Box  

 (Latin Name: Buxus sempervirens)

High Risk 

Description: Evergreen shrub with small, opposite, simple leaves, broadest near or below the middle; flowers small, in clusters, 4-parted. 

Symptoms may include: Diarrhoea, inco-ordination, convulsions and coma. Respiratory failure is the usual cause of death. 

Notes: Poisoning has been reported in horses, usually after gaining access to gardens containing the plant or access to clippings. Box hedge has a nasty odour when bitten. 

Bracken 

(Latin Name: Pteridium aquilinum)

High Risk 

Description: Native perennial herb with black horizontal rhizomes deep in the soil (often below plough depth), by means of which it spreads and forms large patches; leaves 3-4 feet tall in good sites; leaf stalk forks into three main parts, producing a triangular  blade; spores produced in late summer.  

Symptoms may include: Un-coordination, pronounced heartbeat after mild exercise and muscle tremors. If untreated this is followed by convulsions and death. 

Notes:  The whole plant contains toxins which remain after cutting and drying. The roots are said to be five times more poisonous than the fronds. Common cause of serious or fatal poisoning in horses especially between August and October when the fronds are turning brown. 

Foxglove 

(Latin Name: Digitalis purpurea)

High Risk 

Description: Foxglove is most easily recognized by the flowers which are tubular, about 3 inches in length, and droop downwards. They are usually purple or pink (rarely white) and are usually spotted along the inside bottom of the tube.  

Symptoms may include: Diarrhoea, abdominal pain, irregular pulse, tremors and convulsions. 

Notes: Not normally eaten as it has a nasty taste but animals can develop a craving for it once eaten. Does not lose its toxicity when dried. 

Horsetail 

(Latin Name: Equisetum spp.) 

High Risk 

Symptoms may include: Inco-ordination, pronounced heartbeat after mild exercise and muscle tremors. If untreated this is followed by convulsions and death. Significant intake can lead to kidney damage. 

Notes: Common cause of serious or fatal poisoning in horses. This plant likes to grow in crops and pastures. 

Laburnum 

(Latin Name: Laburnum anagyroides) 

Other names for Laburnum include Golden Chain Tree and Golden Rain Tree. 

High Risk 

Description: The yellow flowers of early summer produce the pods and pea-like fruit. 

Symptoms may include: Abdominal pain, elevated temperature, tremors, unsteady gate and convulsions. 

Notes: Fatal poisoning in horses has been reported, mostly involving high consumption of seeds and pods eaten from trees to which they had been tied. Even the roots contain a poisonous alkaloid. The bark and seeds do more damage than the leaves. Oral toxicity of seeds for horses is about 0.05% of the animal's weight. 

Linseed 

(Latin Name: Linum usitatissimum) 

High Risk 

Description: Slender, erect, annual herb; leaves simple, alternate, narrow, smooth-margined; flowers pale blue, 5-parted, the petals broad and spreading; fruit a capsule. 

Symptoms may include: Salivation, staggering, dilated pupils, rapid pulse, gasping, inability to stand and convulsions. In some cases death can be instantaneous and no symptoms are seen. 

Notes: Poisonous principle of the plant is destroyed by heat and linseed must be thoroughly cooked before being given to horses. 

Privet

(Latin Name: Ligustrum spp.) 

High Risk 

Description: Evergreen or deciduous shrubs; leaves simple, opposite, with smooth margins; flowers small, white, 4-parted, tubular, fruit a semi-fleshy, black berry. 

Symptoms may include: Staggering, intestinal disruption, paralysis, rapid pulse, congested mucous membrane and dilated pupils. 

Notes: All arial parts of the plant have caused poisoning. Fatal cases of poisoning in horses have been reported. Death occurring from 4-48 hours after ingestion. Most cases involve garden hedges or trimmings. 

Ragwort 

(Latin Name: Senecio Jacobaea) 

High Risk 

Description: Ragwort is a perennial, sometimes biennial, plant that grows up to 3 feet tall. It has flat-topped clusters of small, yellow, daisy-like flowers. The leaves are dark green, deeply dissected and toothed. It forms rosettes in the first year and flowers in the next.  During the rosette stage, which comes after the seedling stage, it lies flat on the ground about 7cms across. seeds can be dormant in the soil for up to 20 years. 

