April 9, 2025—Researchers from the University of Minnesota (UMN) College of Veterinary Medicine (CVM) are conducting a pioneering research initiative aimed at advancing the understanding and treatment of Pituitary Pars Intermedia Dysfunction (PPID) in horses.

PPID, commonly known as equine Cushing’s disease, is the most prevalent endocrine disorder in aging horses. It affects up to 30% of horses over the age of 15. The disease leads to a range of clinical signs and serious health complications. These include abnormal hair coat shedding, muscle wasting, laminitis and increased susceptibility to infections.

Despite its prevalence, significant challenges exist in accurate diagnosis, especially early in the disease process. In addition, treatment is lifelong and not effective in all horses.

The study is led by Dr. Molly McCue and Dr. Lauren Hughes from the UMN Equine Genetics and Genomics Laboratory in collaboration with Dr. Dianne McFarlane from the University of Florida. It represents a critical step in understanding and managing this challenging disease. 

ISO a better understanding

The current standard treatment for PPID is a drug called pergolide. This drug can have variable efficacy, with less than 75% of cases fully responding. Additionally, pergolide can cause adverse effects that impact both quality of life and the outcomes of treatment.  Genetics may play a key role in disease progression and treatment response. This study aims to better understand these factors and optimize long-term management strategies for affected horses.

The key objective is to understand the genetic variants (mutations) that contribute to the effectiveness and adverse effects of pergolide in managing PPID signs. The long-term goal is enhancing treatment protocols to improve the quality of life for horses affected by PPID.

“As a veterinarian I understand just how devastating PPID can be for horses and the owners that love them,” said Hughes in the UMN CVM news release. “I am very excited about the potential outcomes of this study and improving our understanding of how genetics impact pergolide response. Our research team is dedicated to learning more about this very important equine disease with the goal of improving the way we screen, diagnose, treat and manage these horses.” 

How you can participate

Horse owners and veterinarians are invited to enroll equine participants in this important study. By enrolling your horse, you play a crucial role in shaping the future of PPID treatment. You can help researchers unlock new insights into this prevalent disease and improve the lives of horses worldwide.

To enroll, horses must meet the following criteria:

• Over the age of 15 at the time of PPID diagnosis
• Diagnosis made by veterinarian and diagnosis included bloodwork (ACTH levels)
• Horse has/had clinical signs consistent with PPID (long shaggy haircoat, muscle atrophy, changes in mentation or recurrent infections)
• Horse has been on pergolide therapy for a minimum of 6 months and has had rechecked blood values (ACTH, TRH stim or dexamethasone suppression)

Study participation requires the following:

1. Taking an enrollment survey (15-30 minutes);
2. Submitting a hair or blood sample by mail (detailed instructions provided); and
3. Sharing pertinent medical records and photos via email.

To learn more about the study or to enroll, please visit the UMN College of Veterinary Medicine website or watch this video.

About UMN Equine Genetics and Genomics Laboratory

The University of Minnesota Equine Genetics and Genomics Laboratory is at the forefront of equine health research. It is dedicated to advancing veterinary medicine through innovative genetic studies and clinical trials.