Exmoor Ponies - conserved by conserving

Sustainable
Biodiversity

THE HEALTHY PONY.

Indicators of Health:

First Stand back and look:

    Alert with ears pricking to and fro,
  1. Glossy coat, lying flat,
  2. Skin loose and supple,
  3. Breathing normally (Resp rate 8 - 16 breathes per min),
  4. Eyes open and bright with the mucous membranes salmon pink,
  5. No discharges from eyes or nostrils,
  6. Eating well and chewing normally,
  7. Body well filled out but not gross,
  8. Limbs free from swellings or heat
  9. Standing evenly on all four feet and sound when moving,
  10. Urine fairly thick, either colourless or straw coloured passed several times a day,
  11. Droppings, which vary in colour wrt diet - should be passed ~8 times per day in the form of damp balls not like soft cow dung,
  12. Temperature - Roughly 38įC (100-101įF)
  13. Pulse - 25 - 42 bpm.

When to call the Vet:

  1. Call in cases of injury or if there is doubt of a horse's state of health.
  2. An early visit may prevent serious repercussions occurring at a later date.
  3. Don't be afraid to ask for advice.
  4. Welfare Codes of Practice - "All animals used in conservation grazing should receive veterinary attention when required".

Worming of the Exmoor Pony.

When considering the welfare of the Exmoor pony, you must take into account the possibility of external and internal parasites. (See codes of practice - All animals in conservation grazing should receive appropriate regular worming). However, treating the wild pony can present the Veterinary surgeon and owner with unique problems. Often the animals are not broken and are contained in very large, unfenced areas, running wild with many other ponies of varying ages, fitness and health. Thus the routine worming regimes of the average horse become difficult to implement. Even the management of picking up dropping becomes an overwhelming task.

First you must consider the various parasites you wish to control:

STRONGYLES;

LARGE STRONGYLES (LARGE RED WORMS): Strongylus and Triodontophorus Members of this genus live in the large intestine of the horse and cause significant disease, often with mixed infections.

The Strongylus Spp live in the Caecum and colon of the horse and the adults eat the lining of the intestine and suck blood. They also have a migratory stage depending on the species (Vulgaris -Cranial mesenteric artery, most pathogenic, Equinus - Liver and pancreas, rare, Edentatus - Liver and Mesentery.

Triodontophorus Spp feed in "herds" round ulcers in the RDColon and don't have a migratory stage. Both of the above produce eggs that are passed out in the faeces and undergo 3 larval stages. The eggs and the larvae can be washed away from the faeces by rain droplets and then are able to undergo the changes to the infective L3 stage. This can occur within 2 weeks if the climate is good. The pony then ingests this larval stage which can then undergo its migration and cause damage to the pony as they emerge through the gut wall and feed as young adults.

DISEASE:

  1. The nodules in the bowl wall cause thickening, functional and nutritional disturbances, unthriftiness and debility.
  2. Thickening of the arteries by Vulgaris may cause colic.
  3. Symptoms most often seen in 1 - 2 yr. olds.
  4. Causes unthriftiness, Lethargy, Anaemia, Debility, Occ D+ and rarely death.
    • Egg counts can be useful -
      • Mild infection - 500 eggs pg,
      • Moderate infection 500-1000eggs pg
      • Importance varies with the Spp.

SMALL STRONGYLES/ CYATHOSTOMES (SMALL RED WORMS): Trichonema Spp.

These are non-migratory worms and cause problems when they form nodules in the large intestinal walls and then hatch as adults. These parasites can cause the greatest problem as they can undergo HYPOBIOSIS - This is when the cycle in the host becomes arrested due to external factors such as climate in the autumn. Then in early spring all the arrested larvae suddenly hatch together and cause severe damage with perfuse D+, weight loss, colic and death. This is called Larval Cyathostomiasis.

Faecal egg counts of 150 eggs pg can still be significant as there may still be large number arrested.

Now very common - poss encouraged by poor husbandry.

Some resistance to Benzimidazoles, use 5day Fenbendazole (Panacur equine guard)

TREATMENT AND CONTROL:

IMMUNITY only occurs SLOWLY, due to EXPOSURE and is INCOMPLETE.

Benzimidazoles, Pyrantel(Strongid-P), Ivermectin(Eqvalan), all have good efficacy against lumen-dwelling adults, but less against migrating larvae. Fenbendazole (Panacur Equine Guard) is used against the small red worm Hypobiosed Small Red Worms are very difficult to treat with ANY drug!

