Situated away from the axis of the body.

Insertion of a trocar through a small incision in the abdominal wall into the abdominal cavity to collect abdominal fluid for evaluation.

Away from the mouth.

Termination of a pregnancy prior to the fetus being viable.

A wound caused by rubbing or scrapping of the skin or mucus membranes.

Localized collection of pus in a cavity formed by the disintegration of tissue. Most are formed by bacteria that invade tissues.

Adrenocorticotropic hormone produced by the pituitary gland. Elevated blood levels can be diagnostic in horses with Cushing's Disease.

The Chinese practice of inserting needles into specific points along meridians in the body to relieve discomfort.

Acute Renal Failure
The result of an abrupt decrease in filtration (glomerular) of blood through the kidneys resulting in elevated BUN and creatinine (azotemia) and fluid and electrolyte imbalances.

This laparacopic surgical procedure removes adhesions within the abdomen.

Any fibrous band that connects two surfaces that are normally separate. In surgery, adhesions may form inelastic bands between loops of intestines. These bands often cause no clinical signs but can lead to colic.

A bacteria that grows only in the presence of oxygen.

Failure of lactation or lack of milk production after giving birth.

A plasma protein formed in the liver that is responsible for maintaining and regulating the exchange of water between the blood vessels and the rest of the body.

Loss of hair.

A bacteria that grows in the absence of oxygen.

An unusual or exaggerated allergic reaction of an animal to a foreign protein of other substance.

Decreased number of red blood cells.

Loss of feeling or sensation. It is induced to permit the performance of painful procedures.

The inability to sweat effectively in response to stimulation of the sweat glands.

Annular Desmotomy
The annular ligament passes around the flexor tendons as they pass down behind the fetlock through the digital flexor tendon sheath. In some cases of chronic tendon sheath effusion, this ligament restricts the gliding function of the flexor tendons, exacerbating lameness and effusion. Transection of this ligament can restore soundness and athletic function. This surgery should not be considered for simple "wind-puffs" in a sound horse.

Lack or loss of appetite for food.

A chemical substance that has the capacity to kill or inhibit the growth of bacteria.

Aortic Regurgitation
Occurs when the aortic valve of the heart becomes insufficient or incompetent thus allowing blood to leak back into the heart (left ventricle) during the relaxation or filling phase (diastolic phase) of the heart. This leads to a left sided murmur heard during diastole.

Inflammation of a joint.

Arthrodesis refers to surgical fusion of a joint. The two most common indications for arthrodesis are severe (end-stage) osteoarthritis and high-energy (comminuted) fractures that damage an articular surface beyond repair. Any remaining cartilage is removed and locking compression plates and bone screws are applied to stabilize the joint as it fuses. In some cases of advanced osteoarthritis, the procedure can be done with a minimally invasive approach. It is the motion of bone-on-bone contact that is so painful. Once the arthritic/damaged joint fuses motion is eliminated and the horse regains comfort. Fusion of low-motion joints (i.e. pastern and distal hock joints) does not eliminate the possibility of advanced athletic activity. Fusion of high-motion joints (i.e. fetlock, knee) offers comfort but alters the gait enough to preclude any real athletic activity.

Roundworms capable of infesting the small intestinal tract. Seen primarily in foals and weanlings 6-9 months of age.

Aspiration Pneumonia
May develop after inhalation of foreign material (feed) and bacteria into the lower respiratory tract (lungs).

Failure of muscular coordination.

Atrial Fibrillation
A common heart arrhythmia characterized by an irregular heart rhythm.

Listening for sounds produced within the body with a stethoscope.

Situated toward the axis of the body.

The accumulation of nitrogenous wastes such as BUN (Blood Urea Nitrogen) and creatinine in blood most often due to either 1. Decreased perfusion of the kidneys seen with dehydration, 2. Renal failure or insufficiency, or 3. Rupture of the bladder or any other part of the urinary tract.


Bacterial Pleuropneumonia
Pleuropneumonia is a severe form of pneumonia most often seen in racehorses. Upper respiratory tract viral infections, as well as stressful events such as long distance transportation and racing may all contribute to development of disease. General anesthesia, immunosuppressive therapy, and poor nutritional status may also lead to compromise of the respiratory defense mechanisms. These stressful events may alter your horse's respiratory defense mechanisms. Bacterial pleuropneumonia as a result of esophageal obstruction from the aspiration of feed material is also seen in other breeds.

Clear yellow fluid produced by the liver.

Regional anesthesia.

Blood Urea Nitrogen (BUN)
The urea concentration of blood or plasma. It is an important indicator of renal function. An elevated BUN is indicative of compromised renal function. Normal value (7-25 mg/dl).

Gradual or acute generalized weakness in horses caused by the potent toxin produced by Clostridium botulinum bacterium characterized by difficulty swallowing and progressive weakness leading to an inability to stand.

Slow heart rate.

