It could be arthritis which is common in older dogs just like humans.
If this is sudden, take him/her to the vet immediately as they could be getting weaker because of an illness.
Monitor if they are eating properly and breathing properly. Any abnormalities should be reported to the vet.
If this is sudden, take him/her to the vet immediately as they could be getting weaker because of an illness.
Monitor if they are eating properly and breathing properly. Any abnormalities should be reported to the vet.