Category: Glossary

A splint is a rigid or semi-rigid support applied externally to a limb to restrict movement, reduce pain, and protect damaged tissue while it heals. In equine medicine, splints are used after fractures of the lower leg, post-surgical stabilization, or when a soft-tissue injury requiring immobilization or ligament injury requires immobilization. Unlike a cast, a splint does not fully encircle the limb, which allows for swelling without creating a pressure injury.

Splinting materials range from traditional wooden or metal stays wrapped in bandaging to modern fiberglass and thermoplastic materials that can be molded to the contour of the bony splint calcification site and surrounding structures. Correct padding underneath the splint is critical: inadequate padding leads to pressure sores, while excessive padding can allow the limb to shift inside the device and defeat the purpose of immobilization.

In the context of equine bony “splints” (an unrelated but common usage), the term also describes a calcified growth on the interosseous ligament between the cannon bone and the splint bones of the lower leg. This calcification is not a device but a pathological change, though the same word is applied in barn usage. Both senses appear in veterinary literature, so context determines meaning. Proper diagnosis, whether the injury requires a physical splint or involves a bony splint lesion, requires veterinary assessment and often radiographs of the hoof and lower limb.

Recovery under a splint varies with the severity of the underlying injury. Horses with lower-limb fractures stabilized by splinting before transport to a referral hospital have significantly better surgical outcomes than those moved without support. After removal, gradual reintroduction to weight-bearing and monitoring for acute pain episodes guides the rehabilitation timeline.

Septicemia is a condition in which bacteria or their toxins are circulating in the bloodstream and triggering a systemic inflammatory response. In horses, the term is applied most commonly to neonatal newborn foals, for whom it is one of the leading causes of early death. The neonatal foal is born with a naive immune system and depends entirely on absorbing immunoglobulins from the mare’s colostrum in the first 12 to 24 hours of life. When that transfer fails, whether because colostrum was inadequate, not consumed in time, or the foal did not absorb it, the foal is left without antibody protection, and bacteria that would be contained by a functional immune system proliferate freely in the blood.

Common causative organisms in foal septicemia include Actinobacillus equuli, Escherichia coli, Klebsiella, and Salmonella. Clinical signs, depression, failure to nurse, weak suck reflex, fever, joint swelling, or diarrhea, can appear within 12 to 48 hours in severe failure-of-passive-transfer cases. Diagnosis uses blood culture, complete blood count (low or high white cell count with toxic change), and IgG measurement to quantify the passive transfer deficit.

Treatment requires aggressive intravenous antibiotics, plasma transfusion to supplement immunoglobulins, supportive fluids, and intensive nursing care. Even with treatment, mortality in septic foals is significant. Prevention centers on ensuring every foal receives adequate quality colostrum within two hours of birth and on IgG testing at 12 to 24 hours to confirm successful passive transfer before the gut closes to macromolecules. See the neonatal health and vaccination guide for the broader preventive care context.

Further Reading: Neonatal sepsis mechanisms and failure of passive transfer are explained in the Wikipedia overview of neonatal sepsis. The Merck Veterinary Manual covers septicemia in foals including diagnostic criteria and treatment protocols.

Cold-blooded is a classification applied to heavy draft horse breeds characterized by calm, placid temperaments, large body size (often 1,500 to 2,200 pounds or more), and selective breeding for pulling power and endurance at slow work rather than speed. Cold-blooded horses were developed in northern European climates for agricultural and transport work, where massive pulling ability was more valuable than speed. The term refers to their temperament and breeding heritage, not to actual body temperature.

Primary Cold-Blooded Breeds

• Clydesdale: A Scottish draft breed standing 16 to 18 hh, known for its feathered (long, silky hair on the lower legs) fetlocks and its association with Budweiser advertising in the United States. Used in agriculture, parades, and competitive horse pulling.
• Shire: England's largest horse breed; official record holders for height include Shires exceeding 20 hh. Historically used to haul trade goods in English cities and for farm work.
• Belgian (Brabant): One of the strongest draft breeds by pulling ability, developed in Belgium. The most popular draft breed in the United States by registration numbers. Compact, heavily muscled, extremely strong.
• Percheron: A French draft breed with Arabian influence in its background, somewhat more refined than other drafts. Known for good feet and an active trot that made it suited for both agricultural and coaching use.
• Suffolk Punch: An English draft breed notable for always being chestnut in color and for extreme pulling power at low, slow work.