Bronchoalveolar Lavage (BAL)
A lavage of the lower respiratory tract (small airways and alveoli) with saline. Samples are collected and cell counts and cytology performed to determine whether there is inflammation present in the lungs. Bacterial culture of the fluid can also be performed; however, this is not a sterile procedure, thus the sample may be contaminated with bacteria from the upper respiratory tract. Commonly performed in patients with Heaves or inflammatory airway disease.

Bruised Sole
Injury to the laminae of the horse's foot caused by stepping on sharp objects.

Behavior characterized by rhythmic grinding of the teeth. It is often a manifestation of pain. In foals it is most often associated with ulceration of the stomach or small intestine. In adult horses it can also be seen but not limited to the pain associated with gastric ulceration.

A small fluid filled sac situated in placed to prevent friction.


Caesarian Section
Performed under general anesthesia. Surgical delivery of a foal through an abdominal incision either electively or as an emergency procedure during a dystocia.

The deposit of calcium salts in a tissue.

Excessive proliferation of the frog portion of the sole of the foot.

Capillary Refill Time
Physical examination procedure that estimates peripheral circulation.

Specialized connective tissue in joints that prevents concussive forces of bone on bone interaction.

Excision of the gonad.

Plastic cannula inserted into a blood vessel to allow for the administration of medications and fluids.

Towards the tail.

Proximal portion of the large intestine forming a dilated pouch distal to the ileum and proximal colon.

A diffuse inflammatory process within solid tissues causing redness, pain, and interference with function.

Cervical Laceration/Tear
A laceration of the cervix of the mare during foaling that causes loss of normal architecture of separation between the uterine environment and the vaginal vault and potential inability to become pregnant.

Cervical Vertebral Malformation
Cervical Vertebral Malformation (CVM) a malformation of the vertebrae of the neck region resulting in compression of the spinal cord and stumbling and incoordination. It is also known as Cervical Stenotic Myelopathy (CSM) or Cervical Compressive Myelopathy or "Wobblers" syndrome.

Chip Fractures
Small pieces of bone that are chipped off that can cause lameness and swelling.

Liver stones, also known as choleliths or hepatoliths, occur infrequently in horses. The stones are composed of calcium and bilirubin, which is a breakdown product of hemoglobin derived from red blood cells. Middle-aged horses are most commonly affected, and clinical signs often include icterus or jaundice, abdominal pain, weight loss and poor appetite. The presence of theses stones can give rise to secondary bacterial infections of the liver, leading to fevers in some cases. Advanced cases may lead to liver failure and neurologic signs, as the levels of ammonia in the blood accumulate.

See Esophageal Obstruction.

Clostridial Myositis
An infection of muscle tissue caused by Clostridium Spp of bacteria. Occurs most frequently in association with or as a complication of an intramuscular injection.

Clostridium Difficile
Bacterium capable of causing inflammation and diarrhea of the colon in both foals and adults via production of a toxin.

Generically, this refers to the clinical signs(pawing, flank watching, rolling, stretching to urinate, flehmen response) of any type of abdominal pain. The causes and severity of the colic signs seen are varied and range from simple impactions with mild signs of pain to twisted or entrapped segments of the intestinal tract that cause violent thrashing of the horse. Many types of colic can be treated with medical therapy such as stomach lavage and oral laxatives a, IV fluids and pain medications, while others require surgical intervention via an exploratory laparotomy under general anesthesia to delineate the cause and surgical treatment necessary to correct the problem.

An inflammatory condition involving the large colon resulting in a variety of clinical signs, of which diarrhea is usually the most significant.

A condition present at birth.

Able to be transmitted from animal to animal.

A nitrogenous compound formed from the breakdown of creatine. It is formed in the muscle and excreted in the urine. It is used as a measurement of kidney function. An elevated level indicates compromised renal function. (Normal value 0.6-2.2 mg/dl)

An acquired habit in stabled horses where the horse grips a solid object with his incisor teeth, arches the neck, pulls upwards and backwards and swallows air.

A developmental defect characterized by the failure of the testes to descend into the scrotum. The testicle can either be found in the inguinal region or abdomen.

Cryptorchid Castration
Surgical removal of a testicle that has failed to descend normally into the scrotal sac. The affected testicle may be retained either in the abdomen or the inguinal canal.

Cushing's Syndrome
A syndrome associated with a functional abnormality of the pituitary gland, resulting in excessive production of hormones such as ACTH. Clinical signs often include abnormal haircoat shedding pattern, laminitis, and increased sweating, drinking and urination.

A bluish discoloration of mucus membranes due to decreased oxygen.

Closed epithelium lined sac containing liquid, usually harmless but can cause disease.


Degenerative Myelopathy (also Equine Degenerative Myelopathy or EDM)
A neurologic disease of young growing horses resulting in degeneration of spinal cord tissue. Suggestive role of low blood Vitamin E levels in the development of the disease. Lack of access to green pasture during developmental stages may predispose foals to development of disease.

