Serum Cytokine and Cortisol Dynamics in Foals: From Pre-colostral Status to 21 Days After Colostrum Intake

Abstract

Introduction The neonatal period in foals is crucial for immune system adaptation, transitioning from a naïve fetal state to functional competence. Born without maternal antibodies due to the epitheliochorial placenta, foals rely on colostrum for passive immunity, making them vulnerable to early infections. The regulation of immune responses by cytokines is essential, yet their dynamics during this period are not well understood. This study aimed to assess cytokine profiles and cortisol concentrations as indicators of immune homeostasis during the first 21 days of life. Materials and methods Ten clinically healthy Thoroughbred foals were monitored, and blood samples were collected at birth (T0, pre-colostrum) and on days 1 (T1), 7 (T7), 14 (T14), and 21 (T21). Serum concentrations of IL-2, IL-6, IL-10, TNF-α, IFN-γ cytokines, and cortisol were measured using ELISA immunoassay technique. Results Repeated measures ANOVA revealed a significant effect of time for cortisol (F=17.64, p<0.01), IL-2 (F=19.16, p<0.01), IL-6 (F=16.27, p<0.01), IFN-γ (F=13.84, p<0.01), and TNF-α (F=7.62, p<0.01), while IL-10 showed no significant variation (F=3.83, p=0.14). These results show that neonatal foals undergo a temporary pro-inflammatory state at birth. Conclusion This study offers quantitative baseline data crucial for differentiating normal immune adaptation from pathological states, enhancing neonatal management and disease prevention strategies.