It is 9:00pm and 90 degrees, heat index 99 degrees and 60% humidity.

Like a steam bath out there!

Are they PANTING,or,are their nostrils flaring out somewhat? I didn't think horses panted to cool down,only the canines,etc.

Sweating is very normal in this type of heat/humidity,even without activity.

I have seen this happen when the humidity is very, very high.  Sweat will not evaporate when the humidity gets really high and thus  no cooling happens.  They'll pant and flare nostrils trying to cool themselves.  I'd allow them access to their stalls with fans and misters 24/7 if possible.  Some horses will splash in their water troughs trying to get water up on their necks and chests in this weather too.

Shade in a windy part of the pasture is a must in this heat.  Placing misters along a fence or hanging from a shady structure are also good ideas.

Your right Crowleysridgegirl. Dogs pant. They aren't panting I guess, but the nostrils flaring out and their breathing more labored than it should be. You can see them breathing harder by looking at their flanks as well.

Makes sense Huntseat, but we have always lived here(high humidity) and I have never noticed it before. There is plenty of shade, but they were more interested in grazing. The other suggestions are good as well. Looks like we might get some rain tonight and tomorrow. Sure hope so. We have been dry about 3 weeks now and we sure don't need to be back in the drought situation this early in the summer. I will see what my vet says as well, first thing in the am.

Horses do pant. Some pant more often than others. Usually the horses with the largest body mass have a tendancy to pant. It is not the most effeicient cooling method but it is one of the methods horses use to cool their bodies. Panting in itself is not a big issue, it's panting in lieu of sweating that can be a big issue. Horses can develope anhidrosis in extreme heat and humidity. Anhidrosis is when the body becomes overwhelmed and its cooling mechanism shuts down. Some horses are more prone to it than others and it can be very dangerous. If your horses are sweating normally and their rectal temps are normal, then you should be fine. If the sweat is only under the mane (for example) or only under the tack after being ridden, then your horse may be suffering from some degree of anhidrosis...the skin will also feel dry and hot and sometimes look a bit wrinkled. There is a big difference in the way a horse with anhidrosis feels than one that doesn't have it. Be careful with your horses in these conditions especially if they aren't particularly fit going into them.

I have dealt with anhidrosis before and it is not fun. I was fortunate that the horse did not contiue with it after the first summer that he developed it and I'm a bit paranoid about it. It's interesting that these horses, when sent North, will begin sweating normally again....Be careful out there! 

I can't believe this is just the beginning!! I hate summers down here. I have one horse that really pants in this weather and he's a big boy so I keep a close eye on him especially. I'm sure yours will be fine but it's a good thing to be aware of.

Stay cool!

Yesterday, I was summoned to take my friends horse to the clinic as she was "colicy".  Indeed she had limpomas on her intestines, but she was also suffering from heat stroke.  She has access to her stall with a fan and a large paddock.  Unfortunately . . . she had to be put down.  I asked the vet if he had seen others suffering from heat stroke.  He said they had seen 3 in the last 2 weeks.  I too am in Alabama.

The last couple of weeks heat has put a damper on my plans of riding, dang it... Wanted to try my new boy out. He would of been fine, it's me. 30 min. outside and the sweat is in my dang eyes, all down my face, soaked shirt, and the patience is very short. Been carrying around a water bottle with ice water...LOL...