Our bodies (both human and horse) are designed to defend against a variety of infectious, disease-causing agents or pathogens, including bacteria, fungi, protozoa, and viruses.
It has been said that a horse’s hoof can be considered a window into the state of his health, acting as a barometer by reflecting (through the external expression of the hoof wall growth ring patterns) how much pressure/stress the horse’s body is experiencing.
Even under normal circumstances your horse faces many conditions that could challenge his health:
- Sudden weather/temperature change
- Climate extremes of wet or dry
- Mineral toxicity – i.e., selenium in large amounts (usually 5 ppm and greater)
- Vitamin deficiency - Vitamin A is essential for normal hoof growth. If a horse is deficient in Vitamin A his feet can loose all elasticity and bonding capability and the hoof can become “crumbly” and literally fall apart.
- Viral infections - Among the most common are Influenza, Equine Infectious Anemia (EIA) and various combinations of encephalomyelitis, such as Eastern (EEE), Western (WEE) or Venezuelan (VEE).
To fully comprehend virology and its relevance to our horses, we should consider a reaction to a virus as a main event that will likely have a sequel. Though signs can vary from one individual to another, depending on one’s level of acquired immunity, common initial reactions to viruses include:
- frequent cough
- nasal discharge
- increased respiratory rate
- decreased appetite
These and possibly other side effects may all be occurring simultaneously, making up what
we could consider the main event. But, equally important is what to expect as a sequel. As the horse continues to cope, various secondary stress factors can surface. Systemically, the first change will be an increased level of lethargy and an elevated body temperature, usually accompanied by a doubling of his digital pulse rate (80-100 bpm).
Also occurring is a breakdown in the lymph vessels, located under the frog of his hoof, in the deepest portion of that tissue (deep digital cushion). Finally, under the worst of conditions, all the complications of a viral episode could predispose your horse to laminitis (inflammation of the connective tissue responsible for maintaining an attachment between the hoof wall and the coffin bone).
When you develop a keen eye for reading your horses hooves, the first indicator of any trouble will be reflected in the horizontal rings that surround a hoof from the hairline to the ground. On the healthiest hoof, these rings should be hard to spot; they are evenly spaced, smooth to the touch, and correspond as an exact parallel to the coronary band region of the hoof. The presence of these slightly perceptible hoof rings is normal.
One of the first visual indicators of a hoof reaction to any stressor will be a slight indented growth ring or coronary band depression, appearing just below the hairline of the hoof wall. In the following weeks, as this growth pattern continues, these rings, often referred to as fever rings, may become more wavy and sporadic.
Awareness of stress-inducing situations, and guarding against them, will aid in the prevention of the development of abnormal and unwanted hoof rings – a sure sign your horse is reacting to some sort of stressor.
Bryan S. Farcus MA, CJF, is the creator of a select line of “Farrier-Friendly™” products and author of the “Farrier-Friendly™” series of articles that appear in horse magazines throughout the US. Bryan currently works with horses and their owners in Ohio and West Virginia. www.farrierfriendly.com