The state when the body loses more water than it takes in (negative fluid balance).

Inflammation of the skin.

Surgical cutting of ligaments to release excess limb contracture as seen in a club foot. Performed under general anesthesia.

Diaphragmatic Hernia
A hole in the diaphragm (the musculotendinous tissue that separates the abdominal cavity from the thoracic cavity) can create serious problems, including hemorrhage or herniation of intestines into the chest cavity. By introducing a small camera into either the thoracic cavity or the abdominal cavity, the defect can be visualized and subsequently repaired.

Rapid movement of fecal material through the intestine resulting in poor absorption of water, nutritive elements and electrolytes.

Space between the incisors and canine teeth.

Disseminated Intravascular Coagulation (DIC)
Disruption of the blood clotting system leading to clotting factor consumption. It results in often fatal bleeding throughout the body. It is seen as a secondary complication to severe cases of colic and diarrhea.

State of depressed consciousness in which a still mobile animal is non-responsive to normal stimuli.

Dynamic Stenosis
Defined as deformation of the vertebral column with compression of the spinal cord with the neck in flexion or extension. Affected animals are typically younger (6-18 months).

The term applied to foals born after 320 days that show clinical signs of immaturity such as ligamentous laxity, pliable ears and fine haircoat.

Refers to difficulty in giving birth, or inability to give birth. This is estimated to occur in 1-2% of the foal population. The problem may arise from malposition of the fetus, an oversized fetus, fetal death in utero or when the mare cannot initiate normal contractures to expel the fetus.

Labored breathing.


An abnormal accumulation of fluid in cavities and spaces of the body.

Eastern Equine Encephalitis

Escape of fluid into a part.

Equine Herpes Virus

Equine Infections Anemia

Exercise Induced Pulmonary Hemorrhage

Excessive leanness, wasted condition of the body.

The sudden blocking of an artery by a clot of foreign material.

Accumulation of air in tissues that don't normally contain air.

A bacterial infection of the heart valves or inner lining of the heart (endocardium).

Infectious/noninfectious inflammation of the lining or the uterus (endometrium). It a major cause of infertility in broodmares.

The presence of endotoxin in the bloodstream, and the subsequent effects that the toxin has on the various organ systems of the body. Endotoxemia commonly occurs in horses that are systemically ill (colic, diarrhea, pneumonia). The endotoxin is released from certain types (Gram -ve) bacteria when their cell walls are disrupted during multiplication or death. The endotoxin is either absorbed into the bloodstream or released directly into the bloodstream.

Portion of the cell wall of certain bacteria that can get into the blood stream and cause systemic disease.

Introduction of fluid into the rectum to evacuate fecal material.

Epiglottic Entrapment
A cause of respiratory noise and exercise intolerance in which a fold of tissue (aryepiglottic fold) envelopes the epiglottis. This typically requires surgical transection of the fold of tissue with endoscopically guided laser transection or via sharp excision. This may be performed under standing sedation or general anesthesia.

Equine Granulocytic Ehrlichiosis
Seasonal tick-borne disease caused by the Rickettsial organism Anaplasma phagocytophilium, formerly known as Ehrlichia Equi.

Equine Multinodular Pulmonary Fibrosis
A form of pneumonia characterized by the presence of nodular lesions of fibrosis in the lungs associated with the presence of Equine Herpesvirus 5.

Equine Protozoal Myeloencephalitis
Neurologic disease caused by invasion of the central nervous system by the protozoal organism Sarcocystis neurona. Clinical signs vary with migration of the organism through the nervous system.

Esophageal Obstruction (Choke)
An inability to swallow as a result of partial or complete obstruction of the esophageal lumen by feed material or a foreign body.

Time in the reproductive cycle where an animal displays interest in mating.

Ethmoid Hematoma
A progressive mass that grows off of the ethmoid turbinates of the nasal passage or from the sinus floor causing intermittent nasal bleeding and eventually enlarging enough to cause obstruction in air flow. These are typically resolved with surgical excision using laser therapy, scalpel excision or intratumoral serial formaldehyde injections.

Normal respiration.

The deliberate ending of life of an animal suffering from an incurable disease. An easy or painless death.

Equine Viral Arteritis

Exercise Induced Pulmonary Hemorrhage (EIPH)
Hemorrhage from the lungs associated with exertion. It is characterized by blood in the airways, and occasionally by bleeding out of the nostrils.


Facilitated Ankylosis
Performed under general anesthesia, laser energy is directed into the affected osteoarthritic joint via hypodermic needles to vaporize the synovial fluid, heat the cartilage and joint capsule lining causing cell death with eventual joint fusion and alleviation of pain and lameness.

Failure of Passive Transfer (FPT)
Inadequate absorption of maternal antibodies (Immunoglobulin) from colostrum by foals during the first 24 hours of life. Complete FPT is defined as an immunoglobulin G concentration of less than 200 mg/dl.

