My family has had two Havanese/Coton mix dogs (Teddy and Tula - brother and sister) for about a year and a half now. Although they are my 2 sisters' dogs, I take them over to my house during the day every weekday while they are at work.
Tula has always been the smaller one between the two of them and has always been a healthy weight. However, Teddy has recently "ballooned" in weight - he's always been the larger one, but I didn't notice his weight until the last time we took him to the Vet's. They said he was about 1 pound overweight, so we have cut out all table scraps and treats except for very little. He only has access to open feeding during the night when he's with my sister, but otherwise I feed him and his sister under the suggested amount on his food (it does get a bit complicated though because I have another dog). Despite the cutting back, he is still gaining weight I think! I can't be sure, but I think he's gained about 3 pounds (I weighed him with my own scale by subtracting my weight when I picked him up from my regular weight) since his last visit to the vet which was around 4 months ago. He looks like he's gained weight, too.
Outside of the weight gain, there has been one other symptom I've been noticing (don't know if they're related at all or not!). The first time we noticed it was about 2 weeks ago when my sons stayed over at my sisters' house. Teddy crawled up to sleep with one of them but started randomly shaking. He wouldn't respond to attempts to calm him down and eventually started panting, so my son took him over to get some water thinking he was overheated, but he just crawled up with my other son and eventually went to bed.
After this incident, he has been shaking periodically. The second time we noticed it was when one of my sisters went to take a nap - he stayed out in the living room and just started shaking. He did this the next day as soon as she took a nap again. Now he supposedly does it every night when they go to bed - I'm told he goes to the kitchen, gets in a corner, and just starts shaking.
They take him with them to bed but he continues to shake for about a half hour.
Has anyone heard of something like this? Any ideas would be much appreciated! Thanks!