Earlier today I noticed my mare breathing kind of heavily, she was otherwise acting normal, eating, drinking, etc., so I chalked it up to the heat and didn't think too much. (I realize now this was a mistake...). Around 230 pm I turned her out to our neighbors pasture... here in AZ they have sparse prarie type grass to nibble on. Stupid me, she seemed fine so I didn't pay attention to her breathing, I had honestly kind of forgotten about it. So by 330-345, she came back up to the house, standing in the shade, absolutely just heaving, breathing probably 60/min, like she had just been loped hard... temp was 103.8, she was hanging her head, HR 60's... also pawing the ground, and very little bowel sounds, pale gums, slow cap refill. Had vet out, we gave IV Bute, some Rompum (sp?), and an antispasmodic that started with a B? By the time he got there her temp was 104.4. He palped, said she was gassy but no other abnormalities, tubed, said her stomach smelled ok, gave oil/water. Vet pulled blood, told me to cold hose, give a very light dinner of alfalfa pellets wetted down, keep checking temps and hose her down as needed, give more bute in AM if she has another temp. No full meals until she passes oil. Just got a call back on the blood, apparently one of her white cells is decreased and he suspects a virus of some kind. Possibly the fever made her dehydrated and colicky? He told me to expect a possible roller coaster with her temp over the next few days, possible a snotty nose, lethargic, etc. We just got a new horse 2 weeks ago, he said it would be a long incubation but it's possible that my new horse carries a virus that Lic has never been exposed to before. Any thoughts at all? Anyone ever have this happen?