The grass changed. So did the diet.
Spring grass is a feed change - even if you haven't changed a thing in the feed room.
Every horse owner watches the feed room in spring. Fewer of us are watching the paddock the same way - and that's the feed change that actually matters most right now.
As pasture moves out of winter dormancy, it doesn't just get greener. It gets wetter, softer, and nutritionally different, almost week to week. Spring grass typically carries far more moisture than hay or dry pasture, which means a horse can eat a large volume of forage while actually taking in less dry matter than it looks like from the fence line. At the same time, the grass itself is changing composition — more rapidly growing, more fermentable carbohydrate, less of the fibrous structure that dominates mature, stemmy pasture.
Why the hindgut notices before you do
None of this is a problem on its own. Horses are built to eat forage, and pasture is the most natural feed there is. The issue is speed. A hindgut microbial population adapts to what it's regularly fed — and it adapts on its own timeline, not the calendar's. When the composition of forage shifts quickly (which is exactly what spring does), the shift can outpace that adaptation, especially in horses with little turnout over winter or those moved onto lush pasture all at once.
What "gradual" actually means
This is why every reputable nutrition guide says the same unglamorous thing: introduce spring turnout gradually. Short periods to start, building over one to two weeks, ideally alongside continued access to hay so the gut isn't relying on pasture alone from day one. It's not exciting advice. It's just the advice that works.
We tend to think of a feed change as something that happens in a bucket — a new supplement, a different hard feed, a changed brand. In spring, sometimes the biggest feed change is happening in the paddock, and it deserves the same care.
This is also where digestive support can help underpin the transition. GUTonic was formulated to provide targeted nutritional and digestive support alongside a forage-first diet — not to replace good management, but to sit alongside it.
Takeaway: Before you touch anything in the feed room this spring, look at the paddock. That's where the real change is happening.