Involuntary muscular contractions visible under the skin.

Fescue Toxicosis
Toxicosis in pregnant mares associated with ingestion of fescue infected with a fungus (Acremonium coenophialum) during late gestation. It can result in prolonged gestation, a thickened placenta, birth of a dysmature foal, and lack of milk production (agalactia).

Surgically cutting fascia (tissue) that is restricting an area such as seen in the high suspensory area on the hind limbs.

An elevation in core body temperature, due to resetting of the body's thermostat (hypothalamus). Normal rectal temperature in adult horses is 99.5-101F, and in foals can be as high as 102F depending on the ambient temperature.

An insoluble protein that is formed when being clotted.

A non-specific indicator of acute inflammation of infection. Elevated levels are usually associated with a bacterial infection. Blood levels usually peak between 5-7 days in association with an infection. Normal value ranges from 200-400 mg/dl.

Flexion Test
The act of bending the limb to test for pain in the flexed joint.

Flexural Deformity
Fixation of the joints in flexion (contracted tendons).

An instrument used to file or rasp a horses teeth.

A fluid filled structure in the ovary that grows until it is ready to ovulate.

See Laminitis


Gastric Ulceration/Erosions
Gastric ulceration refers to defects in the mucosal (inner) lining of the stomach that extend into your horse's underlying muscular layer. In contrast, gastric erosions do not extend into the muscular layer. Ulceration occurs when there is an imbalance of digestive factors such as hydrochloric acid and protective factors such as mucus, protective prostaglandins and blood flow to the mucosal lining.

Inspection of the stomach with an endoscope.

The period of development from fertilization of the egg to birth.

Glucose Tolerance Test
Performed to evaluate a horse's ability to metabolize glucose efficiently. Dextrose is administered intravenously, and the horse's glucose and insulin are monitored every 30 minutes for the next 4 hours. It is used primarily to determine whether a horse is insulin resistant, as seen in some horses with Cushing's Disease.

Guttural Pouch Empyema (GPE)
Accumulation of purulent material or pus within the guttural pouches, usually due to a bacterial infection. The most common bacterial infections seen in association with GPE are Streptococcus zooepidemicus, and Streptococcus equi, the organism that causes Strangles.

Guttural Pouch Mycosis (GPM)
Typically a fungal infection most commonly caused by Aspergillus spp in which plaques of the fungus grow along one of the arterial walls in the guttural pouch(internal carotid artery or branches of the external carotid artery may be involved). Frequently this infection requires balloon or coil embolization of the affected artery to prevent the risk of severe hemorrhage and possible death while the fungal infection is treated.

Guttural Pouch Tympany
A non-painful accumulation of air within the guttural pouches seen in foals. The swelling is usually visible in the throatlatch region.


Heart Failure
Inability of the heart to maintain a circulation sufficient to meet the body's demand.

A manageable inflammatory condition of the lower airways characterized by spasming of the airways and excessive mucus production leading to airway obstruction and respiratory compromise. Occurs secondary to inhalation of dusts/molds that trigger an inflammatory response within the respiratory tract. Usually seen in older horses > 7 years.

A localized collection of extravasated blood.

Rupture of red blood cells.

The escape of blood from a ruptured vessel.

Inflammation of the liver.

Transmissible from parent to offspring.

The abnormal protrusion of a part of an organ or tissues through the structures normally containing it.

Herpesvirus Myeloencephalopathy
Spinal cord disorder due to infection with Equine Herpesvirus 1, giving rise to signs of incoordination, weakness, and in severe cases an inability to stand and death.



Insufficient production of thyroid hormones to support the metabolic needs of the horse.

Diminished availability of oxygen to the tissues.

Hypoxic Encephalopathy
A condition that arises as a result of transient damage to the brain secondary to oxygen deprivation either while in utero or at the time of parturition. Also referred to as dummy foal syndrome.


Yellow discoloration of the sclera and mucous membranes due to elevated levels of bilirubin in the bloodstream. It can be seen in cases of liver disease and diseases causing destruction of red blood cells.

Disease occurring with no known cause.

Intestinal obstruction or failure of the intestine to contract.

Obstructed lumen of the intestine by feed material.

Inability to control excretory function.

Lack of normal adjustment of muscle reaction so that the intended movement of a limb is made smoothly.

Infectious Gastrointestinal Disease
This syndrome can be caused by a variety of infectious agents that typically inflict damage to the large intestine (colon and cecum). Infection and inflammation of the large intestine is referred to as colitis, and may be associated with infectious agents such as Salmonella, Clostridium difficile, Clostridium perfringens, Neorickettsia risticii (Potomac Horse Fever) and Coronavirus. The infection and inflammation may cause diarrhea, fever and inappetance. The endotoxins that are released from dying gram negative bacteria in the affected colon, put these patients at an increased risk of developing laminitis.

