Is My Horse Lying Down Too Much? Guide to Recumbency & Treating a Down Horse

Recumbency in horses refers to lying down, usually on one side. As prey animals with considerable size and weight, horses have evolved to minimize the need for lying down since this position increases vulnerability to predators and hinders rapid escape.

While horses do spend a portion of each day lying down, remaining recumbent for extended periods of time is often a symptom of severe health conditions that may be life-threatening.

Prolonged recumbency, or a “down horse,” can result from various conditions such as injury, neurological disorders, or poisoning. Extended periods of recumbency put horses at risk for serious complications, including pressure sores, muscle loss, decreased gut motility, and respiratory problems.

Horse owners and caretakers need to know the difference between normal recumbency and a downed horse showing signs of symptomatic recumbency, which requires immediate veterinary attention.

Recumbency in Horses

Recumbency describes the state in which a horse is lying down, either on its side (lateral recumbency) or on its chest with its legs tucked under (sternal recumbency).

Unlike many other domesticated animals, horses generally do not spend much time lying down, an evolutionary adaptation that arose from being prey animals. Additionally, their large size makes getting up more difficult than for smaller, more agile prey species. ^[1]

For these reasons, horses evolved the unusual skill of sleeping upright and spend only small portions of the day lying down. ^[1]

As such, prolonged recumbency, especially when the horse is unable or unwilling to get up, can be a sign of a serious medical issue.

Sleeping Standing Up

The anatomical feature that allows horses to sleep upright is known as the stay apparatus. This system of ligaments and tendons in the horse’s legs allows the joints to “lock” in place, supporting the horse’s weight even as its muscles relax during sleep. ^[2][3]

When the stay apparatus is engaged, the horse’s legs are stabilized, allowing them to stand with reduced muscle tension. When the stay apparatus is locked, the horse’s legs are stabilized, allowing the horse to stand with reduced muscle tension. Horses also rely on the stay apparatus during waking hours to mitigate muscle fatigue while standing. ^[1][2]

Although horses usually sleep standing up, they need to lie down sometimes to complete their full sleep cycle and receive adequate rest.

A horse’s sleep is divided into two phases: ^[4]

• Rapid Eye Movement (REM): REM sleep is the deepest phase of sleep, where dreaming occurs. Horses need to lie down for this phase of sleep and require about 30 minutes of REM sleep each day.
• Non-REM: This is the longer phase of sleep and contains several sub-stages. Horses usually stand during non-REM sleep but may transition to REM sleep from sternal recumbency between phases.

Types of Equine Recumbency

Horses can lie down in one of two separate positions: sternal and lateral recumbency.

• Sternal recumbency describes lying down on the belly with the legs tucked underneath. In this position, the horse’s head and neck are still upright, even when sleeping.
• Lateral recumbency describes lying down on one side with the legs extended. In this position, the horses head and neck are also recumbent. This is the position horses use during REM sleep.

Under normal conditions, foals spend about 15% of their day lying on one side, in lateral recumbency. Healthy adult horses lie down for 5% to 12% of the day, with 80% of this time spent in sternal recumbency. ^[5]

Risks of Prolonged Recumbency

Although lying down is essential for proper sleep and metabolic recovery, remaining in this position for extended periods can be hazardous for horses. Prolonged pressure on the parts of the body in contact with the ground can lead to severe complications.

Complications associated with sustained recumbency in down horses include: ^[6]

• Skin sores
• Muscle degeneration
• Decreased motility of the gastrointestinal tract, which may result in colic

Recumbency becomes a medically concerning symptom if it is prolonged or if the horse is unable to stand at all. ^[6]

Concurrent Symptoms

Recumbent horses can exhibit several other symptoms depending on the underlying condition causing the recumbency. Common concurrent symptoms include:

• Difficulty breathing
• Collapse
• Ataxia (incoordination)
• Excessive sweating
• Difficulty swallowing
• Dilated pupils
• Generalized weakness
• Neurological deficits and alterations
• Weight loss

Causes

Recumbency in horses is associated with a wide range of medical conditions, from physical injury to deadly viruses.

