Ruby has always been good with other dogs.....until recently. A few weeks ago when we were on holiday in Scotland, she met lots of dogs with no problem. That was until she met 2 Shih Tzu's. She went completely beserk and screamed so loud you would think she was being murdered!! For a few days after that she met lots of other dogs, again no problem. Then she met a Yorkshire Terrier. Same reaction, screaming!!! She has not been agressive at all, more excited I would say. No more problems until today when she met a Bearded Collie and started screaming again! Any ideas why she is doing this?