Bracken is a common fern that grows throughout Britain and you must be careful it does not dominate your grassland. The whole plant contains several toxic substances, some of which remain after cutting and drying. The root of bracken is five times more poisonous than the fronds.
Not all poisonings are fatal; sometimes the result can be serious digestive upsets, convulsions or your donkey may be off colour. We recommend that you buy good quality hay and check that it does not contain poisonous plants. Prevention is better than cure. If you suspect your donkey has eaten parts of poisonous plants or trees, or the donkey shows any unusual symptoms, call your vet immediately.
Although fruit trees are not poisonous at all, we have included fruit trees, because during the autumn when they are full of fruit, the fruit can cause digestive upsets in donkeys. We recommend that the trees should be fenced off to prevent donkeys gorging themselves on the fruit.
Hemlock is very common to Britain and is generally associated with damp places, and often found in the hedgerows. Hemlock will grow to 6ft in height. It has large fine cauliflower type flowers in abundance on each stem. Poisoning is most likely in spring when young leaves are eaten with other herbage, or on poor pasture.
All varieties of horsetail (mare's tail) is poisonous but field horsetail and marsh horsetail are most likely to cause poisoning. It is a perennial plant with creeping underground stems from which green, jointed, upright stems grow in spring. Poisoning is most likely to occur when horsetail is present in hay or bedding.
British oaks are usually deciduous trees up to 30 metres tall with rough, fissured bark and broad spreading branches. Leaves have smoothly indented wavy margins, and the acorns are shed when ripe. If animals eat a large quantity of oak leaves or acorns then oak poisoning is likely. The most likely time for this is when grazing is scarce.
Wild privet is a branched shrub, found on chalky soils and garden privet is a popular hedge plant. The wild species has narrow, pointed, smooth leaves that are bright green and shiny when young and become darker and dull as they mature. Those of the garden privet are shorter, rarely more than 3cm long and are more oval in shape with small white flowers with a tubular base and a sweetish smell, black berries appear in the autumn. Most cases of poisoning involve garden trimmings.
Ragwort acts as a cumulative poison, eventually destroying the liver. It is a yellow flowering weed and is poisonous both dead and alive. Ragwort can cause serious liver damage over a period of time. It must be pulled with gloves in the early floret stage and burnt. Be very aware of this weed both on your pasture and in the hay. High risk and a common cause of chronic liver disease.
Rhododendron is an evergreen shrub with tough and leathery elongated leaves, dark green above and paler beneath. The large cone shaped buds develop into domed clusters of bell shaped flowers. Rhododendrons are often eaten when animals escape and eat the hedgerow or garden refuge or when food is scarce. Can kill after a few hours of being eaten.