The underlying causes of recumbency can be subdivided into two broad categories:

• Neurological
• Non-neurological

Recumbency is also associated with colic, which is broadly defined as abdominal pain and has a number of specific sub-types and symptoms.

Generally, the physiological cause of recumbency is due to one or a combination of the following:

• Weakness
• Pain
• Nervous system dysfunction
• Catastrophic injury

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Musculoskeletal Injury

Fractures and luxations (dislocations) are common emergencies in horses. Severe fractures and bone dislocations, especially when the injury affects the legs, can cause recumbency.

Injured horses who are recumbent require prompt medical assessment prior to attempting to move or relocate them. If a horse sustains an injury serious enough to cause excessive lying down, they are severely injured and usually require sedation or even anesthesia before transport to a clinic for intervention.

Following initial assessment and sedation, horses with injuries generally undergo diagnostic imaging such as X-rays or bone scans (scintigraphy) to further assess the extent of damage and determine the proper course of treatment. ^[7]

Treatment for equine injuries may include: ^[7]

• Immobilization: Securing the joints above and below the affected bone to prevent movement and promote healing.
• Wound Care: Cleaning any external wounds thoroughly to prevent secondary infections and tissue necrosis.
• Stall Rest: Movement should be restricted to avoid hindering recovery.
• Rehabilitation: A gradual return to exercise guided by the treating veterinarian and other qualified professionals is the best course to prevent further injury or recurrence.

Head Injury

Head injuries are an emergency as they can cause severe central nervous system (CNS) damage that can lead to permanent neurological deficits and even death.

Types of head injuries include

• Contusion
• Concussion
• Skull fracture
• Internal hemorrhage

Head injuries in horses are often the result of direct trauma to the head following blows or falls. Horses that develop recumbency as a result of a head injury must be sedated prior to transport to a veterinary hospital. ^[7]

Once in medical care, horses undergo diagnostic tests to evaluate the severity and extent of the damage. Following diagnosis, treatment focuses on supportive care and aims at reducing damage to the central nervous system. ^[7]

Treatment options may include: ^[7]

• Fluid Therapy
• Pain Medications
• Anti-inflammatory Medications
• Seizure Medications
• Neuroprotectants
• Antibiotics

Poisoning

Several types of toxicosis can lead to recumbency in horses. Horses exposed to various toxins – including plants, chemicals, and contaminated feeds – are at risk.

Common causes of toxicosis in horses include: ^[8][9]

• Plants: Including Oleander, Mountain laurel, Boxelder, Nightshade, Water hemlock, Sudan grass
• Fungi: Ingestion of fumonisins, a mycotoxin produced by Fusarium fungus species, can cause equine leukoencephalomalacia (ELEM). This condition leads to CNS symptoms such as ataxia, muscle tremors, and recumbency.
• Arsenic: The ingestion of elevated quantities of arsenic leads to acute arsenic poisoning, which in turn causes recumbency.

Heatstroke

Heatstroke is another condition associated with recumbency. Horses living in extremely high temperatures, in particular those with pre-existing conditions that impact their ability to thermoregulate, can develop life-threatening heatstroke if body temperature exceeds 106 °F (41 °C).

Horses with heat stroke develop severe CNS symptoms and present with: ^[10]

• Seizures
• Ataxia (incoordination)
• Difficulty rising
• Falling down
• Severe dehydration
• Rapid breathing
• Rapid resting heart rate
• Collapse
• Recumbency

Affected horses require immediate medical attention. Unfortunately, horses that develop prolonged recumbency as a consequence of heatstroke carry a poor prognosis.

