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Colic, defined as abdominal pain in horses, is a condition that ranges from mild discomfort to severe, life-threatening situations. In foals, colic presents unique challenges and concerns, due to their physiology and development.
Colic in foals can be challenging to diagnose, as there are numerous potential causes that a veterinarian must assess. Veterinarians use a combination of physical examination, X-rays, ultrasound, and other diagnostic tests to identify the cause of colic, and to determine the possible treatment options.
Many causes of colic in foals have a good prognosis with early recognition and treatment. This article aims to provide a comprehensive overview of colic in foals, covering its causes, symptoms, diagnosis, treatment, and prevention strategies.
Colic in Foals
Colic is a complex and potentially serious condition characterized by abdominal pain and discomfort. It is not a disease in itself but rather a symptom or clinical sign of an underlying issue in the horse’s abdomen, usually involving the gastrointestinal system.
Colic in foals presents slightly different than in adults. Foals are less likely to show traditional symptoms such as kicking or biting at the abdomen, rolling excessively, or the Flehmen response.
The main symptoms of colic in foals include: [1][2]
- Drooling and/or teeth grinding
- Laying on their back for long periods, particularly after nursing
- Dog-sitting
- Lack of interest in nursing
- Diarrhea
- Reduced appetite
- A distended abdomen
- Straining or difficulty defecating
- Elevated heart rate and respiratory rate
Causes of Colic in Foals
The causes of colic in foals can be multifaceted and sometimes differ from those in adult horses. Common causes include:
- Digestive Tract Obstructions: These can be due to meconium impaction in newborns or other blockages in older foals.
- Gastrointestinal Malformations: Congenital issues like atresia ani or intestinal torsions can lead to colic symptoms.
- Infections: Gastrointestinal infections, such as clostridial enterocolitis or viral infections, can cause colic.
- Ulcers: Gastric ulcers are relatively common in foals and can lead to colic.
- Parasitic Infestations: As foals age, they become more exposed to parasites, which can cause gastrointestinal distress. Strongyloides larvae can be passed in the dam’s milk.
- Dietary Issues: Improper feeding practices, including overfeeding, can disrupt a foal’s delicate digestive system.
The management of colic varies based on the underlying cause and the severity of the condition. In the following sections, we will delve deeper into some of the common causes of colic, and discuss risk factors, diagnosis and treatment.
Meconium Impaction
Meconium impaction is a frequent cause of colic in newborn foals, most commonly occurring in foals between 1 and 2 days old. [1][3] Meconium is the first feces of the foal, and consists primarily of intestinal secretions and cellular debris that accumulate while the foal is in utero. [1]
Normally, meconium passes within the first few hours after birth, and is black or dark green in colour, with a firm consistency. [1][2] If the foal does not pass the meconium normally, it can block the intestinal tract and prevent the flow of contents.
The accumulation of intestinal contents results in severe abdominal distention and pain for the foal. Some foals may posture as if they are urinating, as they strain to pass their meconium. [1]
Risk Factors
Male foals have a higher risk of meconium impaction compared to females. [2] The exact reason for this is unknown, but it may be related to the smaller pelvic size in males. [2]
Other risk factors for impaction colic in foals include: [4]
- Delayed colostrum intake
- Dystocia
- Prolonged gestation
- Prematurity
- Dehydration
Diagnosis
Diagnosis of meconium impaction involves digital examination of the rectum. In this procedure the veterinarian gently inserts a gloved finger into the foal’s rectum to palpate for any hard masses of meconium.
If the meconium is not palpable, the veterinarian may need ultrasound or X-rays of the abdomen to identify the meconium mass.
Treatment
Treatment typically involves an enema of mild soap and water, to loosen the meconium and allow it to pass freely. [1] Commercially available enemas for humans are not recommended as they can result in phosphate toxicity in foals if used multiple times. [1]
If the foal does not respond to multiple enemas, more advanced treatment such as acetylcysteine enemas or surgical intervention may be necessary. [1][4][5]
Treating foals with enemas can be risky, as aggressive or repeated enema administration can cause irritation or injury to the rectum. [2] In severe cases, the rectum may rupture, releasing intestinal contents into the abdomen. [2]
If multiple enemas have not successfully resolved the impaction, a veterinarian must be consulted before proceeding with further enema treatment. [2]
Some foals may require analgesics such as flunixin meglumine (banamine) to reduce pain and prevent self-trauma. [2]
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Gastric Ulcers
Similar to older horses, gastric ulcers are very common in foals, particularly those experiencing stress or other illnesses. [1] Gastric ulcers most commonly affect nursing and recently weaned foals. [1]
Signs of gastric ulcers in foals include colic symptoms, loss of appetite, teeth grinding and excess saliva production. [1]
In adult horses, gastric ulcers are most commonly caused by irritation of the stomach lining due to excessive contact with stomach acid. [1] Foals, however, often have low or variable gastric acid production.
