Spatial dependence of udder surface temperature variation in dairy cows with healthy status and mastitis

Abstract

The objective of this research was to assess the spatial variability pattern concerning udder surface temperature in dairy cows that were healthy and in those with mastitis. A total of 24 animals were selected-eight healthy, eight with subclinical mastitis, and eight with clinical mastitis. Images were taken with a Flir i60 thermographic camera-resolution of 0.01°C, focal length of 1.0 m, and emissivity adjusted to 0.98-between 05:00 and 07:00, totaling 96 images, three per animal, of the front and rear, right and left mammary quarters. Analyses were run through geostatistics, with semivariogram adjustment to validate the theoretical model and build kriging maps. The average surface temperature of the mammary quarters with positive classification for subclinical mastitis stood between 33.2 ± 0.67C and 34.64± 1.07C; for negative quarters, values ranged from 29.3 ± 1.78C to 32.24 ± 0.62C. The udder surface temperatures of healthy animals were lower than those of animals with subclinical mastitis (29.3C ± 1.78 and 31.58C ± 0.62). The udder surface temperature of animals with clinical mastitis was higher, between 34.0 and 37.5°C, compared to the other clinical statuses. The scale adopted for image pattern analysis successfully identified the spatial dependence of udder surface temperature, which helped standardize diagnostic procedures for healthy animals, and for those with subclinical and clinical mastitis, by means of geostatistics.