Treatment and prevention

Chilling out laminitis: the cool benefits of cryotherapy

You constantly try your hardest to avoid laminitis. If things unexpectedly go wrong, you do all in your ability to fix the damage and get your horse back on its feet as soon as possible, both literally and figuratively. So, you grab the garden hose and splash down the hooves with cold water. Because cold therapy, or – with a fancy word – cryotherapy seems to help. Right?

Cryotherapy for laminitis involves the prolonged, continuous, and vigorous cooling of the lower legs. Cold constricts blood vessels, reduces inflammation, alleviates pain, and slows metabolism in hoof tissue [1]. The treatment is most successful in the very first stage of laminitis. At this developmental stage, nothing can yet be seen with the naked eye. It is then used as a preventive measure to keep the disease from developing into the acute phase, when clinical signs become visible or measurable. Veterinary clinics apply this treatment successfully, for example, to prevent laminitis as a complication of severe colic.

Sepsis-related laminitis

The prophylactic nature of cryotherapy is particularly relevant for sepsis-related laminitis, as this form of laminitis is more or less predictable. In sepsis-related laminitis, there is a whole-body inflammatory response. As a result, toxins circulate in the blood. Among other things, the toxins cause clogged capillaries in the lamellar connection, causing it to partially die. The lamellar connection is the structure that holds the hoof wall and the coffin bone together. Laminitis is essentially the damaging and breaking of this connection.

Vasoconstriction

Blood vessels constrict (narrow) as a result of cryotherapy. Blood flow to the hooves will be reduced. Fewer toxins now enter hoof tissues, which results in fewer blood vessel blockages. Vasoconstriction also inhibits the supply of specific enzymes (so-called MMPs) that break down crucial lamellar protein junctions (hemidesmosomes). Some of the toxins are probably also responsible for activating the MMPs. As a result, if fewer toxins enter the hoof, this process is likewise inhibited too.

Causes

Sepsis-related laminitis frequently follows an ‘incident’, thus you can usually see it coming. Think colic, devouring all of the feed bin, or a bacterial infection when the placenta does not come off in mares that have foaled. Other inflammations and infections, such as pneumonia and eye infections, also create toxins in the blood. The list goes on with poisonous plants, mouldy hay, polluted water and a few other things.

What about traumatic laminitis?

This is a third form of laminitis, also known as supporting limb laminitis. The key problem is a lack of oxygen in the hoof tissues due to heavy, prolonged or incorrect hoof loading. No research has yet been done on the use of cryotherapy in traumatic laminitis. Therefore, we leave it out of consideration here.

How to apply cryotherapy?

Put your horse in buckets of ice slurry (half water, half ice) as soon as you believe laminitis may hit at any time or if it has already occurred. The deeper its legs are in it, the better. To keep the temperature below 5 degrees Celsius (41 °F), keep adding crushed ice or ice cubes and replacing warmed up water with cold water. A lower limit of 2 degrees Celsius (35.6 °F) for a minimum of 24 hours and a maximum of 72 hours is considered safe. In consultation with your vet, you can cool for longer than 72 hours.

The deeper in ice slurry, the better
(photo: Polyplas)

Make sure someone is always with your horse or is keeping a close eye on him from a distance (e.g. with a camera). You don’t want it to hurt itself while trying to escape its footbath. If your horse won’t stay willingly in the chilly water very long, you could wrap the legs in heavy plastic bags filled with ice water and secure them with tape.

Good to know: horse legs tolerate the cold well. Contrary to what you might think, leaving your horse in ice water for 72 hours has no negative consequences [2]. This is most likely due to fluctuations in hoof temperature, as is common during extreme cold in winter. We think this serves as a defence mechanism against cold injury. But, apart from the cold, standing in water for three days softens the hoof. It increases the likelihood of bacteria and fungi entering. This may cause hoof abscesses and white line disease. Also, following treatment, thoroughly dry the legs to minimise the risk of skin problems. The image below is of a horse that developed mud fever as a consequence of long-term cryotherapy.

Mud fever following cryotherapy
(photo: Patricia Coune)

Are there other ways?

Letting your horse stand in the snow or a river, hosing down his legs, applying cold compresses (gel packs) or cooling ointment will not do the trick. By doing so, you will not achieve the desired therapeutic effect. Ice-filled poultice boots could be an option, were it not for the fact that the water has to be changed all the time in those too. Moreover, the blood is not cooled high enough in the leg already.

Knee-high ice boots do perform well, even if they do not enclose the hoof itself [3]. There are also dry cryotherapy systems that give good results [4]. These two solutions, however, are something hardly anyone has at hand. They are also fairly pricey, though everyone must decide for themselves whether this is a problem. If you have a horse that, despite all your good care, gets laminitis time after time, you might consider buying it.