Infectious Lower Respiratory Tract Disease
This refers to infectious diseases that affect the lungs and thoracic cavity. Horses with this syndrome are referred to as having pneumonia, and typically exhibit fever, cough, nasal discharge and an increased respiratory rate. Their respiratory effort may be increased and characterized by nostril flare and increased abdominal effort. The primary cause of pneumonia is bacterial, however pneumonia can also be caused by viral and fungal infections of the lower respiratory tract. At the Mid-Atlantic Equine Medical Center a large number of horses are treated for pneumonia annually.

Infectious Respiratory Disease (IURD)
This clinical syndrome refers to infectious diseases that affect the upper respiratory tract of the horse. The upper respiratory tract encompasses from the nasal passages to the larynx. This syndrome occurs worldwide, is generally contagious and can be caused by several viruses and bacteria, such as equine influenza virus, equine herpesviruses, equine adenovirus virus, equine rhinitis viruses and the bacteria Streptococcus equi subspecies equi. Horses with IURD generally develop a fever, cough, and nasal discharge. They also may demonstrate lethargy, reduced feed intake, and enlarged lymph nodes of the head and neck.

Inferior Check Desmotomy
Upright, or "club foot", hoof conformation is caused by contraction of the deep digital flexor tendon. The inferior check ligament attaches the lower part of this tendon to the back of the cannon bone. Surgical transection of this tether releases contraction by allowing tension to diffuse into the deep digital flexor muscle belly. Therapeutic shoes with toe extensions are applied at the time of surgery to maximize correction. Ideally, surgery is performed when the horse is young (4-12 months old, depending on severity).

A localized protective response elicited by injury or destruction of tissues which serves to destroy, dilute, or wall the injurious agent and injured tissue.

Inflammatory Airway Disease
A recurrent reversible allergic airway disease characterized by accumulation of inflammatory cells leading to excess mucus production and increased responsiveness of the airways. Can lead to poor performance. Similar to heaves, but is seen in younger performing horses.

A highly contagious upper respiratory tract viral disease caused by the Equine Influenza Virus. It is the most important respiratory disease seen worldwide.

Inguinal Hernia Repair with Testicle-Sparing
Replacement of intestine that has herniated into the scrotum through the inguinal ring with partial closure of the inguinal ring and without removal of the testicle can be performed using "keyhole" surgery in both foals and adult horses. This procedure allows for maintenance of the reproductive potential of the patient.

The forcing of a liquid into a part be it intravascular, subcutaneous, intradermal, intramuscular.

A recent veterinary graduate serving and often residing in a hospital with the objective of getting a concentrated, supervised, postgraduate, in service training in a particular field of veterinary medicine.

Injection into the muscle.

Injection into the vein.


Yellowness of the skin, sclerae, mucus membranes.

The site of union of two or more bones that provide motion and flexibility to the skeletal frame.


Forward bending at the fetlock joint.


A wound produced by the tearing of body tissue.

Incapable of normal locomotion, deviation from normal gait.

Inflammation of the laminae of the foot, which may lead to degeneration and subsequent failure of the attachments between the coffin bone and hoof wall.

Position farther from the midline of the body, towards the outside.

Washing out of an organ or cavity.

A bacterial disease caused by various strains of Leptospira. It has been associated with recurrent uveitis, abortions, stillbirths and neonatal infections.

Decreased energy.

A white blood cell.

Benign fatty tumor that can occasionally strangulate small intestine.

Lyme Disease
A condition caused by the spirochete Borrelia bugdorferi. Reported clinical findings include arthritis, shifting limb lameness, limb swelling and lethargy. Definitive diagnosis can be difficult due to accuracy of available tests, and is usually based on clinical signs and response to treatment.

Inflammation of a lymphatic vessel that may lead to edema within a limb or body cavity.

The most common form of cancer/neoplasia seen in horses. It can affect various organ systems of the body including the skin, intestinal tract and mediastinum.


An anatomical aberration.

Tending to become progressively worse and may result in death.

Inflammation of the mammary gland.

The first fecal material produced by a newborn foal. Its retention can give rise to signs of abdominal discomfort and distension.

Towards midline, the inside aspect.

A tumor arising from pigmented cells, occur commonly in the skin of grey horses, but can be in the abdominal cavity.

A membranous sheet attaching various organs to the body wall.

Inflammation of the uterus.

The free slime secreted by mucus membranes.

An auscultatory sound that is abnormal during cardiac function.

Contrast enhanced radiography of the cervical spinal cord. It is utilized in cases of suspected cervical vertebral malformation or wobblers to determine the site of spinal cord compression.


Nasogastric Intubation
Passing a tube through the nose and into the esophagus and down into the stomach.

The examination of a body after death.

Cell death.

Neonatal Isoerythrolysis
Destruction of red blood cells in a newborn foal by the immune system. It is triggered by antibodies (IgG) acquired from the mare through ingestion of colostrum.

A macroscopic cord-like structure of the body that carries electrical impulses.