Equine Protozoal Myeloencephalitis (EPM)

EPM is a neurological condition endemic to North and South America. It is caused by the protozoan Sarcocystis neurona, which is found in contaminated feed and water. ^[11]

While up to half of all horses in America may come into contact with the organism, only a small percentage develop symptoms of the condition. After ingestion of the contaminated source, the protozoa enter the horse’s system and infect the central nervous system. ^[11]

Since EPM can affect any part of the CNS, symptoms may encompass a wide range of neurological signs, including: ^[11][12]

• Facial paralysis
• Head tilt
• Lameness
• Seizures
• Difficulty swallowing
• Back pain
• Ataxia (lack of coordination)
• Muscle atrophy

Left untreated, EPM can lead to recumbency and eventually death. The progression to recumbency is unpredictable; it can occur within hours or develop gradually over years. ^[11][12]

Definitive diagnosis of EPM is challenging while the horse is still alive. A suspected diagnosis of EPM is based on the presence of neurological symptoms, the exclusion of other possible conditions, and identification of antibodies to Sarcocystis neurona in the horse’s cerebrospinal fluid and serum. ^[11][12]

Suspected cases require prompt intervention to prevent disease progression. Treatment typically includes the administration of immunomodulators and antiprotozoal drugs. Unfortunately, this treatment is not highly effective, and complete recovery is rare. Additionally, affected horses may relapse. ^[11][12]

Equine Encephalitis

Equine encephalitis viruses are a group of mosquito-borne, life-threatening viral infections that affect the central nervous system in horses. These infections are divided into three subgroups: ^[12][13]

• Eastern Equine Encephalitis (EEE)
• Venezuelan Equine Encephalitis (VEE)
• Western Equine Encephalitis (WEE)

These conditions are caused by alphaviruses, and are transmitted to horses by mosquito bites. Mosquitoes often become infected after feeding on birds and rodents that carry the virus. ^[12][13]

Symptoms of all types of equine encephalitis viruses are similar and include: ^[12][13]

• Fever
• Lethargy
• Impaired vision
• Ataxia (incoordination)
• Seizures
• Head pressing
• Circling
• Recumbency

Diagnosis is based on clinical signs, blood tests, and cerebrospinal fluid tests (“spinal tap”). ^[12][13]

There are no specific treatment options for equine encephalitis viruses available and mortality rates are high. The majority of affected horses succumb within three days from the onset of symptoms. While there is no specific treatment or cure, annual vaccines are available and are considered the best way to prevent these deadly conditions. ^[12][13]

In addition to vaccination, reducing horses’ exposure to mosquitoes should be a priority, as they are vectors for other potentially fatal conditions in addition to alphaviruses.

Rabies

Rabies is a rare and fatal viral zoonotic infection that affects the nervous system in all infected mammals. Skunks, opossums, raccoons, foxes, and bats are reservoirs for rabies and transmit the virus to domestic animals through the saliva when they bite and puncture the skin.

Horses infected by the rabies virus develop symptoms two to nine weeks after exposure; these include: ^[14]

• Ataxia (incoordination)
• Colic
• Jaw paralysis
• Excessive salivation
• Recumbency

There is no treatment for rabies. At-risk domestic animals should be vaccinated against the disease. Consult with a veterinarian if you are unsure if your horse or other animals are candidates for the rabies vaccine.

Colic

Abdominal pain, medically known as colic, is a frequent symptom in horses that can stem from a wide array of conditions. It can vary from mild discomfort to severe pain and may lead to sudden death.

Common causes of colic include: ^[15][16]

• Intoxication
• Misuse of medications
• High levels of stress
• Poor dental health
• Dehydration
• Heavy worm infestation
• Obstruction of the intestine
• Abdominal tumors
• Accumulation of excessive gas in the digestive tract
• Displacement of the colon

Colic is the leading cause of death in adult horses. If a horse with abdominal pain becomes recumbent, it signals severe and potentially life-threatening colic, requiring immediate veterinary intervention.

Horses presenting with symptoms of abdominal pain undergo a thorough veterinary examination, including: ^[15][16]

• Assessment of vital signs
• Abdominal palpation
• Rectal examination

Further diagnostic tools include diagnostic imaging and blood tests. Treatment and prognosis vary greatly depending on the underlying cause.