LARGE ROUND WORMS

PARASCARIS EQUORUM - THE HORSE ASCARID:

These are very common but usually only affect young animals. Following egg ingestion (the eggs being very resilient to environmental conditions), they migrate through the liver and pulmonary areas and can cause two different syndromes.

Resp. disease - Tracheal exudate with Cough and Nasal Discharge.

Intestinal signs - Ill thrift, wt loss, D+, pot bellied, occ intestinal obstruction/intersusception - colic resulting to sudden death of worms due to anthelmintics or immunity at 6m of age.

TREATMENT:

Double dose Benzimidazoles, single dose Ivermectins or Piperazine.

Alternate young stock grazing from year to year.

THE HORSE PINWORM

OXYURIS EQUI:

The adult worms are found in the Colon of the horse and the female migrates to the anus and lays her eggs around the perineum. The eggs can then develop in 4-5 days and are ingested.

Intestinal signs are very rare. Most commonly it is the irritation around the anus that causes a problem of the horse rubbing and causing bare patches and inflammation.

TREATMENT:

Routine anthelmintic use,

Good stable hygiene , with cleaning and then disposal of cloth.

THE HORSE LUNG WORM

DICTYOCAULUS ARNFIELDI :

This is really a parasite of the Donkey but can cause clinical disease in the horse, usually only young animals. The eggs are ingested after being laid in the donkeys faeces. Resp signs, cough +/_ limited exercise ability may occur.

TREATMENT:

Ivermectins, Levamisol.

TAPEWORMS

ANOPLOCEPHALA PERFOLIATA(Caecum) / MAGNA(Small intestine):

Life cycle involves the Orbatid mite which ingests the segments and then is ingested by the horse. The adults tend to collect around specific areas and may cause blockage resulting in colic. All ages of horse may be affected.

TREATMENT:

Pyrantel at a double dose. (Pyratape P or Strongid-P)

BOTS

GASTROPHILUS SSP:

The adult fly lays eggs on the horse during summer. These are then ingested by the horse and may remain in the stomach of the horse till the following year. They generally cause few problems, the adults being the most irritating to the horse.

TREATMENT:

Use of a Boticide during the winter e.g. ivermectins (Eqvalan)

WHICH ANTHELMINTIC AND WHEN?

"Good worm control consists of sound pasture management, SUPPLEMENTED by an effective worming programme." (see pasture management)

Ideally:

  1. Have low stocking rates.
  2. Rotate pastures, stock or crops.
  3. Donít have mixed age groups.
  4. Treat all grazing animals over 2 months of age.
  5. Isolate and treat all new stock.
  6. Graze nursing mares and foals on different pasture from year to year.
  7. Regular Anthelmintic treatment of all stock, rotating the drug used.

Remove faeces from the pasture or break up the dung pile so as to expose the larvae to daylight and warmth so increasing their activity so reducing their reserves and thus period of survival.

The Exmoor Pony:

The natural balance between alterations in condition - weight loss in winter and spring and weight gain in summer and autumn can be severely affected by worms. Also the difficulties in treating and controlling worm populations in the large groups of semi-wild, mixed aged groups, on large, unfenced areas is obvious.

It can be impossible to round up large numbers and worm these in 1 day and so different strategies must be found.

  1. Egg counts in faeces and the number of infective larvae on the ground are highest in late autumn, thus worming, if only done once a year would be most effective at this time.
  2. Treat those most at risk - Animals less than 2 years, pregnant mares and mares with foals at foot.
  3. Remove droppings, Harrow or use Pasture Vacuums - Horses tend to graze the grassy lawn areas (6% of the total area of Newforest for example) and also dung here so these are the areas to target.

There are 4 main groups of wormer and each year a worming programme should be based on just one of these. However to treat certain parasites, specific wormers should be used at specific times of year.

BENZIMIDAZOLES

Fenbendazole (Panacur)

Mebendazole (Equivurm, Telmin)

Oxbendazole (Equidin, Equitac)

AVERMECTINS

Ivermectin (Eqvalan, Furexel)

MILBEMYCINS

Moxidectin(Equest)

TETRAHYDROPYRIMIDINES

Pyrantel Embonate (Strongid-P, Pyratape P)

WHO, WHEN WHERE?

