Good work on this draft. A couple things to remember
Capitalize the first letter of every word (except “a”, “the”, “of”, and other small filler words).
Try to make it a coherent title without keyword stuffing
Try to mix up the kinds of keywords you use
You did a good job to start, but I am going to see if I can add a few good suggestions here for you.
Dog Lift Harness – Large And Elderly Dog Sling Used to Lift Your Dog – Makes Lifting Rear Legs of Bigger Canines Easier – Comfortably Supports Back Legs And Hips to Help Transport Your Dog – For Senior Or Handicapped Dogs
I took out the part about “avoiding Joint Pain”, but only because I think that can be added to the bullet points, and you don’t want the title to be too long.
You can see I added some benefit/problem solution stuff into the title as well (such as “comfortably supports”, “Makes lifting easier”, “help transport your dog”).
I think it has a good amount of keywords and benefits in the title now to make it very clear what it is used for. 🙂