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temperature of each thermal image was considered because the skin of the animals
had temperatures much higher than the bedding, walls, and sides of the compart-
ment. The relationship between maximum skin temperatures and the environmental
temperatures recorded in the vehicle during the two transports was examined by
regression analysis using Proc Reg of SAS (
1996
).
32.3 Results
Table
32.1
shows the mean values and the measures of variability of the maximum
temperatures of the piglets' skin surfaces that were recorded in the vehicle during
the journeys of July and September. The different positions of the thermo-camera,
shot angles, distances of recording, and body areas made it impossible to directly
compare the temperatures recorded in the two journeys. During the second journey,
the placement of the camera above the pen led to higher values of skin temperatures
and reduced the variability of thermal measurements.
Figure
32.1
shows the results of regression analysis. In both journeys, the
relationship between skin temperatures and the temperatures inside the vehicle
was linear (
P
0.001). The
R
2
values were 0.44 and 0.57 in July and September,
<
Table 32.1 Mean values and measures of variability of environmental temperatures in the vehicle
and maximum skin temperatures as measured by thermography
Mean
S.D.
Minimum
Maximum
July journey
Temperature inside the vehicle (
C)
26.32
3.79
21.5
35.5
Skin temperature (
C)
35.97
1.12
33.3
38.7
September journey
Temperature inside the vehicle (
C)
22.27
3.31
16.0
27.7
Skin temperature (
C)
38.13
0.87
36.0
39.9
Fig. 32.1 Linear regression between the maximum skin temperature of piglets and the environ-
mental temperature inside the vehicle during the journeys of July and September
