What abnormal condition may cause a horse to display hirsutism or abnormal shedding patterns?

Hirsutism and abnormal shedding patterns in horses can be indicative of Cushing's Syndrome, also known as Pituitary Pars Intermedia Dysfunction (PPID). This condition affects the horse's endocrine system, leading to an overproduction of hormones, particularly adrenocorticotropic hormone (ACTH). The excessive levels of this hormone can result in a variety of symptoms, including the characteristic long, curly coat that does not shed properly.

In a healthy horse, the shedding process is regulated and coordinated with seasonal changes, thanks to the action of hormones that respond to light and temperature. However, in horses with Cushing's Syndrome, the hormonal imbalance disrupts this natural cycle, leading to the abnormal coat that may remain in a winter-like state even during warmer months. This condition is often observed in older horses and requires veterinary diagnosis and management for appropriate treatment.

Other options such as Equine Influenza, Laminitis, and Heaves primarily affect other systems or present different symptoms. For instance, Equine Influenza is a viral infection that leads to respiratory issues, while Laminitis is a painful condition affecting the hooves. Heaves, a chronic respiratory condition, results in difficulty breathing but does not directly affect the horse's coat or shedding pattern. Thus