Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
Now Cookie's signs won't be directly related to the spaying, but we can see them develop GI bugs do to immune weakness post spay (as the body is focused on healing) or secondary to any medications they are given afterwards (ie antibiotics, anti-inflammatories, etc). And if we are seeing tissue/mucus, we do have to be concerned that we either have a colitis or possible stomach ulcer present (the latter often related to anti-inflammatory use in sensitive dogs).
With this all in mind, if she is on any medication just now we will need to ring her vet about reactions, stop these, and have her switched to another gut safe option as well as have them start gastroprotectants. If there is any delay in contacting them, then we can try some home supportive care to see if we can settle her stomach. To start, if she hasn’t just vomited (since otherwise we’d need to rest her stomach for a few hours first), then you can try an OTC pet safe antacid like Zantac (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/ranitidine-hcl-zantac). Whichever you choose, we’d give this 20 minutes before offering food to allow absorption. Of course, do check with your vet before use if she has any known health issues or is on any medications you didn’t mention. As well, if you try this and find the nausea just too severe to keep it down, then that is usually a red flag that we need the local vet to bypass her mouth with injectable anti-vomiting medication.
After that has had time to absorb, we can start small meals of a light/easily digestible diet. Examples you can use are cooked white rice with boiled chicken, boiled white fish, cottage cheese, scrambled eggs, or meat baby food (as long as its garlic/onion free). There are also OTC vet diets that can be used (ie Hill’s I/D or Royal Canin’s sensitivity) too. When you offer these meals, give her 30 minutes after to settle. If she keeps the food down, you can give a bit more and so on. The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. You can also add fiber (ie canned pumpkin, weetabix, 0.25 tsp Benefibre mixed into canned food, etc) to these meals to help bulk up her stools. Therefore, it should get more nutrients in and result in less GI upset. As long as improvement is being seen, I usually advise that the diet be continued until her signs are settled, and that they are then slowly weaned back to their normal diet.
Since dehydration is a risk, we need to keep a close eye on her hydration. To check this and ensure she’s not becoming dehydrated, there are a few things you can test. Further to checking for gum moisture, you will want to make sure her eyes are not looking sunken and that she doesn’t have a "skin tent" when you lift the skin. To see how to check these parameters for dehydration, you can find a good video HERE (http://www.ehow.com/video_12232503_dog-dehydrated.html). If you do find these dehydration signs, then that would be our cue to have her seen before this becomes an additional issue (especially as it is often dehydration that makes them feel unwell).
Overall, a wide range of agents could trigger the signs we are seeing but we need to be careful if you are seeing pink tissue in her sickness and diarrhea. Therefore, we’d want to start supportive care to settle her stomach but would also want to ring her vet regarding the above medication options. They can assess her hydration, rule out a drug reaction, make sure there aren't any sinister infections present. Depending on their findings, your vet can treat her with injectable anti-vomiting medication, fluids, gastroprotectants +/- antibiotics to get her back feeling like herself.
Finally, just to note in case you were keen to have your wee one seen today, some veterinary practices in our country have office hours today. As well, I wanted to mention that most veterinary practices here do have contingency plans for emergency care for their patients even when they are not open. Therefore, it is worth ringing the practice. If they are open, you can get in today. If they aren't, then they will likely have a message to direct you on how to contact their out of hours service. And if you don't have a vet, you can find one local to you via the RCVS Register (http://findavet.rcvs.org.uk/find-a-vet/) to find your local vets or Vets Now (http://www.vets-now.com/find-an-emergency-vet/) who are open all nights/weekends. In any case, if you wanted to get this checked out sooner then there are options to be seen today.
Please take care,
If you have any other questions, please ask me – I’ll be happy to respond. **Afterwards, I would be grateful if you would rate my service by clicking on the "Rate my Expert' button at the top of the page as this is the only way I am credited for helping you. Thank you for your feedback!: )