What is Diarrheal Disease?
Despite the fact that a cause is often not found, treatment is often very similar for all cases, with supportive, therapeutic management offered. Diarrhea in horses is usually a very easily noticed disease characterised by watery, frequent diarrhea that can quickly lead to massive fluid loss and dehydration. If your horse is suffering from this condition, it is vital a veterinarian is contacted to provide care.
Diarrheal disease in horses, or colitis (inflammation of the colon) is a very common disorder that affects thousands of horses every year. This disease can be caused by many different factors, these include infectious agents such as Salmonella serovars, poisonings and sand enterocolopathy. As there are many possible causes of this condition, diagnostics may be time consuming and a definitive cause is found in less than half of all cases.
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Symptoms of Diarrheal Disease in Horses
The most obvious symptom of diarrheal disorder in horses is excessive watery diarrhea. Other symptoms that you may observe are:
- Depression and reduced appetite
- Increased heart rate
- Dehydration – signs include increased skin tenting, sunken eyes, reduced perspiration
Another symptom that may be seen is red gums and a toxic line – a pink to purple discoloured line on the gums around the incisors. This is caused by endotoxemia, the build up of the toxin lipopolysaccharide (LPS) in the blood due to the breakdown of excessive levels of gram negative bacteria.
Causes of Diarrheal Disease in Horses
Diarrhea is seen when an excess of water is present in the manure, this can be caused by a range of conditions. This can cause a rapid loss of fluid, leading to dehydration, low blood pressure and reduced blood flow to vital organs which can result in shock. This condition is often caused by damage to the cell wall, this can be caused by:
- Chronic parasite infection
- Inflammation of the colon (colitis) – This is often caused by the disruption of the normal bacterial flora of the gut, caused by a range of factors, however is often due to rapid change in feed
- Bacterial colitis – This can be caused when an overgrowth of naturally occurring bacteria in the gut occurs, or following the introduction of a new bacteria and is often caused by bacteria of the Salmonella and Clostridial organisms; treatment with antimicrobial drugs is considered a risk factor for developing this condition
- Sand colic – This is caused by the accumulation of sand in the gut due to the accidental ingestion of sand while grazing in a sandy environment
- Right dorsal colitis – This may be caused by the prolonged use or inappropriate dosage of non-steroidal medication that causes disruption of mucosal protective mechanisms of the gut
Diagnosis of Diarrheal Disease in Horses
Your veterinarian will carefully examine your horse, performing a head to tail examination. During this time, they will carefully listen to the heart, lungs and gastrointestinal tract. While auscultating the gastrointestinal tract, they may hear hypermotile intestinal sounds, typical of this disorder. Your veterinarian will discuss your horse’s clinical history with you. Your veterinarian may also choose to perform the following diagnostic tests:
- Blood test for complete blood count to measure leukocytes in the blood, and serum chemistry for protein and electrolyte levels, and to check for acidosis
- Abdominocentesis – A sample of fluid is taken from the abdomen for analysis (this may involve your horse being sedated and local anaesthetic being given); the veterinarian will carefully clip and clean the site and make a small incision to enter a catheter through, this will then be entered into the abdomen and a sample taken
- Ultrasound and radiograph examination of the abdomen may also be considered, particularly if sand enteropathy is suspected; this allows the volume of sand to be determined and the need for surgical exploration assessed
- Fecal cultures may be performed on stool samples (because many types of bacteria, such as Salmonella, are intermittent shedders, five or more samples may be taken)
Treatment of Diarrheal Disease in Horses
The specific type of treatment will vary depending on the underlying cause of the disease (and if this can be determined). However often the following treatments are indicated
- Intravenous fluid therapy to correct fluid loss and support blood pressure
- Anti-inflammatories to reduce gut inflammation
- Electrolyte supplementation as indicated by serum chemistry results
If endotoxemia has occurred further, carefully monitored treatment may be required (intravenous therapy, medication, anti-endotoxin serum).
Recovery of Diarrheal Disease in Horses
The prognosis for your horse varies depending on the underlying cause of the condition, some horses may require very little supportive care, while others may require intensive care and hospitalisation. Further steps of supportive care you can offer your horse are
- Braiding your horse’s tail to reduce fluid on the hair
- Apply ointment to prevent or reduce scalding
- Gently clean your horse’s hindquarters with warm water
- Reduce stress
- Feed a good quality, constant diet of top quality hay or weed free pasture
- Prevent rapid change to the diet occurring
- Ensure your horse has access to clean drinking water and prevent access to contaminated waterways
- Remove your horse from sandy pastures