Characteristics and Uses

Cold-blooded horses are gentle, patient, and tolerant, making them suitable for beginning riders and handlers despite their size. Their calm temperament and predictability contrast sharply with hot-blooded breeds. Primary uses today include competitive horse pulling (draft competitions), logging, farm work in areas where equipment is impractical, parades and exhibition, and recreational riding. Cold-blood draft horses crossed with hot-blood or warm-blood breeds produce working types with combined pulling substance and more athletic movement. See also warm-blood and hot-blood for the full three-part classification system.

A seizure in a horse is an episode of abnormal, uncontrolled electrical activity in the brain that results in involuntary muscle contractions, loss of balance, altered consciousness, or collapse. The horse may paddle its legs, exhibit rhythmic jaw clenching, fall to the ground and thrash, or simply display sudden behavioral changes and ataxia depending on which region of the brain is involved and the seizure’s intensity.

Common causes of equine seizures include hepatic encephalopathy (liver failure elevating ammonia and toxins in the blood), hypocalcemia (low blood calcium, particularly in lactating mares), head trauma, ingestion of neurotoxic plants such as yellow star thistle or water hemlock, and idiopathic epilepsy. In neonates, neonatal maladjustment syndrome (dummy foal syndrome) can produce seizure activity within hours of birth. Infections causing encephalitis (equine herpesvirus neurological form, West Nile virus) are also recognized triggers.

A seizing horse is a safety emergency. Bystanders should clear the area of hard objects and avoid restraint, which can worsen injury; if the horse falls, do not approach until activity has stopped. Post-seizure, the horse typically shows a recovery period (post-ictal phase) of confusion, weakness, or incoordination. Veterinary evaluation is required to identify the underlying cause, as treatment depends entirely on etiology, anticonvulsants, calcium supplementation, liver support, or toxin management depending on what triggered the event. Recurrent seizures warrant neurological workup and may indicate structural brain pathology requiring imaging. Note that sedative overdose is itself a recognized pharmacological trigger and should be confirmed as ruled out before any sedation protocol is adjusted.

Further Reading: Wikipedia’s article on seizures explains the underlying electrical mechanisms and classification system. The Wikipedia entry on hepatic encephalopathy details the ammonia-driven neurological disruption that is among the more common triggers in adult horses.

Malabsorption is the impaired uptake of one or more nutrients from the intestinal lumen into the body’s systemic circulation despite adequate dietary intake, resulting in nutritional deficiency, weight loss, and secondary clinical signs that reflect the specific nutrients failing to be absorbed. In horses, malabsorption can affect simple sugars (glucose), proteins (amino acids), fats, fat-soluble vitamins, and minerals, and may result from disease of the small intestine, where most nutrient absorption occurs, or from diffuse infiltration of the intestinal wall that reduces functional absorptive surface area.

The clinical presentation depends on the degree and duration of the disorder. Weight loss despite an adequate ration is the most consistent sign; a horse that is fed appropriately but fails to maintain condition despite dental health and parasite control should prompt investigation of intestinal absorptive function. Protein malabsorption leads to hypoproteinemia, with low serum albumin causing ventral edema (kept fluid in the belly and lower limbs). Fat malabsorption produces pale, malodorous, voluminous feces and fat-soluble vitamin deficiencies over time. loose stool accompanying absorptive failure often accompanies malabsorption but is not invariably present.

Diagnosis relies on oral glucose absorption or D-xylose absorption tests: a baseline blood sample is taken, glucose or xylose is administered orally at a measured dose, and blood glucose or xylose concentrations are measured at timed intervals. A blunted or flat absorption curve indicates small intestinal dysfunction. Conditions underlying equine malabsorption include inflammatory bowel disease (granulomatous enteritis, lymphocytic-plasmacytic enterocolitis), alimentary lymphoma, widespread small intestinal lesions from migrating parasitic larvae, and intestinal lymphangiectasia. Treatment is directed at the underlying cause where possible; supportive management includes highly digestible feed, parenteral nutrition in severe acute cases, and corticosteroid therapy for inflammatory conditions. Regular monitoring weight loss over treatment is essential to monitor treatment response.

Hot-blooded is a classification applied to horse breeds characterized by high energy levels, heightened sensitivity to stimuli, speed, and physical refinement. The term originates in the centuries-old practice of classifying horses by their breeding heritage and associated temperament. It refers to the horse's disposition and genetic heritage, not to its actual body temperature. Hot-blooded horses were developed in hot, arid climates and have been selectively bred for speed and endurance over cold or draft power.

