Ascaris suum in Saskatchewan pigs: an abattoir survey of prevalence and intensity of infection.

In a survey of 2500 market weight pigs in a Saskatchewan abattoir, 37% were infected with adult Ascaris suum and in 46% there were milkspot hepatic lesions. A total of 60% of the pigs examined had some evidence of A. suum infection. Most infected pigs contained less than 50 adult ascarids. In a second abattoir survey of a further 2500 market weight pigs, 44% of the animals had milk-spot hepatic lesions. In approximately 12% of the affected pigs these lesions were very severe and a very similar proportion of pigs' livers were condemned or sent for use as animal feed. The results of these surveys are discussed with particular reference to the significance of A. suum infection in growing pigs in Saskatchewan.