Horses prone to laminitis need management when grazing on grass pastures, especially in the Spring time and early Summer, when grasses grow quickly and lush.
In the Northeastern US, all of the cool season grasses will accumulate fructans and sugars under certain environmental conditions.
- The highest sugar accumulations are after cold less than 32 degrees F. overnight followed by bright sunshine, just after cutting, or during droughts. Timothy and Orchard grass have been reported to accumulate less than ryegrass.
- As long as the temperature overnight is above freezing, the lowest content of sugars is between 6 AM - 10 AM.
- Graze horses during the active growing seasons (spring and early summer.) Remember, that the late summer grass as brown grasses can be very high in sugars.
- Pastures are healthiest for horses (lowest in sugars) during the active growing season when plants are green and not stressed (not burned out).
Implement a good rotational grazing system on your farm to avoid overgrazing. The greatest amount of sugar in a grass plant is in the bottom three inches, so rotate pastures before they are grazed below three inches. Shady pastures and cloudy days will result in lower carb and sugar levels in grasses. Or move high risk horses to shady pastures.
Restricting access to only the early morning hours during the summer and keeping at-risk horses off pasture or keeping off a day or two after mowing, if there is a drought or after an overnight freeze should help reduce the risks.
Source : psu.edu