Severe Emaciation

Severe emaciation in horses can lead to significant weakness, making it difficult or impossible for them to rise. Neglected horses are at a high risk of developing several life-threatening conditions.

Severely underweight horses need close care from veterinarians and nutritionists, as the reintroduction of food must be carefully controlled and done gradually to allow proper adjustment and prevent rapid metabolic changes.^[17]

Emaciated horses that develop recumbency carry a poor prognosis. Those who are recumbent for over 24 hours are unlikely to recover. ^[17]

Recovering horses that cannot stand require regular turning every two to six hours to ensure adequate blood flow to the muscles, skin, and lower lungs. Additionally, points of contact with the ground should be padded to minimize pressure necrosis and protect body tissues. ^[17]

Diagnostics

Diagnosing the underlying cause of recumbency in horses is challenging due to the wide range of possible conditions. While some conditions, such as bone fractures, may be immediately apparent, others require a thorough diagnostic work up to accurately identify the cause and rule out other potential conditions.

An initial diagnosis involves a comprehensive physical examination and a detailed discussion of the horse’s history. Following this, additional diagnostic tools may be employed to determine the cause of recumbency, including:

• Blood tests
• Urinalysis
• Diagnostic imaging
• Stomach content analysis
• Serum analysis
• Cerebrospinal fluid analysis (“spinal tap”)

Management

The two main objectives in the management and treatment of a recumbent horse are:

• Supportive care aimed at stabilizing vital signs
• Specific treatment addressing the underlying condition causing the symptoms

Supportive General Care

Down horses that exhibit difficulty or an inability to swallow require nutritional support, which can be obtained via one or a combination of: ^[18]

• Nasogastric tube
• Liquid diet
• Parenteral (or intravenous) nutrition

In conjunction with nutritional support, recumbent horses may need assistance maintaining hydration if they are unable to drink on their own. Fluid therapy can be administered either by intravenous fluids or through a nasogastric tube. ^[18]

Horses suffering from prolonged recumbency can develop pressure sores and nerve compression syndrome. To reduce the severity of these conditions, affected horses should be placed on comfortable and absorbent bedding. In addition to comfortable bedding, horses must be turned every two to six hours to ensure proper blood flow. ^[17]

Preventing Complications

Recumbent horses are at a higher risk of developing several severe complications, including: ^[18]

• Impactions and ileus
• Respiratory tract diseases
• Corneal ulcers and keratitis

To prevent complications, recumbent horses require constant monitoring in hospital and may need: ^[18]

• Urinary catheterization
• Administration of laxatives
• Antibiotic treatment
• Eye protection (bandages or padding)

Once the horse’s vital signs are stabilized, a central element of care is physiotherapy. While the horse is still recumbent, a member of the veterinary team will manipulate the limbs as part of routine care. As the horse’s condition improves, rehabilitation includes controlled exercise, periodically standing with a sling, and massage therapy. ^[18]

Slings

Slings are a central tool in the management of a recumbent horse as they can aid in all phases of recovery, including:

• Assessment of the condition: slinging a horse allows medical professional to examine the horse
• Prevention of complications: slinging can prevent the formation of pressure sores and respiratory issues linked with prolonged lying down. However, prolonged dependence on a sling can cause pressure sores as well. The treating veterinary team has to carefully balance the use of slings with periods of rest. Many cases of catastrophic limb injury in horses do not lend themselves well to recovery for this reason.
• Support during active phase of recovery: once horses are able to stand, but are still weak, slings are valuable tools in helping the patient recover mobility

Summary

Prolonged recumbency or the inability to rise is a severe symptom often caused by life-threatening conditions in horses.

• Horses that have been lying down for more than a few hours or those who are unable to rise require prompt veterinary intervention
• A wide range of medical conditions are associated with recumbency in horses, including poisoning, head trauma, infectious diseases, and limb injuries
• The prognosis for recumbent horses is variable; many of the associated conditions are very severe
• Supportive care and rehabilitation are cornerstones of recovery for downed horses