Bracken ferns are poisonous to horses, as they contain a toxic enzyme known as thiamase. This enzyme prohibits the absorption and utilisation of vitamin B1 and leads to impaired cellular respiration and the development of neurological problems. Some curious horses will develop a taste for bracken, while others will avoid it unless they don't have enough edible plants in the field they graze in. Read on for more information on bracken poisoning.
Identifying Bracken Ferns
It's wise to check your horse's grazing land regularly for bracken ferns. In spring, the leaf-like parts of the bracken plant, which are known as fronds, are coiled up tightly. As temperatures increase during summer, the fronds uncurl and have a triangular appearance. Bracken ferns are bright green and can grow to over a metre tall before they wither in autumn. During the winter, you are unlikely to spot any bracken ferns, as they die back to ground level, so don't assume your grazing land is clear of bracken if you don't spot any during the winter.
Symptoms Of Bracken Poisoning
Horses suffering from bracken poisoning tend to develop poor coordination and muscle spasms. They will present as being very nervous and will spend much more time lying down than they usually would. Without prompt treatment, your horse can experience sight loss, seizures and organ failure. If you discover bracken in a field your horse has spent any time in, don't assume they are fine if they are not currently showing any symptoms. Have them examined by your vet, as prompt treatment can save your horse's life.
Treating Bracken Poisoning
Your vet will diagnose bracken poisoning based on your horse's symptoms and what you're able to tell them about the presence of bracken in any area they've been grazing in. Treatment requires supplementation of vitamin B1 in large doses to neutralise the toxin in your horse's body and help them recover. It's typical for treatment to be required for a couple of weeks, and your vet will keep a close eye on your horse during this time. They will monitor your horse's breathing, heart rate and organ function and will provide any additional treatment required to stabilise your horse.
Prompt treatment can prevent your horse from experiencing unnecessary suffering and give them the best chance of recovering. So, if you think there is any chance your horse has consumed bracken, get in touch with your vet right away.