Equine Diseases & Ailments Flashcards
RINGWORM
A contagious fungal infection of the skin that presents as circular lesions around the head, neck, saddle and girth regions.
RAIN ROT / RAIN SCALD
A skin infection caused by a softening of the skin following persistent saturation. This can occur in horses that have a weakened immunity or are already in poor condition and lack the natural grease in their coat to keep warm and dry. It can also occur when leaking or non-breathable turnout rugs are used, when there is poor air circulation under the rug and when the horse’s back is constantly getting wet with moisture from rain or sweat. An affected horse may show patchy hair loss along the back and quarters. The hair can become matted, and the skin may develop sores and weeping lesions.
SCRATCHES (aka MUD FEVER)
A skin condition usually associated with wet and muddy conditions. The skin of the legs and the stomach become inflamed and scaly and, in severe cases, the horse may develop a high temperature or fever. The infection is caused by bacteria that enters the waterlogged skin and causes scabs to form, sealing in the infection.
THRUSH (aka CRACKED HEELS)
An unpleasant infection of the horse’s frog that is predisposed by moist, damp, dirty ground or stall conditions. Thrush produces a foul smelling black discharge in the affected sulcus of the frog. There is pain on applying pressure to the area. The hind feet are more often affected than the front feet and, occasionally, infection may result in a general swelling of the distal (lower) limb.
SWEET ITCH (aka SUMMER ITCH)
An allergic reaction to the Culicoides biting midge or “no-see-um” gnat, although horses can develop allergies to other insects such as black flies, horn flies, and stable flies. The classic signs of “sweet itch” are a horse that becomes very itchy in the spring, often to the point of rubbing out its mane and tail hair. In addition to this “buzzed mane” and “rat tail” appearance, there may be a pattern of skin irritation all along the topline: from head and face, to neck and withers, to back and rump. Because other species of Culicoides have different feeding patterns, they may cause oozing, crusting, and thickened skin in different areas such as between the jaw, in the armpit or axillary region, the ventral midline, and between the hind legs.
AURAL PLAQUES
Whitish, flaky lesions on the inside of the ear. They are thought to be the body’s chronic, inflammatory response to a papilloma viral infection (similar to warts) spread by biting insects. Aural Plaques can be a purely cosmetic problem or cause severe ear sensitivity. However, it is not exactly known what aspect of this condition specifically makes the ears sensitive to grooming, haltering, bridling and other common handling procedures.
Potential causes of a dull coat and/or dry skin
Parasites
Ulcers
Dental disease
Poor nutrition
HIVES
Also known as urticaria - fluid-filled, raised swellings or “wheals” on a horse’s skin. These bumps or plaque-like eruptions are generally round in shape and flat-topped, ranging from ½-inch in diameter to as large as 8 inches wide. They may or may not be itchy, appear minutes to hours to days after exposure, are often seasonal in nature, and can develop anywhere on a horse’s body, although the most common sites are the neck, back, flank, and legs. Tough to pinpoint cause.
MELANOMA
A skin tumor. Specifically, they result from abnormal growth of the skin cells that make the pigment melanin. Melanomas are roundish, black, firm nodules most commonly found under the tail, around the anus, below the anus (the perineum), on external genitalia, and in various other sites around the body. Approximately 80% of all gray horses will eventually develop melanomas while the tumor only occurs in about 30% of non-gray horses. However, when melanomas occur in a horse that is not gray, the tumor tends to be a more aggressive form of cancer.
Which horse breeds are most prone to melanoma?
Arabians, Lipizzans, and Percherons
PROUD FLESH
Overgrowth of the normal tissue that fills in healing wounds. Also known as exuberant granulation tissue, it occurs most commonly with injuries on the lower legs of horses and can be recognized by its rough, red appearance. However, any wound that has been left open to heal rather than sutured closed is at risk of developing proud flesh.
SARCOID
The most common skin tumor in horses. Most experts believe they are caused by the bovine papilloma virus (BPV) although there is a genetic component to tumor development. That is, Sarcoids tend to run in families. They occur in young to middle-aged horses (3-12 years) and can be found anywhere on the body, although most are located on the head, legs and belly.
Name the 4 types of sarcoids.
