The coat is usually the giveaway
Cushing's disease in horses — pituitary pars intermedia dysfunction, or PPID — interferes with the hormones that run the seasonal coat cycle. The sign owners spot first is a coat that will not shed: while herdmates slick out in spring, the affected horse hangs on to a long, thick winter coat, which may grow wavy or even curly over the body and legs. Some horses shed partially or late, leaving a patchwork of long and short hair, and many sweat oddly — sweating in cool weather, or in patches — because the coat and the temperature control behind it are both out of step. A horse that suddenly needs clipping to stay comfortable through a mild summer, when she never did before, is showing you something worth investigating. Owners sometimes blame a failure to shed on age alone, but a normal aged horse still sheds — it is the change from that horse's own previous springs that matters.
Changes in shape, thirst and energy
As the condition progresses, muscle melts away from the topline while the belly drops, giving the strange combination of a bony, dipped back over a pot-bellied frame, often with fatty deposits above the eyes and along the crest. Many owners notice their horse drinking far more and flooding the bed with urine, eating normally yet looking less thrifty than the feed should explain. Sweating patterns shift as well — some horses sweat heavily in mild weather while others barely sweat at all — and both changes point the same way when the coat has stopped cycling normally. The personality often dulls: a bright horse becomes quiet, sleepy and slow to respond, and minor cuts, skin infections and hoof abscesses take noticeably longer to heal because the immune system is suppressed. None of these signs alone proves Cushing's — age, teeth and worms can mimic several of them — but the pattern together is characteristic.
The sign that demands prompt action
The most serious consequence of PPID is laminitis. The hormonal disruption drives up insulin, and insulin is hard on the laminae inside the hoof. An older horse that develops tender feet, a rocking-back stance, strong digital pulses or full laminitis without the usual trigger of rich grazing or a grain raid should be treated as a Cushing's suspect until a vet rules it out — and laminitis itself always warrants an urgent vet call. Repeated hoof abscesses through the year are another feet-first clue that the underlying hormone problem, not the trim, needs attention.
Confirming it and managing the seasons
Only testing confirms PPID: a vet takes blood to measure hormone levels, interpreting results with the season in mind because values shift naturally in autumn. Once identified, management is a partnership of medication prescribed by the vet, thoughtful clipping to keep the horse comfortable, dental and worming care kept scrupulously current, careful weight and grazing control, and regular hoof care with laminitis always in mind. Track it all — test results, medication notes, clipping dates, farrier findings — in KinsLe's Pet Passport, where the record builds season by season and any vet or farrier picking up the case can see the whole picture at a glance.