Pasture Management for Sugar-Sensitive Horses: Good vs. Bad Practices

Graze in Early Morning

If the temperature stayed above 5ºC (40F) during the night, then the sugars that the grass stored during the day before are going to be used for it’s growth. Then you can let your horse out from around 6am to 10am, when the sugar levels have already been used.

Dawn is the best time of day to graze your horse. Sugar levels start elevating in the afternoon. So make sure that if the sun comes out, you horse is safely in his dry lot / track system / box.

Cut Seed Heads Early

Developing seed heads are sugar bombs. Remove them before they mature to prevent horses from targeting the high-sugar parts of grass.

Cloudy Weather Makes Low NSC Grass

Less sun = less sugar production. Photosynthesis makes sugar in grass, so you understand what I mean. Two weeks of cloudy weather can significantly drop NSC levels in both pasture and future hay cuts. If you can, time turnout with overcast forecasts.

This can also translate into making hay… if hay is cut after a period of cloudy weather then it will be lower in sugar. You are welcome to try this yourself or ask your broker to try it, then you can test it and verify for yourself.

Cloudy climates like Ireland tend to have lower NSC in their grass.

Use Shade to Your Advantage

Photosynthesis is light-dependent. Less sun, less sugar. Grass growing under trees or along north-facing fencelines naturally produces less NSC. Fence off shady areas for safe grazing zones.

A very good idea is grazing horses in the woods. Sugar levels are going to be way lower than in an open field.

Thick grass shades itself, creating a cooler, lower-light microclimate that suppresses sugar production. Think of how it feels lying down in thick green grass vs in thin and sparse grass, which is fresher? The thick green grass. That is because the thinner and sparse grass is, the more the sunrays can hit it = creating more sugar.

Fertile fields not only reduce NSC — they smother out weeds.

Teff Grass (With Caution)

Warm-season grasses like teff are often lower in sugar — but test to be sure. NSC can still spike depending on how, when, and where it was grown.

You can get advise from Natalie Sullivan, she is part of a Low Carb Horse Hay project using Teff that links horse owners with responsible hay growers. I can imagine that she can also give you advise on who to reach out to https://www.oncourseequinenutrition.com/projects

Rotational Grazing and Limited Pasture Time

By rotating paddocks and giving forage time to recover, you avoid overgrazing, encourage healthy regrowth, and reduce NSC accumulation.

Properly Fertilized Grass

So this is very interesting because a strategic, early-season nitrogen fertilization actually lowers sugar per bite. Why? Because well-fed grass grows — it doesn’t just sit in the sun and make sugar. Aim for thick, green, fast-growing pasture, not stressed yellow grass.

Yes. Yellow grass, overgrazed and neglected pastures can be high in NSC, because of what I have been explaining earlier. Grass accumulates more sugar when it is stressed.

Now it doesn’t mean that because you have beautiful green grass that is lower in NSC, that you can leave your horse to eat whatever he wants. You still have to provide limited pasture access.

Use Grazing Muzzles

Muzzles don’t reduce sugar per bite, but they do limit how much a horse can consume per hour. That alone can save a laminitis-prone horse in spring.

Maintain a Sacrifice Area / Dry Lot

A dry lot or grass-free turnout area is not optional for metabolic horses — it’s extremely important. Use it when sugar conditions are high, and never feel guilty for protecting your horse’s feet over their feelings.

Afternoon Turnout

This one’s a big no. Sugar levels spike in late afternoon — especially after sunny days. Grazing at 4 PM on a clear day is like giving your horse a bag of Skittles.

Grazing After Frosty Nights

When the night temperatures lower to near or below freezing, the grass won’t grow and therefore it can’t use up yesterday’s sugar, so it keeps accumulating. Frosted grass is especially risky.

Cold nights (below 5ºC / 40°F) + sunny days = terrible idea for sensitive horses. So in spring and fall, you should stop grazing them if the weather is like this.

Letting Horses Graze Seed Heads

Grasses dump sugar into their seed heads as they mature. Horses will sniff them out and gorge. Mow or top pastures before seeding starts.

Grass Just Outside the Fence

We all know that pony who stretches under the hot tape to nibble a few “innocent” weeds. Trouble is, those fence-line grasses and weeds are often sweet, lush, and highly stressed = high NSC.

Nitrogen-Starved Fields

Low-nitrogen soil leads to weak, slow-growing grass. That stress response triggers sugar accumulation and the weeds take over the pasture. As weeds can be higher in sugar than grass, we are in a no win situation. Fix the soil instead of blaming the grass, to be able to have good pasture management.

Nitrogen deficient grass can become yellow, because nitrogen is a component in chlorophyll, the pigment that gives grass its green color.

High-Altitude, Sunny Pastures

Cool nights + intense sun = high sugar. Mountain regions (think Colorado, Utah) are notorious for metabolically risky pasture conditions. It will be hard to find low sugar hay if you live in these regions, so maybe you will have to ship from another region.