Thrush in horses

thrush in horses

Most horsey folk think that thrush is a condition that horses develop because they are kept in dirty conditions but this is not always the case. Read our blog to find out more about this condition that many owners struggle with.

What is Thrush?

Thrush, or Spherophorus neaophorus as it is technically known, starts with degeneration of the frog. Normally, the central sulcus is fairly shallow. In a horse that has limited exercise and/or other hoof health issues, this central sulcus can deepen. If the crevice deepens, debris can become lodged there and infection can take hold.

Horse's frog

What causes thrush?

Horse’s hooves are naturally “self-cleaning”. “Self cleaning” means that when a horse puts its foot to the ground be it in walk, trot, canter or even gallop, the debris that builds up in it, especially around the frog, is expelled by the movement of the foot itself. When this process of self cleaning is interrupted, debris builds up in the hoof and it’s then that infection sets in. Other causes include incorrect trimming of the frog as well as failing to pick hooves out regularly.

How will I know if my horse has Thrush?

Initially a thrush infection is usually superficial and it might even be difficult to identify its presence. So much so that in a significant number of cases, the owner isn't even aware that a problem exists and it’s often the farrier who is the first to recognize the condition. The most obvious sign of thrush is a foul-smelling, black discharge from the central and collateral sulci of the frog.

If you’re not sure what Thrush looks like, look at the photo below. Can you see the black discharge in the crevices of the frog?

Horse with Thrush

How can I prevent it?

Thrush thrives in dirty and damp conditions. Consequently, a horse whose exposed to "clean" mud that is predominantly free of manure and urine, isn't likely to develop thrush but one who stands in urine-soaked bedding for most of the day is a prime candidate.

Having said this some horses are just prone to thrush and have recurrent episodes no matter how clean their environment is kept. If this is the case, the owner inevitably feels frustrated at the unfairness of it.

Owner observation and rapid recognition of the problem are key in prevention. Once the problem is identified, steps can be taken to eradicate the infection and prevent recurrence.

Keep your horse’s field and stable clean. Daily removal or soiled bedding and dropping is important. Try to restrict, if possible, access to areas which look like simmering pools of bacteria!

Look carefully for any abnormal changes when you pick out your horse's hooves each day - the earlier you’re able to identify thrush, the better.

Be gentle with the hoof pick - some cases are potentially created by an overly aggressive use of a hoof pick. While daily use of a hoof pick is essential, care when using it is required.

Get your horse’s frogs trimmed regularly - don’t allow the frog to grow to a point where it overlaps the clefts in the hoof as this will keep the clefts open for “self-cleaning” as the horse walks, gallops around the field, is schooled or hacked out.

What’s the best way to treat it?

Treating thrush needs a two-pronged attack: first you need to eradicate the resident infection. Remember the bacteria, S. necrophorus, lives in the many cracks and crevices of the hoof and a simple splash of liquid will over the frog will not get in to its hiding spaces. You need to get the liquid deep in to the hiding spaces to ensure its defeat!

Invest in some latex rubber gloves or antiseptic hand wash. Wash your hands thoroughly after treatment or wear latex gloves. If you decide to use your bare hands, take care to scrub under fingernails as well.  Continue this routine for the duration of the treatment.

The second prong is to make some subtle changes to your horse’s routine: keep his stable cleaner and drier; turnout in a clean field free of droppings and finally increase his exercise. Not only will these changes help clear up a case of thrush, but it will prevent its return.

The photograph below will give you an idea of before and after treatment of thrush.

Horse with thrush before and after

Is there anything else I need to know?

In the early stages, your horse will probably not be lame which can be another factor that makes this condition difficult to identify at first. However, a horse can become lame through treatment by continual probing or squeezing of the tender heel and frog areas affected by thrush. Equally if the thrush is extreme and persistent, it can make a horse lame. In cases like this or if there is a hint of any other type of complication, you should call your vet.

Over to you!

Do you have any experience with this condition in horses? Do you have any tips for your fellow equestrians? Add a comment below - you never know, your tip may just help someone else who is struggling!

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Kim Horton

Co-Founder of EQUUS and a keen equestrian, when Kim's not at her desk she's with her horse, Waldo.


  • Michaela barrett posted on February 25 2019 at 11:02 AM

    I can smell the thrush in my ponies feet really bad & have improved the thrush over time but it just won’t clear up. We gave the farrier every six weeks who yells me to use a disinfectant to scrub them out then liberally apply friskes. Not getting any better drastically though, had enough😩

  • Gerry Barker posted on December 21 2020 at 04:12 PM

    After cleaning out the hooves I use a solution of Milton (the baby bottle sterilizer) diluted with water and spray that on regularly .

  • Anji posted on December 21 2020 at 04:12 PM

    Thrush, yes can be nasty, but if you use a little antiseptic scrub and use the brush you would use when cleaning out stud holes in the clefts. Then apply daily for the first two weeks this product. It is by Red Horse and it’s called Field paste, using a back of a spoon press into the clean clefts and the sides around the frog, preferably in the evening when your horse goes to bed. My friends and I think this is the only product that works!!! Best of luck, but you won’t need it, if you use field paste.


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