EXCESS SELENIUM SUPPLEMENT

Selenium is a trace mineral that is an essential element in the horse’s diet and is available from the soil via plants. Selenium is deficient in the soil in several areas in Australia and therefore can be deficient in hay and cereal grain.

With this in mind, Selenium is often added to many commercial feeds and supplements and it can be easy to overdo it!

The recommended level of Selenium is very small. A 500kg horse requires between 1 and 3.5mg per day dependent on the level of exercise (National Research Council, 2007).

Regular supplementation with excess selenium can affect the hair and the hooves. The excess selenium replaces the sulphur bonds in the keratin in the hoof horn with a weaker bond which causes a lack of structure and weak hoof tissue.

The result can be hooves which become brittle or soft, chip easily, develop horizontal rings and cracks around the coronary band and loss of hair in the tail and mane and straggly mane and tail.

Supplements and feeds which contain selenium will state the concentration on the label which makes it quite easy to check the amount you are feeding.

As with all supplementation, it is important to analyse the diet for proper nutrient balance – both excess and deficiency.