The Grass Really Is Greener in September. The Trap Nobody Warns You About

No grass, or hardly any. No grain. The same hay you’ve fed for months. And still, one morning, that careful, reluctant walk that every pony owner dreads.

If that’s you right now, the first thing to say is this: laminitis in September is not proof you failed your horse. It usually means one of two hidden things is at work. One lives in the grass. The other lives in your horse’s own hormones. By the end of this article you’ll know how to tell them apart, and what to do about each.

Early signs of autumn laminitis in horses

• He’s suddenly walking short or shifting his weight, and nothing in his routine changed.
• Your pony had laminitis before, and you’re bracing for it to come back.
• He’s off grass, on soaked hay, on almost nothing, and it happened anyway.
• He’s getting older, sheds late, and this is his first episode.

None of these mean you did something wrong. They mean it’s time to look past the paddock gate.

The grass isn’t done with you yet

Most owners assume that once summer ends, pasture stops being a risk. Fair assumption. Grass looks less lush, growth has slowed, so surely the sugar content has dropped too.

Here’s the plot twist: early autumn can be as risky as April. Grass makes sugar in daylight and burns most of it overnight as it grows. On a cold night, that overnight burn stalls. The sugar sits in the leaf by morning, banked instead of spent. String together autumn’s pattern of bright days and near-frosty nights, and a sad-looking September paddock can quietly carry a spring-sized sugar load. Under the right conditions, sugars and storage carbohydrates can climb to a startling share of what grass contains, up to 40 percent of its dry weight (Longland & Byrd, 2006). Forage is already the biggest source of sugar in most horses’ diets by far (Williams, 2025).

And richer forage shows up in the horse. A recent study of traditionally kept horses found that animals grazing carbohydrate-heavier forage had higher insulin, the hormone that manages blood sugar, along with more body fat and crestier necks (Daradics et al., 2025). For a pony that has had laminitis before, that autumn regrowth is the relapse nobody sees coming.

“But he wasn’t even on grass”

Maybe you’ve said this sentence yourself, out loud, to a vet or a farrier who didn’t have an answer. Your pony was on a bare paddock. He got a carrot now and then, nothing more. And he still got footsore.

You’ve probably also heard the standard advice by now, which is some version of “less grass.” Helpful, until you’re staring at your pony on sand wondering what’s left to take away.

Here’s what’s left: two suspects, and you can check both. The first is your hay. Hay is dried grass, and it keeps whatever sugar the grass held on cutting day. A first cut from young spring growth can be too rich for your pony even though it looks and smells like every other bale you’ve ever fed. You cannot see sugar. You can test for it, though. A forage analysis costs less than a single vet visit, and while you wait for the result, soaking the hay for several hours draws part of the sugar out.

The second suspect is your horse’s own hormone system. Which brings us to the number that should take a weight off your shoulders.

The hormone problem behind nine in ten cases

When researchers reviewed horses arriving at an equine hospital with laminitis, up to 89 percent turned out to have an underlying hormonal condition (Karikoski et al., 2011). Not careless owners. Hormones.

Two conditions dominate. The first is equine metabolic syndrome, usually shortened to EMS: the horse’s body stops responding properly to insulin, so sugar that would pass through another horse unremarked sets off trouble in his feet. These are often the “easy keepers,” the ponies and native breeds that live on air. The pattern is measurable years in advance. In a study that followed 446 ponies over three years, the ones that went on to develop laminitis already had higher insulin long before the first episode (Menzies-Gow et al., 2017). An honest body condition score is often the first place that pattern becomes visible at home.

The second is PPID, short for pituitary pars intermedia dysfunction, and better known by its old name, Cushing’s disease. A small gland at the base of the brain gradually loses its brakes and overproduces hormones, and one of the results is a much higher risk of laminitis. It’s usually a condition of older horses, but “older” starts earlier than most people think, and a late-shedding coat or a first laminitis episode in the teens is a classic opening scene.

