Gastric dilation is the stretching of the stomach due to a buildup of pressure which does not move properly through the GI tract. Left untreated, gastric dilation leads quickly to gastric rupture, where the stomach tears open.
Sepsis or septicemia is an infection of the blood caused by bacteria or bacterial toxins (endotoxins). Foals become infected with harmful bacteria *in utero* or after birth from environmental bacteria.
A strangulating (or pedunculated) lipoma is a benign tumor that is suspended within the abdomen by a stalk of tissue. The lipoma moves behind or around the structures of the gastrointestinal tract, in some cases wrapping the stalk tightly enough to cut off the blood supply.
Slaframine toxicosis occurs when horses ingest high levels of slaframine toxin. Slaframine is a fungal toxin produced by the Rhizoctonia leguminicola fungus, commonly found on the red clover plant, alfalfa, and legumes. Slaframine toxicosis is not life threatening.
Strangles is a bacterial infection caused by Streptococcus equi equi, a highly contagious bacteria that spreads through contaminated nasal discharge. Horses with strangles characteristically develop swollen lymph nodes that drain pus, nasal discharge, and fever.
Selenium (Se) is a micronutrient mineral that, in small doses, plays an essential role in a healthy diet in horses. Selenium poisoning is a potentially life-threatening condition that occurs when an excessive amount of selenium is ingested.
Cyanide toxicosis, also known as sorghum poisoning, is an uncommon condition that occurs when horses ingest toxic levels of plants that contain cyanogenic glycosides. The most common cause of cyanide toxicosis in horses is ingestion of sorghum plants.
Squamous cell carcinoma (SCC) is a malignant skin cancer that arises from the superficial layer of the skin. SCC appears as a single, raised mass that often ulcerates and may bleed or as soft flesh-colored masses that mimic “proud flesh."
Strongyles are a group of highly infectious parasites that spend part of their life cycle in horses’ lower intestines.
Sheared heels in horses are a form of imbalance in the hoof, resulting in one heel becoming visibly taller than the other when viewed from behind.
Sarcoids are a common, benign tumor on the skin of horses. These masses can present anywhere on the skin, but are commonly on the face, chest, abdomen, genitals, and legs.
Sole bruises are a common condition affecting horses.
Hoof cracks are common in horses, and sand cracks (cracks involving the coronary band and extending downward) are the most common type, as well as one of the most severe.