Thyroid hormones and redox balance: a review of their correlation under stress conditions in small ruminants.

Thyroid hormones and oxidative stress are intrinsically linked, with thyroid dysfunctions often triggering redox imbalances. Beyond clinical pathology, it is crucial to investigate how environmental and physiological stressors influence thyroid function and oxidative status in livestock. Ruminants are frequently exposed to diverse stressors that compromise their health, welfare, and overall farm profitability. Understanding these interactions is essential for developing integrated therapeutic and management protocols. This review aims to synthesize recent research (2020-2026) investigating the correlation between stressor exposure and fluctuations in serum thyroid hormones and redox parameters in small ruminants. A systematic search across PubMed, Scopus, and Web of Science identified only twelve relevant studies. The stressors analyzed included extreme environmental temperatures (n=9), infectious diseases (n=2), and heavy metal exposure (n=1). Evidence suggests that environmental, pathological, and chemical challenges significantly alter thyroid profiles and redox homeostasis; Notably, antioxidant supplementation mitigated these alterations in the studies in which it was tested.