Assessment of nitrite and transferrin levels in the blood of cows with subclinical mastitis by the electron paramagnetic resonance method

A major problem in veterinary medicine is the lack of timely and quantitative diagnosis of subclinical mastitis in highly productive cows. Currently, the main indicator for diagnosis of udder pathology is milk analysis for leukocytes (i.e., neutrophils, macrophages, lymphocytes) and epithelial cells. Inflammation in the mammary gland is directly related to nitric oxide synthesis and the paramagnetic NO complex with hemoglobin has characteristic spectroscopic parameters of hyperfine cleavage. The level of (NO)x in the milk of cows with subclinical mastitis differed significantly from that of healthy cows. The electron paramagnetic resonance method was used to study the level of nitric oxide NO by the stable oxidation product nitrite and transferrin in the blood of cows with subclinical mastitis. From the EPR signal of transferrin with g = 4.3, it was found that the blood of the control group contains more transferrin, and consequently iron, and the blood of the control group contains significantly less. Therefore, changes in nitrite and transferrin concentrations, along with blood Fe and ferritin, may serve as biomarkers of inflammatory diseases, including in cows with subclinical mastitis.