“Scores of British horses are dying from a rare illness linked to sycamore trees…”

Spotting headlines like this, horse owners could be forgiven for cutting down their ancient sycamore trees in a bid to protect their horses from the risk of Atypical Myopathy.

Atypical Myopathy is a truly distressing disease – horses that have ingested seedlings (and anecdotally the leaves) of the sycamore display many symptoms, mostly related to a lack of muscle function.

Symptoms include muscle tremors; abnormal stiffness; head tossing or a low head carriage; and fast or laboured breathing. In more severe cases, I have noticed that the urine is red or a dark red-brown.

Yet, dramatic stories and headlines, such as the one above from the Daily Mail (published in April 2014), has led some concerned horse owners to overreact.

Over the past year, I have had several conversations with horse owners around the country with concerns about the risk of their horses suffering from Atypical Myopathy, as their paddocks had sycamore trees either bordering them or in the near vicinity.

Scary articles have made it difficult for me to get some balance into the discussion.

For me, there are a couple of questions that I suggest need addressing before sycamores are felled:

• How long have the sycamores been there without causing a problem for the horses?

• And, crucially, why are the horses eating sycamore seedlings or leaves?

In a recent local case at Driffield, where I was asked to manage grassland, both questions were relevant. On investigating the paddocks and their surrounding environment, it was obvious that the trees had been there for many years without causing any distress to the horses. That was a good start!

Horses are sentient beings, and will only eat what they perceive will supply them with essential nutrition. It is my firmly held opinion that the horses only eat the sycamore seedlings as their paddocks are lacking nutrition. A seedling will be full of sugar and nutrients to help the plant grow and horses will be attracted to them because of this.

Once I had the soil analysis results back from the Driffield investigation, it was apparent that the soil had significant levels of organic matter to drive productivity. Also, the trace element status was correspondingly good.

The implication of all this is that the horses wouldn’t have needed to eat the sycamore seedlings as they could access nutrients from the grass. The issue that did need addressing was that the prevailing grass species were significantly unproductive.

When I investigated the case of Atypical Myopathy that I belatedly heard about, it was apparent that the grazing environment was exhausted and the horses were struggling for nutrition.

I could not take soil samples as the owner was still so distressed, but a visual assessment of the soil and grass indicated that the sward had ceased functioning as an environment capable of healthily sustaining horses.

To say that Atypical Myopathy is a distressing disease is an understatement. If you have ANY doubts, consult a veterinary surgeon immediately.