The use of infrared cameras to record surface temperature has shown some promise in older pigs, but neonatal piglets are metabolically less mature and experience rapid temperature changes during their first 24 h. The present experiment aimed to compare rectal temperature to surface temperature at the base of the ear, measured using an infrared camera, for piglets of different birth weights. During farrowing, 48 multiparous sows were monitored, and rectal and surface temperatures were recorded for their lower-birth-weight (≤1.2 kg) piglets within 3 min of birth and at 0.25, 0.50, 0.75, 1, 1.25, 1.50, 2, 3, 4, and 24 h. Piglet birth weights were assigned to one of three categories (BWC): BWC1 (≤0.80 kg), BWC2 (0.81 to 1.10 kg), or BWC3 (1.11 to 1.20 kg). Piglet rectal temperatures at 1.25 h after birth were assigned to one of three categories: RC1 (≤32.0 °C), RC2 (32.1 to 35.0 °C), or RC3 (≥35.1 °C). Surface temperatures showed a similar recovery pattern to rectal temperatures in the first 24 h across all piglet birth weights, although large and variable differences seen in the current study militate against surface temperature being an appropriate replacement for neonatal rectal temperature for use in production.
Keywords: birth weight; infrared camera; piglet; rectal; surface; temperature; thermoregulation.