rottie sick

Question
I have a 16 month old male rottweiler, & weighs approx. 90 lbs. I came home last night, He was outside all day, has shading and plenty of water, temps were in the mid 90's . (hot). He was very lethargic. He didnt jump around as normal when my wife and I call to him. We had to call for him to come into the house many times, and when he did finally come, he was very slow in movement. We tried to feed him some scrambled eggs which he likes, but he wouldn't touch themm or drink any water. He didn't whine or make any sounds. We live in East Texas (near Houston). He sleeps in the house at night. This morning he was drooling and still very slow and not responsive to any playing aroubd as we normally do each day. We think he may either have a heat related illness, been poisoned (no evidence outside though) or snake bit, ( but no bodily signs ). Any ideas?  

Answer
You need to get him to the vet A.S.A.P.  Heat stroke can lead to brain damage and seizures.  If he was poisoned, you want to get him activated charcoal and on IV FLUIDS as soon as possible to flush out his system.  Otherwise, some blood testing to check kidney and liver function would be adviseable.  Also, I would recommend checking for tick-borne diseases such as Lyme and Ehrlichia.