ABSTRACT 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 °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.

Conduziu-se este estudo com o objetivo de avaliar níveis de energia líquida na dieta de suínos machos castrados em terminação. Foram utilizados 100 suínos, com peso inicial de 73,60±4,80kg, distribuídos em delineamento de blocos ao acaso, com cinco níveis de energia líquida (2.300, 2.425, 2.550, 2.675 e 2.800kcal kg-1 de dieta), dez repetições e dois animais por unidade experimental. Os níveis de energia líquida foram obtidos através da inclusão crescente de óleo de soja em substituição ao caulim. Houve redução (P<0,05) no consumo de ração diário, consumo de lisina e consumo de proteína bruta e melhora da conversão alimentar com o aumento dos níveis de energia líquida das dietas. O melhor nível de energia líquida para suínos machos castrados em terminação é de 2.800kcal kg-1 de dieta, pois promove redução no consumo de ração diário (P<0,05) e melhora a conversão alimentar (P<0,05), sem alterar o ganho de peso e as características de carcaça

This study was carried out to evaluated levels of net energy in the diet of finishing barrows. Were used 100 swines with an initial body weight of 73.60±4.80kg, distributed in a randomized block design, with five levels of net energy (2,300; 2,425; 2,550; 2,675 and 2,800kcal kg-1 of diet), ten replicates and two animals per experimental unit. The net energy levels were obtained by replacement of soybean oil to replace kaolin. There was a reduction in feed intake, of lysine and crude protein intake and improves feed conversion with increasing levels of net energy diets. The best level of net energy for finishing barrows is 2,800kcal kg-1 of diet as it foment reduction in feed intake and improves feed conversion without changing the weight gain and carcass characteristics