Surgical removal of a segment of nerve to a specific area (hind suspensory or heel region of the hoof) to alleviate pain.

Non-Infectious Gastrointestinal Disease
These conditions are inflammatory in nature and may give rise to diarrhea, weight loss and inappetance. There may be an accompanying fever. These inflammatory bowel diseases may be associated with inflammation with no specific cause or cancer of the intestinal tract such as lymphoma or adenocarcinoma.

Non-Infectious Respiratory Disease
This refers to diseases of the lung that are inflammatory in nature. Horses with this condition typically exhibit an increased respiratory rate and effort. A cough or nasal discharge may also be observed. Inflammatory conditions typically do not elicit a fever, so the presence of a fever is a reliable way to distinguish between a condition that is infectious as opposed to inflammatory. An individual may have an inflammatory disease without an infectious component, however most infectious diseases are usually accompanied by an inflammatory component.


Excessive accumulation of fat in the body.

The aiding of parturition.

A semisolid preparation for external application to the body.

Not pregnant.

Non-inflammatory degenerative joint disease marked by degeneration of the articular cartilage, hypertrophy of the bone at the margins and changes in the synovial membrane.

Surgical removal of a mare's ovaries or ovary as in the case of a granulosa cell tumor or for managing behavioral issues in performance horses. This procedure may be performed standing under laparosocopic guidance or under general anesthesia through a routine abdominal incision.

Female gonad that produces eggs.


A feeling of distress, suffering or agony, caused by stimulation of specialized nerve endings.

Paleness of the skin, commonly associated with anemia.

Performed under standing sedation and endoscopic guidance, laser energy stimulates fibrosis or scarring of the soft palate to treat dorsal displacement of the soft palate.

Loss or impairment of motor function due to disease with the nervous system.

The act of giving birth.

Patent Urachus
Congenital or acquired failure of the urachal remnant to close, resulting in leakage of urine from the umbilical stump.

Capable of causing disease.

Per Os
By mouth.

A hole or leak in the walls of an organ.

Perineal Laceration
An injury sustained during foaling in which the vulvar tissue and Anus are torn or lacerated as the foal is expelled, once again causing direct communication between the rectum and vagina.

Periosteal Transection/Elevation
Also known as periosteal "stripping", the periosteum over the growth plate on the concave side of the angular deformity is cut and lifted from the bone, accelerating growth on that side of the physis.

The coordinated movement of the intestines to move food particles along the tract.

Inflammation of the peritoneum.

Inflammation of a vein.

The development of abnormally heightened sensitivity of the skin to sunlight.

Physiologic Castration
With local anesthetic and sedation or under general anesthesia, a small camera is introduced through a small incision in the body wall to visualize the spermatic cord, which contains the vascular and nerve supply to the testis. After localization of the cord, electrocautery and transection of the spermatic cord to eliminate the testicular blood supply is performed without removal of the testicles. This results in a loss of reproductive function and, eventually, the testicles begin to shrink. The benefits of this procedure include a fast return to athletic function and an excellent cosmetic outcome.

The organ formed during pregnancy that allows the diffusion of nutrients and oxygen to the fetus.

Inflammation of the placenta, usually due to a bacterial infection; however, viral and fungal causes are seen as well. Can lead to vulvar discharge and premature lactation.

Inflammation and infection of the pleural/chest cavity extending from infected lung tissue (pneumonia). This gives rise to fluid build-up within the chest cavity and associated respiratory distress.

Inflammation of the parenchyma of the airways leading to difficulty breathing.

Inflammation of several joints.

Polydipsia (PD)
Excessive fluid intake defined as greater than 50 liters per day for the average sized horse.

Polyuria (PU)
Excessive urine output defined as greater than 25 liters per day for an average sized horse.

Post-Castration Hemorrhage
Bleeding following castration is not an uncommon complication but has life-threatening implications, especially if the bleeding cannot be controlled. In some cases, with a standing approach, a small camera may be introduced through the body wall into the abdomen to locate the blood vessel that is the source of the hemorrhage and, using a Ligasure device, the vascular pedicle that once supplied the testicle is cauterized to stop the hemorrhage.

Post-partum Metritis
Acute infection and fluid accumulation of the uterus resulting from retained fetal membranes or contamination of the uterus after foaling.

Potomac Horse Fever
A syndrome of fever and/or diarrhea caused by the organism Neorickettsia risticii. The disease is seasonal with most cases occurring between June and September. The organism has a predilection for the cecum and large colon. Infected horses are at very high risk for the development of laminitis.

Premature Placental Separation
Premature detachment of the chorioallantoic membrane from the endometrium of the uterus before delivery of a term fetus. Occurs mostly as a result of placentitis, and results in decreased delivery of oxygen and nutrients to the fetus.

Foals born at a gestational age of less than 320 days. These foals may experience clinical problems such as respiratory distress due to lack of surfactant and incomplete ossification of cuboidal bones of the hocks and carpi.

