Thermographic Image of the Hoof Print in Leisure and Cross-Country Warmblood Horses: A Pilot Study

Abstract

Background: The field of veterinary medicine lacks information on equine thermal hoof printing, and few data on the same subject are available in dogs. In human medicine, thermography is used to detect heat emitted by the foot when it comes in contact with a flat surface to detect the abnormalities of the foot balance. The hypothesis states that the thermal pattern of the hoof print in Warmblood horses is detectable and it does not vary among the four limbs in leisure and cross-country Warmblood horses in terms of mean temperature of the hoof print surface. A pilot study was conducted to investigate the accuracy of thermography in temperature detection of the hoof print and to investigate the occurrence of possible differences in the mean value of six selected areas and whether there are any differences in the mean temperature of the hoof print between leisure and cross-country Warmblood horses.

Methods: The study included sixty non-lame Warmblood horses with all limbs taken into consideration (n = 240). The selection criteria for the horses were: no alterations in posture and no muscle group asymmetry during visual examination, no lateral or medial deviation of the carpus or hock, no reaction to the flexion tests, negative reactions to the hoof tester, no lameness during walking, trotting or lunging, no anti-inflammatory medication in the last three weeks prior to examination and rectal temperature between 37 °C and 38 °C. The hoof print of each hoof was measured with the horse in the standing position, all four limbs on the ground, using a FLIR E50 thermal camera. Six areas of temperature from the hoof print were taken into consideration, and for each of them, the mean value was identified using FLIR Tools software for photo interpretation. The One-Way ANOVA test was used to test the differences between the mean temperatures obtained for each selected area from all limbs and to compare the hoof print temperature values between the leisure horses and cross-country horses. Data were statistically processed using SAS Studio.

Results: Thermography can detect the temperature emitted by the hoof but the thermal patterns of the hoof print show no difference for all four studied limbs. No significant statistical differences were noticed between the mean temperatures identified for each studied area. Also, there were no statistical differences between the mean temperature of the selected areas from the forelimbs and hindlimbs from the horses used for leisure and those used for cross-country. Based on this aspect, the mean temperature of one selected area can be determined in any of the four limbs, without visible variations.

Conclusions: Thermography can detect the hoof print on a flat surface and the mean temperature for each studied area can be proposed as a reference temperature value. There were no differences in the mean temperature of the hoofprint between leisure and cross-country Warmblood Horses. Further investigations are required to clarify whether there are any differences in the thermal pattern of hoof prints from other breeds or from horses with musculoskeletal conditions.

Keywords: Warmblood horses; hoof print; reference temperature; thermography.

Figure 1

Photo of the floor surface: (a) normal image obtained with Flir E50; (b) thermographic image obtained with Flir E50; + (cross symbol) - spot of temperature.

Figure 2

Hoofprint with marked areas: toe—El1, hoof wall—El2 and El3, sole—El4 and El5, frog apex—El6, frog—El7, heels—El8 and El9; minimum temperature recorded in the area—blue triangle; maximum temperature recorded in the area—red triangle.

Figure 3

Thermography of the forelimbs: (a) left hoofprint: yellow circle—intense red color in frog apex corresponding with increased temperature; blue circles—sole areas with uniform color and temperature; red circle—uniform color for toe area with a decreased value of temperature; blue arrows—thermal aspect of the frog with red color which denotes increased temperature; red arrows—uniform color in heel area; black arrow—color variation in hoof wall areas with inequality in temperature; spot—temperature of the floor surface. (b) Right hoofprint: yellow circle—uniform red color corresponding with increased temperature in frog apex area; blue circles—uniform color for the sole area; red circle—uniform color in toe area; blue arrows—outline of the frog area with red color and increased value of temperature; black arrows—same color distribution among the hoof wall area; spot—temperature of the floor surface.

Figure 4

Thermography of the hindlimbs: (a) left hoofprint: yellow circle—uniform red color in frog apex corresponding with increased value of temperature; blue circles –uniform color and decreased value of temperature; red circle—uniform color for toe area with a decreased value of temperature; blue arrows—thermal aspect of the frog with red color which denotes increased temperature; red arrows—uniform color in heels area; black arrow—color variation in hoof wall areas with inequality in temperature; spot—temperature of the floor surface. (b) Right hooprint: yellow circle—uniform red color corresponding with increased temperature in frog apex area; blue circles—sole area with uniform thermal pattern; red circle—increased area of temperature in toe area with uniform color patter; blue arrows—outline of the frog area with red color and increased value of temperature; black arrows—same color distribution among the hoof wall area, red arrows—constant color distribution in heels area with decreased value of temperature; spot—temperature of the floor surface.

Figure 5

Comparative boxplot referring to results obtained from hoof print thermography for toe area; ◊—mean referee value; ―—median; HL—left hindlimb; HR—right hindlimb; TL—left forelimb; TR—right forelimb.

Figure 6

Comparative boxplot referring to results obtained from hoof print thermography for sole area; ◊—mean referee value; ―—median; HL—left hindlimb; HR—right hindlimb; TL—left forelimb; TR—right forelimb.

Figure 7

Comparative boxplot referring to results obtained from hoof print thermography for frog area; ◊—mean referee value; ―—median; HL—left hindlimb; HR—right hindlimb; TL—left forelimb; TR—right forelimb.

Figure 8

Comparative boxplot referring to results obtained from hoof print thermography for frog apex area; ◊—mean referee value; ―—median; HL—left hindlimb; HR—right hindlimb; TL—left forelimb; TR—right forelimb.

Figure 9

Comparative boxplot referring to results obtained from hoof print thermography for pentru hoof wall area; ◊—mean referee value; ―—median; HL—left hindlimb; HR—right hindlimb; TL—left forelimb; TR—right forelimb.

Figure 10

Comparative boxplot referring to results obtained from hoof print thermography for heels area; ◊—mean referee value; ―—median; HL—left hindlimb; HR—right hindlimb; TL—left forelimb; TR—right forelimb.