There is a layer of milky white sticky jelly-like substance on my dog’s stool

The white jelly-like substance on the stool is shed intestinal mucosa from the dog’s gut, usually caused by poor digestion and absorption such as gut flora imbalance, cold exposure, parasite infection, or excessive food or meat intake.

If the dog is energetic and produces formed stools, improve the diet with light, non-greasy food and add pet-specific probiotics or lactase to support digestion. If diarrhea with frequent mucosal passage occurs, have the gut function and feces checked; enteritis or parasites need targeted anti-inflammatory and deworming medicine.