Effect of heat stress on body temperature, respiratory frequency and performance of pigs

Abstract

The effect of ambient temperature (AT) on body temperature (BT), respiratory frequency (RF), and performance of pigs was evaluated. Eighteen pigs (32.6 kg body weight) were distributed in three treatments: 1) housed at 25 °C (Comfort) and fed ad libitum (AL); 2) as in 1, but feed restricted (REST); 3) housed under heat stress (34.3 °C, HS). The AT, heat index (HI), BT, RF and pig performance were measured. The amount of feed consumed (FI) by HS pigs fed ad lib was the same offered to the REST pigs. Average HI in the Comfort and HS rooms was 81 and 102. Treatment results for AL, REST, and HS were: BT, 38.3, 37.9, 39.2 °C; RF, 60, 49, 103; weight gain (ADG), 688, 525, 501 g/d; feed intake (FI), 1.47, 1.20, 1.17, respectively. HS pigs had higher BT, RF but lower ADG and FI (P<0.01) than those in comfort. AL pigs had higher BT, RF, ADG and FI than REST pigs (P<0.01). BT and RF of HS pigs, measured from 0800 to 2000 h, increased from 38.4 to 39.6 °C and from 62 to 113, as AT increased from 26 to 42 °C. These results show a marked effect of AT on BT, RF, ADG and FI of pigs, and suggest that pigs are capable of overcoming rapid and huge AT changes when they are exposed to HS. Financial support by UABC.