Reminder: Beware of laminitis risk in fall pasture!
As temperatures begin to dip, Dr. Juliet Getty, equine nutrition specialist, reminds you to help your horse make the transition to winter feeding in good shape—and that means you being informed about the sugar and starch that lurk in your fall pasture growth.
If you have horses that are overweight, insulin resistant, or suffer from equine Cushing’s disease, you know about keeping them off of spring grasses. The non-structural carbohydrate (NSC–sugars, starch, and fructans) content is too high for free-choice pasture grazing to be safe, increasing the risk for laminitis. But don’t think you’re out of the woods once spring is over. True, summer is safer, but as early fall nights cool down below 40 degrees F for the majority of the night, the dangerous carbohydrates once again increase.
Grass accumulates NSC as it is exposed to sunlight. The levels reach a peak in the late afternoon. During the dark hours, the grass uses this fuel for itself, and by morning, the levels are at their lowest. But cold nights prevent grass from using as much NSC, resulting in a higher NSC concentration remaining during the day.
Don’t be fooled by the brown grass you see in the late fall. Spread it apart and you’ll likely see some green at the base, which is high in sugar and starch. If it hasn’t rained in a while, your grass will look dried out, but be careful – dry grass can actually have a higher NSC percentage than long, lush-looking grass.
Testing your pasture every couple of weeks may be a good option this time of year, especially if your horse is otherwise at high risk for laminitis. Equi-Analytical Labs offers their economical “Fast Track” test that provides WSC (simple sugars and fructans), ESC (simple sugars), and starch levels. Though just a snapshot of what is happening to the grass at that moment in time, consistent testing will provide a trend that may offer some peace of mind in determining when the grass has gone dormant for the winter.
Too Much Iron Can Be Detrimental to the Insulin Resistant Horse
Are you adding a supplement to your horse’s diet that contains iron? If your horse is overweight, diagnosed with insulin resistance, or suffers from equine Cushing’s disease, here’s a word to the wise: You may want to reconsider giving that supplement. Studies have shown a direct correlation between iron intake and insulin levels in the blood, making it an important factor in managing the diet for these horses.
Iron deficiency anemia is rare and too much iron can potentially lead to laminitis, as well as create an imbalance with other minerals. Furthermore, forages (pasture, hay, hay pellets or cubes) are already high in iron, making supplementation unnecessary and possibly dangerous. To protect your horse, choose a vitamin/mineral supplement that does not include iron and have your hay analyzed.
Calculate the total iron intake in the diet; though an upper tolerable limit for all horses is 500 ppm, it should be far less for sensitive horses. Soaking hay can remove much of the iron, but will also remove other minerals. Balance iron with zinc and copper: iron should not be more than 5 times the level of zinc, and the zinc to copper ratio should range from 3:1 to 5:1.
One more comment: Forages grown from acidic soils will be higher in iron. If you grow your own hay, or can discuss this issue with your hay provider, consider increasing the pH of the soil through lime application.
Juliet M. Getty, Ph.D. is an independent equine nutritionist with a wide U.S. and international following. Her research-based approach optimizes equine health by aligning physiology and instincts with correct feeding and nutrition practices.
Find a world of useful information for the horseperson at www.GettyEquineNutrition.com: Sign up for Dr. Getty’s informative, free e-newsletter, Forage for Thought; browse her library of reference articles; search her nutrition forum; and purchase recordings of her educational teleseminars. Reach Dr. Getty directly at email@example.com. She is available for private consultations and speaking engagements.
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This article was printed in Performance Horse Digest, Volume 9, Issue 10