asking advice on sugar levels in pasture grass throughout the day and night

Barbara Sollner-Webb

Hello wonderful Equine Cushings folks,
    I apologize if you all have covered this before, but am hoping someone can tell me about the variation of sugar content of pasture grass during the day and night.  One always hears the general summary that the sugar in pasture grass (in conditions of sunny days, and nights above something like 50 degrees) is lowest pre-dawn, rises to become highest in the late afternoon/early evening and then falls during the night.  My main question is how rapidly/slowly the sugar content falls during the night. For example, by midnight is the sugar is nearly as low as it will get later in the night, or about half way down, or what?
   In fact, I assume some diligent person has assessed the sugar content of pasture grasses each hour over the 24 hour cycle, both when the nights are over 50 degrees and when the nights are much colder.  Can anyone tell me how to access such data?  They sure would be MOST valuable to know.
   Thank you so very much for any help you can give me, in managing my (previously) foundered wonderful horse -- who for the last 15 month has never been out without a muzzle, and happily has grown in great, attached hoofs again.
appreciatively yours, Barbara
Barbara Sollner-Webb (bws@..., cell-301-655-3553)

Eleanor Kellon, VMD

 Nice to see you back here, Barbara,

I don't have hard numbers for you but the grasses need to rely on store carbohydrates overnight so levels will continue to drop over each hour of darkness.

In late afternoon, the sun has produced an excess of sugar that will eventually be stored as starch or fructan, or used overnight. When temps are over 50, the grass will continue to grow and actively use that sugar. Lower than that it becomes dormant overnight.

When nights are over 50, the safest time to graze is the early morning hours before dawn. When nights are cooler, but days are warm (fall) that is still the safest times but won't be as low as when nights are over 50.

Eleanor in PA 
EC Owner 2001
The first step to wisdom is "I don't know."