Equine Distichiasis

Description

Description

What is Distichiasis in Horses?
Distichiasis is a condition characterized by the presence of extra eyelashes (distichia) that grow from the meibomian glands along the edge of the eyelids. In Friesian horses, this condition can cause various ocular issues due to the abnormal location and growth of these eyelashes. Here’s a detailed overview:
Etiology
Distichiasis in Friesian horses is believed to have a genetic component, as it tends to occur more frequently in this breed compared to others. The exact mode of inheritance is not fully understood, but there is a higher prevalence in purebred Friesians.
Clinical Signs
The extra eyelashes can rub against the cornea and conjunctiva, causing irritation.

-Tearing (Epiphora): Excessive tearing is often observed as the eye tries to lubricate itself to counteract the irritation.

-Corneal Ulcers: Prolonged irritation can lead to corneal ulcers or abrasions, which are painful and can lead to more severe eye problems if untreated.

-Blepharospasm: This refers to the involuntary tight closure of the eyelids, a sign of ocular discomfort.
Diagnosis:
A thorough eye examination by a veterinarian or an equine ophthalmologist is necessary. This often involves using fluorescein dye to detect corneal ulcers and careful inspection of the eyelid margins for extra eyelashes.

-History and Breed: Knowing the horse’s breed and medical history helps in making a presumptive diagnosis, as Friesians are predisposed to this condition.
Treatment:
Plucking the extra eyelashes can provide temporary relief, but they often grow back.

-Electroepilation: This method uses electrical current to destroy the hair follicle, preventing regrowth. It’s more permanent than manual removal.

-Cryotherapy: Freezing the hair follicles can also provide a more permanent solution.

-Surgical Options: In severe cases, surgical removal of the affected part of the eyelid margin may be necessary.
Prognosis:
The prognosis depends on the severity of the condition and the success of the treatment. Mild cases managed with appropriate treatment can result in minimal complications. However, severe cases, especially those leading to recurrent corneal ulcers, can have a more guarded prognosis.
Management:
Regular eye check-ups are crucial for Friesian horses with a history of distichiasis to catch and treat any complications early.

-Owner Education: Educating the horse owner about the signs of ocular discomfort and the importance of timely veterinary care is essential.
Genetic Counseling:
Since there is a genetic predisposition, it may be advisable for breeders to avoid using affected horses for breeding to reduce the incidence of this condition in the breed.

In conclusion, while distichiasis can be a problematic condition for Friesian horses, timely and appropriate management can alleviate symptoms and prevent severe complications. Regular veterinary care and informed breeding practices are key to managing this condition within the breed.

A nonsense mutation (a type of mutation that codes for a premature stop in DNA code) was found to be associated with hydrocephalus in a number of horse breeds. Hydrocephalus is primarily a result of years of inbreeding in the horse population and the widespread use of only a few influential ancestors.

Foals can only be affected by hydrocephalus if the foal inherits the disease from both parents. Parents that are carriers do not have any symptoms associated with the disorder. If breeding two carriers together, there is a 25% chance per foal born of developing symptoms of hydrocephalus. There is a 50% chance per foal born that they will inherit a copy of the mutated gene and become a carrier of hydrocephalus. This makes genetic testing an important tool while breeding.