STRINGHAULT
Stringhalt is a disorder in the nervous system caused by either a lack of magnesium, minerals or trace elements that are necessary to absorbing the magnesium. It is usually described as exaggerated upward flexion in one or both hind legs. Often it starts as a slight inco-ordination in the horses gait, developing into what can only be described as a ‘goose’ stepping movement in severe cases. While some horses may be more suseptible, all breeds of horses can be affected.
Stringhalt is often a seasonal condition that develops in horses grazing on sparse pastures, where a substantial amount of weed is present, after the break of the season in Summer and usually following a few days of rain then warm, humid weather. Stringhalt is more specific to Australia and New Zealand, especially following drought conditions. Horses grazing on pasture containing Cats Earor Flat Weed have been found to be associated with the damaging effect on the long nerves of the hind limbs and neck in seasonal occurances of Stringhault.
Medical Description - The nerves affected are the long myelinated nerves in the hind limbs and also the long left Recurrent Laryngeal Nerve in the neck. Severe cases develop the characteristic ‘goose-stepping’ gait and often a ‘roaring’ like sound when exercised due to collapse of the left laryngeal structure.
Symptoms of Stringhault may present as early as after a few days grazing in flat weed affected pasture and may be as simple as a minor short high step in one or another of thehind legs. The more time that passes or the more the horse moves, the more severe the action until it resembles a pronounced goose step. Often horses are unable to be backed without severe inco-ordination and risk of falling over.
Management - When stringhalt occurs after the break of the season where pastures contain Flat Weed, the horses should be removed from the pasture to a pasture free of any Flat Weed or into a holding area and hand fed hay. Dampened lucerne hay is considered the best roughage as it contains higher energy, protein and minerals than grassy hay, along with supplements - as described below. It is of no use to feed hay to horses left to graze the contaminated pasture as they will continue to eat Flat Weed.
Keep the horse quiet and avoid working it until the symptoms improve and the horse can walk more comfortably. If the signs are recognised early, often improvement occurs over a 2-3 week period, with recovery in 2-3 months. More severe symptoms will often improve over 6-12 months but some cases take 18 months and do not fully recover. In the chronic condition, loss of muscle on the outside of the gaskin area and weakness in the fetlock joint on one or both hind limbs can complicate recovery. Where a horse develops a ‘roaring’ on inspiration during exercise, it should be scoped to determine the severity of the left vocal cord collapse.
Treatment
- Move the affected horse to a 'dry' paddock or one free of flat weed. If this is not possible, the weed will have to be removed manually or with the use of an animal friendly weed spray (personal choice)
- Feed moist hay only
- Rest - keep the horses environmet calm - This is of the utmost importance as the horse may be quite distressed with its new affliction.
- Dietary Supplementation - A well balanced Equine mineral powder or Equine mineral block readily available - be sure the product you buy contains Vitamin E, Vitamin B1, magnesium proteinate, (NOT Dolomite or Epsom Salts (magnesium sulfate))
- Extra magnesium may be needed.
Allow the horse unrestricted access to the mineral suppliment. The horse will only eat the amount of mineral suppliment it needs. There are drugs on the market that may or may not assist with the horses potential recovery.. these vary as does their individual effectivness. Unfortunately, there is no miricle cure... Some horse may show improvement while other horses show little improvement despite long term therapy.
Preventing Stringhault - The control of Flat Weed, manually or with selective herbicides will reduce the risk of poisoning. However, establishment of more competitive, vigorous improved pastures for grazing horses is the best long term strategy to reduce the spread of Flat Weed.
Flat Weed - Description - is a relatively common plant in native pastures in higher rainfall areas, especially where pastures have been overstocked and grazed out over a period of time. It grows rapidly after a break in the season, being one of the first succulent plants, sprouting from a tap root, providing ground cover which is grazed before more sustainable grass and legume pasture species which are slow to germinate from seeds, can provide the bulk of the grazing intake. It often becomes established in patches where hay containing seeds of the plant is spread out to feed horses under dry summer conditions. Flat Weed, or Cat’s Ear as it is sometimes referred to, is a prostrate plant with long flat, cat’s ear shaped green leaves radiating from the central crown. It has hairy, deeply etched leaves with a yellow daisy flower. It is often confused with Dandelion or Cape Weed, which has more upright leaves and a daisy flower with a black centre. Dandelion is often present with Flat Weed in pastures during Autumn after rain. It is a succulent plant that attracts hungry horses seeking green pasture after a relatively dry period. It is considered that a fungus may colonise the prostrate leaves of Flat Weed and its spread is facilitated by periods of rainy, humid weather. |
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