An outbreak of narasin poisoning in swine.

An outbreak of narasin poisoning in swine is described. Forty nine out of 108 lactating sows died over a period of one month after being fed a ration accidentally contaminated with narasin. Clinical signs included anorexia, respiratory distress, lethargy and posterior paresis, progressing to lateral recumbency and death. Necropsy examination in 3 pigs revealed extensive myocardial and skeletal muscle damage. Analysis of the feed confirmed the presence of high concentrations of narasin.