Verrucous (or wart-like tumors)
Fibroblastic (or proud flesh-like tumors)
Mixed (verrucous and fibroblastic tumors)
Occult (or flat tumors - hair loss, scales and crusting)
SUMMER SORES
A seasonal skin disease in horses referred to by veterinarians as Cutaneous Habronemiasis. It is caused by infection of the skin by the larvae of the large-mouth stomach worm Habronema (and Draschia). Summer Sores are characterized by one or more open and draining nodules and are typically found on the legs, inner corner of the eyes, prepuce (sheath) and penis, as well as moist areas especially where the skin has undergone injury or irritation such as an open wound.
WARTS
Small growths on the muzzle of young horses caused by the papilloma virus. They are usually only seen on horses four years of age and younger because the immune system of the young horse is not yet fully developed. Most adult horses have developed immunity to the virus. Because warts are caused by a contagious virus, infected horses (and their tack and equipment) should be kept separate from other horses to limit spread of the condition.
BOG SPAVIN
Extra fluid in the upper joints of the hock. It’s a cosmetic blemish of the hock area that is similar in appearance to windpuffs and thoroughpin. Specifically, fluid swelling of one of the joint capsules of the jock causes the hock joint to appear swollen. This swelling is not accompanied by heat or pain, and it does not usually cause lameness. However, it can be a sign of osteoarthritis. Poor hindlimb conformation, poor shoeing, poor trimming, poor footing, heavy training, or any trauma can lead to bog spavin.
BONE SPAVIN
Bone spavin is the horseman’s term for osteoarthritis or degenerative joint disease of the hock joint. A very common cause of lameness in the adult performance horse, it generally occurs because of wear and tear or repetitive trauma to the hock joint. Other risk factors include poor footing, poor conformation and poor trimming/shoeing. Horses with bone spavin may be outright lame or develop performance issues such as refusing fences, swapping leads or stopping poorly.
KISSING SPINE
Officially known as “overriding dorsal spinous processes” or “spinous process impingement” this term describes the touching or “kissing” of the long, thin bones that project upward from the vertebrae of the spinal column in the horse’s back. These bony prominences start at the horse’s withers with the first thoracic vertebra (T1) and continue to the point of the hip with the last lumbar vertebra (L6), with T13 – T18 being the most commonly affected. In fact, most Kissing Spines are seen between T14 - T15 and T15 - T16, where the slant of the spinous processes change direction from a slight angle backward to a slight angle forward. This is also directly underneath where the rider sits.
OCD (OSTEOCHONDRITIS DISSECANS)
Osteochondritis dissecans, like osteochondrosis (OC), is a type of growth disturbance of horses that falls under the general heading Developmental Orthopedic Disease (DOD). Specifically the two terms refer to bone diseases of young horses in which cartilage fails to mature properly. Although the terms OCD and OC are often used interchangeably, osteochondritis dissecans is a more advanced form of osteochondrosis where the abnormal joint cartilage actually develops cracks and fissures. Abnormal cartilage that becomes loose in the joint is commonly referred to as “joint mice.”
SPLINT
When a horse “pops” a splint, it means the splint bone and surrounding tissue have become inflamed or swollen. The splint bones are the small bones on the inside and outside of the cannon bone, beginning just below the knee and ending just above the ankle, where they taper to a “button.” Causes of “popped” splints which are more common in younger horses–include a direct blow, concussion, poor conformation and improper shoeing. Trainers often protect horses’ legs with boots or bandages to help prevent “popped” splints.
STOCKING UP
Harmless swelling in the lower legs due to decreased circulation. Reduced activity is what usually leads to this pooling of blood and other fluids in the extremities. The swelling can be found from the coronary band to the ankle or all the way up the cannon bone to the knee or hock and can occur in all four legs or just one pair. Often seen when an active horse is kept in a stall for several days, Stocking up is more common in older horses as well as horses with large bodies and small feet.
STRINGHALT
A neuromuscular disorder of the hindquarters that can be caused by the Hypochoeris radicata plant (a pasture weed) but can also occur for unknown reasons. Sometimes called “goose-stepping,” this rapid flexion of the hind legs toward the belly with each step is made worse by turning or backing the horse. Stringhalt can progress to dragging of the hind toes, a bunny-hop type of gait, and even muscle wasting of the hindquarters. It can affect all breeds of horses at any age and of any gender.
