Sarah Helm


Controlling Parasites in your Horses

There are three groups of internal parasite which can damage the gut and cause disease in the horse. The information below will hopefully explain the importance of developing a good worming regime, using the appropriate products at the correct time:

ROUNDWORMS are grazed of f the pasture as microscopic larvae which bury their way through the gut and over many months migrate around certain organs of the body. They then return in the larval form to the wall of the intestine where they live for a while before bursting out into the gut to form adult worms which produce eggs to contaminate your pasture.

TAPEWORMS have an interesting life cycle which cannot be completed without an ‘intermediate host’ known as the harvest mite found on the pasture during the summer and autumn and to a lesser degree in hay. When the horse ingests the mite, the tapeworm is liberated in an immature form and over many weeks, changes into an adult tapeworm.

BOTS are a bee-like fly. Eggs are laid by the fly on the horse, mainly on the legs, which are ingested when the horse’s mouth comes into contact with the eggs. The eggs hatch by this process, the larvae bury their way through the back of the tongue and all the way down to the stomach, where they erupt and form masses of large grubs which cling to the stomach wall.

There are many different horse worming products on the market. We believe that EQUEST & EQUEST PRAMOX will provide the spectrum of ant parasitic cover necessary to protect your horse’s health.

Your worm control will only be as good as your management. Using the appropriate wormer, picking up droppings in the field, rotating your grazing fields, and ploughing, liming and reseeding every few years will help prevent worm infestation on the pasture. Any new horse introduced to a yard should be wormed with EQUEST and kept in a box or restricted paddock for a couple of days with collection and disposal of droppings prior to any introduction to communally grazed pasture. The following worming protocol is advised:

  • Winter/Summer: EQUEST (Adult and encysted roundworms / Bots)
  • Autumn/Spring: EQUEST PRAMOX (Adult and encysted roundworms / Bots/Tapeworms)

Remember to either keep the horse in for 24hours after worming or to make sure that ALL droppings are picked up ASAP. No worm product kills 100% of worms, hence the necessity to follow the above protocol.

Equine PPID – Cushing’s Disease

Equine Cushing’s disease most commonly occurs in horses aged 19years or older but can occur in horses of a much younger age.
Clinical signs of the disease include:

• Polyuria (increased urination)
• Polydipsia (increased drinking• Polyphagia (increased appetite)
• Weight loss
• Muscle wastage
• Hirutism (thick, curly coat with delayed shedding)
• Laminitis
• Supraorbital (above the eyes) fat pads
• Lethargy and depression
• Hyperhidrosis (increased sweating)suprorbital fat pads

There is no significant breed or gender predilection, but studies have shown that ponies are more commonly affected than horses.


Diagnosis is usually made by the presence of one or more of the above clinical signs, signalment (age, type etc) and diagnostic tests. The tests that are most commonly used are:
• Basal ACTH level testing – this is best carried out during the months of August – October as there is a seasonal rise in the levels of ACTH at this time which gives us an increased diagnostic rate. It involves a simple blood test. bloodsample-300x168

• The overnight dexamethasone suppression test (ODST) – this is not very popular anymore due to the more involved nature of the test and also because of the risks associated with dexamethasone administration in horses with a suspected elevated level of steroid already in their system.
• Thyrotropin-releasing hormone (TRH) stimulation test – this involves injecting TRH into the horse and then collecting a blood sample 2-10 minutes after administration. However, TRH is not licensed in horses and some adverse reactions have been seen. These are usually short lived and not severe.


Treatment is aimed at reducing the clinical signs of Cushings rather than curing the disease. It is also about improving the quality of life of your horse, with this in mind treatment consists of:
• Clipping excess hair to reduce sweating
• Treating secondary infections
• Increasing weight with diet management
• Treating any laminitis that may occur.VT44.02 master.indd

Medical management consists of using a dopamine agonist (pergolide) which comes in the commercially available form of Prascend. This is started at an initial dose of 2g/kg/day. Bloods tests measuring ACTH levels should then be assessed with a repeat blood sample 30days after the initial blood test confirming Cushings. This way doses can be adjusted as required. After this 6monthly repeat blood tests are recommended, these are best carried out in autumn and spring as this is when naturally occurring peaks in ACTH will occur

Generally the prognosis with Cushings is good; however, this is a lifelong condition that requires lifelong treatment and management.



Ringworm is one of the top 10 most common skin diseases in the horse and is more common in young horses.  It is a superficial fungal infection effecting the epidermal layer of the skin.

It is highly contagious and caused by both Microsporum and Trichophyton species of fungi, some of these are specific to horses whereas others can be passed to other animals and humans.

The spore stage of the fungi is very resistant and can survive in the environment for months to years if the conditions are favourable


  • Small areas of tufted hair similar to urticaria (hives) initially
  • Circular areas of hair loss usually 1-10cm in diameter
  • Moderate reddening of the skin may be visible in white horses
  • Broken hair shafts around lesions with thick crusting
  • Minimal itching
  • Lesions may spontaneously heal and begin to grow hair from the centre outwards.
  • The mane and tail are usually spared


Diagnosis is made by a fungal culture of hairs sampled from the edges of the lesions.  Fungal culture is hard to perform as there is a high chance of contamination interrupting the culturing process.


Ringworm is a self limiting disease meaning it will eventually resolve itself without treatment. However, the contagious nature of the disease often requires it to be treated to prevent its spread.

The best treatment is usually a full body topical application of a veterinary antifungal lotion or solution (such as enilconazole or 2% lime sulfur) two times a week for at least 3-4 weeks.  Oral antifungal medicine (such as Grisofulvin) is not as effective at treating Ringworm but may be used in addition to a topical treatment.


If you have a confirmed or suspected case of Ringworm it is important to prevent transmission of the disease to other people or animals. A licensed antifungal disinfectant should be used to decontaminate the horses stall and any contaminated grooming or yard equipment.  Diluted bleach water can be used as an alternative disinfectant for equipment if a licensed product is not immediately available.

If you are worried your horse has contracted ringworm, or have questions, please call us to discuss on 01306 627 706.


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