It is important to recognise poisonous plants, because horses at pasture have access to a wide variety of plants in the sward (grassland) and hedgerows; few fields are wholly free from danger. Trouble is most likely to occur when the horse is first turned out into the paddock. If the sward provides a varied diet, eating something poisonous is much less likely to occur. Good paddock management is the best safeguard against poisonous plants.
Here are some of the most common plants to be wary of in UK fields.
BUTTERCUPS - varies widely in size and habit of growth, but all have similar golden flowers and all are poisonous, but dried in hay are harmless.
CELERY-LEAVED - Ranunculus sceleratus grows on mud, in ditches or near the edge of lowland ponds and streams. All parts of the plant produce blistering and sores when they touch the skin.
MEADOW - R.acris - the tallest of the common buttercups, growing up to 1 metre (3 feet) tall.
CORN - R.arvensis - once common on lime-rich soils in England, but has become less frequent due to the widespread use of weed-killers.
BULBOUS - R.bulbosus - is usually found on dry, lime rich grassland.
CREEPING - R. repens - spreads rapidly by overground runners in many locations, even flood plane meadows.
BRACKEN - Pteridium aquilinum. The rhizomes (roots) are said to be five times more poisonous than the fronds, something to be remembered if ploughing and re-seeding pasture.
The most common period for poisoning is between August and October, when the fronds are turning brown. Bracken contains an enzyme that induces vitamin B1 deficiency.
FOXGLOVE - Digitalis purpurea. All parts on the plant are poisonous growing throughout Britain in woods, on heaths, banks, rocks in acid soils. It is however grown especially for the drug digitalis, which is used, in small doses for the treatment of heart complaints, under medical supervision.
FRUIT TREES - although not in the slightest poisonous, they are included here, because during the Autumn when they are full of fruit, the fruit can cause digestive upsets in horses and ponies and the trees should therefore be fenced off to prevent horses gorging themselves on the fruit.
