Journal or Book Title
Applied Engineering in Agriculture
Neonatal piglets (1.7 to 7.1 kg; 3.7 to 15.7 lb body weight) were allowed to choose at will a heat source (lamp or mat) in a wind tunnel at cool (20°C; 68°F) or warm (30°C; 86°F) air temperature coupled with various air velocities (0.05 to 0.45 m/s; 10 to 90 ft/min). The effects of original heat source in the farrowing crates on the choice of the piglets were included. At the cool temperature (20°C), piglets from heat lamp-equipped farrowing crates showed preference for lamp heat at 1.7 kg (3.7 lb) and similar usage of mat and lamp at 2.4 to 5.3 kg (5.3 to 11.7 lb). Piglets up to 5.3 kg from the heat mat-equipped farrowing crates generally did not show distinct preference for lamp or mat heat, except at the high draft condition (0.45 m/s; 90 ft/min) where preference for heat mat was exhibited. Piglets of 7.1 kg (15.6 lb) preferred mat independent of the original heat source type. At the warm temperature (30°C), piglets of 2.6 to 5.3 kg (5.7 to 11.7 lb) showed almost equal usage of mat and lamp independent of the original heat source type. Air temperature affected heat needs of the piglets. At 20°C, total (i.e., lamp + mat) heat usage (THU) by piglets of 1.7 to 2.4 kg (3.7 to 5.3 lb) averaged 98% of the exposure time for all air velocities tested. At 30°C, THU ranged from 24% for 2.6 kg (5.7 lb) piglets to 5% for 4.4 kg (9.7 lb) piglets. THU declined substantially as piglets reached 3.4 kg (7.5 lb), especially at the low air velocities. Piglets were more sensitive to drafts at the cool temperature. Drafts up to 0.45 m/s (90 ft/min) had little effect on THU at the warm temperature.
American Society of Agricultural Engineers
Xin, Hongwei and Zhang, Qiang, "Preference for Lamp or Mat Heat by Piglets at Cool and Warm Ambient Temperatures with Low to High Drafts" (1999). Agricultural and Biosystems Engineering Publications. 199.