First, I must say that I am concerned about your lass. Though its good to hear that the stools are brown again.
The reason for my concern is because black stool usually is a sign of bleeding in the stomach or upper gut. As I am sure you can appreciate, that when we see this we do have to be concerned about something causing trauma or ulceration (ie foreign bodies, stomach ulcers, growths, etc). And if she chews odd sticks and plaster those could certainly hurt her gut.
Now since she has had a normal stool and her gums are pink, we'd want to try to reduce the loose stools but also start some stomach protective supportive care. Of course, any more black stool or any of those signs I asked about and we'd want her seen right away to be safe. Anyway, to protect her stomach (by reducing stomach acid), we can put her onto an OTC pet safe antacid like Pepcid (More Info/Dose @http://www.petplace.com/article/drug-library/library/over-the-counter/famotidine-pepcid) or 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 food to allow absorption and plan to use it every 12 hours. Of course, do double check with your vet if she has a known health issues or is on any medications you haven't mentioned. You can also use Milk of Magnesia (after the antacid has absorbed) at a dose of 0.5-1 teaspoon every 8-12 hous. This will coat the stomach and help protect it.
Afterwards, you can consider starting her on an easily digestible diet like cooked white rice with boiled chicken, boiled white fish, cottage cheese, scrambled eggs, or meat baby food (as long as its garlic/onion free). The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. Therefore, it should get more nutrients in and result in less GI upset. Fiber (ie canned pumpkin) and OTC probiotics (ie Benebac, Fortiflora) can be added to these meals to firm those loose stools quicker and support digestion.
And if she is quite runny, we can also consider trying a pet safe anti-diarrheal. As I am sure you appreciate, these would not be a cure for infectious issues; but it can still be of benefit. It will reduce diarrhea load, allow the body to absorb more water/nutrients, and soothe the upset gut. In regards ***** ***** options, the one we most commonly use is Kaolin/Kaopectate (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/kaolin-and-pectin-kapectolin-k-p)). This is available OTC at most pharmacies. Otherwise, Propectalin, Canikur, Fast Balance, and Protexin Pro-Fiber (all OTC at vets, pet stores, and even Amazon) would be another option. All will slow diarrhea and those last ones have the added bonus of probiotics added in. So, these can be used as a short-term means of soothing her upset GI.
Overall, her signs sound like more than one issue present. The cow pat stools suggest bacterial, viral, protozoal or parasitic issues. The black stool worries us about gut bleeding. So, do start the above to protect her stomach and reduce the looseness of her stools. As well, if Poppy isn't up to date on worming, that too would be a base to cover. But if those stools don't settle down with the above or we see any more black ones, then we'd want her checked at that point +/- a stool sample tested so we can target treatment to nip this in the bud.
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