Table 2.
Studies showing relationship between surface (measured by infrared devices) and body temperature in pigs
| Source | N | Breed | Size/Age | Surface area(s) | Thermal window (X: yes) | T ambient [°C] | Correlation (r) ( A ) | Remarks |
|---|---|---|---|---|---|---|---|---|
| Zinn et al. [33] | 15 | York × Landrace (LR) × Duroc | 225 kg | Eyeball | X | N/A | 0.14 → 0.51 | Before → after parturition. Hairy sites were trimmed. |
| Ear (outer side, 5 cm from base) | X | 0.12 → 0.39 | ||||||
| Tail head | 0.23 → 0.29 | |||||||
| Shoulder | 0.18 → 0.47 (*) | |||||||
| Flank | 0.28 → 0.42 | |||||||
| Perineum | X | 0.21 → 0.30 | ||||||
| Vulva | X | 0.16 → 0.23 | ||||||
| Udder (cranial) | X | 0.06 → 0.27 | ||||||
| Udder (middle) | X | 0.12 → 0.44 | ||||||
| Udder (caudal) | X | 0.13 → 0.39 | ||||||
| Loughmiller et al. [2] | 24 | Crossbred | 30 kg | Loin | 21 ± 2 | 0.52 (***) | ||
| Warriss et al. [7] | 384 | ~91 kg | Inner side of ear pinna | XB | 21 | 0.71 (***) | (C) | |
| Traulsen et al. [32] | 42 | Crossbred | 1st–6th parity | Eyes | X | 20.5–24.3 | 0.33 (*) | |
| Udder | X | 0.41 (*) | ||||||
| Inner ear | X | 0.31 (*) | ||||||
| Ear base | X | 0.32 (*) | ||||||
| Vulva region (lying) | X | 0.49 (*) | ||||||
| Vulva region (standing) | X | 0.32 (*) | ||||||
| Magnani et al. [4] | 108 | 10–17 days | Eye | X | 22–30 | 0.02 | ||
| Side, back and womb | XB | 0.02–0.33 | ||||||
| Axilla | X | 0.33 | ||||||
| Chung et al. [38] | 10 | Yorkshire × LR (Gnotobiotic) | Piglets | Central abdomen | X | 21 ± 1 | 0.58 (***) | |
| Central dorsum | 0.30 (***) | |||||||
| Perianal region | X | 0.43 (***) | ||||||
| Malmkvist et al. [31] | 39 | Danish LR × Yorkshire | 1st–3rd parity | Snout | 15–25 | 0.21 (**) | (D) | |
| Eye | X | 0.49 (***) | (D) | |||||
| Udder (caudal third) | X | 0.60 (***) | (D) | |||||
| Sykes et al. [14] | 32 | Yorkshire × LR | ~85 kg | Vulva (estrus) | X | 1.5–25.8 | −0.099 to 0.011 | |
| Vulva (diestrus) | X | −0.115 to −0.068 | ||||||
| Tabuaciri et al. [39] | 485 | Large White (LW) × LR, LW × Duroc | <2 kg | Ear base | X | N/A | 0.85 | |
| Ear tip | 0.27 | |||||||
| Back (crown to rump) | 0.75 |
AIf only the coefficient of determination (R2) was provided in the article, the magnitude of the correlation (r) between body and IR measured skin temperature was calculated by taking the square root of R2. *:P < 0.05, **:P < 0.01, ***:P < 0.001.
BIndicates measurement sites that are both thermal windows and not thermal windows.
CTemperature was the mean of the 3 spots of the ear (base, middle, and tip). Body temperature was measured by aiming IR spotmeter on blood on concrete floor, lost from sticking neck vessels.
DNumbers provided from personal communication.