Treatment of feedyard dust containing endotoxin and its effect on weanling goats

Abstract

Forty-two, mixed-sex, weanling goats were randomly allotted to six treatment groups: principal autoclaved dust ( n=6), control non-autoclaved dust ( n=6), principal dry-heat dust ( n=6), and control non-dry-heat dust ( n=6). Principals were treated with appropriate dust for one 4 h treatment in a closed tent. The data from the principal dust group ( n=9) and the control non-dust group ( n=9) were recorded after one 4 h dust treatment prior to the start of the present study. The endotoxin (ET) concentrations were determined for autoclaved dust (13.3 μg ET/g), dry-heated dust (0.173 μg ET/g), and non-treated dust 26.9 μg ET/g. The tent aerosolized dust concentrations were: autoclaved dust 0.369 g/(m 3 min) with 4.904 μg ET/(m 3 min); dry-heated dust 0.347 g/(m 3 min) with 0.0015 μg ET/(m 3 min); and non-treated dust 0.539 g/(m 3 min) with 4.904 μg ET/(m 3 min). These ET aerosol concentrations caused the autoclave dust goat group and the non-treated dust goat group to significantly increase their rectal temperatures at 4, and 8 h and total white blood cells (WBCs) increased at 12 and 24 h compared to their respective non-dust control groups. The dry-heat aerosol dust ET concentration in the tent did not induce an increased mean rectal temperature response or an increased mean total WBC count. Of the three principal dust products only the non-treated dust contained viable microbes.