My dog is suddenly very calm. Should I be worried about his health?

Lethargy can be a sign of illness, but it doesn't point to any one particular issue, and is rather a symptom than a cause. Unfortunately, without a vet exam, it would be hard to determine more than that. I would keep an eye on Oso for any other signs of illness that may indicate he needs to go to the vet. If you're having trouble affording care, this site can help give you some options that might help: https://www.humanesociety.org/resources/having-trouble-affording-veterinary-care

Any abrupt change in behavior without a known cause should be investigated by your vet as soon as possible. Sometimes this is the only sign we get of a medical condition. The behavior could be due to feeling ill, being in pain or may be because of a developing neurological condition. Your vet will do an exam, labwork and possibly some diagnostic imaging, x-rays or ultrasound to determine the cause for your pet's change in behavior and, based on the results, will be better able to advise you on treatment options.

This can be caused by many different things, including impending illness, stress, pain, a change in his environment, behavioral, etc. I would recommend a good checkup with a vet to see if there is a medical cause. The vet will perform a thorough physical exam and look for any abnormalities or sources of potential pain. Bloodwork may be recommended to for internal medical illnesses. If nothing is uncovered, then they may discuss other treatments such as things for stress or help you evaluate what started this new attitude.

Thanks for using Petco Pet Education Center, formerly Petcoach! It sounds like Bear is just a little on edge from his itchy skin, unusual bath, and (I’m guessing) recent vet visit. I wouldn’t worry too much about it. Keep doing your daily walks and training reinforcement and give him a few days. Even if this anxiety persists, it can often be managed with extra exercise and training in dogs of this age and breed. Best wishes to you and Bear!

Poor Bear. He sounds sick, and his symptoms could be caused by a systemic illness, infection, or injury. I'm concerned this is going on, and I think it's best you take him into a vet today. To help diagnose what is causing his symptoms, the vet can do a geriatric blood panel and urinalysis. Once a cause is found, the vet can discuss treatment options. I hope this helps!

At 3years of age he would generally expected to be more active but every dogs character is different and some are very placid. If his behavior has changed over the last 3 months I strongly recommend a full health check by your vet to rule out medical or painful conditions which may be reducing his mobility

Anytime there is a sudden change in behavior, an exam with your veterinarian is recommended. Such a change can be due to trauma or infection. Considering the recent history, it is possible Kane may have suffered an injury which will need to be diagnosed and treated by your veterinarian. At the very least, he will get a clean bill of health and may simply be "shaken up" by recent events. If this is the case, he should gradually return to normal activity.