I have a 4-ish year old (was a stray) schnauzer-poodle mix. I suspect she has luxating patella and started her on Cosequin Plus. After researching online I noticed that there are two types of Cosequin.... the Plus and the DS which has the chondroitin. How important is it to have the chondroitin? The Cosequin Plus just has Glucosamine Hydrochloride (HCI) and Methylsulfonylmethane (MSM).