The presumed cause of gastric ulcers in foals is disruption of the protective mechanisms in the stomach, such as the mucus layer that coats the stomach lining and acts as a barrier against gastric acid. [1][2][5]
Risk Factors
The main risk factors for developing gastric ulcers in foals are illness and stress. Common causes include: [1]
- Critical illness affecting acid production and gastric motility
- Hospitalization
- Non-steroidal anti-inflammatory treatment
- Transport
- Early weaning
- Orphaned foals
Consequences of Gastric Ulcers
Gastric ulcers can have serious consequences for the long-term health of the foal. Untreated gastric ulcers can result in gastric rupture, where the stomach lining becomes so compromised that it eventually tears and releases stomach contents into the abdomen. [1]
Symptoms of gastric rupture include: [1]
- Rapid heart rate
- Rapid breathing
- Weak pulses
- Death within a few hours
Even when treated, severe gastric ulcers can form scar tissue, which may impair the flow of stomach contents. [1] The most common locations for scar tissue to form are as follows: [1]
- Pylorus – the valve between the stomach and small intestine
- Duodenum – the first section of the intestine
Diagnosis
Diagnosis of gastric ulcers typically involves endoscopy, where the veterinarian passes a camera through the foal’s nose into their stomach to examine the stomach lining. [1][2] This technique can also identify any scar tissue that has formed. [1]
If scar tissue is suspected, the veterinarian may use contrast X-rays to see how quickly the foal’s stomach empties. [2] In this technique, the veterinarian administers barium, a liquid that shows up on X-rays, into the foal’s stomach.
Repeated X-rays are taken to see how long it takes for the barium to leave the stomach and enter the intestine. [2]
Treatment
Treatment of gastric ulcers primarily focuses on reducing stomach acid production and improving the protective mucus barrier. Treatments include: [1][2][5]
- Sucralfate, which coats the stomach lining
- Omeprazole, which reduces stomach acid production
If scar tissue forms, treatment typically requires surgical intervention to remove the scar tissue and allow gastric contents to flow normally. [1][6][7] In mild cases, treatment may include: [1]
- Metoclopramide, to increase the rate of stomach emptying
- Supportive care, such as intravenous fluids and nutrition
Hernias
Hernias are outpouchings or holes within the wall of the abdominal cavity that may entrap the intestines. Hernias are common in foals, with some studies reporting up to 2% of foals having the condition. [1]
Most foals are either born with a hernia, or develop the hernia within several days after birth. [7] The most common locations for hernias are: [1][8]
- The scrotum (in male foals)
- The umbilical area
- The diaphragm, allowing intestines to enter the chest cavity
Most hernias do not cause colic. Colic develops if a portion of the entrapped intestine twists, cutting off blood supply and preventing flow of intestinal contents. [1]
Risk Factors
Some breeds are predisposed to developing different types of hernias: [8]
- Scrotal hernias: Standardbreds, Tennessee Walking Horses
- Umbilical hernias: Quarter Horses, Thoroughbreds
For diaphragmatic hernias, the main risk factor is dystocia. [8] During a difficult delivery, foals may fracture their ribs, causing tears in the diaphragm that allow the intestines to enter the chest cavity. [8]
Diagnosis
Scrotal and umbilical hernias are easily identifiable, as they produce large swellings of the scrotum and umbilical area respectively. [1] The veterinarian may ultrasound the swelling to determine if intestines are present within the hernia, and if the intestines are compromised. [1][8]
For diaphragmatic hernias, either X-rays or ultrasound can identify loops of intestine within the chest cavity, confirming a diagnosis. [7][8]
Treatment
Treatment of hernias depends on the size of the hernia and whether the intestines are involved. Surgical repair of the defect in the abdominal wall is the most common treatment, particularly in cases where the foal develops colic symptoms. [1][8]
In cases of scrotal hernias, the veterinarian often castrates the foal at the same time. [8]
Small Intestinal Accidents
Small intestinal accidents are a common cause of colic in foals. [3] These conditions occur when a portion of the small intestine shifts into an irregular position, preventing the intestinal contents from flowing properly.
