Bovine malignant melanosis

Abstract

A 2-year-old primiparous Holstein cow was presented with a history of anorexia and difficulty rising. Physical examination revealed a left displaced abomasum, which was corrected surgically using a right flank omentopexy. Appetite and milk production initially improved following surgery, but the cow became progressively ataxic. At slaughter, she was condemned due to melanosis throughout the carcass, which included a spinal lesion at L2-3. Histologically, clusters of melanin were found within the dura and pia mater of the spinal cord, the adrenal gland and adipose tissue. Gross and histological lesions were compatible with a diagnosis of malignant melanosis.