Dry cryotherapy
(photo: Equisea)

Research

After reading this, it seems evident that cryotherapy is most suited for usage in equine clinics. Nonetheless, it is frequently promoted as a therapy strategy on social media (and, by the way, in my books). Initially, the rationale for this is primarily practical. For a long time, laminitis could only be produced experimentally by inserting a substantial amount of oligofructose (a type of fructan) into a horse’s stomach with a probe. This results in digestive problems, which increase the amount of toxins produced by proliferating and dying intestinal bacteria to the point where sepsis-related laminitis develops. By then applying cryotherapy, one can easily measure its effect; even between two forelegs of the same horse. A 2014 study showed this way that less damage to the lamellar connection occurs if cryotherapy is started immediately as lameness appears [5]. In other words, at the very beginning of the acute phase. Pain was also much lower in the treated leg compared to the untreated leg. As of yet, it is impossible to tell whether this is attributable to the analgesic qualities of cryotherapy or to lesser tissue injury.

Left the intact lamellar connection after cryotherapy, right the damaged lamellar connection in the non-treated foot of the same horse
(photo: A. van Eps)

Two years earlier, researchers concluded that inflammatory response early in the disease process is much less when cryotherapy is used in sepsis-related laminitis [6]. However, the treatment started immediately after the insertion of the oligofructose. So, in fact even before the developmental phase of the subsequent laminitis. In practice, this will never be the case.

Endocrinopathic laminitis

All very interesting, but with less than 10% of cases, sepsis-related laminitis is relatively rare. Endocrinopathic laminitis (or: hormone-related laminitis) is the most common type of laminitis. Around 9 out of 10 cases fall under this. The majority of these are due to insulin dysregulation. In short, insulin dysregulation is the collective term for any combination of abnormalities in bodily processes involving insulin.

Always too late… Or is it?

Insulin dysregulation is the state where there is too much insulin in the blood (hyperinsulinemia) and the body’s cells do not respond properly to insulin (insulin resistance). We know that hyperinsulinemia, in particular, plays a crucial role in the development of laminitis, but we still don’t know exactly how this happens. What we do know is that the preventive use of cryotherapy is difficult in endocrinopathic laminitis. This is because its onset and progression are much more gradual or even insidious than in the two other forms. It is therefore more difficult to predict. Often it is the attentive hoof care provider or vet who spots subtle changes in the hooves that alerts us to what is going on. Pain, too, appears later in the process. The disease has then already progressed to the acute stage.

Endocrinopathic laminitis is usually chronic and subclinical, with epidodes when the disease flares up, especially after grazing on sugary pasture. This makes it theoretically predictable, but more importantly, practically preventable. Nobody would put their insulin-dysregulated horse in a high-risk pasture and then knee-deep in ice water.

Grazing on high sugar grass is asking for trouble
(photo: J. Rábli)

Nowadays, we can also induce endocrinopathic laminitis experimentally. This allowed a 2019 study to provide a confirmatory answer to the question whether cryotherapy, even in this form of laminitis, can reduce tissue damage in the acute phase [7]. With the side note that the ongoing very strong hyperinsulinemia created in an experimental set-up may not be comparable one-to-one with endocrinopathic laminitis as it occurs ‘in real life’.

Inflammatory response

A reduced inflammatory response is a key benefit of cryotherapy. After all, inflammation of hoof tissue is responsible for some of the damage that eventually leads to the rupture of the lamellar connection [8]. A recent study shows that a milder inflammatory response occurs when cryotherapy is applied in acute laminitis caused by hyperinsulinemia [9].

Decreased metabolism

Slowing down metabolism in lamellar tissue is another benefit. A 2020 study suggests that this may reduce the energy supply to disease processes at a cellular level, while the processes essential for lamellar connection continue [10]. This could be thought of as an emergency brake, allowing more time to address the underlying issue or plan another treatment. An added advantage is that the lower metabolism means that hoof tissues do not suffer from the lower blood flow due to (targeted) vasoconstriction.

Therapeutic effect

In all this, it must be said that in both studies, treatment had already begun before the laminitis revealed itself through lameness. In other words, at the developmental stage. Therefore, the researchers say they are not sure whether cryotherapy will have therapeutic benefits if applied only after the acute phase of laminitis has begun. For that matter, the same goes for the other studies where the researchers did examine changes in the lamellar connection at the cellular level or the presence of inflammatory mediators (antibodies) but did not look at improvement in the horses’ clinical picture. The wait is for a study that does.

In conclusion

Cryotherapy is starting to prove its usefulness more and more. The slightly negative note is that it is difficult for horse owners to really apply it in a timely and effective manner. But the fact that you have read this post to understand more about laminitis is a huge plus. This may help your horse even more than a few buckets of cold water.

Do you like this kind of comprehensive and objective information on laminitis?
Laminitis : understanding, cure, prevention‘ jam-packed with it!
266 pages full of accessible, science-based knowledge, insights and advice that will help you and your horse.

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