Oats are a cereal grain that are high in starch – however the starch is considered to be more digestible than some other starchy foods.
Otherwise known as “groats”, oatmeal is just oat grain that’s been hulled. Rolled oats and steel cut oats are all types of oatmeal. You’ll find these in human breakfast cereals and porridge.
Guinea pigs are not grain eaters.
Therefore, oats, oatmeal and anything derived from oats is generally not a suitable food for guinea pigs.
However: some people feed a very small amount of oats if a guinea pig is concerningly underweight. Oats are high in carbohydrates and thus, contribute quickly to weight gain.
Guinea pigs who are showing signs of weight loss are sometimes recommended by some vets to consume very small amounts of oats – generally rolled oats.
Needless to say, a guinea pig who is dropping weight needs to be checked out and diagnosed as to the underlying cause. Guinea pigs who have been diagnosed with cancer, for example, and require ongoing weight maintenance are good candidates for the feeding of moderate amounts of raw oats. These can be mixed with a Critical Care mix (after obtaining advice from your vet).