Canadian Equine Hoof Care logo

single default

Dealing with winter laminitis

What is winter laminitis?

More and more horses are being diagnosed with cold induced hoof pain, also known as winter laminitis. Winter laminitis is a condition affecting the hooves of domesticated horses. The condition was identified and diagnosed a few years ago mainly in the northern hemisphere where temperatures go well below zero Celsius. It describes painful hooves which are triggered by cold weather.

To understand winter laminitis, we first must understand laminitis. Simply put, laminitis is a condition that can be very debilitating and painful. It has effects on the whole horse but mainly is seen in the hooves.  It is an inflammation of the connective tissue in the hoof capsule which can be triggered by many possible factors. Laminitis occurs when there is a change in the blood circulation and its chemistry within the hoof capsule, resulting in inflammation.

Laminitis can be divided into three main categories :

(1) septic/systemic inflammatory conditions,  (2) endocrine/metabolic,

and (3) mechanical overload.

Winter laminitis can be related to all 3 categories, as it appears to be a side effect of the above conditions, however we see more cases with category 2 (metabolic and endocrine induced laminitis) than any other category who suffers from cold induced hoof pain. Insulin levels naturally rise in the winter months, and for horses who already have high insulin levels, this combination of factors spells trouble.

The mechanism of winter laminitis/ Cold induce hoof pain:

The trigger for winter foot pain is obviously- cold! Cold induced hoof pain has similar symptoms to other forms of laminitis, but differs in cause. In cold temperatures, blood flow is limited in the extremities and directed towards the core of the body to limit the loss of body heat. Cold induced hoof pain often occurs as a combination of two circulation-limiting factors: general cold-induced blood vessel constriction and limited blood flow to the limbs specifically. This combination of limited circulation and blood vessel constriction causes reduced oxygen and glucose delivery to the laminae. While horses with cold induced hoof pain may have a typical rocked back laminitis stance and obvious discomfort, it won’t be accompanied by elevated digital pulses or heat in the hooves.

According to Dr. Chris Politt from Australia, the arteriovenous anastomosis (AVA) shunts inside the hoof capsule change the direction of blood flow to aid in cooling or warming the extremities. In cold temperatures, the shunts inside of the horse’s hooves will allow for increased blood flow and therefore maintain heat within the hoof. He observed that these shunts can be damaged, sometimes when horses have had a small bout of laminitis that went unnoticed or considered to have full recovery from the condition in the past.

Horses who exhibit hoof pain in colder weather could have damaged AVA shunts and therefore inadequate thermoregulation to the hoof.

Dr. Eleanor Kellon, who has worked with laminitic horses for the past decade, observes that high cortisol levels increase the probability of blood vessels to constrict. This explains why horses with Cushing’s disease will be particularly prone to winter laminitis. Insulin resistance further aggravates the condition, as insulin dilates blood vessels but without proper insulin reception, it cannot do its job properly, added to which the exposure of tissues to high blood insulin is damaging on its own.

Horses are masters of adaptation and have been able to thrive in diverse climates. Some breeds have specifically adapted to be very hardy in colder conditions, like fjords and Icelandics for example.

So why has this condition only been described and talked about in recent years?

What has changed in their system?

If we look closely, it may not be the horse who has changed much but the way we keep, feed and manage horses. These days, our horses don’t have to move nearly as much as their ancestors, and we are feeding richer foods which means that not only have we reduced impetus for circulation but we’ve also decreased hormonal health etc’.

How do we know our horses have cold-induced hoof pain?

Horses with hoof pain in the front limbs or all 4 limbs will be reluctant to move, and some might take the common laminitis stance where the hind feet are well under the horse’s hind end and the front feet are stretched forwards. They may also decide to remain laying down for much longer than is typical for them, to reduce the pressure on their sore feet.

These behavioral and physical signs, especially in horses who are metabolically challenged already, should be the red flag to call the vet.

The horses most susceptible to cold induced hoof pain are ones who have already had bouts of laminitis in the past, and ones with preexisting metabolic conditions.

The discomfort of cold induced hoof pain may be managed in different ways including:

  • The veterinarian may prescribe L-arginine. This amino acid has a vasodilatory (widening) effect on blood vessels
  • Increase movement of the horse to aid with blood circulation.
  • Continue to feed low sugar and starch hay and even consider feeding straw.
  • Using leg wraps and/or hoof boots with wool socks can help to protect the horse’s legs and hooves from the cold, aiding in circulation.
  • Using adaptogen herbs such as Jiaogulan that can increase blood circulation and dilation of blood vessels. A consultation with a herbalist is important before use as some of the herbs should not be used alongside NSAIDS (non steroid anti inflammatory drugs) such as Bute, and are not an alternative to a properly balanced, low sugar diet.

Prevention is key – preventing winter laminitis doesn’t start in winter, it’s a year round commitment to the horses’ health.

  • Remaining on a regular trim schedule throughout the winter, as longer hoof walls restrict circulation via reducing overall hoof plasticity.
  • Make sure your horse have free access to adequate forage (fiber digestion creates body heat as a byproduct)Freedom and motivation to move and roam around, (Forage that is spread across the pasture or track system is a great way to keep the horses moving, or allowing horses to paw through snow for dead pasture grass in winter)
  • Leg wraps and hoof boots
  • Proper shelter
  • Keeping them in tip top health by making sure they are appropriately supplemented (herbs, minerals, vitamins) for the nutrients that are lacking in their hay (making sure to avoid products with grain bases)
  • Appropriately managing Cushing’s and insulin resistant horses who are the most prone to this issue.

Understanding better  how winter can affect your horse, will help us manage some condition in a better way. Of course in any doubt on your horses health you should call your vet.

“The resilience of horses through all the seasons never ceases to amaze me. But the tenacity of their caregivers throughout Canadian winters is truly a labor of love”

References

F. GAUFF, B. PATAN-ZUGAJ and T. F. LICKA. Hyperinsulinaemia increases vascular resistance and endothelin-1 expression in the equine digit. Equine Vet J. 2013 Sep; 45(5): 613–618.

Published online 2013 Mar 12. doi: 10.1111/evj.12040

Ruth A. Morgan ,John A. Keen,Brian R. Walker,Patrick W. F. Hadoke. Vascular Dysfunction in Horses with Endocrinopathic Laminitis, Published: September 29, 2016 Vascular Dysfunction in Horses with Endocrinopathic Laminitis | PLOS ONE

J A Keen 1, C Hillier, B C McGorum, J E Nally. Endothelin mediated contraction of equine laminar veins. Equine Vet J. 2008 Jul;40(5):488-92. doi: 10.2746/042516408X313634.

Bowker RM. The Vascular Cushion of the Frog: What Does It Do? ECIR Group Inc., 2013 NO Laminitis! Conference, Jacksonville, 2 OR, USA. http://www.ivis.org/proceedings/ecir/2013/toc.asp

https://ker.com/equinews/seasonal-soundness-avoiding-winter-laminitis-in-horses/

https://www.ecirhorse.org/proceedings-2015.php