The effect of supplementing rations with selenium and vitamin E on biochemical parameters in blood and performance of cows in the early stage of lactation

Thirty-two cows (Black-and-While x HF) in the first 100 days of lactation w ere divided into 4 groups and fed rations composed of equal proportions of roughages and concentrates in amount of 1 kg per 2 kg of milk at yield exce eding 12 kg/day. The concentrates were supplemented with vitamin E (group I , 336 mg; groups II, III, and IV, 672 mg/cow/day) and selenium: group I, no supplementation: group II, 4 mg/cow/day as sodium selenite; group III, 4 m g/cow/day as selenium yeast; group IV, 2 mg/cow/day as selenium yeast. Cows fed selenium-supplemented rations had significantly elevated serum sel enium concentrations (group I, 0.0214 meg/ml; II-0.0453 meg/ml; III, 0.0654 mcg/ml; IV, 0.0573 mcg/ml). Selenium from yeast was utilized better than s odium selenite. Regardless of the source of selenium, Se lowered serum a-to copherol (0.245 vs 0.229; 0.187; 0.232 mg/dl) and retinol (35.57 vs 31.46; 32.25; 29.29 mcg/dl) levels. The addition of selenium when the vitamin E co ntent of the ration was increased modified the lipid metabolism of cows (el evated HDL and triglycerides).