Blood vitamin E, selenium and glutathione peroxidase concentrations in heifers fed either on grass or on winter feed

Plasma and liver alpha-tocopherol in dairy cows with left abomasal displacement and fatty liver

Thirty dairy cows with left abomasal displacement (LAD) and 14 healthy control cows were studied to assess the status of the natural antioxidant vitamin E, lipid peroxidation in the liver (malondialdehyde-formation) and its relationship to hepatic lipidosis. Blood concentrations of alpha-tocopherol, aminotransferase, glutamin dehydrogenase, free fatty acids, beta-hydroxybutyrate and glucose were determined. alpha-tocopherol, tryglyceride, glycogen and malondialdehyde (MDA) in wer liver tissue samples were examined. The dietary alpha-tocopherol intake and its plasma changes in LDA cows were also investigated. Cows were divided into four groups according to their liver triglyceride contents (< 20; 20-80; > 80 mg/g of fresh tissue; and control groups). The lowest plasma vitamin E and the highest liver vitamin E levels were found in cows with highest hepatic triglyceride content. The highest increase in plasma alpha-tocopherol within 5 days was seen in cows with the lowest liver triglyceride (P < 0.01). The liver triglyceride was positively correlated with liver MDA (r = 0.38; P < 0.05) and negatively with plasma alpha-tocopherol (r = -0.41; P < 0.01).

Fat-soluble vitamin nutrition for dairy cattle

The need for supplementation of dairy cow diets with fat-soluble vitamins depends on the amount of vitamins naturally present in the diet, the availability of dietary vitamins, and the vitamin utilization rate of the animal. Fresh forage contains ample amounts of the vitamin A precursor beta-carotene as well as vitamin E. Irrespective of the dietary amount, however, the availability of vitamins A, D, and E, as well as beta-carotene, can be adversely influenced by poor fat digestion, as commonly occurs due to enteric disease in young calves. In addition, high-grain diets appear to increase the amount of ruminal vitamin destruction and may thus increase vitamin requirements. The vitamin utilization rate may be increased by inflammation as well as dietary and environmental factors. The factors influencing vitamin availability and utilization rate should be considered when formulating rations. Because the vitamin requirement is variable, blood concentrations of vitamins should be monitored when conditions such as poor fertility, weak calves, and poor immune response are present.

Plasma tocopherol in sheep and cattle after ingesting free or acetylated tocopherol

Two trials were carried out to evaluate the bioavailability of dl-alpha-tocopherol and dl-alpha-tocopherol acetate administered to sheep and cattle in a single oral dose. In the first trial, two groups of five sheep were used. They received 100 mg/kg body weight of either dl-alpha-tocopherol or its acetylated form. The blood plasma alpha-tocopherol tolerance curve area was higher in the dl-alpha-tocopherol group than in its ester form. The time to reach maximum plasma alpha-tocopherol concentration was less in the dl-alpha-tocopherol group than in its ester form. In a second trial, four heifers received the two forms (50 mg/kg body weight) in rotation after an appropriate washing period between the two dosings. Again, plasma tolerance curve area was greater in the cattle following administration of dl-alpha-tocopherol than its acetylated form.