Utilização da termografia infravermelha na detecção de mastite subclínica em búfalas mestiças Murrah × Jafarabadi (Bubalus bubalis – Linnaeus, 1758)

Abstract

Mastitis is an inflammation of the inflammation of the mammary gland of origin, causing multifunctionality mainly for the entire dairy production sector. In general, mastitis diagnosis control is expensive on farms, due to the demand for laboratory tests and other procedures that financially affect this sector. Diagnostic imaging by infrared thermography (IRT) has become promising in veterinary medicine, as it is a non-invasive and non- method of direct contact and containment of the animal need, being able to determine the thermal variations indicated as red fever to inflammation processes, and physical changes. The aim of the present research was to evaluate the efficiency of IRT for the detection of subclinical mastitis in dairy buffaloes, making the association between the infrared images of the udder surface and the results of the conventional tests for the diagnosis of mastitis: Somatic cell count (SCC) and California Mastitis Test (CMT). A total of 266 mammary quarters of crossbred dairy buffaloes (Murrah × Jafarabadi) were evaluated. Thermographic images were obtained from the quarters: right hindquarters (RBR) and left hindquarters (LBR). Thermal imaging and milk samples were taken at 60-day intervals between the years 2021 and 2022. Samples were obtained before the morning milking. To obtain the thermographic images, a thermographic camera model FLIR TG165®. The diagnosis of subclinical mastitis was performed by CMT and SCC. Descriptive analyzes of SCC and udder surface skin temperature (USST) were performed according to each CMT score (0, 1+, 2++ and 3+++). Pearson's correlation analyzes were performed between CCS, CMT and USST. The sensitivity and specificity of IRT, considering two categories of indication of mastitis by CCS: >200×103 cell/mL and >400×103 cell/mL using the Receiver Operating Characteristic (ROC) package, MedCalc software. The CMT results showed that 61.28% (n=163) of the evaluated mammary quarters (n=266) were healthy (CMT=0), while 38.27% (n=103) had subclinical mastitis (CMT= 1+, 2++ and 3+++). The means of SCC (×103 cell/mL) and USST (ºC) according to each CMT category were: 55.86 and 32.85 (CMT = 0); 509.35 and 33.52 (CMT = 1+); 1032.26 and 34.32 (CMT = 2++); 2839.48 and 34.83 (CMT = 3+++). Correlations were positive between: USST/SCC (r=0.58) and USST/CMT (r=0.60), (P<0.0001). The values (%) of sensitivity specificity and accuracy were 68.93, 80.37 and 80.70%, respectively, considering the quarters with SCC >200 ×103 cell/mL with subclinical mastitis. Whereas, considering that the quarters with SCC >400 ×103 cel/mL have subclinical mastitis, the values (%) of sensitivity, specificity and accuracy were 79.52%, 79.78%, and 86.00%, respectively. IRT was able to detect alterations in the surface of the skin of the udder of buffaloes caused by subclinical mastitis. The significant and positive relationship between the subclinical mastitis indicators (CMT and SCC) and the predictive values of sensitivity, specificity and efficacy of the test indicated that this technology is a promising and noninvasive tool for the early diagnosis of subclinical mastitis in dairy buffaloes.