typically leading to death before adulthood. Carrier bulls appear healthy but can transmit the disease through semen via artificial insemination, even across borders.

Causes (Etiology):

• BLAD is linked to a deficiency in CD18 gene expression in neutrophils, resulting in the lack of three glycoproteins (LFA-1, MAC-1, P150/95) and improper subunit expression.- The absence of these glycoproteins hampers leukocyte adhesion, crucial for the body's defense mechanism.

Development of the Disease (Pathogenesis):

• Proper leukocyte adhesion is vital for the body's defense mechanism.- Glycoproteins on leukocytes aid in this adhesion process.- Deficiency of the three glycoproteins disrupts normal defense mechanisms.- Impaired expression of the subunit prevents binding with other glycoproteins, hindering leukocyte adhesion and mobilization.

Symptoms:

• BLAD symptoms manifest early in calves' lives.- Symptoms include enteritis, stomatitis, recurrent pneumonia, lymph node swelling, delayed wound healing, and persistent neutrophils.- Common symptoms involve cutaneous infections, ulcerative gingivitis, and biochemical changes like hypoalbuminemia and hypocalcemia.

Diagnosis:

• BLAD carriers and affected animals are diagnosed through various methods like functional neutrophil tests, CD18 genotype analysis, Ligase Chain Reaction (LCR), and image analysis of chromosomes and sperm characteristics.

Importance in the Indian Context:

• India's extensive cross-breeding with Holstein Friesian cattle poses a risk of importing BLAD due to the CD-18 gene expression.- Screening and identifying BLAD carriers through DNA-PCR techniques are crucial to prevent the disease's spread and safeguard India's cattle wealth.