Why is my senior dog suddenly weak in the back legs overnight?
I am very sorry that Manny is having a hard time after his birthday celebrations. It sounds to me for what you are describing there could potentially be an osteoarthritis component to his issues. It is possible that he has muscle weakness, thought as you are noting, it is less likely to appear so quickly. Whereas, osteoarthritis flare-ups can appear immediately following a walk.
I would advise the following for you and Manny;
Shorter walks more frequently to prevent flare-ups and build up lean muscle mass
Cool compresses after a walk on his hips for a few minutes every few hours for the first 24 hours
After first 24 hours, switch to warm compresses
Adding a joint supplement to Manny's diet such as this one;
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=29218
If he does not return to himself within 48 hours, and really start to improve in the first 24 hours, I would advise taking him into his veterinarian to ensure he doesn't need any changes to his medication, or perhaps adding a long term medication for osteoarthritis.
Updated on September 23, 2025