Infectious diarrhea in foals is a significant health concern that can lead to dehydration, weight loss, and systemic illness. Without timely intervention, it can lead to severe complications and even be life-threatening.

Diarrhea in foals can be caused by a variety of pathogens including bacteria, viruses, and parasites. Signs of infectious diarrhea include watery feces, decreased appetite, lethargy and weakness.

Foals are particularly susceptible to infectious diarrhea because their immune system is not fully developed. Their gut microbiome, which plays a crucial role in fighting infections, is also not yet well-established.

Treatment must be administered promptly and may consist of fluid therapy, electrolyte supplementation and antibiotic medications. Through a combination of good management practices, vigilant observation, and prompt veterinary care, the risks associated with infectious diarrhea in foals can be significantly reduced.

Infectious Diarrhea in Foals

Diarrhea refers to an increased volume or fluidity of the feces, resulting in the passage of frequent, watery stool. Diarrhea is a common condition in foals, with one study reporting a prevalence of 48% in foals from birth up to the age of two months. [2]

Unfortunately, diarrhea frequently results in death of affected foals, particularly those under 7 days of age. [1] Early recognition of the signs of diarrhea by breeders is crucial to allow rapid medical intervention and reduce the risk of mortality. [1]

Treatment is primarily supportive in nature, and focuses on maintaining hydration, nutritional support, and protecting the gastrointestinal lining. Specific medications that target the cause of the diarrhea are added to these support measures to complete the treatment plan.

The most common causes of infectious foal diarrhea are: [1]

  • Salmonella
  • Clostridium
  • Rotavirus
  • Cryptosporidium
  • Strongyloides

For all of these infections, early identification and treatment are essential for a good prognosis for the foal.

Risk Factors

Several studies have identified common environmental and management factors that contribute to a heightened risk of diarrhea in foals. Common risk factors include: [1][2][12]

  • Mares that are not vaccinated against rotavirus prior to foaling
  • Administering antibiotics to the foal
  • Foaling in a stall
  • Not receiving adequate colostrum (failure of passive transfer)
  • Inadequate deworming of the mares prior to foaling
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Symptoms of Infectious Diarrhea

The symptoms of foal diarrhea are typically related to severe dehydration. In addition to diarrhea, foals may exhibit signs such as: [1][2]

  • Colic
  • Distention of the abdomen
  • Sunken in eyes
  • Prolonged skin tent
  • Lethargy
  • Weakness
  • Grinding teeth
  • Fever or hypothermia

Systemic Inflammatory Response Syndrome

Some foals develop systemic inflammatory response syndrome (SIRS), in which the infection triggers an inflammatory response spread widely throughout the body. Symptoms of SIRS include: [2]

  • Red gums
  • Rapid heart rate
  • Rapid breathing