Thiamine-responsive neurological disorder of swine

Abstract

This report describes a thiamine-responsive neurological disease and the methodology leading to its diagnosis. The initial case involved one nursery farm. Approximately 5% of pigs at 5 to 7 days after weaning exhibited central nervous system signs. Over the next 3 weeks, 16 of the company’s 41 nursery farms had pigs with similar clinical signs. One month later, neurologic signs were observed in unweaned piglets in several sow farms. Pigs were weaned at approximately 19 days and moved to off-site nurseries. Live pigs and fresh and formalin-fixed samples from acutely affected pigs were sent to diagnostic laboratories. Feed samples were submitted for mycotoxin and nutrient analyses. Initial reports revealed no precise cause of the neurological condition; however, polioencephalomalacia (PEM) subsequently was identified in affected pigs. A field trial determined the response to treatment with atropine, a vitamin A, D, and E preparation, or vitamin B12 plus thiamine. Pigs treated with thiamine recovered from the neurological condition. Upon implementation of thiamine injections on a company-wide basis, neurological signs associated with PEM were no longer evident. The authors do not recommend routine thiamine injections under normal circumstances. In this case, compromised dietary thiamine levels during feed manufacturing possibly contributed to the PEM.