Is it ok if horses are left outside 24/7 on very rich grass

Our pastures are full of rich grass. Usually they only come in from 11am to about 6pm, but it's going to be so nice the next couple of days that I think I'm just going to leave them out.

My horses stay out all the time except during lightening storms, ice storms(no grass usually) and really buggy times.

I hope you have had your horses vaccinated for anything and everything that your vet advises as mosquitos are often vectors for transmission of disease (west nile and several of the encephalituses to name a few). Horses like routine so be sure to check on them a least twice a day. Horses that are very upset and anxious can colic if you are not there to bring them in when you usually bring them in(think of the movie RAINMAN, the main character would get very very upset about changes in the schedule). I walk the fencelines every other day and test the electric as well.

In regard to the very rich grass comment. Laminitis ( a systemic illness) can affect any horse of any breed, but some are more susceptible. Laminitis is caused when volatile fatty acids (which are high in rich growing grass) are too much for the horses digestive system to handle and the VFA"S get released into the circulatory system. Think acid...It is in the name. The acids eat away at the samllest blood vessels first. Usually the hoof has the smallest blood vessels. For every day that the horse has laminitis without being treated, treatment will last about 8 days and can be very expensive. This means that if you fail to notice the signs of laminitis for 2 days your horse will require treatment for 8 days and this is best case scenario. Signs of laminitis (founder) are hot hooves, presence of a digital pulse, and a stance that looks like the horse is trying to rock his weight onto the hind feet.