maybe this?
http://www.mangago.me/read-manga/kaichou_san_chi_no_koneko/
that`s the only one i could remember being quite similar to your description...
ahh, sorry @sakuracry, but this isn't it. The cat was fat and big, that's why it got called buchou (not really sure if it was buchou, but it was a position in the office)
okay, goodluck finding the right one ;o)
thanks!! already found it. It's strobe edge. XD
Pretty sure its this
http://www.mangago.me/read-manga/strobe_edge/
The page where he calls the cat Buchou and Shachou is Chpt 20 pg 23 & 24
Yep! It is indeed. Thanks! ^^
HELP!
Forgot the title of the manga..
I remember it was a high school shoujo manga, and the girl named the cat buchou/kachou/kaichou because the cat was fat. I remember I liked it and I would like to read it again.