<b>Potential for improving serum content of β-carotene, antioxidant status, immunity and serum biochemistry of dairy cows at the beginning of lactation by using the pumpkin (</b> <i> <b>Cucurbita maxima</b> </i> <b>D.) silage in the diets</b>

The 40 Simmental cows were enrolled in the experiment 4 weeks before the expected calving date. Initially, cows received diets for dried and next for lactating cows. Group I (control) received a diet with grass and corn silages and concentrate. Group II was fed similarly to group I plus 400 mg/day/cow of β-carotene preparation. In group III, 40% of the corn silage dry matter was replaced with pumpkin silage to ensure 400 mg higher β-carotene intake than group I. In group IV, 60% of the corn silage dry matter was replaced with pumpkin silage without balancing β-carotene. Blood samples were collected one day after calving (measurement-1), four weeks (measurement-2) and 12 weeks after calving (measurement-3). In the blood, β-carotene, total antioxidant status (TAS), superoxide dismutase (SOD), glutathione peroxidase (GPx), immunoglobulins (IgG, IgM, IgA) and biochemical markers were measured. In groups III-IV, subsequent measurements found a higher concentration of β-carotene than those in group I. Throughout all the measurements in groups II-IV, higher levels of TAS, SOD and GPx were observed than those in group I. A higher β-carotene intake in the diet of pumpkin silage increased the immunoglobulins in the serum. The use of pumpkin silage in diets reduced the BHB level.