Fall Laminitis in Horses

by Michael Hipp

As I was coming back from town on an errand yesterday my sweetheart calls me and says “Whiskey is looking laminitic to me. You’ll want to check him when you get home.” Sure enough she was right, as she usually is, so he is staying in a few days and we are taking measures to relieve him of the problem. But, I wondered, what could have caused such a normally healthy horse to become laminitic?  

We all know to be careful when turning out our horses onto fresh spring grass because of the high levels of sugar (fructan) that the grass contains that can cause problems such as laminitis, but…fall grass? Isn’t that the safest from an increased sugar load?

Actually, no. It can be just as problematic, or even more so, than spring. 

Fructan levels become elevated in late summer and early fall as well, and can trigger laminitis just as readily as spring grasses. Although we typically think of the lush, green grasses of spring as the more dangerous forage, fructan also elevates during times of stress and arrested growth like we typically experience during the summer dormancy and usual drought pressures that occur in late summer and early fall. Also, a re-growth period, which typically occurs with the return of moisture like we have had this last week or so, followed by much colder nights (the lows are dropping down into the upper 40’s later this week where I live) are perfect conditions for fructan levels to rise. Add all that up (the increased sugar from summer dormancy pressures and re-growth with the return of fall rains) and what you have is a grass that can contain just as high or higher fructan levels than spring. And it doesn’t matter what type of pasture grass you have, from the best to the worst they all experience the same rise in fructan under the same conditions. 

If you are noticing, as I am, a re-growth occurring in your pasture (it looks more green than it did a few days ago) then you will want to consider this information carefully. Especially if you have a horse who is at increased risk of laminitis or who is obese or insulin resistant. You may want to muzzle him when he is out in pasture, or move him to a dry lot. Also consider carefully his hay. If you are feeding late cutting hay (harvested in the last month or so when re-growth may have occurred where it is sourced) you may want to test the hay to see if it is higher in sugars or find a hay with a lower risk. Another way to reduce his risk of laminitis from increased sugar in the forage is to ride him more. Sugar burned positively through proper exercise is sugar not used to contribute negatively to laminitis.

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While we are extremely blessed with such good grass and forage and the moisture needed to sustain it here in the beautiful Pacific Northwest, we must also be vigilant to not let that blessing become a curse for our equine companions by practicing good pasture management. If you would like to discuss ways you can do that on your property or manage what you have better for your horse please contact me any time. With good management and focus on the important points of horse keeping not only can your pasture be healthier but so can your horse as well. 

Please call Michael Hipp, Sound Horsekeeping Program Coordinator, if you have questions about pasture management.


Call your veterinarian if you see symptoms of laminitis in your horses.