I'm sorry Minka is experiencing this problem that has you worried.
Is she a long-haired cat? Does she mutually groom with the other cats in the household? If so, she may be ingesting more fur than the average cat and this is causing the hairballs. The brown substance you see with the hairball is most likely digested food or excess acid mixed with contents from her stomach.
Follow directions on the hairball medicine, to know how much to give her and when.
In addition to the hairball problem, Minka may have acid reflux or excess stomach acid, which can lead to nausea, hence the vomiting the brown substance with the hairballs. For the moment, you can give her 1/4 of a 10mg. tablet of Pepcid AC (Famotidine) a half hour before her meals. Do this every 12 hours. The tablet itself is very small, so 1/4 is tiny; it should be easy to hide in a small amount of smooth, paté canned cat food or some plain, jarred baby food chicken or turkey containing NO onion or garlic products. Follow the pill with a little bit more of the food you put it in and encourage her to drink, to make sure it goes down properly.
I'm glad you changed her over to canned food, because it's healthier for cats. Make sure it's a high quality food that's grain-free and contains nothing artificial, like coloring, additives and/or preservatives. She may be allergic or sensitive to one or some of the ingredients in her food. Here is an article written by a feline veterinarian about the best way to feed our cats:
For the hairballs, groom her 2-3 times a day with a comb and/or brush, whichever she prefers and this will remove the 'dead' hair she's been ingesting. Try to groom all your cats, so if they mutually
groom, they will each ingest less fur from each other.
I'm glad you got the cat drinking fountain to encourage her to drink more; cats love drinking from a moving water source.
You can add some Alaskan Salmon Oil to her food once a day; this will provide additional Omega 3's.
It would be a good idea to discuss this vomiting with her vet at an in-person examination and a basic blood panel would be a good idea, too.
I hope all will be well with Minka!
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