The effect of season on some blood metabolites and haptoglobin in dairy cows during postpartum period

The aim of this study was to evaluate the effect of season (ambient temperature and relative humidity) on some blood metabolite in dairy cows during postpartum period. Blood samples were collected from 195 clinically healthy dairy cows of 8 Italian dairy herds in spring (April-May 15.5\ub14\ub0C and 69.5\ub10.7%), summer (June- July 23\ub11.5\ub0C and 69\ub11.3%) and autumn (September-October 17\ub12\ub0C and 72.5\ub12%). Total proteins, albumin, globulins, urea, glucose, triglycerides, total cholesterol, non esterified fatty acids (NEFA), B-hydroxybutyrate (B-HBA) and haptoglobin (Hp) were analysed. One-way repeated measures analysis of variance (ANOVA) showed a significant effect of season (P<0.05) on all studied parameters, except to PCV, globulins and B-HBA. A positive significant correlation was found only between albumin and total cholesterol in summer (r=0.39; P<0.01) and autumn (r=0.40; P