Effects of negative pressure and directed ducted cooling systems on the performance of lactating sows

The objective of the present study was to evaluate the effects of cooling systems by negative pressure versus directed ducts on the performance of lactating sows and their litter. The experiment was conducted in a tropical climatic region in Brazil. Ninety-four lactating sows during 26.2 +/- 1.7 days of lactation were included with their 1,236 piglets. Sows were distributed using a completely randomized block design into two treatments: a negative pressure cooling (NPC) system and a directed duct cooling (DDC) system. We adopted sow parity as blocking criterion. During the experimental period, environmental temperatures inside the farrowing rooms were 22.9 +/- 1.5 and 25.4 +/- 2.5 degrees C, respectively, using the NPC and DDC systems. Sow daily feed intake, litter weight at weaning, piglet weight at weaning, litter daily weight gain, piglet daily gain, and daily milk production per sow were greater in the NPC system than in the DDC system. The type of cooling system did not affect piglet weight after standardization, mortality, number of piglets weaned per sow, and estrus return. The use of an NPC system can reduce the effects of higher environmental temperatures better than the DDC system. The NPC system allowed for greater feed intake, piglet and litter weight gain, weight of piglets and litter at weaning, and milk production compared with the DDC system.