Prepubic Tendon Rupture
Separation of the prepubic tendon from its attachment to the pubis, which typically occurs in late gestation as the fetus enlarges and that quantity of fetal fluids increases.

Intense itching.

Purpura Hemorrhagica
An immune mediated vasculitis most often associated with infection of vaccination against Streptococcus equi, the organism that causes Strangles. Clinical signs include hot painful edema or swelling of the head and limbs and hemorrhages on the mucous membranes (gums).



Dropping feed due to a problem with being able to chew the food.


A virally induced neurologic disease seen in mammals. It occurs rarely in the horse, and clinical signs are variable.

Rectal Tear
Partial or complete perforation of the rectum is a life-threatening condition in horses that can result in an uncontrollable infection within the abdominal cavity. With sedation, local anesthesia, and epidural anesthesia, emergency repair of the defect can be performed in a standing horse. A small camera is introduced into the abdomen to allow repair of the defect with suture and/or placement of a liner to bypass the tear.

Rectovaginal Fistula
An injury sustained during foaling in which the hoof of the foal penetrates the roof of the vagina and the wall of the rectum creating a direct communication between the 2 structures and subsequent contamination of the vagina with manure.

Clinical term used to describe an animal lying down.

Recurrent Uveitis
Equine recurrent uveitis (ERU) (also known as moon blindness, iridocyclitis and periodic ophthalmia) is a major ophthalmic disease of the horse and is the most common cause of blindness in this species. It is an immune-mediated disease of multiple origins, with an approximately 8 to 25% prevalence rate in horses in the United States.

Rhabomyolysis (Tying-up)
A complex syndrome characterized by varying degrees of muscular dysfunction ranging from mild stiffness to rigid immobility and sometimes an inability to stand. Muscles may be firm on palpation.

Stomach contents and fluid that is obtained when using a nasogastric tube.

Rhodococcus Equi
An important cause of respiratory disease in foals less than 6 months of age. Infection may also result in septic joints, diarrhea, osteomyelitis and intra-abdominal abscessation.

Right Dorsal Colitis
Localized ulcerative inflammation of the right dorsal colon. Some cases have been associated with the administration of high doses of phenylbutazone.

Osteoarthritis of the first and second phalanx.

Towards the head


Refers to clinical syndromes that may arise as a result of infection with Salmonella species. The gastrointestinal tract is most commonly affected, leading to fever, lethargy and diarrhea.

Excoriations along the back of the pastern also known as greasy heel.

Scrotal Hernia
An abnormal protrusion occuring in the scrotal region of a colt or adult stallion. This condition is usually indicated by swelling.

Seedy Toe
Defect in the wall of the hoof.

A conclusion or sudden onset of uncontrolled motor function.

Present of pathogenic organisms in the blood and other tissues.

Systemic disease associated with the presence of bacteria or their toxins in the bloodstream. Typically seen in neonatal foals. It can lead to fevers, lethargy and infected joints.

Septic Joints/Tendon Sheaths
Contamination of a joint with bacteria or fungi secondary to a puncture, laceration, injection or blood borne route. This frequently requires a combination of surgical lavage, local and systemic antibiotics or anti-fungals and pain medications.

A condition of acute peripheral circulatory failure.

Primary sinusitis is an inflammatory reaction of the sinus lining to bacterial or fungal infections. It is typically treated with sinus lavage and systemic antibiotics or anti-fungals.

Sinusitis Secondary to Dental Disease
Typically secondary to a tooth root infection contaminating the sinus, or a fractured tooth allowing direct communication with the mouth and subsequent contamination.

Having the capacity to perform the function for which the animal is used for.

Static Stenosis
Bony and soft tissue impingement into the vertebral canal resulting from degenerative joint disease of the articular facets. Affected animals are typically older (greater than 18 months-3 years).

An acute upper respiratory tract infection caused by Streptococcus equi infection. Infection is characterized by fever, lethargy, submandibular lymph node abscessation and/or purulent nasal discharge.

Superior check desmotomy
Carpal contraction, or "over at the knee" conformation, is caused by contraction of the superficial digital flexor tendon. The superior check ligament attaches the upper portion of this tendon to the back of the radius. Surgical transection of this tether releases contraction by allowing tension to diffuse into the superficial digital flexor muscle belly. Therapeutic shoes are applied at the time of surgery to maximize correction. Ideally, surgery is performed when the horse is young (6-12 months old, depending on severity). This surgery can be done via an open approach or a tenoscopic approach through the carpal canal.

Synchronous Diaphragmatic Flutter (SDF)
Also known as the "thumps". It is a contraction of the diaphragm synchronous with the heartbeat. Most often due to electrolyte (low blood calcium and potassium) and acid base abnormalities.

Synovial Fluid
Fluid in joints that aids to lubricate and protect the joints.

Inflammation of a synovial membrane.


Increased heart rate.

