What is the relationship between nutritional changes and fever or stress rings? This feature uniquely addresses whether or not nutritional changes can explain stress rings.

Richard A. Mansmann, VMD, Ph.D, and hon. DACVIM-LA 

Nutrition plays a role in the creation of the hoof wall because nutrients help regulate hoof growth. Sudden changes in a horse's diet can affect the environment within the gastrointestinal tract by encouraging some bacteria to grow while inhibiting the growth of others. A change in the horse’s gut environment may cause an episode of systemic change that incites laminar hyperplasia and/or a change in hoof growth rate, resulting in the formation of raised rings in the hoof wall. 

If a sudden change in diet also brings a sudden increase in the horse’s body weight, buckling of the tubules may contribute to the development of these rings.

A ring in just one hoof is likely the result of a change only in that one limb and likely is due to an injury.

However, finding a ring in all four feet is likely due to a systemic change or inflammatory response. The duration of the inflammatory response or buckling of the tubules determines the vertical measurement of the ring (how thick it is from top to bottom). 

To learn about nutrition changes and their relation to fever rings, be sure to read the Nutrient Strategies series in the December 2010 issue.