Photobiomodulation of the mammary gland for the treatment of mastitis in dairy cattle

Abstract Mastitis remains the most economically significant disease in dairy production, impacting milk yield and quality from the mammary gland and impairing overall animal welfare. Conventional treatment strategies rely heavily on antibiotics, raising concerns about antimicrobial resistance, withdrawal periods, and consumer demand for residue-free milk. Photobiomodulation (PBM), a noninvasive therapy utilizing low-level laser light, has emerged as a promising adjunct for udder health management. This review synthesizes current evidence on PBM’s physiological mechanisms, therapeutic benefits, and practical implications for dairy herd health. PBM operates through the activation of mitochondrial chromophores, primarily cytochrome c oxidase, triggering enhanced ATP synthesis, nitric oxide release, and redox signaling. These processes modulate inflammatory pathways, including NF-κB and MAPK signaling, and regulate cytokine production, thereby promoting tissue repair without broadly suppressing immune function. In cows, PBM has been shown to reduce oxidative stress, inflammatory mediators, and the somatic cell count (SCC), contributing to improved milk quality and accelerated recovery. Studies report up to a 60% reduction in subclinical mastitis cases and an enhanced recovery of 31.2% when PBM is combined with antibiotics, underscoring the role of PBM in antimicrobial stewardship. Beyond therapeutic outcomes, PBM offers welfare advantages by alleviating pain and minimizing stress during treatment. Its noninvasive nature reduces handling-related anxiety compared with conventional interventions. Emerging evidence also suggests potential benefits for milk composition (increase in de novo fatty acids) and metabolic stability, although further research is needed to confirm these effects in vivo. Despite its promise, PBM faces limitations, including variability in treatment parameters, restricted tissue penetration, and logistical challenges in large herds. Standardization of dosing protocols and cost-effectiveness analyses remain critical for widespread adoption. Thus, PBM represents a viable complementary strategy for mastitis management, aligning with industry goals to reduce antibiotic dependence while enhancing animal welfare and milk quality. Continued research into optimized applications, long-term efficacy, and economic feasibility will determine its integration into sustainable dairy health programs.