Royal CaninSkin & Coat Supplement Soft Chews for Adult Dogs

A plant oil with the source unspecified, usually soybean, canola or a blend. It supplies the omega-6 fat linoleic acid, which dogs and cats need for skin and coat. The unnamed source means it can change between batches, which matters little nutritionally since the common vegetable oils are similar. Its omega-3 is the plant form, which pets convert poorly, so a food relying on it will add fish oil or flaxseed for balance.

A plant source of omega-3 fat (alpha-linolenic acid) and fiber, used in about a third of dog foods for coat and stool quality. Dogs and cats convert plant omega-3 to the useful forms inefficiently, so fish oil does the job better. Flax is not a documented common allergen, though some pets tolerate it poorly, most often as loose stool. Fine in a food; not a reason to prefer it over one using fish oil.

The most common protein in pet food, and for dogs one of the most common food allergens, with beef and dairy. If chicken is what your pet reacts to, it hides everywhere: chicken fat, chicken broth, chicken meal, natural flavor. On a label, chicken listed first is weighed with its water still in, so a food leading with fresh chicken often has less chicken protein than one leading with chicken meal. Neither is better; they are different measures.

Oil pressed from whole fish, usually menhaden, herring or sardine, added as the source of the omega-3 fats EPA and DHA. Those fats support skin, coat, joints and brain development, and a food that names fish oil is delivering them in the form pets use directly. It goes rancid quickly, so look for a preservative named alongside it, usually mixed tocopherols. The species is rarely stated, which matters only if your pet reacts to fish.

Almost always rosemary extract, used as a natural antioxidant to keep fats fresh, usually alongside mixed tocopherols. The amounts are tiny. A persistent internet claim links rosemary to seizures in dogs; there is no published evidence for it at food levels. If your dog has epilepsy, ask your neurologist rather than avoiding foods on this basis alone.