Primary Hot-Blooded Breeds

• Arabian: The archetype of the hot-blooded horse; developed on the Arabian Peninsula and considered the foundation of most other hot-blooded breeds. See Arabian breed profile.
• Thoroughbred: Developed in England from Arabian, Turkoman, and Barb foundation sires crossed with native English mares. The world's racing standard. See Thoroughbred breed profile.
• Akhal-Teke: An ancient Central Asian breed from Turkmenistan, renowned for its metallic coat sheen, extreme endurance, and athletic ability over long desert distances.
• Barb: A North African breed that contributed to Thoroughbred foundation and to Iberian breeds; hardy, high-energy, and fast over short distances.

Characteristics

Hot-blooded horses are typically lean and refined in build, with thin skin that allows superficial blood vessels to show during exertion. They have a high stride frequency and efficient aerobic metabolism suited to speed and sustained effort. Their sensitivity makes them highly responsive to skilled riding and potentially challenging for inexperienced handlers. They are generally not recommended as beginner horses.

The Three Blood Classifications

Horse breeds are traditionally divided into three temperature-based categories:

• Hot-blooded: High energy, refined, speed-oriented. Arabian, Thoroughbred, Akhal-Teke.
• Cold-blooded: Heavy, calm, draft-oriented. Clydesdale, Shire, Belgian. See cold-blood.
• Warm-blooded: Sport horses combining draft substance and hot-blood refinement. KWPN, Hanoverian, Oldenburg, Trakehner. See warm-blood.

In foal is the standard equine term for a pregnant mare. The phrase appears in sales listings, breeding records, and veterinary documentation as confirmation that a mare is carrying a developing foal. A mare is confirmed in foal by a veterinary examination that may include rectal palpation, transrectal ultrasound (the most common modern method), or blood/urine hormone testing. Ultrasound confirmation is typically possible by day 14 to 16 after ovulation; a heartbeat is visible by day 25 to 28.

Gestation Length

The average equine gestation period is 340 days (approximately 11 months), with a normal range of 320 to 360 days. Individual mares tend toward consistent gestations. Foals born before day 300 are premature and have significantly reduced survival rates without intensive veterinary care. Foals born between days 300 and 320 are premature to early-term and may require additional support. The foaling season in the Northern Hemisphere is typically February through June, as horses are seasonally polyestrous and naturally cycle in spring.

In Foal in Sales Listings

A mare listed for sale as in foal to [stallion name] is being sold with a confirmed pregnancy. This is a significant value factor: the buyer receives both the mare and a foal due in the next breeding season, plus the stud fee (already paid) is effectively included in the purchase price. The listing should specify: the stallion name, breeding date or confirmed pregnancy date, the method of confirmation (ultrasound is standard), the number of days of gestation at time of sale, and whether a live foal guarantee applies. Buyers should verify the pregnancy independently via veterinary examination before completing the purchase.

Care of the In-Foal Mare

Nutritional needs increase significantly in the final trimester (months 9-11), when 80% of fetal growth occurs. Mares in late pregnancy require increased digestible energy, protein (especially lysine), calcium, phosphorus, and vitamin E. Vaccination and deworming protocols for in-foal mares follow specific timing restrictions; consult a veterinarian before administering any product to a pregnant mare. Exercise continues to be beneficial through late pregnancy unless complications arise.

See also: dam; foal; at stud; selective breeding.

At stud is a phrase used to describe a stallion that has been retired from racing or competition and is now available for breeding service. A stallion stands at stud at a breeding farm or stud farm that manages bookings, collects semen, arranges breedings with visiting mares, and handles the associated logistics. The phrase appears in breed registries, sales catalogs, bloodline research, and marketplace listings as a standard descriptor of a stallion's current status and purpose.

Types of Breeding Service

• Live cover (natural service): The mare is transported to the stallion's location and bred directly. Required by some breed registries, including the Jockey Club for Thoroughbreds. Produces 100% of registered Thoroughbred foals.
• Cooled shipped semen (AI): Semen is collected, extended in a cooling medium, and shipped overnight to the mare's location for artificial insemination within 24-48 hours. Accepted by most registries except Thoroughbred. More convenient for mare owners; allows geographic access to distant stallions.
• Frozen semen: Semen is cryogenically preserved and stored indefinitely. Allows use of a stallion's genetics after death. Accepted by many registries; conception rates are typically lower than fresh or cooled semen.

