Table 2.

Main correlations between temperature asymmetries from the different measurements within each area (Ear, ocular/periocular and nostril/nasal passages), data from 216 images (n = 36 dairy calves × 6 recording sessions)

Ear area
ROI (measurement)		Correlation
Ear base front (max) L–R*	Ear base front (ave) L–R	r = 0.785, P<0.001
	Ear base back (ave) L–R	r = 0.436, P<0.001
	Ear base back (max) L–R**	r = 0.394, P<0.001
Ocular / periocular area
ROI (measurement)		Correlation
Inner corner of the eye (max) L–R*	Rostral eye surrounding (max) L–R	r = 0.518, P<0.001
	Eyeball (ave) L–R	r = 0.248, P<0.001
	Caudal eye surrounding (max) L–R **	r = 0.181, P = 0.008
Nostrils / nasal passages
ROI (measurement)		Correlation
Nostril (ave) L–R*	Nostril (max) L–R	r = 0.770, P<0.001
	Nasal passage (ave) L–R	r = 0.573, P<0.001
	Nasal passage (max) L–R**	r = 0.551, P<0.001

The abbreviation L-R means the temperature asymmetry is expressed as the left-side temperature minus the right-side temperature. The abbreviation (max) means the data-point is the highest temperature of any pixel within the delimited region of interest, and (ave) means the data-point is the average temperature across the delimited region of interest. *These measurements were selected for further analysis as they had the highest correlations with other ROIs within each area **These measurements were selected for further analysis as they had the lowest correlation with the first ROI selected within each area.