COLIC IN HORSES
Sonam Sarita Bal, Geeta Devi Leishangthem and Nittin Dev Singh
Department of veterinary Pathology, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab
Corresponding author- Sonam Sarita Bal, E-mail- sonamsarita1996@gmail.com
Abstract
Colic is one of the most common problems in equine practice, significantly impacting the racehorse industry and causing major concern for horse owners. Colic refers to acute abdominal pain of digestive origin. Risk factors for colic include both extrinsic (feeding, housing, management) and intrinsic factors (age, breed, sex). Early identification and referral of horses are crucial for a successful outcome. Initial colic evaluation should include physical, rectal, and nasogastric examinations, with advanced diagnostics like ultrasound and abdominocentesis guiding further intervention decisions.
Colic is one of the most common problems in equine practice, significantly impacting the racehorse industry and causing major concern for horse owners. Colic refers to acute abdominal pain of digestive origin and is the most frequent emergency in equine medicine, affecting about 4 out of every 100 horses annually. Approximately 7% to 10% of these cases require surgical intervention. Colic-related lesions are categorized anatomically and functionally as obstruction, strangulation, non-strangulating infarction, enteritis, peritonitis, ulceration, or ileus. The decision to manage colic medically or surgically depends on five main factors: severity of pain, cardiovascular and systemic status, transrectal palpation findings, presence of nasogastric reflux, and results of abdominocentesis. Most gastrointestinal colic cases can be managed medically, with only a small percentage requiring surgery.
Types/causes
The major types and causes of colic include large colon impaction, large colon displacement, and spasmodic colic, followed by large colon volvulus, strangulating small intestine lesions, enteritis, and verminous peritonitis.
RISK FACTORS
- Extrinsic factors
- Feeding
Recent changes in the batch of hay, grain, or concentrate feed, feeding more than 2.5 kg of concentrate per day, decrease pasture exposure or changes in feeding schedules throughout the year can all contribute to colic. The arrival of concentrate in the colon decreases luminal pH and alters intestinal flora, favouring endotoxin production, causing colic. Feeding whole grains (except corn) reduces the risk of colic. Irregular watering also increases colic risk.
- Internal Parasitism
Intestinal parasites, particularly tapeworms and strongyles (Strongylus vulgaris), can trigger colic through obstructive, traumatic, irritating actions. Strongyle larvae disrupt small intestine motility and migrate in blood vessels, causing thromboembolic disorders.
- Deworming Treatments
Horses that do not receive regular deworming treatments have an increased risk of colic.
- Management
Horses kept on pastures year-round are less prone to develop colic than those living indoors, as confinement can cause stress and boredom, increasing the risk of chronic colic. Intense activity (training, competition) or stress can also raise the risk of colic. More colic cases occur during hot months.
- Intrinsic Factors
- Breed, Sex, and Age
Arabian and Thoroughbred horses are at higher risk for colic. Colic is more common in geldings than in mares and stallions. The risk increases for horses older than 10 years.
- Medical History
Horses with a previous history of colic are more likely to develop it again, especially if they have undergone abdominal surgery.
Diagnosis and treatment
Early identification and referral of horses are crucial for a successful outcome, minimizing postoperative complications and costs. Most large colon obstructions can be managed medically i.e. with oral or intravenous fluids, mineral oils, analgesic etc and thorough initial assessments by veterinarians ensure appropriate treatment. A complete history, a full physical examination that includes nasogastric intubation and transrectal palpation, and the execution of the necessary diagnostic tests and procedures are all included in this study.
- Complete History: Pain assessment and general appearance:
General appearance assessment should include pain evaluation, abdominal distension, stance, and body condition scoring. Severe pain or a “shocky” appearance post-colic can indicate a strangulating obstruction or intestinal rupture. Degree of abdominal distention and the need for multiple analgesic treatments are indicators for surgical intervention. Temperature:
Obtaining body temperature in a horse with colic helps diagnose the cause, except in severe cases needing immediate surgery. Febrile horses often have inflammatory or infectious conditions, so surgical intervention should be approached cautiously, with further diagnostics recommended.
- Gastrointestinal Motility:
Horses with progressive intestinal motility typically do not need surgery. Colic is often associated with increased gastrointestinal motility. Decreased or absent intestinal sounds usually indicate mechanical obstruction or systemic inflammatory response and may require surgery.
- Rectal Palpation:
Serial rectal palpation helps assess disease progression and determine the need for surgical intervention in colicky horses.
- Presence of Gastric Reflux:
Passing a nasogastric tube is critical in colic examinations, especially for horses in severe pain. A distended stomach that prevents tube passage indicates a serious condition. High gastric reflux volumes (>4 L) suggest severe disease, warranting referral, while pH (>5) and color indicate potential small intestinal or enteritic origins of fluid accumulation.
- Abdominocentesis:
Peritoneal fluid composition reflects abdominal pathology and can be sampled using a spinal needle, bitch catheter, or teat cannula for rapid evaluation. Total protein concentration typically should be below 2.5 g/dL in healthy horses. Elevated levels suggest increased visceral permeability, indicating potential medical (peritonitis) or surgical conditions affecting the abdomen. Total nucleated cell count in abdominal fluid typically remains low (under 5000 cells/mL). Cloudiness indicates potential elevation in cell count. Differential counts are more diagnostic, revealing band neutrophils or toxic changes indicative of peritonitis, aiding in distinguishing medical from surgical colic cases. High blood lactate (>1.5 mmol/L) indicates poor prognosis in colic cases, often elevated due to physical exertion. Hyperglycemia is prevalent in colic horses, linked to poor outcomes caused due to action of endotoxins causing dysregulation of blood glucose.
- Imaging and additional testing:
Additional diagnostic tests, including transabdominal ultrasound, aid in determining if referral is necessary in colic cases. Ultrasonography, using a 3 to 5 mHz curvilinear probe, is pivotal for detecting gastrointestinal issues.
Conclusion
Many factors contribute to colic risk in horses, with intrinsic and weather-related factors being beyond human control but warranting attention. Feeding practices, parasitism, and management are controllable factors that significantly influence colic risk and require further study to fully understand their impact. Initial evaluation of colic cases should include thorough physical examination, rectal examination, and nasogastric tube passage to assess gastric distention. Advanced diagnostics like ultrasound and abdominocentesis can guide decisions on referral for further monitoring and potential medical or surgical intervention.
