Homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations were determined in the cerebrospinal fluid (CSF) of 28 normal calves and 29 spastic calves. Concentrations of HVA were significantly (P less than 0.01) lower in spastic calves, whereas differences in 5-HIAA concentrations were not found between normal and spastic calves. These findings indicate that a lower dopaminergic metabolism takes place in the central nervous system (CNS) of spastic calves.