My boy Maynard is going on 13 years now. Up until last year he didn't show his age, he would run and jump amd play liked a pup. But age has caught up with him so I took him to the vet and the doc prescribed him meloxicam (sp) to go along with the coseqiun that I've been giving since he started slowing down. He has some pain but he is still active, he runs (kind of like a jack rabbit runs with both hind legs at once where as before he would gallop like a horse). And his hind legs splay out now and then but no where as bad as before.
My concern now is that he is losing weight. The vet told me that what happens is that the arthritis causes the weightloss (I forgot the exact mechanism by which he explained it though).

He used to be around 80lbs but now he's dropped to around 65 and it's very visible in his rear area. I feed him Natural Balance lamb which he Liked to eat. Then he stopped eating it so now I mix it with soft food also and he eats most of the soft food and leaves the kibble alone.

The vet says that he is healthy, other than the arthritis. His blood work came back great. He eats and drinks lots of water and has regular bowl movements.

Is there something different I should be feeding him to gain more weight? I've tried all the different foods at the pet store and this brand is the one he seemed to eat. I was thinking of switching him to something like Freshpet and maybe he will eat more of that and gain some weight back.
Or should I just let him eat as he wants to eat? Maybe adding weight won't be good for his condition.
My vet said I can feed him more if I like.
Thanks for any suggestions. Sorry if this is confusing to read.

We use an Equine anti-inflammatory called Bute. It's Rx, comes in 1000 gram tablets. We give 1/2 a tab, approximately 500mg, once a day. Check with your vet. Also Glucosamine Chondroitin, 500mg a day. Good luck!

There has been good data on feeding arthritic dogs raw diets to improve symptoms. You can also go to a grain free diet. Many brands offer grain free. Blue Wilderness or Taste of the Wild are good examples.  I bought my Doberman Nature's Recipe.

You also want to add glucosamine to their diet or give them the pill if they'll take it well.  You can ask your vet the proper dose to give your dog by weight. You can also add coconut oil to their food.  It acts as a natural wormer and kills most parasites like Giardia and Coccidia. The benefits of coconut oil and pets is widely published online.  L-lysine is also a good immunity booster.

Dasuquin is what I give my senior dogs.