AbstractThe aim of this study was to evaluate the dietary supplementation of organic selenium (Se) and vitamin E for sows from 1st and 2nd parity order, without adiabatic cooling on physiological parameters, reproductive performance, milk composition, litter performance and blood concentrations of antioxidant enzymes. A total of 96 sows were allotted in a 4 × 2 completely factorial design, with 4 experimental groups and 2 parity orders (1st and 2nd). The experimental groups consisted of: ACCon—sows receiving adiabatic cooling and no dietary supplementation of organic Se and vitamin E; WACCon—sows without adiabatic cooling and no dietary supplementation of organic Se and vitamin E; WACSe—sows without adiabatic cooling with dietary supplementation of 0.3 mg/kg organic Se; WACSeE—sows without adiabatic cooling with dietary supplementation of 0.3 mg/kg organic Se and 90 UI of vitamin E. ACCon Sows had lower respiratory rate, rectal temperature and body surface temperature when compared to the others sows (p < 0.05). Sows without evaporative cooling had lower daily milk production and weaned litters with lower weight and average daily gain when compared to the other groups (p < 0.05). ACCon sows presented higher weaned piglets to WACSeE sows. WACSeE Sows had higher concentrations of GSH‐Px when compared to other experimental groups and higher levels of SOD than sows from ACCon and WACSe. Piglets of sows from WACSeE group presented higher levels of GSH‐Px and SOD when compared to the other experimental groups. ACCon sows have higher milk yield and higher litter weight than others groups. Under equatorial climate conditions, dietary supplementation of organic Se and vitamin E from first and second parity order sows does not respond efficiently on thermoregulatory physiology and performance compared to adiabatic cooling, but modulates the enzymatic antioxidant balance of sows and piglets.