Symptoms may include: Digestive disturbance, depression, frequent yawning, lack of co-ordination, photosensitisation, abdominal pain and diarrhoea, restlessness, inco-ordination and paralysis.  Symptoms may not appear for several weeks or months but can appear immediately ingested. 

Notes: Does not lose its toxicity after drying and storage and contaminated hay has caused many problems. Plant should be sought out, uprooted and burnt. ALWAYS WEAR GLOVES. 

Rhododendron 

(Latin Name: Rhododendron ponticum)

High Risk 

 

Description: A bush that has large, oblong, smooth leathery evergreen leaves. The flowers, spotted on the inside, form in large showy terminal clusters and can be a variety of colours.  

Symptoms may include: Abdominal pain, salivation, diarrhoea, constipation, staggering, trembling, weak pulse, slow irregular breathing and collapse. 

Notes: Risk is normally associated with animals gaining access to woodland or gardens. Rhododendron can kill after a few hours of it being eaten. 

Yew 

(Latin Name: Taxus baccata)

High Risk 

Description: Yews are evergreen trees and shrubs that have flat needle-like leaves, about 1 inch long. They grow in opposite pairs along twigs. A distinguishing feature of the yew is the red fleshy berry that forms a cup around a black seed.  

Symptoms may include: Inco-ordination, coldness, rapid then weak pulse, excitability preceded by collapse. Sudden death can occur a few hours after ingestion without any symptoms shown. 

Notes: Yew is one of the very few poisonous plants that animals will eat voluntarily at all times of the year.  All parts are poisonous with the possible exception of the fleshy fruit. Many cases of poisoning in horses have been reported. Animals can die a few hours after eating it. 

St Johns Wort

(Latin Name: Hypericum perforatum)

Low Risk

Symptoms may include: Photo-sensitisation where the skin becomes sensitive to sunlight and develops small lesions on its surface which may allow infection to set in. Loss of appetite, debility, staggering gait and coma. 

Notes: Low level poisoning is probably more common in Britain than is realised. Severe cases have been reported in horses. St John's Wort loses 80% of its toxicity when dried, but it can still be dangerous in Hay. 

Acorn 

(Latin Name: Quercus spp.)

Low Risk 

Symptoms may include: Constipation, and blood stained faeces, refusal to drink, weakness and staggering, irregular and slow heart beat, pale mucus membrane and watery eyes. The kidneys can be damaged in extreme cases. 

Notes: Reports of horses eating acorns with little effect, but fatalities have occurred after eating  acorns and other parts of the tree. Reports of poisoning are common in the autumn when acorns are more abundant. Rake and remove any acorns from your fields to be sure. 

Buttercup 

(Latin Name: Ranunculus acris) 

Low Risk 

Symptoms may include:  In large quantities the compound, protoanemonin, causes salivation, together with inflammation of the mouth, blisters and abdominal pain with convulsions usually preceding death.

Notes:  Don't worry if you find them in hay as they change to non toxic when dried. Buttercup has an acrid burning taste that makes them repulsive. Few reported cases of equine poisoning have been reported as horses do not normally eat them. Alkaloid, A poisonous substance, is present in Buttercups, and they are undesirable in a horse's pasture. Buttercups contain varying amounts of a poisonous oil. Alkaloids are mainly irritant and contact with the sensitive pink skin can result in a reaction. Buttercups are very invasive and thrive in poor soil conditions.  They can be killed by spraying.  Horses must not be allowed to graze sprayed pasture for at least two weeks afterwards. An effective means of reduction is to aerate and drain the fields. Any water and compacted soil will provide growing conditions for buttercups. Harrowing to break up any runners will slow and reduce their numbers. 

Black Bryony

(Latin Name: Tamus)

Low Risk

Symptoms may include: Decreased appetite with severe abdominal pains, high temperature and profuse sweating.

Notes: Some reported cases of fatal equine poisoning

White Bryony 

(Latin Name: Bryonia dioica) 

Low Risk 

Description: Greenish-white flowers with five lobed leaves and coiled tendrils.  Brilliant orange-red berries in winter. 

Symptoms may include: Digestive disturbance with acute diarrhoea, profuse urination, profuse sweating, respiratory difficulty, inco-ordination, convulsions and occasionally cessation of defecation. Also animals are unwilling to move. 

Notes: The roots are especially dangerous and should be burnt. Cases of poisoning in horses has been reported.