Presently described are compositions and methods which utilize stearidonic acid (SDA). In one embodiment, the disclosure is directed to pet food compositions comprising SDA. In optional embodiments, the compositions are nutritionally balanced compositions, or supplements. In yet another embodiment, the disclosure is directed to methods selected from promoting bone or joint health, promoting chondrocyte functioning, maintaining tissue concentration of omega-3 fatty acids, promoting tissue concentration of omega-3 fatty acids, and combinations thereof, including the like, in a pet, comprising administration of a composition comprising SDA to the pet. In optional embodiments, the pet is a puppy, kitten, large breed dog, or geriatric animal.