During oxidative stress situations, such as calving, dairy cows require extra antioxidants, and the vitamin E content in the blood can decrease sharply. In order to prevent reduced immunity and other health-related disorders, dry cattle should be given more vitamin E than during the lactation period.
Vitamin E is an essential vitamin that is vital to the metabolism but that cattle are unable to produce. For this reason, all the necessary vitamin E, both natural and synthetic, needs to be administered via the feed ration. The amount required daily by an adult animal varies. When an animal is ill or suffers from oxidative stress caused by other reasons, such as in the period around calving, the vitamin E content of the blood can often decrease sharply. This can lead to a series of health-related complaints.
Vitamin E is actually a collective name for a group of fat-soluble alcohols with α-tocopherol activity. The antioxidative effect prevents fat oxidation and protects the cell membranes from the effects of free radicals. In addition, vitamin E also promotes the synthesis of stress hormones and the working of the immune system, boosts fertility and the health of offspring and contributes to proper regulation of the protein and energy metabolisms within the cells.
Symptoms of deficiency
A host of health complaints and disorders are related to a lesser or greater extent to a vitamin E deficiency. These include muscular dystrophy, white muscle disease, mastitis, retained placenta, metritis, ovarian cysts, udder oedema, stillborn calves, reduced resistance to infection, a stiff gait and discolouration of the meat.
Dry period and lactation
It is clear that dairy cattle should have an adequate vitamin E intake, for the benefit of both their own health and that of their offspring. Due to its rapid degradation during stress situations, a higher daily intake is recommended during the dry period than during lactation: 1,000-1,500 mg/day versus 500-1,000 mg/day. For optimal effects, the levels of other antioxidants and minerals should also be correct, particularly those of vitamin C and selenium.
For further information on this subject, please contact Elwin Brons, ruminant nutritionist, for the complete article.