Throughout the body, vitamins serve crucial functions to maintain cells in a state of health. Perhaps unimaginatively named for the letters of the alphabet, the vitamins are A, B, C, D and E. Vitamin K breaks the order but is no less important.
A recent conversation with a fellow veterinarian led me to review the function of vitamin E in animals and I thought I would share what I learned.
Vitamin E in animals serves as an antioxidant in conjunction with the mineral selenium. Routine cell functions that use energy to move molecules around generate a great deal of waste.
One type of these waste products is called free radicals. As their name implies, free radicals are wicked little molecules that bind and damage other molecules they contact.
As one of my physiology professors described it, free radicals are analogous to vampires. When a vampire bites, its victim turns into a vampire. That vampire then goes on to bite others. The process repeats and the corruption spreads, injuring cells in the process.
This is where antioxidants, including vitamin E, come into play. It works in tandem with other antioxidants to bind up free radicals and remove them from cells to prevent them from causing damage.
Animals get their vitamin E from their diets. For livestock, this means access to lush, rich grasses and fresh hay. Animals grazing on poor quality pastures or fed poor quality hay may not be getting enough vitamin E.
Grains including corn, oats and soybeans also contain some vitamin E. It is important to remember that the amount of vitamin E in rations will deplete with time.
In its most severe form, low vitamin E can lead to serious diseases. The cell damage from free radicals accumulates most severely in tissues with high cell metabolism including the nervous system and muscles.
The most common condition associated with low vitamin E is white muscle disease, which affects calves and foals. Heart and skeletal muscle cells are damaged and lose their ability to regulate calcium, leading to mineral accumulation, heart failure and pain. Muscles are pale with white streaks from the abnormal accumulation of calcium.
Horses with low vitamin E can also develop neurological diseases.
There are less insidious conditions associated with low vitamin E. Because it plays an important role in maintaining the function of the immune, nervous, reproductive and muscle systems, low vitamin E can manifest in a variety of ways. Increased infections including mastitis, reproductive failure and retained placentas are a few conditions associated with low vitamin E. Horses in heavy exercise create a large number of free radicals and may benefit from vitamin E supplementation.
As with most things in life, too much of a good thing can be problematic. But in the case of vitamin E, it is considered quite safe. Overdoses in livestock are not typical. There may be a relationship between high levels of vitamin E and reduced ability to absorb other vitamins but for average livestock on the Prairies, this is unlikely to be an issue.
Vitamin E deficiency can be diagnosed by a blood test. In dead animals, the liver can be tested. Forage can also be tested to determine levels of vitamin E, although this would give indirect information about the vitamin status of animals that feed on it.
Vitamin E can be supplemented in the feed and is available in injectable form for livestock.
Livestock on the Prairies are prone to vitamin E deficiency so it is worthwhile to keep this important nutrient in mind when formulating rations and working through cases of cattle that are doing poorly on farm.
Dr. Jamie Rothenburger, DVM, MVetSc, PhD, DACVP, is a veterinarian who practices pathology and is an assistant professor at the University of Calgary’s Faculty of Veterinary Medicine.