03/04/2023
๐๐ญ๐ฒ๐ฉ๐ข๐๐๐ฅ ๐๐ฒ๐จ๐ฉ๐๐ญ๐ก๐ฒ ๐๐ง๐ ๐๐ฒ๐๐๐ฆ๐จ๐ซ๐ ๐๐จ๐ฑ๐ข๐๐ข๐ญ๐ฒ
We are seeing huge numbers of sycamore seedlings on pastures at the moment, and many will be aware that the helicopter-like seeds are toxic, and traditionally many cases are seen in the autumn when the seeds drop. It's less well known that the seedlings are also dangerous at this time of year, and can cause fatal disease. We do not fully understand why some horses are more susceptible than others.
๐๐ก๐ฒ ๐๐ซ๐ ๐ฌ๐ฒ๐๐๐ฆ๐จ๐ซ๐๐ฌ ๐๐๐ง๐ ๐๐ซ๐จ๐ฎ๐ฌ?
Seeds, seedlings, and other plant material from sycamore trees contains the toxin hypoglycin A. This is causes atypical myopathy in horses. This is a disease which causes mitochondrial dysfunction, and effectively starves muscle cells of energy, particularly affecting the heart, respiratory, and postural muscles. There was a high number of cases last year, and numbers are starting to increase again.
๐๐ก๐๐ญ ๐๐ซ๐ ๐ญ๐ก๐ ๐ฌ๐ข๐ ๐ง๐ฌ ๐จ๐ ๐๐ญ๐ฒ๐ฉ๐ข๐๐๐ฅ ๐ฆ๐ฒ๐จ๐ฉ๐๐ญ๐ก๐ฒ?
- Weakness, difficulty walking and standing
- Heart and breathing problems
- Depression and lethargy
- May look similar to colic, but still have a good appetite
- Muscle tremors
- Dark red to brown urine
- Sudden death
๐๐จ๐ฐ ๐๐๐ง ๐ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ ๐๐ญ๐ฒ๐ฉ๐ข๐๐๐ฅ ๐ฆ๐ฒ๐จ๐ฉ๐๐ญ๐ก๐ฒ?
Some tips include:
- If you can, use pasture away from sycamore seedlings; be aware that even pasture a long way from the trees can have seedlings growing as the seeds can travel so far. If this isn't possible, reducing time on pasture may help.
- Removing sycamore seedlings (ideally by pulling them, but mowing may be more practical with very large numbers) is also a good idea. Remember to dispose of the seedlings away from your horses (do not leave them on pasture), and monitor in case they regrow.
- Provide hay/haylage to discourage your horses from eating seedlings - this is best done in a feeder away from the seedlings/any sycamore tree material. Water can also become contaminated, so consider providing water away from any sycamore trees. Do not feed wet hay from the floor around sycamores.
๐๐ก๐ฒ ๐ข๐ฌ ๐๐ญ๐ฒ๐ฉ๐ข๐๐๐ฅ ๐ฆ๐ฒ๐จ๐ฉ๐๐ญ๐ก๐ฒ ๐ฌ๐จ ๐๐๐ง๐ ๐๐ซ๐จ๐ฎ๐ฌ?
There's about a 50% fatality rate, and no specific 'antidote' to the hypoglycin A toxin. Horses can become unable to stand, are extremely painful, and may go into respiratory failure. Due to the pigment (myoglobin) released as muscle cells breakdown (the cause of the red urine) they may also go into renal failure.
๐๐จ๐ฐ ๐๐จ ๐ฐ๐ ๐ญ๐ซ๐๐๐ญ ๐๐ญ๐ฒ๐ฉ๐ข๐๐๐ฅ ๐ฆ๐ฒ๐จ๐ฉ๐๐ญ๐ก๐ฒ?
Intensive care is required rapidly. Horses are given intravenous fluids with a supplementary energy source, and strong pain relief. Research has also shown that supplementation with carnitine and vitamins improves outcome. If horses survive the first few days without being unable to stand, they are more likely to recover.
If you are worried about atypical myopathy, please don't hesitate to give us a call on 01223 760535. One of our vets will be happy to talk to you!