Dr. Connie Larson is a research nutritionist specializing in the equine field with Zinpro Corporation in Eden Prairie, Minn.

Q. Will Feeding Excessive Vitamin E Or Selenium Lead To Hoof Problems?

Minimizing hoof problems in the horses you work with requires attention to management, footcare programs and nutrition. Providing balanced levels of effective nutrients is a key component for maintaining hoof quality, preventing disorders or disease that impact function, and in some cases, for assisting the healing process.

The question regarding excessive levels of specific nutrients leading to hoof problems is appropriate. To explain the impact of feeding excessive levels of selenium and vitamin E on the equine hoof, it’s important to start with information on nutrient requirements for the horse, dietary levels in feeds and the role of these nutrients in the hoof. 

Small Amounts, But Necessary

The dietary selenium requirement for the horse is quite small compared to other trace elements such as zinc, manganese and copper. The minimum recommended selenium level is expressed as a concentration of the total dietary intake at 0.1 ppm (mg/kg of the diet dry matter; to convert values to mg/lb, divide value by 2.204).

Levels in non-fortified equine diets can vary and range from deficient to very high levels. In the United States and Canada, forage and grain selenium contents are generally low for many regions on the East and West coasts as well as across most of Canada. 

Forages and grains produced in selenium rich soils in the Rocky Mountain and…