Coat characteristics, physiological traits, serum metabolites, and thyroid hormones of Canindé and Moxotó goats in a semiarid environment.

This study evaluated the adaptive responses of dark-coated Canindé and light-coated Moxotó goats reared under semiarid conditions in Brazilian semiarid through an integrated assessment of thermoregulatory, biochemical, hormonal, and morphological variables. Sixty non-pregnant and non-lactating goats (30 Canindé and 30 Moxotó) were evaluated during summer and winter under the same grazing and management conditions. Animals received native pasture and concentrate supplementation (200 g/head/day). Significant breed × season interactions (P < 0.05) were observed for physiological, metabolic, hormonal, and coat variables. Dark-coated Canindé goats showed higher coat surface temperature and greater seasonal variation in coat thickness (0.60 vs. 0.51 mm), as well as marked seasonal changes in T4 (1.67 vs. 4.47 µg/dL), glucose (48.87 vs. 105.03 mg/dL), and albumin (4.42 vs. 8.19 mg/dL) from summer to winter, indicating greater metabolic flexibility. In contrast, light-coated Moxotó goats maintained lower and more stable thyroid hormone concentrations across seasons (T4: 1.63 vs. 1.63 µg/dL) and exhibited increased creatinine levels during winter (0.95 vs. 1.57 mg/dL), suggesting a more conservative adaptive strategy. Multivariate analyses demonstrated distinct adaptive profiles between breeds. Factor analysis revealed integration between thermoregulation and metabolism in Canindé goats, whereas Moxotó goats showed stronger biochemical compensation mechanisms. Decision tree analysis identified globulin and coat thickness as the main discriminating variables between breeds and seasons. These findings demonstrate that locally adapted goat breeds use distinct but effective adaptive strategies to cope with semiarid environmental conditions and provide important phenotypic indicators to support conservation programs, breed selection, and climate-resilient small ruminant production systems.