Hello, my name is***** and I have over 20 years of experience as a veterinarian. I'm sorry to hear about your fellow eating a different food, perhaps cat food, which has led to stomach
upset. Eating a different food alone can make a pup nauseous but cat food is higher in fat and protein and that can make his stomach upset even worse. And it sounds like he overate as well if he has a very full belly still today. I expect that you may see some loose stools or even diarrhea in the next 24 hours.His breathing pattern is very likely due to stomach pain and cramping.I am glad to hear that he is drinking, that is very important when they overeat to keep the food from becoming impacted.You can try a few things to try and settle his stomach.To settle his stomach tonight you can try some acid reducers. You can try either:1) Pepcid-ac (famotidine
) at a dose of one half of a 10mg tablet per 10 to 20 pounds of body weight every 12 hours. OR 2) Prilosec (omeprazole) at a dose of one 10mg tablet per 20 to 40 pounds of body weight every 24 hours.These are very safe medications and can be used for several days if necessary.I would not feed him anything for 24 hours to rest his stomach. Offer ice cubes to lick to keep him hydrated. If all goes well with that offer him small amounts of water later and see how he does.If that goes well offer him a small amount of a bland diet after his 24 hour food fast.A homemade bland diet consists of 1/3 boiled, lean hamburger (or boiled, white, skinless chicken
) and 2/3 boiled, plain, white rice. If that goes well feed him this for a few days until his stomach is settled, then slowly start mixing in his regular food, gradually increasing the amount of regular and decreasing the amount of bland over a week's time until he is converted back to all dog food.If he has diarrhea you can immediately start the kaolin/pectin formulation of Kao pectate at 1ml per pound of body weight every 6 to 8 hours. This coats the irritated intestines, absorbs bacterial toxins and should help slow the diarrhea. It is quite safe and can be used for several days as needed.If he tries to vomit with no success, or vomits repeatedly and cannot keep anything down, doesn't eat for you after his fast and seems more lethargic then he should be checked by his veterinarian. Very rich foods can cause a bout of pancreatitis
, or inflammation of the pancreas causing increased enzyme production and release leading to severe abdominal pain.Please let me know if you have any further questions.