Q: My horse seems slow to shed his winter coat this year. Why might that be?

A: A horse shedding more slowly than usual can have a few different causes – some completely benign, others worth checking out:

Seasons and environment

• Shedding is driven by daylight hours (photoperiod), not temperature, so even if it is warm your horse may not shed immediately.
• If your horse has been stabled with lights on late into the evening, or rugged heavily, his body may be getting ‘mixed signals.’
• Some horses are naturally later shedders.

Age

• Older horses often shed more slowly.
• Senior horses, especially those over 18–20 years, may develop a noticeably long or patchy coat change.

Cushing’s/PPID (Pituitary Pars Intermedia Dysfunction)

• This is a very common cause of delayed or incomplete shedding in older horses.
• Horses may keep a long, curly winter coat well into summer.
• Other signs include muscle loss along the topline, increased thirst/urination, lethargy, recurrent laminitis, or infections.
• If your horse is middle-aged or older, it is worth discussing a blood test for PPID with your vet.

Nutrition and health

• Poor coat change can also be linked to:
  • Low protein or certain vitamins/minerals (esp. copper, zinc, selenium).
  • Illness or stress (e.g., after colic, infection, or weight loss).
  • Parasites – heavy burdens can affect coat quality.

What to do

• Consider age and history: If your horse is older, consider a PPID test.
• Evaluate diet: Ensure balanced vitamins/minerals and enough high-quality protein.
• Review environment: Natural daylight exposure helps regulate shedding.
• Vet check: If shedding seems unusually delayed, or the coat looks curly, thick, or abnormal, book a veterinary exam.

Bottom line

A slow shed can sometimes just be an individual quirk or environmental influence, but in older horses, it’s often an early red flag for PPID. A simple blood test can provide peace of mind.