Join Date: Apr 2010
Location: ~*~ NEBRASKA ~*~
I used to live in Southern CA and have boarded both in Lake Forest and Riverside for years. I know it drops below freezing in Riverside. I would say your horse is okay. His hair not fluffing up is a sign that he's not getting too cold (they fluff up to help trap in heat and stay warmer). I have seen a lot of horses in South CA actually get sick from going in and out of blankets, etc too much actually.
I think if you are really worried and it's going to be a cold night, I would give an extra flake at dinner so that your horse has it a few hours before the cold hits, unless it's alfalfa as alfalfa doesn't contribute as much to keeping warm as the grass hays.
Grass hays such as brome, timothy, prairie etc ferment in the horse's gut. Don't worry, this is a good thing that is supposed to happen. The bi-product of the fermentation is heat...this heat will keep your horse warm from the inside out, much like when we eat oatmeal on a cold day. Giving the extra flake in the morning kind of is a little late to keep warm over a cold night.
If your horse is like many I know in CA and gets alfalfa, then I would maybe get some sort of grass hay to help with this process to add to it, don't add alfalfa because it doesn't really ferment and will just add too much protein and can cause colic and other issues. There are some feeds that also has fermenting grains in them, that can help (strategy healthy edge is one of them, I think Omolene does too). Mainly you want to do your research.