Congenital spinal stenosis and dam mortality associated with feeding moldy cereal straw.

We describe herein an epidemiological investigation of the cause of a syndrome of congenital spinal stenosis (CSS) in four beef herds in western Canada. Three of the herds were affected with the syndrome in 1987, the fourth was affected in 1990. The prevalence of CSS in affected groups of calves varied from 29% (16/55) to 100% (14/14). All affected calves had congenital posterior paralysis or paresis; some calves also had one or more of the following: shortened limbs, forelimb varus deformities, superior brachygnathia, and a dome-shaped cranium. Affected calves showed focal premature closure of axial and appendicular metaphyseal growth plates. At three of the four farms most of the pregnant cows were affected with alopecia with or without pruritus in January, and 25% of the cows in one herd died during the winter. The investigation indicated that CSS was associated with feeding moldy cereal straw to pregnant beef cows during the winter. At all four farms, the cereal straw bales were thoroughly soaked by rain prior to stacking, and obvious mold was present when they were broken open for feeding. Species of both Penicillium and Fusarium were abundant within the bales. The most likely cause of the disease was a fungal mycotoxicosis, although the mycotoxin responsible was not isolated.