## 5 Use of IRT in Livestock Production
### Detection of Lameness in Dairy Cows  
Lameness in dairy cows is one of the most important diseases because it reduces animal welfare, causes pain, reduces milk production, and has a negative effect on reproduction [142]. The economic losses caused by lameness can be direct, with the cost of hoof treatment and adjustment, or indirect, associated with the reluctance of the dairy cow to move and stand due to limb soreness [143]. Hoof disease can either be caused by infectious inflammation of the skin of the toe, with the development of digital dermatitis, recrobacillosis, and thymomas contributing to the development of lameness, or by disease of the horn capsule to form laminitis, white line disease, or a foot ulcer [143; 144]. Early detection of gait impairment is important in terms of successful treatment and reducing the overall severity of the disease [145]. Detection of lameness in its early stages is most difficult and the first step should be to assess the prevalence of lameness in the whole herd [146]. Various conventional and advanced diagnostic methods and tools exist for lameness detection and hoof health observation [147], which include assessing animal gait [28], observing hoof changes during hoof care [148], use of parallel force plates [149; 150], determination of locomotor activity using an ALT pedometer [151], or measurement of acceleration of the back and leg regions [27]. The most common detection of lameness is visual inspection, which uses a locomotion score system that has five levels, where a score of 0 corresponds to no lesion; a score of 1 corresponds to a hyperemic area with erect pili; a score of 2 corresponds to a moist, exudative, and hyperemic area with intact epidermis; a score of 3 corresponds to an exudative area, exposed cerium, with no signs of healing; a score of 4 corresponds to an exposed cerium, but in the process of healing, dried-up lesion; and a score of 5 corresponds to a dark brown scab, completely or almost completely healed lesion [152; 153; 154; 155]. The disadvantages of this method are the inconsistencies and subjective views of the observers [156], the time consuming nature of the method, and the presence of lesions on the limb without evidence of lameness [157]. The use of infrared thermography as a noninvasive diagnostic tool for the detection of lameness has been increasing in recent years. The infrared technology helps to detect the localization of areas of increased temperature, which may indicate inflammation, or conversely, areas of decreased temperature (decreased blood flow), with thermographic devices being able to detect skin temperature differences of \(\pm 0.1\)\({}^{\circ}\)C [49]. This allows early detection of lesions on the extremities before the onset of lameness [158]. [PERSON] et al. investigated in their study the potential of IRT for rapid screening of digital dermatitis. Dairy cows with and without lesions present were selected and a thermal image was taken from the plantar direction of each limb at the supra-forearm. The limbs assessed were in three groups: soiled, cleaned, and elevated for visual inspection. It was found that the temperature did not differ significantly between the feet affected by the lesion and other lesions on the skin or hooves, regardless of whether the feet were soiled, cleaned, or visually inspected. Because IRT was not sufficiently sensitive to detect a specific lesion, the temperature threshold above which any lesion causing lameness could be detected was investigated. Setting the temperature threshold at 27 \({}^{\circ}\)C for the soiled limbs identified 80% of the limbs affected by lesions and 73% of the limbs without lesions. Cleaning the limbs increased sensitivity but decreased specificity. Setting the temperature threshold to 22 \({}^{\circ}\)C for cleaned limbs identified 91% of the limbs with lesions but only 54% of the limbs without lesions.