Nov. 21, 2014

Understanding Winter Laminitis

Understanding Winter Laminitis

 

Laminitis has become one of the most heavily researched aspects of lameness because it affects so many horses.  Are some horses more susceptible than others?  How to spot the warning signs and act fast to manage them. 

 

Every winter some owners and caretakers are faced with the onset of obvious foot pain in their horses for no apparent reason. Once a horse has experienced this, it is likely to recur year after year.  What's going on? 

 

The normal reaction of the horse's body during cold exposure may be decreased blood supply to the hoof, sufficient enough to cause pain. In a normal horse, vessels constrict in response to cold but will periodically open up again to increase blood supply if oxygen tension gets too low. If the vascular network is damaged from prior bouts of laminitis, or if constriction is higher than normal because of hormonal issues, this protection might not occur.  High insulin and cortisol make the vessels more sensitive to constrictors.  High insulin is also associated with higher levels of the very potent vasoconstrictor endothelin-1.  

 

The Insulin Factor

For insulin resistant horses or those with Cushing’s disease, high insulin and cortisol levels make the vessels more sensitive to constrictors and therefore more difficult to dilate. High insulin is also associated with higher levels of the very potent vasoconstrictor endothelin-1 so the vessels in these horses are not only more difficult to dilate, they are also more constricted as a starting point.

 

Protection against the cold is therefore the first step in combating winter related hoof pain. Horses should be protected from high winds, rain and snow.  They should be blanketed, wear leg wraps to warm the lower legs, and boots, preferably lined. Effective lower leg wraps include standard polos and cottons, leg warmers or even fleece lined shipping boots.

 

Adaptogens for vascular support

This helps, but for some horses is not enough. If your horse ends up with laminitis, even after blanketing and wrapping, supplements to enhance blood flow may help. Herbal products known as “adaptogens” promote healthy stress responses and may be very beneficial. Jiaogulan (Gynostemma pentaphyllum) is a good one to use because it also strongly supports vascular nitric oxide production, which improves blood delivery to the extremities and feet. Some horses respond better to stronger adaptogens such as North American Ginseng, Eleutherococcus, Rhodiola and Schizandra.  These herbs are also safe for insulin resistant horses.  Jiaogulan can be given twice daily, the others once daily.

 

Amino acids support blood flow and insulin sensitivity

The amino acid arginine, as well as citrulline may also be very beneficial in promoting good blood flow to the hoof by opening up constricted blood vessels.   Arginine is the precursor to nitric oxide, which is a vasodilator. Citrulline is converted to arginine after absorption.   Taurine has been found in a recent study to improve insulin sensitivity. L-glutamine is also useful to support antioxidant glutathione and carnitine derivatives to support horses with neuropathic pain and help with insulin sensitivity.

 

L-arginine can be given at least twice daily, sometimes 3 to 4 times daily, to support blood flow. Alternatively, L-arginine-alphaketoglutarate (AAKG) may be used. This form of arginine seems to have a more prolonged effect.  

 

One of the most devastating effects of winter laminitis is that it can appear to strike out of nowhere. However, if you are alert to the warning signs, you can intervene early to support blood flow and protect your horse before disaster strikes.

 

 

Eleanor Kellon, VMD, currently serves as the Staff Veterinary Specialist for Uckele Health & Nutrition.  An established authority in the field of equine nutrition for over 30 years, Dr. Kellon is a valuable resource in the field of applications and nutraceuticals in horses. She formerly served as Veterinary Editor for 'Horse Journal' and John Lyons 'Perfect Horse' and is owner of Equine Nutritional Solutions, a thriving private practice.  A prolific writer, Dr. Kellon is the author of many best-selling books on a variety of medical and nutritional topics and has contributed to both lay and professional publications.