Usually, there is also a blockage of blood flow to the intestine, which can rapidly cause death of the intestinal tissue. [2]
Intestinal Volvulus
Volvulus is one of the most common reasons for abdominal surgery in foals. [2][8] In this condition, the small intestine twists upon itself, preventing both blood flow and flow of intestinal contents. [2]
Left untreated, volvulus rapidly leads to death of the intestinal tissue and may release intestinal contents into the abdomen. [2]
Intussusception
Intussusception refers to the intestine telescoping in on itself, resulting in sharp turns of the intestinal wall as it forms multiple telescoped layers. These sharp turns compress blood vessels supplying the tissue, resulting in tissue death. [2]
Intussusceptions can occur anywhere along the intestinal tract, but are most common at the junction between the ileum and cecum. [7]
Diagnosis
Diagnosis of intestinal accidents typically involves ultrasound of the abdomen, to identify the affected segment of intestine. [6] Some veterinarians may also use X-rays. [2]
Treatment
The only treatment available for intestinal accidents is abdominal surgery. If tissue death has occurred, the surgeon removes the entire affected portion of intestine and reconnects the two healthy ends. [2] Most foals recover completely from these surgeries. [1]
Intestinal Atresia
Atresia is a rare condition in horses that refers to the failure of a normal body orifice to completely open. [2] In the case of foals, atresia of the colon (atresia coli) and the anus (atresia ani) are the most common forms of atresia. [1]
The cause of atresia is unknown, but is thought to be related to collapse of the vessels supplying the affected area of intestine during fetal development. [1]
Since the intestinal tract is not completely open, fecal material cannot pass through the intestine and begins to accumulate. Most foals with atresia appear normal at birth, then develop progressive colic within 1 – 2 days. Affected foals fail to pass meconium or any fecal material. [1]
Diagnosis
Diagnosing atresia can be difficult, particularly in the case of atresia coli. Physical examination and digital palpation of the anus can identify atresia ani. [1] For atresia coli, colonoscopy, X-rays, or exploratory surgery may be needed for diagnosis. [1][5]
Treatment
Unfortunately, there is no realistic treatment available for atresia coli. Even in foals that underwent abdominal surgery, surgical repair to open the intestinal tract is usually unsuccessful. [1] There are only rare reports of successful treatment. [9][10]
Atresia ani may be treatable, depending on the severity. In cases where foals have a normal anal sphincter and only a thin layer of tissue is blocking the anal opening, surgical correction can be successful. [1][7]
Lethal White Foal Syndrome
Lethal white foal syndrome (LWFS) is a genetic condition that can occur when two parents carrying the gene for overo patterning produce a foal. [1][2] When foals carry two copies of the overo gene, the portion of the nervous system activating the intestinal tract fails to develop. [1][8]
Foals with LWFS are born almost entirely white. Since there is no nervous system to activate the intestinal tract, foals fail to pass feces and their intestinal contents begin to accumulate. [1] Colic symptoms typically develop within 24 hours of birth. [1]
Diagnosis and Treatment
A completely white foal that does not produce feces and is born to two parents carrying the overo gene is typically sufficient evidence to diagnose LWFS. If necessary, X-rays or ultrasound can identify the foal’s dilated and static intestinal tract, confirming the diagnosis. [1]
There is no treatment for LWFS, and most foals are euthanized. [1]
Uroperitoneum
Uroperitoneum refers to urine entering the abdomen, also called the peritoneal cavity. This condition typically results from rupture of part of the urinary tract, such as the urethra or bladder. [1] Most affected foals are between 1 and 6 days of age. [6][8]
Sick foals are particularly prone to uroperitoneum, as they may not urinate on their own. The accumulation of urine ultimately results in rupture of the bladder. [1]
Foals initially show symptoms such as straining to urinate and abdominal distention, progressing to symptoms of colic and severe lethargy. [1]
