In recent years, avian influenza epidemics have occurred from time to time and the prices of poultry meat and eggs have fallen, which not only affects the interests of breeders, but also raises concerns about food safety. Health monitoring of poultry allows early detection of epidemic information and early prevention. It has been shown that thermal imaging technology, as a non-contact modern temperature measurement technology, can be used not only to distinguish the disease status, site, and pathological stage of livestock and poultry, but also to accurately determine whether the animal is in a stressful state. If combined with modern information transmission and image processing technologies, it can monitor the temperature of individual poultry in real time and effectively identify diseased individuals. With the continuous development of welfare and precision agriculture concepts, infrared thermal imaging technology will be widely used.
Foot injury is a common disease in poultry, regardless of the cage breeding method or indoor flat breeding. To apply thermal imaging technology to identify early lesions of plantar dermatitis in chickens, test poultry individuals were placed in different bedding environments, one group was recycled shavings and rice husks, and the other group was new wood chips. The degree of plantar dermatitis was scored on four levels at different growth stages of the poultry and the thermal infrared images of individuals with different levels were compared. The study showed that the infrared thermal images could accurately discriminate the dermatitis grade of poultry.
The application of thermal imaging safety camera to measure the body surface temperature of healthy laying hen individuals and pathological individuals, by comparing the temperature of different body surface areas of both, it was concluded that there is a large difference between the head and leg and foot surface temperature of pathological and healthy individuals, indicating that thermal imaging thermometry can be used for the detection of pathological individuals in poultry.
Compared to research on applications in poultry disease detection, thermal imaging technology has been more widely studied in the detection of large livestock diseases. Animal lameness occurs frequently, and although early detection is beneficial to reduce losses and improve animal welfare, traditional methods are difficult to diagnose mild to moderate lameness. Thermographic safety cameras were applied to measure lower limb temperatures of pregnant sows, and a comparative study of individuals with different gait scores revealed that lameness in pigs could be effectively identified by infrared thermometry. The feasibility of thermal imaging technology to determine respiratory disease syndrome (BRD) in cattle was investigated. A comparative analysis of clinical diagnosis, core body temperature, blood analysis and infrared thermometry values showed that individuals with BRD had infrared thermometry values of (35.7 ± 0.35) °C and normal individuals had infrared thermometry values of (34.9 ± 0.22) °C, indicating that thermal imaging technology thermometry can be effective in determining respiratory disease syndrome in cattle.
In addition, the application of thermal imaging technology technology has correctly discriminated joint swelling in pigs, effectively determined the estrus point in sows, effectively detected subacute rumen acidosis in cows, and effectively detected foot-and-mouth disease virus infection in cattle.
Infrared thermal imaging technology is used in addition to the detection of livestock and poultry diseases, and is also more widely used in other areas. Thermal comfort is an important welfare indicator for poultry, and good thermal comfort is beneficial to the expression of genetic potential of poultry and promotes production. Thermal imaging was applied to evaluate the thermal comfort of broiler chickens, and a comparative analysis of different ventilation conditions revealed that a high wind speed feeding environment is more conducive to heat transfer and provides better thermal comfort for broilers. The differences in body surface temperature of rabbits at different temperatures were investigated. The test individuals were divided into two groups. One group was kept in ambient temperature below 30 ℃ and the other group was kept in a heat stress environment above 32 ℃. Thermal imaging technology was applied to measure the facial temperatures of individuals in both groups, and the comparative analysis of the highest and lowest temperatures in different facial regions revealed that the lowest eye temperature and nose temperature of rabbits could effectively assess heat stress in domestic animals.
In addition to heat stress, environmental stress can also affect poultry production. The changes in body surface temperature of chickens under stress were studied. The thermal imaging camera was used to record the changes in body surface temperature during 20 min, which showed that the crown temperature decreased rapidly by 2 ℃ after the onset of stress, the eye temperature decreased and then increased to a level higher than the non-stressed level, and the head temperature increased continuously during the 20 min of stress. This indicates that thermal infrared thermometry can be used to discriminate stress in poultry. Thermal imaging technology was applied to measure eye temperature changes in cattle after treatment with artificial stress (waving plastic bags, yelling, use of electric products, etc.). The results showed that their ocular temperature would drop rapidly within a few tens of seconds and then return to normal levels, indicating that thermographic thermometry can be used as a non-invasive way to assess the stress status of cattle.
