Ileocolonic aganglionosis in white progeny of overo spotted horses.

This research investigates the occurrence of a congenital condition which prevents normal bowel function in newborn white foals born to overo spotted parents. The condition affects both male and female foals, resulting in their inability to defecate and leading to signs of extreme discomfort or distress within the first day after birth, ultimately resulting in death within the first week of life.

Background

• This study focuses on the congenital absence of myenteric ganglia, a condition known as aganglionosis, in the terminal portion of the ileum, cecum, and entire colon of white foals.
• The myenteric ganglia are an essential part of the nervous system of the gastrointestinal tract, playing a vital role in the regulation of bowel movements. Their absence results in the bowel not functioning properly, causing severe health complications.

Identification of the Condition

• The condition was identified in white foals born to overo spotted parents, a particular breed of horses.
• Both male and female foals were affected, highlighting that the condition is not gender-specific.
• It is notable that the foals were generally normal at birth but were unable to defecate, a key indicator of this condition.

Symptoms and Timeline

• Signs of colic, or severe abdominal pain, were noticed between 5 and 24 hours after birth. The onset of this symptom is likely due to the accumulating waste in the bowel that the foal is unable to pass.
• The condition quickly became fatal, with death occurring at 23 to 132 hours. This swift progression underscores the severity of aganglionosis and the importance of immediate intervention if it is to be treated effectively.