Wormer Frequency Mares/Foals Specific parasite Date
Strongid-P Oral Granules, Paste 6-8wk winter 4-6wk summer Yes, at 4 wks Then 4 wks Till 8 months. Tape worm - Double dose At grass-April+October Winter stabled- 10wks Post turn out + October
Pyratape P Paste 4-6wks Yes/Yes 4 wks Tape worm - Double dose March + September
Panacur 10% Suspension, Granules, Paste 6-8wks Yes/Start 4 wks after 1st tape worm dose. Encysted and Inhibited small Redworms, Migrating large redworms Nov/Dec 6 wks after Routine wormer.
Eqvalan Paste 8-10wks Yes/at 4-6wks Then 8 wks Till 18months Bots Dec
Equest Gel 12-13wks Yes/Not less Than 4 months old. Most bots ? Encysted Small redworms -

THE MARE:

1 Month prior to foaling - Single dose of Fenbendazole or Pyrantel,

10 Days post foaling - Larvicidal dose Fenbendazole or Ivermectin,

Then routine worming.

THE FOAL:

6Weeks - Full dose Fenbendazole or Pyrantel,

Then every 4 weeks alternating with an Avermectin,

Then as normal routine.

EXTERNAL PARASITES:

MITES (Chorioptes):

These mites feed on dead skin/debris and cause crusty lesions with thickened skin on the legs esp around the feathered areas. They cause irritation and self-induced injuries.

TREATMENT: Ivermectin (not licensed), acaricidal washes 14 days apart.

LICE (Haematopinus -sucking, large. Damalinia - biting, small):

They can be found in the main, tail and feather regions or occasionally more wide spread. Animals may be show no signs or severe signs esp in debilitated/neglected animals. Again they cause irritation, hair loss excoriation and can occ cause anaemia.

TREATMENT: Pyrethroid based insecticides, tack etc hygiene.

SWEET ITCH (Culicoides,Simulium,Stomoxys spp):

This is a hypersensitivity reaction that certain individuals have to the above biting flies. It is often seen along the top line of the horse from forelock to tail and starts as nodules with severe irritation leading to self-mutilation and hair loss. Over a period of time the skin becomes permanently damaged with thickened folds. These individuals often are permanently sensitive and so Tx and prevention are required every year.

TREATMENT: Management is vital - Fly repellents (Switch), rugs, stabling esp during dawn and dusk. Steroids, bathing.

LAMINITIS.

"No foot, no horse!" As with any breed, this statement is vital to the management of your Exmoor pony. (See codes of Practice - All animals used in conservation grazing should have access to regular attention from a farrier, as appropriate). In the wild, the non-shod hoof is maintained naturally and may only require occasional human intervention. However, if being used for riding etc then regular trimming/ shoeing is required.

Also the domesticated pony is often fed concentrates or grazes lush grass compared to its wild counterparts and as such is more likely to develop laminitis - inflammation of the laminae.

The causes are controversial and include carbohydrate overload, Septicaemia/toxaemia, concussion, mechanical overload, and certain disease states.

It is usually seen in ponies esp fat ponies with cresty necks, males(4-7yrs), females(7-10yrs) usually in the Spring or Autumn.

It is believed that increased starch causes the death of certain bacteria resulting in their release of toxins which then results in the constriction of blood vessels. This reduces the blood flow to the laminae, causing their death and loss of mechanical support. (See Foot of horse).

This results in altered forces and causes rotation of the pedal bone within the hoof.

Signs vary from stilted stance, through reluctance to walk to recumbency. It usually affects the forelimbs worst with the typical stance. There may be an increased pulse, warmth and sensitivity (esp to shoeing). In severe cases the pedal bone can rotate through the sole of the foot.

Chronic cases show a flat/convex sole, a wide white line and prominent hoof rings - wider at the heels.

TREATMENT:

Recognise the potential candidate and prevent!!!

It is an emergency - irreversible changes can occur in 12 hours.

Treat the cause.

Relieve the pain - NSAID's(Bute, Finadyne, Rimadyl).

Restore digital circulation - ACP( also encourages pony to lie down), Isoxsuprine, Aspirin, Heparin

Hydrotherapy, Donít walk the pony!!

Physical support for the feet - Frog support (Bandages,Lilly pads, Bedding).

Nutrition - Hay only, Supplements Eg. Alfalfa and Farrier's formula.

