Weaning is a critical period for calves, affecting their well-being, health, and productivity. The present study analyzed 61 calves to evaluate the effects of weaning as a stress factor by monitoring hematological, biochemical, and immune parameters. Blood samples were collected at the start of weaning at 130–135 days (T0), 3 (T1) and 7 (T2) days later, and finally at 150 days of age. The results showed changes in the levels of cortisol, inflammatory cytokines (TNF-α, INF-γ and IL-8) and acute-phase proteins. Alterations in white blood cells were also observed, such as neutrophilia and lymphopenia, which are typical signs of an adverse stress response. Biochemically, the switch from milk to solid food caused imbalances in protein, cholesterol, and triglyceride levels, indicating a relevant metabolic adaptation. Serum electrophoresis showed a decrease in albumin and an increase in γ-globulins, a sign of immune maturation. The results suggest that weaning is one of the most important stressors for calves, with both physiological and immune effects. However, this practice is necessary for breeding productivity. Future research could investigate the role of genetics and environment in weaning resilience to further optimize breeding practices.

This study evaluated the short-term response to pour-on eprinomectin (EPM) treatment in buffaloes naturally infested by Haematopinus tuberculatus, focusing on haematobiochemical parameters, serum and milk cortisol levels, and milk production. Twenty-four Italian Mediterranean buffaloes were allocated to two groups: an untreated Control group and a group receiving 0.5 mg EPM/kg body weight. From treatment day (T0), blood was sampled every 14 days, while milk yield was recorded and milk samples collected every 7 days for 4 weeks. Haematobiochemical parameters, serum and milk cortisol, and milk composition were analysed. Data were statistically analysed using a linear mixed-effects model including treatment, time (as fixed categorical effects) and their interaction, T0 as a covariate and the animal as a random effect. No differences were detected for cortisol and most haematobiochemical parameters between groups (p > 0.05). Haptoglobin showed lower values in EPM-treated buffaloes when compared to Controls (34.8 vs. 43.6 μg/mL; p = 0.026). Milk yield remained unaffected by treatment (p > 0.05), whereas milk fat was higher (83.1 vs. 69.1 g/kg; p = 0.011) and milk urea was lower (36.1 vs. 40.1 mg/dL; p = 0.002) in EPM-treated buffaloes. Overall, EPM treatment against H. tuberculatus infestation was associated with limited short-term changes in physiological and productive responses in lactating buffaloes, including lower serum haptoglobin concentrations and differences in selected milk composition traits.