Beware Atypical Myopathy
Kate Hore. RNutr(Animal), R.Anim.Technol (Cert)
If you have Sycamore trees on, or near, your pasture then great care should be taken, due to the risk of Atypical Myopathy. Particularly during Autumn, as the seeds drop, and Spring as seedlings grow, they pose a considerable risk for grazing horses and ponies.
These helicopter seedlings are highly toxic and can be fatal. Autumn is recognized as a risk when the seeds drop, but Spring seedlings are also contain the deadly poison, hyopglycin A, which effectively starves muscles of energy – particularly heart muscles.
Management Tips
- Avoid grazing where seedlings can drop, and remember they can travel far.
- Monitor closely and remove seedlings, ideally by pulling up
- Dispose of seedlings away from horses
- Provide additional forage, ideally off the floor and away from any sycamores
- Check water, which can also be contaminated
- Supplement their diet; additional vitamins and minerals are linked to a better outcome*
Signs of Atypical Myopathy
- Weakness, difficulty walking & standing
- Heart & breathing problems
- Depression & lethargy
- Muscle tremors
- Similar to colic, but with a good appetite
- Dark red, brown, urine
- Sudden death
If you are worried your horse or pony may have grazed on seedlings, or are showing signs of Atypical Myopathy contact your Vet immediately.
* Fabius L.S & Westermann C.M (2017) Evidence-based therapy for atypical myopathy in horses. Equine Veterinary Education. 30(11) 616-622
Selected References:
- Ross SE, Murray JK and Roberts VLH (2018) Prevalence of headshaking within the equine population in the UK. Equine Vet Journal: 50 73-78.
- BETA (2019) National Equestrian Survey.
- Thomson K, Chan C and Dyson S (2020) Head tossing behaviour in six horses: Trigeminal-mediated headshaking or musculoskeletal pain? Equine Vet Education: 32 (Suppl.11) 58-64.
- Newton SA (2005) Idiopathic headshaking in horses. Equine Vet Education: 17 (2) 83-91.