THOROUGHPIN
A cosmetic blemish of the hock area that is similar to windpuffs of the ankles (fetlocks). Specifically, thoroughpin is swelling of the tendon sheath around the deep digital flexor tendon as it passes over the hock. This swelling is not accompanied by heat or pain, and it does not usually cause lameness. Any horse with poor conformation in the hock region, just starting work, or in heavy work may be at risk.
WINDPUFFS
Windpuffs, also known as windgalls, are a cosmetic blemish of the ankles (fetlocks) in horses similar to thoroughpin near the hocks. Specifically, windpuffs are fluid swelling of the tendon sheath makes the legs appear puffy or swollen. This swelling is not accompanied by heat or pain, and it does not usually cause lameness.
RINGBONE
HOOF ABSCESS
a bacterial infection inside the hoof that can cause horses to be suddenly and severely lame. Any break in the hoof wall-sole junction such as a misplaced nail, crack or puncture wound can allow contaminated debris inside the hoof where it migrates to living tissue. The body responds by sending white blood cells (neutrophils) to fight off the invaders. The smelly, gray/black discharge from a hoof abscess is a combination of these white blood cells, the bacteria they are fighting off, and hoof tissue that has been destroyed in the process.
CANKER
Canker (hypertrophic pododermatitis) is an overgrowth of hoof horn tissue on the bottom surface of the horse’s foot. This abnormal production of keratin–which resembles soggy cauliflower and may have a cottage cheese-like discharge–usually begins in the frog but may spread to the sole, bars, and even the weight-bearing portion of the hoof wall. One or more hooves may be affected, and while the condition is more common in the hind feet, it can occur in all four limbs. It may appear in any breed, gender, or location, but there is a higher incidence in draft horses, in stalled horses with little exercise, and in the southeast U.S.
CLUB FOOT
A flexural deformity of the coffin joint and a common problem in young, growing horses. Characteristics of a club foot are a prominent or bulging coronary band, a very upright hoof wall angle, a heel that doesn’t touch the ground, a dish in the hoof wall at the toe, growth rings wider at the heel than the toe, and other abnormal hoof growth. While foals can be born with a club foot (congenital), most develop between the ages of two and six months (acquired), during the time of most rapid growth.
LAMINITIS
Inflammation of the laminae, the tiny, interlocking fingers that attach the coffin bone to the hoof wall. A complex sequence of events occurs during laminitis, potentially altering blood flow or circulation in the foot, resulting in damage to this tissue. When the damage is severe enough, the laminae die and the coffin bone is no longer supported in the hoof. If the bone rotates or sinks in the hoof, the horse is said to have “foundered”.
QUARTER CRACK
A vertical split in the hoof wall at the widest part of the hoof, on the side between the toe and the heel. While it can be caused by damage to the coronary band (where the hoof and hair meet) or damage to the hoof wall from infection or other hoof problem, a Quarter Crack is most often the result of abnormal hoof or limb conformation causing an incorrect landing pattern. This puts excess force on the hoof, causing it to crack where it is weakest.
SIDEBONE
Sidebone is hardening of the cartilages on either side of the coffin bone in the hoof. Experts aren’t sure why these usually springy tissues calcify, or turn to bone, but theories include genetics, hoof concussion or trauma, poor hoof and limb conformation, and poor trimming and shoeing. Sidebone is primarily seen in heavier breeds such as draft horses, warmbloods and cob-type ponies.
WHITE LINE DISEASE
The white line is the junction between the hoof wall and the sole on the bottom of the horse’s hoof. White Line Disease is a widening of the white line, or a separation of the hoof wall from the sole. This separation is then invaded by bacteria and fungi, leading to infection that progresses up towards the coronary band which produces a white or gray powdery material. It is usually first noticed by the farrier during a routine trimming because only severe cases actually cause lameness.
ESOPHAGEAL CHOKE
Choke in horses is an obstruction in the esophagus, not an obstruction in the airway (trachea) like in people. It is still an emergency but the horse should be able to breathe without difficulty. Choke can be caused by swallowing objects that are too large to fit easily down the esophagus (such as apples or corn cobs), eating regular feeds such as grain and hay too quickly, or not being able to chew properly because of dental problems. A horse that is choking may stand with its head and neck extended. He will usually not eat or drink. Saliva and undigested food may be dripping out of his mouth and nostrils and he may cough or gag. Some horses appear anxious while others appear depressed.
