
By Camilla Whishaw, BHSc (Nat)
This short answer is: in the early morning (3am -10am).*
Why is that?
Several key factors influence the level of sugar in the grass our horses and ponies graze:
- The weather
- How stressed the grass is (over-grazed grass and/or grass under drought conditions)
- Grass maturity
- The time of year
- Species of grass
- The time of day.
Sun shining on grass causes the process of photosynthesis to occur. This creates sugar, which the plant stores then uses overnight to keep growing. As a result, grass tends to have higher sugar content later in the day compared to earlier in the day: Grass has had more sunlight exposure and more time to photosynthesize and produce sugar.

What this means from a practical sense is that a horse who is at risk of laminitis (but is still safe to graze) is best turned out to pasture early in the morning and brought off grass by 10-10:30am, cloud coverage and region dependent.
Some key factors to keep in mind:
Turning out late in the afternoon/evening is not the safest option for at risk horses, as sugar levels are at their highest at this time. It takes several hours after the sun sets for sugar levels to drop. In most cases, sugar levels are safe to graze again at around 3am.
*Cool or frosty nights and warm/sunny days promote very high sugar levels in the grass. When the temperature drops below about 5 degrees Celsius (40 degrees Fahrenheit) overnight, yet the day is still sunny and warm, the growth rate of grass slows. As a result, much of the stored sugars in the grass aren’t used up. In this case, sugar levels can still be high in the early morning. This may mean keeping at-risk horses off-pasture on these days.
ABOUT THE AUTHOR
Camilla Whishaw BHSc (Nat) is a highly respected and sought after Equine Naturopath and experienced horsewoman. Based in Australia, Camilla consults globally on challenging equine health cases working both independently and in collaboration with equine vets and health care professionals. Camilla is passionate about solving challenging equine health conditions, through holistically evaluating horses and employing targeted dietary, nutraceutical, western herbal medicine and management practices. She helps to holistically treat and manage a broad range of health conditions and injuries, with a particular passion for stallion fertility, problem pregnancy mares, digestive health, immune challenges, behavioural problems, neurological cases and inflammatory bowel disease. To learn more visit www.optimequine.com
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