## 3 Results  
Although many studies have been devoted to the measurement of the body surface temperature of animals, as well as the measurement of the eye of a dairy cow using infrared thermography, our research team, with long-term measurements, drew attention to the differences that we observed in the same animals by measuring the temperature of the eye by infrared thermography and the rectal temperature by an invasive method in different seasons. This temperature difference is an important parameter for the precise definition of the justification for the use of infrared thermography. As a substitute method, we measured the temperature of the eye using IRT, representing the temperature of dairy cow's body, so that it was a fully replaceable and repeatable method. This has not been undertaken so far, and therefore, a targeted comparison of the difference between eye temperature and rectal temperature gives a measurement-verified picture of the declared justification for using this method for further use in automated work procedures in breeding without disturbing the animals with invasive methods of rectal temperature measurement. Table 1 shows the results of the descriptive statistics of all the data from the farm during the period of study. As can be seen in Table 1, the calculated difference between the average values of eye temperature and rectal temperature was 1.6 \({}^{\circ}\)C. The calculated difference between the minimum eye temperature and the rectal temperature was 1.8 \({}^{\circ}\)C. The calculated difference between the maximum recorded eye temperature and rectal temperature was 0.1 \({}^{\circ}\)C. We carried out our measurements in a period with lower temperatures where there was no threat of heat stress. We tried to avoid days with high temperatures and a THI above 72, as we were aware that a THI above 72 starts to have a stressful effect on high-yielding dairy cows. After measuring the rectal temperature and the temperature of the left eye, the dairy cows were taken back to their group so as not to be unnecessarily stressed. In the statistical evaluation, we focused on the evaluation of the maximum recorded eye temperature and the measured rectal temperature. Figure 2 shows the correlation of the air temperature as an external factor in the object of measurement with the values of the difference between the rectal temperature and the eye temperature of dairy cows. The stated values were expressed with a 95% confidence interval. The regression function has the equation: y = 0.0333x + 0.9585. It can be concluded that the regression function has a logical interpretation. The AT in the object is positively correlated with the difference between RT and ET. The correlation coefficient with a value of 0.22 (\(p\) < 0.05) stands for a low degree of correlation. The data show that the higher the AT in the object, the higher the difference between RT and ET. Figure 3 shows the dependency between the relative humidity as an external factor in the object of measurement and the values of the difference between rectal temperature and eye temperature of dairy cows. The stated values were expressed with a 95% confidence interval. The regression function has the following equation: y = -0.0284x + 3.1898. The \begin{table}
\begin{tabular}{l|l l l l} \hline
**PARAMETER** & **MEAN** & **MINIMUM** & **MAXIMUM** &
\begin{tabular}{l} **STANDARD** \\ **DEVIATION** \\ \end{tabular} \\ \hline COW’S EYE TEMPERATURE (\({}^{\circ}\)C) & 36.7 & 33.9 & 39.1 & 0.92 \\ COW’S RECTAL TEMPERATURE (\({}^{\circ}\)C) & 38.3 & 32.1 & 39.0 & 0.51 \\ AIR TEMPERATURE (\({}^{\circ}\)C) & 16.4 & \(-\)1.8 & 27.4 & 6.98 \\ RELATIVE HUMIDTY (\%) & 59.2 & 38.9 & 76.8 & 11.71 \\ THI & 60.4 & 36.7 & 74.3 & 9.38 \\ \hline \end{tabular}
\end{table} 
Table 1: Results of the descriptive statistics of the farm. Figure 2: Relationship between the air temperature as an external factor in the object of measurement and the values of the difference between rectal temperature and eye temperature of dairy cows. Dots represent individual recorded values.