I've been recently asked about more information on IBD....this link has some of the best information that I have found....
http://www.vetpathology.org/cgi/content/full/37/5/449?ijkey=bcb8663d304c847be997549482f5b6136aae2a83
http://www.vetpathology.org/cgi/content/full/37/5/449?ijkey=bcb8663d304c847be997549482f5b6136aae2a83