Equine Cushing’s Disease (ECD) mostly affects mature horses, but can affect horses under the age of ten. Currently there are no cures for this disease, either conventional or herbal. However there are several support therapies available that can help to extend and improve the quality of life for ECD horses. Early detection, treatment and proper management is extremely advantageous, as this can significantly slow down the progression of the disease.
ECD is normally caused by a benign tumour of the pituitary gland. In simple terms, the pituitary gland (located in the horse’s skull) is responsible for sending chemical triggers out to other parts of the endocrine system in order to control various bodily functions. These include temperature regulation, blood sugar levels, flight or fight response, appetite and thirst. Usually the pituitary gland can stop sending out these chemical triggers when required, but an ECD horse’s pituitary does not. The overproduction of these chemical triggers leads to a disruption of the intricately balanced endocrine system, stimulating a chain reaction of over-and-under produced hormones, which in turn wreaks havoc on the horse’s overall well-being.
The overall impression of an ECD horse is that he or she is ageing at an extremely rapid rate. In addition, neurological symptoms (such as impaired co-ordination of the hind limbs and hyperventilation) can appear at an advanced stage of the disease. This occurs because the enlarged pituitary gland can grow to the point where it causes compression on the brain.
ECD horses need a lot of special care and management, and the precarious state of their health should never be underestimated.
An ECD horse’s diet should be much the same as horses prone to laminitis i.e. low sugar/low starch. Excess protein is also a danger, so lucerne should be limited or restricted altogether. Unsuitable concentrate feeds stimulate the vicious cycle of the disease, and significantly increase the horse’s chance of succumbing to a life-threatening infection. A high starch/sugar diet stimulates the over-production of cortisol, which leads to constant high blood sugar levels and a suppressed immune system. Elevated blood sugar levels over a prolonged period leads to insulin resistance, so in effect, ECD horses have the same dietary vulnerability as human type 2 diabetics.
ECD horses should have constant access to good quality low-sugar grass hays. It’s generally not a good practice to give the horse a huge pile of low-sugar hay, because they will be driven by their insatiable appetite to devour the whole lot in one go, and this may still result in elevated blood sugar levels. At the same time, they should never be denied access to forage, as their increased metabolic rate can literally put them at risk of starvation. Slow feed haynets placed at ground level are the best solution as safe hay trickle feeders.
Constant access to grazing is not necessarily a solution, as it’s known that there are times when grass sugar levels spike. This is a large topic with many variables, so I would highly recommend visiting the website www.safergrass.org to get a better understanding of it.
In brief, grass sugar levels gradually increase through the daylight period, usually starting to rise from around 10am and reaching a peaking around 2pm, and this level will continue for the remainder of the day, steadily decreasing only when the temperature starts to decrease. ECD and laminitic horses should be removed from grazing on “sugar risk days” (particularly from high-risk grazing) from around 12 am-10 pm, depending on the degree of the risk. Various other stressors such as overgrazing, drought, flooding and seeding can also cause grass sugar “spikes”, and some varieties of grasses are naturally higher in sugars than others. Surprisingly, areas of lush grass can be much safer than overgrazed, sparse grass!
The importance of safe grazing for ECD horses was driven home to me earlier this year: Midnight was an elderly mare but was still ridden regularly on outrides when she suddenly developed ECD symptoms, and was confirmed as an ECD case by her vet. Her owner chose instead to contact us for herbal treatment of ECD, rather than using the conventional treatment options. We treated Midnight herbally for the disease for a year and a half, and she had been making steady and noticeable improvement over that period. Both her vet and farrier commented that she was the longest surviving ECD horse they had known.In spite of this, Midnight went downhill extremely abruptly, exactly four days after very hot and humid weather, which in turn had followed directly after 3 days of bitterly cold weather and torrential rain.
These are near perfect conditions to spike grass sugar levels, and correspondingly, caused a spate of problems for laminitic horses in the region. Fairly typical of ECD, Midnight spontaneously developed a small weeping sore on the heel bulb, indicative of a breakdown in circulation. Four days later the weeping sore broke out aggressively and began oozing pus, with Midnight rapidly deteriorating into acute discomfort. By this stage her owner decided she had little chance of recovery, so the decision was made to end her suffering. I have little doubt that the extreme weather pattern influence of the grass sugar levels was the reason for Midnight’s sudden undoing, as nothing else in her management routine had changed. So strict grazing management is vital.
As mentioned earlier, there are no cures available for ECD, but herbal treatment can provide overall health support, resolve some symptoms and slow down the progress of the disease.
First on the list of recommended herbs for ECD is Chaste Tree Berries (Vitex Agnus castus). This herb is a hormonal normaliser, and has been used in several field trials for ECD horses in the UK with great success. It’s believed that the herb stimulates production of the chemical mediator dopamine, which regulates production of the pituitary gland.
Which brings us nicely to the next recommended herbs for ECD – which are anti-oxidant rich herbs. Dopamine producing cells in normal horses are for some reason limited in their antioxidation capacity in ECD horses, and are therefore susceptible to premature death. Anti-oxidant rich herbs which help to prevent this include Rosehips, Turmeric and Green Tea. Grape Seed and Hawthorn are also rich sources of natural anti-oxidants.
Herbs to support circulation (such as Hawthorn, Cayenne, Nettle and Rosehips) are extremely beneficial, as are the liver and kidney support herbs such as Milk Thistle seed and Dandelion, as these organs are put under extreme pressure by the disease. Bilberries are also recommended to improve eyesight, as these fruits improve micro-circulation, especially for individuals suffering from metabolic diseases. Eyebright is another useful herb for the same purpose.
Kelp helps to support the endocrine system, and is a rich source of minerals and amino acids. ECD horses can particularly become deficient in these, because of their increased urination.
ECD horses have an increased risk of infection because of elevated blood sugar levels and a suppressed immune system. For this, immune support herbs such as Garlic, Calendula and Rosehips are recommended.
At this stage it’s slightly controversial as to whether immune system stimulants should be used for ECD, as it is an auto-immune disease and some feel that stimulating the immune system will hasten the progress of the disease. Some would rate Echinacea as an immune stimulant, whereas others regard it as an immune system regulator, as it has the remarkable bi-directional ability to either stimulate or reduce white blood cell production as required. Anecdotally, including Echinacea in ECD herbal treatment programs has received positive reports worldwide.
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