Stud Fees

A stud fee is the charge for one breeding season or one confirmed pregnancy (live foal guarantee) with a specific stallion. Fees range from under $500 for local pleasure-horse stallions to over $300,000 for elite Thoroughbred sires at major breeding farms. Most stud fees are quoted as either a flat service fee (payable at breeding) or a live foal guarantee (payable when the mare produces a live, standing foal). The fee reflects the stallion's own performance record, the earnings and quality of his offspring, and market demand for his bloodlines.

See also: stallion; sire; dam; in foal.

In equestrian terminology, a schoolmaster is a horse that has been trained to a high level in a specific discipline and is used specifically to teach a less experienced rider that same discipline. The schoolmaster's value is that it already knows the job: it carries the muscle memory, the conditioned responses, and the established way of going that allows a developing rider to feel the correct movements, responses, and timing that would otherwise take years to develop on an untrained horse.

Where the Term Is Used

The term is most common in dressage, where a horse trained to Prix St. Georges level or above can allow a lower-level rider to feel half-passes, flying changes, piaffe, and passage that would be impossible to ride on a horse that has not been trained to those movements. In show jumping, a schoolmaster is a horse with experience over difficult courses that allows a junior or developing rider to learn the approach, distances, and rhythm required at height. In eventing, a schoolmaster is a horse with cross-country mileage that allows a novice event rider to learn water, ditches, banks, and combination fences safely.

Characteristics of a Good Schoolmaster

A schoolmaster must combine high-level training with a patient, forgiving temperament. A horse trained to Grand Prix dressage that is tense, reactive, or punishing to rider error is not a schoolmaster, it is a difficult horse. The ideal schoolmaster accepts the aids of a novice rider calmly, performs the movements it knows in response to correct aids (teaching the rider what correct feels like), and tolerates the inevitable errors of a developing rider without escalating. Age is typically an asset: a horse in its late teens that has competed successfully at high level and whose competitive career is winding down is often the ideal schoolmaster, combining deep muscle memory with reduced reactivity.

Price

Schoolmasters command a premium: a Grand Prix dressage schoolmaster capable of teaching flying changes and piaffe may sell for $30,000 to $150,000 or more, despite being past competitive prime, because the teaching value is real and the supply of suitable horses is limited. For jumping, an experienced Preliminary or Intermediate event horse in its mid-teens may sell for $10,000 to $40,000 as a schoolmaster after its competitive career ends.

See also: green-broke (the beginning of the training spectrum); Thoroughbred (OTTB) for a common source of affordable schoolmasters in jumping and eventing.

In horse training terminology, green-broke describes a horse that has received only the initial, most basic training under saddle or in harness. A green-broke horse accepts a rider or driver and will walk, trot, and sometimes canter on request, but it has not been consistently schooled across different environments, does not reliably respond to aids, and is likely to be unpredictable in novel situations such as traffic, water crossings, crowds, or unusual objects. The term derives from the older usage of breaking a horse to accept training, a phrase now often replaced by starting in horsemanship circles that emphasize pressure-and-release methods over force.

What Green-Broke Means in Practice

A green-broke horse has typically experienced: being saddled and accepting a rider's weight; basic forward movement at walk and trot on a familiar surface; rudimentary steering and stopping from light rein contact. It has not experienced: consistent work across varied environments; refined response to leg, seat, and rein aids; exposure to common trail or arena hazards; or the miles and repetition that build reliable behavior. The number of rides defining “green-broke” varies by seller; a horse with 20 rides and a horse with 60 rides can both be described as green-broke. Buyers should ask specifically how many rides, by whom, in what environments, and over what time period.

Green-Broke vs. Other Training Levels

• Unstarted (unbroke): No rides; has been handled on the ground but not ridden.
• Green-broke: Initial rides only; basic acceptance of a rider or driver; unpredictable outside familiar conditions.
• Lightly started: 30-90 days of consistent work; beginning to respond to aids; still developing.
• Finished: Fully trained in a specific discipline; reliable, consistent, appropriate for its intended use.
• Schoolmaster: Experienced horse that has been highly trained in a discipline and can teach a less experienced rider. See schoolmaster.

A green-broke horse is appropriate for experienced riders who have the time and skill to continue its education. It is not appropriate for novice or beginner riders, who need a predictable, well-schooled mount. The price gap between a green-broke and a finished horse reflects this difference: the training investment required to finish a green horse adds significant value.