The purpose of this study was to investigate work-related respiratory symptoms, the prevalence of chronic lung diseases and ODTS, and to study the lung function and bronchial hyperresponsiveness in the workers of Ukrainian fodder production facilities. 240 workers of two Ukrainian fodder production plants have been examined. Dust concentrations in the air of working zone were different, reaching 48.2 mg/m(3) in the first plant and 16.8 mg/m(3) in the second. Endotoxin levels were 240.0 ng/m(3) and 1.8 ng/m(3) respectively. The length of service at the first plant exceeded 2 times that at the second. In the actual research the investigation of respiratory symptoms, lung function and bronchial reactivity was carried out. A comparison between animal feed workers and internal controls revealed work-related symptoms. The predominant symptomatic and lung function effects indicate a clinical picture related to chronic bronchitis. The prevalence of chronic bronchitis was 26.4 +/- 4.0% at the first plant and 8.8 +/- 4.8% at the second one (p < 0.01). The prevalence of respiratory troubles was related to dust exposure more strongly that to smoking. 39.7 +/- 4.4% of exposed workers at the first plant and 14.7 +/- 6.0% at the second one revealed organic dust toxic syndrome (ODTS). In 47.9 +/- 7.2% of workers with ODTS, this syndrome was associated with chronic bronchitis. Examination of lung function revealed obstructive changes which were more expressed in exposed workers of the first plant. Lung function clearly decreased with increasing duration of employment. Obstruction of small bronchi and bronchial hyperresponsiveness (registered in 74.7% of workers) were the early signs of respiratory troubles in exposed workers.