Accepted Answer

The key with food is to not swap it around frequently as that can lead to digestive upset.
I would plan on your vet checking him over for health issues if they have not seen your new dog as yet. Bring a fresh stool sample as a bloody stool can be due to bacterial infection, intestinal parasites such as worms, coccidia, or giardia.
If he has not had his shots potentially this could be a viral infection too.
In the meantime you can see if some bland food and plain pedialyte added to his water bowl will help him.
I would suggest trying boiled chicken meat or hamburger with the fat drained off, mixed with really well cooked rice in a ratio of 1/3 meat to 2/3 rice to see if that works. It's not a balanced diet but OK to use for a few meals while working on controlling digestive upset.
Then you slowly start adding in a dog food again.
If he is having a lot of diarrhea then he could become dehydrated. You can check for dehydration by pulling the skin gently up over his shoulders in a 'tent' and release it. If it goes right back down that is good but if some stays stuck up that’s a dehydration indicator.
Because he is having bloody stools seeing the vet with him soon would be a good idea. Maybe your vet can fit him in tomorrow.
Hope this helps you!

Expert:	NancyH
Pos. Feedback:	99.5 %
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Answered:	6/24/2008

Dog Expert:Rescue, Train,Breed,Care

30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics