What are you feeding Yuki and what measures have you tried already to combat the constipation?
Has Yuki had either an xray or an ultrasound to rule out structural problems in the intestines?
Avoid biting when a simple growl will do
The Spirit Lives As Long As Someone Who Lives Remembers You - Navaho Saying
Vindication ~ For all those pets who became sick or lost their lives from tainted pet food