## 6 Discussion  
Based on research of scientific articles dealing with IRT in animal production, the claim that IRT allows detecting problem areas noninvasively with a high level of reliability can be made. Table 2 is an overview of the basic parameters necessary for a correct evaluation of the thermogram, which have been analyzed in these articles. When evaluating thermograms, it is essential to follow the principles of thermographic measurement. A key element of the measurement is the determination of emissivity. Emissivity values in the range of 0.93-1.00 appear in published texts [126; 162; 171]. The large range of emissivity values corresponds to monitoring the surface temperature of different regions of the cow's foot. The claw of the leg has a different emissivity, and the surface of the leg has a different emissivity. The high emissivity value of 0.98 [126] when measuring the lateral claw and the medial claw corresponds to a similar emissivity value achieved by black matte surfaces, which the claws are close to in appearance. For the surrounding areas, such as the interdigital area, a different emissivity setting is inherently necessary. It is not possible to evaluate them simultaneously as the authorsof the study [126] did. An emissivity value of 1.00 [162], which would correspond to an absolute blackbody, is strongly questionable. Not specifying the emissivity in [159; 172] at all in an experimental measurement is a major obstacle to the possible validation of the data and leads to the unreliability of the published data. For measurements with the least measurement uncertainty, one of the two most commonly used methods for experimental determination of emissivity can be recommended. For the purpose of measurements in dairy cows, which can be carried out by technicians without extensive knowledge of infrared thermography, the procedure of determining emissivity by comparative measurement with a contact thermometer can be recommended. First, the reflected radiation is determined, and this value is set in a thermal imager. The temperature of the object to be measured is measured using a contact thermometer. The surface temperature is then measured using a thermal imager in which an arbitrary emissivity value is set. The difference between the measured temperatures from the contact measurement and the thermal imager is due to an incorrect emissivity setting. As the emissivity setting changes, the measured temperature changes. This is performed until the thermal imager measures the same value with the contact measurement. At that point, the set emissivity corresponds to the emissivity of the surface of the measured object. The emissivity can also be determined by comparative measurement with the thermal imager itself. First, the reflected radiation is determined, and this value is entered into the thermal imager. A tape with the defined emissivity is stuck on the surface of the body. After a short period of time for the temperature to settle, the temperature of the tape adhered to the surface of the object to be measured is measured. The emissivity of the adhesive tape must be set in the thermal imager. This temperature is the reference temperature. The emissivity setting is then adjusted until the thermal imager measures the same temperature as the reference temperature on the surface without adhesive tape. Another key element is the determination of the reflected radiation temperature. It is advisable to remove all possible sources of interference in the vicinity of the object to be measured that may affect the measurement. It can then be determined that the reflected radiation temperature is equal to the ambient temperature. The ambient temperature can be determined with a contact thermometer. In selected studies [145; 171], the authors reported this value, which can be considered evidence of erudition in thermographic measurements. Unfortunately, in most articles [126; 159; 165; 172], this value is absent.