Photobiomodulation in the Treatment of Bovine Subclinical Mastitis

Mastitis is among the most common, impacting and challenging disease in the dairy industry. Mainly in view of the various disadvantages of conventional therapies, this study aimed to verify the treatment of subclinical mastitis through photobiomodulation. Lactating cows (n = 10) were used, nine (n = 9) with positive subclinical mastitis and one (n = 1) negative used as a control. The photobiomodulation protocol using 5 J/cm2, and occurred on alternate days, totaling seven applications of the Ga-Al-As diode laser (685 nm) inside one cow teat. The milk samples were analyzed before, during and after the treatment to realize the reductase test, colony count and California Mastitis Test (CMT). No changes were found in the reductase test, keeping the milk acidity stable in all samples during and after treatment. In the bacteria isolation and colony count we identified Staphylococcus aureus, coagulase-negative Staphylococcus and Bacillus cereus, a better performance was observed in animals treated by coagulase-negative Staphylococcus, keeping the growth of Staphylococcus aureus stable and increased in Bacillus cereus. Regarding the CMT, it was positive for subclinical mastitis before and after treatment, with a decrease in positivity in 60% of the animals 96 h after the last application. The results suggest the development of future research of photobiomodulation protocols for bovine subclinical mastitis with others optical dosimetries, since there were no changes in the milk composition, decreased in the bacteria count, and without generating residues in milk and dairy product losses.