DON'T STARVE AS CAUSES HYPERLIPAEMIA

May require RX.

Regular foot trimming - Shorten toe and trim heal to reshape to the pedal bone axis.

Shoe with wide webbed, seated out shoe, egg bar or Heart bar.

MUD FEVER - Dermatophiliosis:

Also known as Rain scald, or Mycotic Dermatitis and is caused by a bacterium - Dermatophilus congolensis. It is most often seen in Autumn/Winter due to prolonged wetting of the skin esp in dirty / muddy conditions. It may affect groups or individuals and the distribution of lesions can vary - often seen on feathered areas and the back/ tail base. Often affects white limbs more than black limbs?

Get plaques of matted hair overlying inflamed skin, which may become exudative and crusty and often described a paintbrush effect when the hair is removed.

Can cause pain and lameness in severe cases.

TREATMENT:

Most cases are self-limiting if inciting factors eliminated e.g. wet, dirty conditions.

Clip area, wash with antiseptic - Chlorhexidine and keep very dry - may require stabling.

Severe cases may require Penicillin.

Prevent spread by hygiene wrt rugs, grooming kit, tack etc.

NB. Prevention is better than a cure!

VACCINATION:

"One of the easiest and most effective ways to protect your horse's health and well-being is regular vaccination".

Why vaccinate?

Welfare - Your duty to protect the health of your horse.

Prevent spread of infection,

Prevent poor reproductive performance.

EQUINE INFLUENZA - "HORSE FLU":

Similar to the human flu - Affects upper and lower Resp tract.

Short incubation period(Time from infection to evidence of signs) - 2 to 5 days.

Lethargy, cough(dry/harsh), Nasal discharge, anorexia, elevated temp, occ heart disease. Mostly affects groups of young animals.

TREATMENT:

Non-specific, supportive, antibiotics, REST AND MINIMAL STRESS.

CONTROL:

Prevac Plus, Duvaxyn I-E Plus, Equip F.

TETANUS - Clostridium tetani;

This can be a killer and horses seem to be more susceptible than other domestic species. The spores live in soil and often enter the body through a puncture wound or skin injury. Vaccination is highly effective and is often given with the Influenza vaccine.

Incubation period is usually 1-3weeks.

A gradually progressive stiffness and reluctance to move occurs. Soon, signs such as a startled expression, flaring of the nostrils and an unsteady gait occur. The reflexes are heightened and muscle spasms occur. Difficulty chewing - Lockjaw, raised tailhead, prolapse of the 3rd eyelid, sweating, elevated temp and death.

TREATMENT:

Tetanus Antitoxin i/v and at site of wound.

PREVENTION: Tetanus Antitoxin - Last roughly 6weeks, can be used in foals.

Tetanus Vaccination - From 6 weeks of age.

Regular inspection of feet and wounds.

Tetanus Toxoid, Prevac T, Equip T, Equip FT, Duvaxyn IE-T.

POISONING

There are many different causes of poisoning such as poisonous plants, heavy metals or chemicals.

RAGWORT- Senecio jacobaea:

These plants contain Pyrrolizidine alkaloids to which cattle and horses are very susceptible.

The plants are not very palatable and are usually eaten in sufficient quantities to cause disease only when other feed is in short supply or are included in hay. (See Codes of practice - All animals used in conservation grazing should only be used in grazing situations which do not place them under nutritional stress so that they are obliged to eat that which is harmful to them).

The flowers are more toxic than the herbage and the mature plants are usually avoided.

The effects of intoxication are cumulative and fatal intoxication may develop over a number of years.

  • Liver damage results which may result in sudden or progressive onset of clinical signs:
  • Weight loss,
  • Jaundice,
  • Abdominal Pain,
  • Depression,
  • Hepatoencephalopathy : Muscular tremors, Yawning, Head pressing, Manic walking, Circling, Incoordination, Seizures,
  • Ventral oedema - Fluid swellings under the abdomen/chest areas,
  • Photosensitisation - Skin changes esp white/pink areas.

TREATMENT:

By the time signs are seen, the toxins are already in the tissues and have caused damage and no Tx will change that. Thus Tx is supportive with a high nutrient diet. Horses that recover clinically may never regain their former physical fitness.

I hope this is useful in your future conservation grazing projects.

(Tx = Treatment)

Samantha Purcell, BVSc, MRCVS.(©)