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Impact of Heat Stress, such as high temperature and humidity, on the immune system is reported in animals. The pivotal role of cytokines in modulating the immune response is well established. The aim of this study was to evaluate the serum levels of 4 major cytokines (IL-4, IFN-, TNF-, IL-6) in 21 Holstein stabled calves (age, 2-16 months) prior to and 4 days after exposure to a heat stress condition. Furthermore, clinicopathological variables potentially influenced by the latter condition, such as white blood cells count (WBC), plasma muscular enzymes (AST, LDH, CK), serum glucose and β-hydroxybutyrate, were evaluated as well. A condition of heat stress was defined by a mean daily value of Temperature-Humidity Index (THI) higher than 74 for 3 consecutive days. Serum cytokines concentrations were determined using a multiplex sandwich enzyme-linked immunosorbent assay (ELISA) based on chemioluminescent detection of the analytes (SearchLight Multiplex Immunoassay Kits, Aushon Biosystem). Following one week of normal climatic parameters (mean daily THI 68), a Heat Stress condition (mean daily THI = 76) was detected for 4 days in our population. In response to Heat Wave, serum concentrations of IL-4 significantly increased (P |