Temporohyoid Osteoarthropathy
Bony proliferation of the petrous temporal and stylohyoid bone and often fusion of the temporohyoid joint. Most likely occurs secondary to a middle ear infection (otitis media). Bony proliferation leads to microfractures of the petrous temporal bone resulting in damage to the facial (facial paralysis) and vestibular nerves (loss of balance, head tilt).

Fibrous sheet of tissue that convey support and muscle action to the joints.

Performed under general anesthesia, this technique uses arthroscopic equipment to evaluate the tendon sheath allowing a clear view of the structures and access for treatment via small incisions.

Tension Pneumothorax
Increased pressure within the pleural space (the space between the lungs and the chest well) causes severely compromised respiration and is life-threatening. By using thorascopy and introducing a small camera into the thoracic cavity, the source of the tension pneumothorax can be elucidated and allow for relief of the intrapleural pressure.

A disease caused by the toxins of the bacterium Clostridium tetani. It is characterized by muscular rigidity and sometimes death due to respiratory paralysis. The vaccine is highly protective and increases survival in affected animals.

The branch of veterinary medicine dealing with reproductive medicine.

Low peripheral blood platelet count, generally less than 100,000 platelets/uL. Potential causes are numerous, but thrombocytopenia is generally due to decreased production (bone marrow disease), increased consumption (bleeding) and increased destruction (immune mediated disease).

An aggregation of blood products that cause a vascular obstruction.

Surgical procedure performed under general anesthesia to physically tie the most frequently paralyzed left arytenoid cartilage up and out of the airway lumen using 1 or 2 sutures. This optimizes air flow through the larynx during exercise.

Tie Forward
A surgical technique used to aid preventing dorsal displacement of the soft palate in horses in which the problem causes loss of exercise tolerance. Performed under general anesthesia, permanent sutures are placed around the larynx and hyoid apparatus to hold the epiglottis closer to the back edge of the soft palate.

Transphyseal Screw
A bone screw is placed temporarily across the growth plate on the convex side of the angular deformity, slowing growth on that side. The screw is removed (standing: local anesthesia and sedation; no general anesthesia) when the limb is straight (2-4 weeks later, on average).

Transphyseal Screw/Wire Bridge
For more extreme angular deformation, the growth plate on the convex side of the deformity is restricted with a screw and wire bridge. The construct is removed (standing: local anesthesia and sedation; no general anesthesia) when the limb is straight.

Transtracheal Wash
Sterile lavage and aspiration of fluid from the trachea. Samples are collected and cell counts, cytology and bacterial culture performed to determine whether there is inflammation and/or infection present in the lungs. Routinely performed in patients with pneumonia.

Tricuspid Valve
The valve separating the right atrium and ventricle of the heart. When the valve becomes insufficient blood can leak from the ventricle into the right atrium during contraction of the heart.

An aggregation of blood products that cause a vascular obstruction.

Tying Up Syndrome
Disease in which horses become stiff in the their limbs while performing exercise.


Local defect through the level of mucosa.

Imaging technique in which deep structures are visualized by recording the reflections of ultrasonic waves.

Evaluation of selected urinary parameters (protein, glucose, blood etc) via dipstick. Also includes microscopic evaluation of sediment.

Urolith (Urolithiasis)
A calculus or stone located in any portion of the urinary tract. The stone may be located in the kidneys (nephrolith), ureters (ureterolith), bladder (cystolith) and urethra (urethrolith). Accumulation of a large volume of thick urinary sediment in the ventral aspect of the bladder of a horse affected with bladder paresis is referred to as sabulous urolithiasis.

Free urine in the abdominal cavity. Most often seen in neonatal foals when the bladder or urachus ruptures, leading to urine leakage into the abdomen. It can also occur due to ureteral or urethral tears. Rupture of either the bladder or urachus requires surgical correction.

A procedure performed to improve uterine clearence of fluid.


A suspension of attenuated, killed, or modified live organisms that produces immunity to a specific disease.

Inflammation of the blood vessels of the body. It can be associated with a variety of disease such as purpura hemorrhagica, and Equine arteritis Virus (EAV), leading to clinical signs of warm/painful limb edema (swelling) and mucosal hemorrhages.

A surgical procedure performed to treat inward collapse of the vocal cords. It removes the mucosal lining of the ventricle(an outpouching of the larynx) and the vocal cord to create a smooth laryngeal contour to reduce respiratory noise. This may be performed under standing sedation, general anesthesia or using an endoscopic laser assisted technique.


West Nile Virus
Seasonal viral disease borne by mosquitoes. Results in neurologic signs indistinguishable from other more common neurologic diseases such as EPM, Wobblers and Equine Herpesvirus.

Syndrome of incoordination in young horses associated with a variety of pathological processes leading to compression of the cervical (neck) spinal cord.

Uncontrolled movement of the vulva in a mare in heat.


Disease of animals transmissible to humans.