Clinical findings and treatment of 94 cattle presumptively diagnosed with listeriosis

The clinical findings and treatment of 94 cattle with listeriosis are described. The general behaviour and condition of the animals were mostly moderately to severely disturbed. A common abnormality in posture was an exaggerated forward or sideward stance, and 11 of the animals were recumbent. More than half of the animals were ataxic and 22 circled. The most frequent cranial neurological signs observed were facial nerve paralysis, salivation, strabismus, reduced or absent pupillary light reflex, reduced or absent tongue movement and head tilt. The haematological and biochemical findings did not contribute to the diagnosis of listeriosis, but they were useful indicators of dehydration and the acid-base status of the animal. Forty-four of 57 of the animals had high leucocyte counts in the cerebrospinal fluid (CSF), mostly mononuclear cells. Eighty-seven of the animals were treated with various antibiotics (penicillin G, oxytetracycline, amoxicillin, and amoxicillin and gentamicin combined), but there was no significant difference in the success rate of the different treatments. Only two of the nine recumbent animals that were treated survived. Univariable analysis suggested that animals that were recumbent, excited, with an absent or weak menace reflex, nystagmus, high numbers of leucocytes in the CSF, high serum concentrations of urea and calcium and high serum activities of aspartate aminotransferase and creatine kinase, and an acid-base deficit, had a smaller chance of surviving. When a logistic regression model was constructed, only recumbency, excitement and a weak or absent menace reflex remained significant factors affecting the likelihood of survival.