Here’s the part that matters this month: September and October are the best time of year to test for PPID. Vets measure a messenger hormone called ACTH in the blood. It rises in autumn in every horse, healthy or not, but in horses with PPID it rises dramatically more, so the gap between normal and abnormal is at its widest right now (Copas & Durham, 2012). One caveat, and it’s the difference between clarity and an expensive misunderstanding: the “normal” range shifts with the season. In the UK study that mapped this, a healthy reading could be nearly twice as high in autumn as in spring. A number that would look alarming in March can be fine in September, so make sure the result is read against autumn values before anyone reaches for a diagnosis, or for lifelong medication.

Autumn laminitis, decoded

• Sore feet after a sunny week with cold nights, on pasture? Autumn grass sugar is the likely trigger. Off the grass now, not after the vet visit.
• Sore feet with no grass access at all? The trigger is hiding elsewhere. Get the hay tested, and ask your vet about insulin while they’re there.
• First episode in an older horse, or a coat that hung on too long last spring? Ask about a PPID test during the same visit. This season is the best window, as long as autumn reference values are used.
• Been through this before and it’s back? Don’t treat it as a repeat of last time. A relapse on careful management is exactly the case that deserves the hormone workup.

Two different horses, two different plans

If your horse is the easy-keeper type, the pony or cob that gains weight on fresh air and has had a footsore episode before, this is a sugar-and-insulin story. Management does the heavy lifting: limit access to regrowing pasture during warm-day-cold-night spells, know what’s in your hay, keep him moving. Steady & Stable is built for exactly this metabolic pattern, supporting normal sugar and fat metabolism and contributing to the maintenance of a healthy body weight, so autumn’s hidden sugar has less room to cause mischief.

One more thing about the strict diet itself, because it has a hidden cost. A pony on soaked hay and a bare paddock is on the safest diet for his feet and the poorest diet for everything else. Soaking draws out sugar, which is the point, but hay was already losing vitamins from the day it was cut, and a ration this plain rarely covers the minerals and protein a horse needs to keep muscle, hooves, and coat in repair. Which raises a question worth asking: is he still getting his vitamins and minerals? On a diet this bare, probably not all of them. Este Balancer exists for exactly that. It’s a concentrated balancer that fills those gaps without adding the sugar-rich bulk feed you just worked so hard to remove, and it combines without any issue alongside Steady & Stable.

If your horse is getting older, shed late this spring, or just had a laminitis episode nobody can explain, this is a testing story before it is anything else. No supplement diagnoses a hormone condition and none treats PPID. What you can do is use the season: book the blood test now, while the autumn window makes the answer clearest, and ask your vet to interpret it against autumn reference values. An answer, either way, beats another winter of wondering.

These two situations need different responses, and neither one starts in the supplement aisle. Start with what your horse is telling you. If you are feeding a broodmare through this, the sugar side of the story has its own set of rules.

What to do this week

• Walk the field after the next rain-then-sunshine spell and look for fresh shoots at the base.
• If your horse had laminitis before, get your hay tested for sugar instead of judging it by eye.
• If your horse is in his mid-teens or beyond, ask your vet about an ACTH test this month, while the autumn window is open. Especially if you recognise any of these: a coat that shed late or unevenly last spring, curly or longer hair that doesn’t match the season, muscle melting away along the topline while the belly stays round, small fat pads above the eyes where a horse should have hollows, drinking and urinating more than he used to, or a general slowing down that’s easy to blame on age. One of these alone proves nothing. Two or three together are exactly the pattern PPID likes, and a blood test settles it either way.
• If laminitis has already struck without an obvious cause, ask about insulin testing too. Nine in ten cases have a hormonal driver, and finding it changes everything about prevention.

One last thing, because the forums are full of owners quietly blaming themselves: a pony that gets footsore on a careful diet is not evidence of a careless owner. It’s evidence of biology that hides well. Now you know where it hides.