Effect of natural and mechanical ventilation on performance of lactation sows

Air movement has been shown to influence performance of confined swine, and that appropriate air flow is fundamental to better animal comfort, and to minimize sanitary problems. The effect of window with and without aeolic ex haustion and mechanical ventilation designed only for hot season was evalua ted at Concordia, SC, Brazil, during 1991/92. Although effect of season (P< 0.05) had been observed on environment that was not the case on animal perf ormance (P>0.05). The hot season environment was stressing for animals, due to higher environment temperature (Ti) (>22.0 degrees C), low air velocity (Vi) (<0.2 m/s), reduced feed intake (CR) (<4.3 kg/day), as well as increa sed weaning estrus interval (IDC) (>13 days) during the hot season as compa red to cold season: Ti (<19.0 degrees C), Vi (<0.1 m/s), CR (<4.57 kg/day) and IDC (<7 days), respectively. In conclusion, ventilation systems based o nly on natural openings are sufficient for cold season, but are not for hot season due to increase in the ventilation needs.