Effect of Mount St. Helens’ Volcanic Ash on Broiler Performance and Health and on House Environment ,

Abstract

An experiment involving approximately 1300 broilers was carried out in an uninsulated, windowless, negative pressure, mechanically ventilated house to study the effects of Mount St. Helens’ volcanic ash (VA) on broiler performance, health, and house environment. Four treatments were no VA exposure or control; one direct application of VA (10 kg/m2) on wood shaving litter at 20 days of age, and either VA blown in the pens for 1 hr (VA1; calculated at 38.2 g/min for 2 hr) or 3 hr (VA3; calculated at 22.6 g/min for 6 hr) in the morning and afternoon, daily, from day 20 of production. Volcanic ash from the June 12, 1980 eruption was used. The birds were exposed to VA for 28 days.No significant differences among the treatments were observed on mean body weights by sexes, feed conversion, ammonia levels in the pens, percent mortality, and carcass quality. As would be expected, total dust levels were higher from 0830 to 1630 hr (8.5 hr) when VA was blown into the pens than during the period with no VA blown into the pens (1630 to 0830 hr; 15.5 hr). There was some recycling of dust during the period with no ash infusion. Respiratory dust levels (particles ranging in size from .5 to 10 μm diameter) were significantly higher in direct application and VA3 treated pens than either the control or VA1 treated pens. Mean litter moisture levels were significantly lower in VA3 than in VA1 treated pens, but both ash treatments had significantly lower litter moisture levels than in the control pens. In the lung tissues, varying degrees of lymphoid hyperplasia, smooth muscle hyperplasia, and macrophage infiltration were found. In birds exposed for 28 days either to VA1 or VA3 treatments, crystalline structures were found in alveolar macrophages. Moderate lymphoid hyperplasia was found in the lung tissue from birds exposed to either direct application of VA on the litter or no exposure to VA. Microscopic examination of the turbinates for all treatments revealed no significant changes. There was a random distribution of mild tracheitis in all birds examined from all treatments. Broiler performance, carcass quality, and health were not affected, even though lung tissues were damaged by prolonged exposure of broilers to the dusty environment created in this study.