[A horse with grass sickness].

The article describes a case study where a three-year-old warm-blood gelding suffering from severe colic was found to have a condition known as Grass sickness, based on the symptoms, clinical examination, and subsequent histological study after euthanasia.

Case Presentation

• The study presents a case of a three-year-old warm-blood gelding that was found with severe colic symptoms early in the morning. The horse was fully wet, which may be indicative of profuse sweating, a known symptom of colic in horses. The horse was lying in the pasture, presumably due to discomfort or pain.

Clinical Examination

• On clinical examination at the veterinary clinic, several symptoms were observed including a high pulse rate of 92 per minute, a normal respiratory rate of 24 per minute, a packed cell volume (pcv) of 0.50 L.L.-1 which indicates the proportion of blood volume that is filled with red blood cells, body temperature was at 38.0 degrees Celsius, whereas no gastric reflux was observed. The ideal body temperature for a horse is around 37.2 to 38.3 degrees Celsius, indicating that the horse had normal body temperature.
• However, a rectal examination revealed a sticky rectal mucous membrane and colonic impaction along with displacement of the large colon – signs that are often associated with Grass sickness.

Diagnostic Laparotomy and Euthanasia

• A subsequent diagnostic laparotomy – a surgical procedure to examine the abdominal organs – confirmed the presence of an impaction as seen in Grass sickness, which is a serious disease of horses that affects the nerves of the intestine resulting in dysphagia and colic symptoms.
• Given the severity of the condition and the discomfort it was causing the horse, it was euthanized.

Post-Mortem Analysis

• Post-mortem, the coeliac ganglion – a part of the sympathetic nervous system that can be affected in Grass sickness – was removed and analyzed.
• The histological examination revealed the presence of dystrophy and chromatolysis, which are degenerative changes observed in the nervous tissues of horses with Grass sickness, confirming the diagnosis.