PSII-4 Temperature preference of nursery pigs housed in groups by weaning weight quartile

Abstract

Abstract There is a lack of recent research investigating the temperature requirements of pigs housed in groups with the genetics and management practices currently being used in commercial production. The objective of this study was to establish the preferred temperature of pigs housed in groups with uniform body weight (BW) over the first 4 wk after weaning (at 21 ± 1 d). The study involved 320 newly-weaned pigs that were kept in mixed-sex pens (barrows and gilts) of 20. Three temperature treatments were compared: 26°C vs. 30°C vs. 34°C. The temperature treatments were created in 3 distinct zones of each pen using a heat lamp suspended over an insulated mat and pigs had free access to each zone. Room temperature was set at 22°C for the duration of the study. The population of pigs was divided into weaning-weight quartiles (Quartile 1, 2, 3, and 4, lightest to heaviest; initial BW 4.5, 5.6, 6.5, and 7.7 ± 0.4 kg, respectively; final BW 12.8, 14.4, 16,3, and 18.2 ± 2.0 kg, respectively). The weight quartiles were kept in different pens. The pigs had ad libitum access to nursery diets throughout the study period formulated to meet the requirements proposed by NRC (2012). Cameras captured images of the pen area every 15 min during the study period. The location (in the temperature treatment zones or other areas of the pen) and posture (lying, sitting, and standing) of every pig in the pen were recorded from the images. The ambient temperature in the temperature treatment zones and other areas of the pen were recorded every 2 h throughout the study period using a thermal camera. The preferred temperature was calculated by weighting the percentage of observations of pigs located within each temperature treatment zone and the other areas of the pen by the average temperature in each zone and area. The percentage of observations of pigs in the 26, 30, and 34°C temperature treatment zones for the overall period were: Quartile 1 (15.3, 15.2, and 42.9%, respectively), Quartile 2 (5.3, 23.1, 39.8%, respectively), Quartile 3 (8.5, 15.7, and 41.2%, respectively), and Quartile 4 (5.0, 34.0, and 25.9%, respectively). The calculated preferred temperatures for the weight quartiles for each week of the study are summarized in Table 1. The preferred temperature for the overall period was 30.0, 30.3, 29.3, and 28.6°C for Quartiles 1, 2, 3, and 4, respectively. The impact of housing nursery pigs at these temperatures on pig performance needs to be established.