Thermal-humidity exposure and water deprivation alter the immune response, and hair but not plasma mineral profiles, in Holstein dairy cows

Abstract

ABSTRACT In this study, we aimed to determine the effects of thermal-humidity exposure (THE) and water deprivation on the immune response, and hair and plasma mineral profiles of lactating Holstein cows. Thirty multiparous lactating Holstein cows were divided into two groups of 15 cows each: a treatment (T) group subjected to THE and water deprivation for 2 h following feeding, and a control (C) group subjected to THE but with free access to water. Higher levels of sodium (Na), potassium (K), and copper (Cu) in hair were observed in the C group, whereas higher levels of magnesium (Mg), phosphorus (P), calcium (Ca), manganese (Mn), and iron (Fe) in hair were observed in the PC group compared to the other groups. In plasma, mineral contents did not differ between the C and T groups. Additionally, water deprivation during THE decreased hair Mg content. Neutrophil levels and neutrophil/lymphocyte ratios were higher in the T group than in the C group at day 50, but did not differ between the two groups at day 60. Overall, the combination of THE with water deprivation for 2 h altered the hair mineral content, and decreased the immune response, in high-yielding lactating cows.