Photographing senior dogs can be quite and interesting adventure. Some dogs can tend to be on the hyper side, while others are a little more laid back to the point where it can be too laid back. You also have to take into consideration the physical abilities of senior dogs. They might not be able to last as long or be able to handle certain environments, so this also plays a huge part in the results of a photo session. Photographing dogs can be difficult, but with practice and the right motivation for the dog the results can be amazing.
Most of the time, at least with my experiences you get extremely well behaved and trained dogs that are happy to stay focused and be interested in what is going on during the photo session. Some get more curious than others about the camera, but that is what makes for the silly, cute up close shots.
Other times you get a dog that just doesn't have the patience to pose for the camera. I usually call these side shots the "Get my good side." photos. Usually when this happens, one of my tricks for senior dogs is to pull out the treats. Some older dogs that I photograph don't get as excited or alert with toys so I like to use treats to stimulate their sense of smell and help them put their focus towards something. Also by giving the dogs treats when the camera is around they learn to associate the camera with a reward, resulting them into enjoying having the camera in front of them and they begin to think of it as something positive rather than this strange black box in their face that makes funny clicking noises.
If you keep the senior pups happy and interested the photo session becomes a fun experience for them and allows you to catch some truly magical moments.