I have a 6 year old female black lab pointer mix who recently (since 11/16/13, so about a week) has been vomiting, sometimes in the even after work (about twice), but usually in the middle of the night after 12am and before 5am. It's always yellow in color and foamy, with no food in it since it usually occurs about 3-4 hours after eating.
Everything else is normal, her activity level is the same, she still loves to eat, and her stool is firm. The only personality change I have seen is she use to love to play tug of war when we got home, but now she doesn't seem to be interested. She still loves to chase squirls and go on walks though.
I noticed these changes when we for a new foster pup for about 2 weeks. He was 7 month old and was quite a hand full. He always tried playing with her and when she didn't feel like it he wouldn't always listen to her corrections. This is when she started getting a lot of yellow eye gunk as well, but they has gone away since he left and we have used some eye drops on her.
At first we thought it was acid reflex and her tummy was hurting from being empty, so we started to give her a snack at night (a homemade pumpkin pie dog biscuit, wheat free, and a few spoonfuls of plain low fat yogurt. Then when she was still vomiting in the evening we start giver her 3 meals a day instead of 2. She gets 1 cup of Blue Buffalo for large breed adult dogs in the morning since lasts the longest she has to go without food, then 1/2 cup after I get home from work around 4:30, then another 1/2 cup around 8:30 and her new snack before bed. We have also started to soak her dry food in some warm water to help aid digestion. Out next effort will be giving a little organic unfiltered apple cider vinegar since I have read it has several health benefits, including to aid digestion.
Does anyone else have any ideas as to what might be wrong or things we could try to help before going to the vet? I wasn't sure if these are the signs of a grain allergy and if we should switch her food to a grain free one. She has been on the same Blue Buffalo since about April (when we adopted her).