ALIMENTARY AND RESPIRATORY-TRACT LESIONS IN 8 MEDICALLY FRAGILE HOLSTEIN CATTLE WITH BOVINE LEUKOCYTE ADHESION DEFICIENCY (BLAD)

Lesions in the alimentary tract were studied in eight medically fragil e Holstein cattle homozygous for the bovine leukocyte adhesion deficie ncy (BLAD) allele as determined by polymerase chain reaction and restr iction endonuclease analysis. These cattle received institutional medi cal care but died or were euthanatized because of chronic debilitation associated with diarrhea (6/8) and pneumonia (4/8). The six cattle wi th diarrhea had acute (n = 3) or chronic (n = 3) intestinal ulcers, bu t the other two remained relatively healthy for 3 years and did not de velop intestinal tract ulcers. Ulcerated areas were present in the sma ll intestine in six animals, and two of these also had ulcers in the l arge intestine. Ulcers were covered by thick exudates that, in chronic lesions, partially occluded the intestinal lumen. Intramural and sero sal fibrosis also contributed to lumen constriction. Pseudomonas aerug inosa was isolated from the intestine of four cattle. Bovine viral dis ease virus and Salmonella were not isolated from the five cattle that were tested. Respiratory tract lesions consisted of dense infiltrates of neutrophils in bronchi, bronchioles, and alveoli. This study sugges ts that intestinal lesions are integral to the demise of BLAD cattle t hat receive intensive medical care and that neutrophils do infiltrate the lung and enter airway lumina, despite the adhesion deficiency.