Telomere Length as a Genomic Biomarker of Environmental Stress in Dairy Goats

The identification of sensitive molecular indicators capable of capturing physiological responses to environmental stressors is a priority in livestock farming. In this context, molecular biomarkers can support precision livestock farming approaches by complementing sensor‑based data with biologically meaningful information. Among these, telomere length (TL), a marker of cellular aging and oxidative stress, is emerging as a promising genomic biomarker in domestic species, being relatively rapid and cost‑effective to measure under standardized conditions. Longer telomeres are generally associated with better health status and improved welfare. Moreover, TL dynamics are generally coordinated across tissues and reflect systemic physiological conditions, supporting their assessment in minimally invasive matrices such as milk. This study evaluated TL dynamics in dairy goats exposed to acute environmental stress under field conditions. Twenty grazing goats were monitored across three sampling points. A period characterized by high humidity and severe storm events was associated with a significant increase in serum cortisol concentrations (P < 0.01), accompanied by a significant decrease in milk‑derived TL (expressed as T/S ratio; P < 0.05). Following the return to stable environmental conditions, both cortisol levels and TL values showed recovery trends. Correlation analysis revealed significant negative associations between TL and humidity (r = –0.62; P < 0.01) as well as dew point (r = –0.58; P < 0.05), supporting the sensitivity of TL to climatic stressors. These findings indicate that acute environmental challenges can induce measurable telomere shortening, reflecting increased cellular strain. Overall, TL responded consistently to short‑term physiological stress and aligned with endocrine changes, supporting its role as an integrative biomarker of animal welfare. The integration of TL into field‑based assessments may provide a valuable tool to detect early biological responses to environmental challenges, contributing to more informed and adaptive management strategies in small ruminant production systems.