Respiratory morbidity in relationship to farm characteristics in swine confinement work: possible preventive measures

Swine confinement farming is associated with an increased risk of respiratory morbidity. Adverse health effects have been shown in association with levels of dust, endotoxins, and ammonia. This study was conducted to evaluate characteristics of confinement farms associated with respiratory morbidity in order to establish priorities for preventive measures. A questionnaire on symptoms and farm characteristics was completed by 1,432 male swine confinement farmers. Of these, 200 with and 200 without chronic respiratory symptoms were randomly selected for lung function testing. A significantly increased risk for chronic respiratory symptoms was shown if farmers used wood-shavings as bedding (prevalent odds ratio [POR]2.2), used disinfectants (POR 1.7), used natural ventilation (POR 2.6), had floor types other than slatted or half-slatted (POR 2.1), or used a mechanical feeding system (POR 1.4). Lung function (FEV1) was significantly lower with increasing numbers of years worked (51 ml/10 years), with smaller numbers of pigs (8.5 ml/100 pigs), and when the air outlet of the ventilation system was via the pit (248 ml). To decrease the risk of respiratory morbidity the following preventive measures are proposed: discouragement of the use of disinfectants and of wood-shavings as bedding, and promotion of the use of mechanical ventilation systems.