Uroperitoneum may also occur following a ruptured urachus. [1] The urachus is a tube that runs alongside the umbilical vessels and connects the foal’s bladder to the placenta. When the umbilical cord ruptures at birth, the urachus normally seals itself off and retracts into the abdomen. If the urachus does not seal properly, it can become distended and rupture, releasing urine into the abdominal cavity. [1]
Diagnosis
Ultrasound can quickly identify free fluid within the abdomen, which can be sampled by the veterinarian to confirm the presence of urine. [1][8] In some cases, ultrasound may show the ruptured area of the urinary tract, further confirming the diagnosis. [1]
Bloodwork can further support the diagnosis by showing electrolyte imbalances characteristic of uroperitoneum. [1][6]
Treatment
Treatment of uroperitoneum requires surgical intervention to repair the ruptured area. [1] Before surgery, foals may require intravenous fluids and electrolytes to stabilize them before they undergo anesthesia. [1][8]
Frequently Asked Questions
Here are some frequently asked questions about colic in foals:
The difference between colic and a generic tummy ache comes down to definition and stakes in foals. Colic labels abdominal pain as a clinical sign of an underlying problem in the abdomen, ranging from mild discomfort to life-threatening disease that calls for veterinary assessment with exam and imaging. A casual belly ache suggests brief, self-limiting unease, yet in foals even subtle signs such as drooling, teeth grinding, lying on the back after nursing, dog-sitting, or a distended belly deserve treatment as potential colic until a veterinarian rules out serious causes.
Meconium impaction in a newborn foal sits in the first-day causes of belly pain seen soon after birth. The condition means the first black to dark green, firm feces fails to pass, blocking the intestine and causing abdominal distention, straining, and discomfort. Diagnosis uses rectal exam with ultrasound or X-rays if needed, and treatment starts with mild soap-and-water enemas, with acetylcysteine enemas or surgery reserved for cases that do not respond.
Gastric ulcers are a concern for foals because the lesions are common in nursing and recently weaned youngsters, especially with illness or stress. Signs include colic, loss of appetite, teeth grinding, and excess saliva, and severe disease can progress to rupture or scarring at the pylorus or duodenum that impedes emptying. Care focuses on protecting the lining and reducing acid with sucralfate and omeprazole, with surgery or prokinetics considered only if scarring or delayed emptying develops.
The outlook for colic in foals ranges from good to guarded, depending on the specific cause and how quickly care begins. Many problems resolve well with prompt diagnosis and treatment, and even small intestinal accidents can end in full recovery after surgery. Certain congenital issues carry poor prospects, including intestinal atresia that rarely responds to surgery and lethal white foal syndrome that lacks effective treatment.
Summary
- There are many possible causes of colic in foals, requiring thorough veterinary examination to make a diagnosis
- Common causes of colic in foals include meconium impaction, intestinal accidents, hernias, gastric ulcers, and others
- Prompt diagnosis and treatment provides the best chance for a successful outcome
References
- Slovis, N. and Irvin, L., Neonates and Periparturient Mares. Veterinary Clinics of North America: Equine Practice. 2023. View Summary
- McKinnon, A. O. et al., Equine Reproduction. Wiley-Blackwell, 2010.
- MacKinnon, M. C. et al., Colic in Equine Neonates: 137 Cases (2000–2010). Journal of the American Veterinary Medical Association. 2013.
- McCue, P., Meconium Impaction in Newborn Foals. Journal of Equine Veterinary Science. 2006.
- Reed, S. M. et al., Equine internal medicine, 3rd ed. Saunders Elsevier, 2010.
- Bernard, W., Colic in the Foal. Equine Veterinary Education. 2004.
- Orsini, J. A., Abdominal Surgery in Foals. Veterinary Clinics of North America: Equine Practice. 1997. View Summary
- Bartmann, C. P. et al., Diagnosis and Surgical Management of Colic in the Foal: Literature Review and a Retrospective Study. Clinical Techniques in Equine Practice. 2002.
- Dart, A. J., Intestinal Atresia in Foals: A Diagnostic and Treatment Challenge. Equine Veterinary Education. 2021.
- Young, R. L. et al., Atresia Coli in the Foal: A Review of Six Cases. Equine Veterinary Journal. 1992. View Summary
