Conditions

Hives, also known as urticaria, are a common skin reaction in horses characterized by the sudden appearance of raised, swollen wheals on the skin. These wheals can vary in size, and may be accompanied by itching or discomfort. Hives in...

Selenium (Se) is a micronutrient that horses require in trace amounts to support cellular function. The selenium content in soil contributes to its final concentration in plants. Worldwide, selenium levels in soil vary widely. Selenium imbalances are common in horses....

Parasites are organisms that live in or on the horse, and rely on the horse for sustenance while often causing harm or disease. These include worms like roundworms, tapeworms, and bots, as well as external parasites such as ticks and...

Keratosis is an equine skin condition where patches or bands of skin become thickened, rough, dark, and oily. The patches are not painful nor itchy, are not contagious, and do not impact the overall health of the horse. There are...

Ringworm, or dermatophytosis, is a common fungal skin infection. Despite its name, ringworm isn't caused by a worm but rather by various fungi, or dermatophytes, that infect the skin. This fungal infection presents circular hair loss patches with crusty, scaly...

Pyrrolizidine alkaloids (PAs) are a naturally occurring type of compound found in many species of plants. When ingested, PAs are toxic to horses. Some of the most common plants that contain high concentrations of PAs include Ragwort (Senecio spp.), Rattlepod,...

As horse owners the world over know, equines are prone to many forms of gastrointestinal disease and dysfunction. Strangulating lipomas are among the varied and complex risks of GI disruption in horses. A lipoma is a tumor made of fat...

Hereditary Equine Regional Dermal Asthenia (HERDA), or Hyperelastosis Cutis (HC), is a genetic degenerative skin disease that primarily affects Quarter Horses. It's characterized by a collagen deficiency, a crucial protein responsible for maintaining the strength and elasticity of the skin....

Proximal Enteritis (also known as Anterior Enteritis) describes inflammation of the first two parts of the horse's small intestine. Proximal Enteritis (PE) is a serious concern for horse owners, as it can block passage of food and water through the...

Horses are susceptible to a variety of external pests and parasites. Most equine pests are either insects or arachnids, some of which can cause irritation, discomfort, and even life-threatening reactions. Several species of external parasite can cause severe health problems...

Vesicular stomatitis is a viral disease that more commonly affects horses living in warmer climates. The disease typically results in blister-like lesions (referred to as vesicles) forming in and around the mouths of horses and other farm animals. This condition...

Hendra virus (HeV), also known as equine morbillivirus, is a frequently fatal viral infection that can affect both horses and people. All reported cases of human Hendra virus infection occurred after exposure to an affected horse, emphasizing the significance of...

African horse sickness (AHS) is a viral infection transmitted by biting midges. Up to 90% of horses infected with the virus die after initial infection. [ref n="1"] Due to international trade and climate change, there is a risk of AHS...

Horse eyes are prominent, making them prone to injury. This is especially true of the cornea, which is the outermost layer of the eye. An injury to this layer is known as a corneal ulcer or keratitis. Corneal ulcers can...

Equine recurrent uveitis (ERU) is an autoimmune disease and the leading cause of blindness in horses. The disease results in the immune system repeatedly attacking the structures of the eye causing tissue damage, inflammation, and eventually blindness. The underlying cause...

Ear mites are tiny, wingless, external parasites that live in the ears of horses and cause psoroptic mange. They are round with eight legs and are sometimes visible to the naked eye. They do not burrow into the horse but...

Mange is a skin and coat condition in horses caused by microscopic parasites called mites. Although mange is not common in horses, specific conditions can lead to a mite infestation that can spread rapidly between horses in direct contact. Mange...

When a horse lies down for extended periods, especially with long-heeled horseshoes or on shallow bedding, prolonged pressure and "squishing" from the hoof on the elbow can occur, leading to a condition known as shoe boil. Shoe boils, otherwise known...

As with other parasites that feed on blood, mosquitoes can transmit diseases between hosts. In horses, Eastern, Western, and Venezuelan Equine Encephalitis (EEE, WEE, and VEE, respectively) and West Nile Virus are mosquito-borne illnesses. Equine encephalitis and West Nile viruses...

Lice are an external parasite found on the hair or fur of mammalian hosts, including horses. A lice infestation is also referred to as pediculosis. There are different species of these small, wingless insects, and horses are usually infested with...

Cataracts are cloudy areas within the horse's lens, the structure within the eye that directs light to the retina. [ref n="1"] The lens must be clear to allow light to pass through correctly, meaning that cataracts can cause blindness in...

Glaucoma refers to increased intraocular pressure, the fluid pressure within the eyeball that gives the eye its shape. [ref n="1"] Glaucoma in horses develops when there is an imbalance in fluid drainage at the front of the eye, leading to...

Equine herpesvirus-1 myeloencephalopathy (EHM) is a potentially fatal consequence of equine herpesvirus-1 (EHV-1) infection in horses. EHV-1 spreads through contact with an infected horse or surfaces contaminated with the virus. Affected horses develop incoordination, weakness, and paralysis 6-10 days after...

Degenerative joint disease (also called arthritis) refers to degeneration and loss of the articular cartilage, cartilage within a joint space that protects the bones on either side of a joint. As the articular cartilage degenerates, the bones contact each other,...

Equine degenerative myeloencephalopathy (EDM) is a degenerative neurologic disease affecting the brain and spinal cord in horses. [ref n="1"] The precise cause of EDM is unknown, but it may be related to a combination of vitamin E deficiency in the...

Neurectomy refers to the surgical cutting and removal of a nerve to prevent pain sensation. In horses, neurectomy is considered a salvage procedure, meaning it is a last resort only performed if no other treatments were effective. Veterinarians may recommend...

Blister beetles, also known as oil beetles, secrete a blistering agent called cantharidin as a natural defense against predators. Beetles in this family feed on flower blossoms, particularly in alfalfa plants, which makes them a common contaminant in alfalfa hay....

Alsike clover toxicosis is a potentially life-threatening condition in horses caused by ingesting large quantities of the Trifolium hybridum plant, commonly referred to as Alsike clover. To date, neither the precise mechanism of action nor the specific toxin from Alsike...

Poisonous snake bites (snake envenomation) in horses, while not common, are a medical emergency. Without prompt veterinary attention, snake envenomation can result in severe injury and, in some cases, death. In North America, venomous snakes belong to either the Elapid...

The guttural pouches are large, air-filled structures within the horse's skull, in the throatlatch region. These pouches can develop bacterial infections, fungal infections, or tympany, the excessive accumulation of air. Most diseases of the guttural pouches are not life-threatening. However,...