Hi DekaDawson as said, you seem to be doing everything for your Lab
I have a 100 lb pup with pretty bad arthritis and give her 2000 mg X 2 daily of Glu/Chon/MSM like Rainbow. On worse days I also give her bufferin 500 mg which seems to help.
I can relate it's very hard keeping their weight down when it's hard for them to move around but I found as Growler pointed out swimming *miracle drug* sheds the weight and it's so relaxing for sore bones. My girl swims daily in the river and it seems to really help
re Cartrophen Injections & Dog Aware dot com thanks for both links, very interesting reading
for your girl