10/10/2026
Fall Grass 🌱🌾
Most horse owners know to watch their horse closely during summer grazing, but what about when the seasons change?
Depending on where you live, right now it might be getting cold and frosty in the mornings, darker earlier and the fall holiday season is finally here! These colder temperatures at night are a welcome change from the intense heat many of us have been feeling this summer, but they also mean that the grass in our pastures is changing and it could be affecting our horses more than we realize.
When our horses are out on the grass in the fall and the temperatures drop below 40°F the grass can halt growing temporarily, and then reactivate once the temperatures rise. For example, today in my part of Maryland it was 39°F overnight and then rose to 75°F during the day, and will drop again tonight. This dropping and pausing in growth can cause WSC (water soluble carbohydrates), fructan (sugars) and starch to accumulate in a more concentrated way in the grass. This gives us a high NSC, which most horse owners have heard about - NSC stands for non-structural carbohydrates, and is the combination of WSC + starch. This is a number we watch especially closely in our metabolic horses.
This rise in sugars + starch poses a high risk to horses with metabolic conditions, but can also potentially affect any horse who is on the grass for long periods of time regardless of their weight and even metabolic condition.
Later in the season the temperatures will begin to drop even lower and when temperatures are below freezing for multiple hours at night the season for pasture growth is officially over, which can lead to further NSC accumulation temporarily. And even when the grass stops growing for the season entirely, that doesn't mean it suddenly loses all of its nutrients and sugars!
(There's an old school saying that "After The Third Frost it's safe to graze", but that's not necessarily true, it's especially not true for many individual horses. Instead of counting frosts, I recommend evaluating the individual horse on a daily basis and consult with your vet or nutrition expert.)
Another thing to think about is grass height over winter, especially when grazing our non-metabolic horses over the winter but it helps our metabolic friends too.
The ideal horse pasture for many is a lush green field with 10 in. of grass that lasts all winter. The reality at the average horse farm is more often fields that have been grazed on over summer by the horses enjoying their time outside, possibly (and hopefully) in a rotation, often mowed, and many are getting to a "winter height"- the fields are looking a little shorter, still mostly green, and now more grass and less weeds as many warm weather plants begin to die out, or in some cases less good grass left than the hardier weeds that are remaining after a summer of grazing. These fields that have been grazed on over the last few months and are the shorter side may be rested now, but many that are still in good shape will still be used. If they aren't, a smaller area is sometimes picked as a "sacrifice paddock" over winter. The issue with these shorter grass fields or even sacrifice lots that start off with grass is that once the growing season is over, even after the accumulation of NSCs has started to settle down, the grass can become and even stay stressed over the winter. This can affect growth during the next season, as well as pose safety concerns for grazing due to sugar accumulation over winter.
Now, that's not to say that there is anything wrong with using your fields over winter, you absolutely should, and sacrifice areas are fantastic! And many horses will do well on these winter fields.
However there are a few things you can do to help your more "at risk" horses stay safe from winter grass under these conditions!
1. Try to remove your horse from pasture or at least limit their grazing after temperatures have dropped below 40°F overnight, the recommendation is to stop/limit grazing sensitive and metabolic horses for at least 7 days.
2. Use a muzzle during turn out on longer fields to limit grass intake in sensitive horses.
3. Allow designated winter grazing fields to grow past at minimum 4 in. prior to the stop of the growing season. Ideally pasture will be at 8-10 in. prior to horses grazing over the winter (or anytime of the year).
4. Having a sacrifice lot that either starts grass-free or can be grazed/trampled/scraped down to dirt quickly or having an area that is surfaced will be safer than having a larger field with short grass between 1-4 in. which will have issues with NSCs and winter stress. Especially for metabolic horses and those at high risk, it is better to be safe than sorry.
5. If you do remove your horse from grass for the full 7 days due to metabolic stress and it is helpful to them, remember you may need to continue this every time the weather drops again.
6. If you do remove your horse from grass temporarily and plan to put them back out to pasture grazing, be sure to keep their gut health in mind. Having horses come on and off of pasture, swapping from water filled grass to dry hay can be hard on their systems, so be sure to transition slowly and even consider making the transition permanent for the winter once it is done.
7. Remember to check on your horses daily during this time- check digital pulse, check for heat in the hooves, bruising or lameness and consult your farrier if you have any concerns, plus keep an eye on body condition score and any fat deposits (including above the eyes), look out for signs of PPID or EMS and consult your vet if you have any concerns, and be sure your are feeding an appropriate diet.
7. And finally, if you would like help with setting your horse up for success this winter, reach out to me anytime to schedule a nutrition consult!
