SIFT-MS is used for the first time in profiling the volatile organic profile in faecal headspace in two groups of
horses admitted to an equine hospital, one group with acute intestinal disease (colic) affecting the large colon, plus a control
group of similarly managed horses admitted for non-gastrointestinal/metabolic reasons (e.g. acute orthopaedic injury).
Compounds in faecal headspace which show statistically significant concentration differences between the groups are acetone
and methanol. In addition, some ions at various m/z values show significantly different ion counts between the
groups. Further information may be gleaned by using multivariate statistics in evaluating the differences between the two
horse groups. Principal components analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA)
were evaluated for reducing the dimensionality of the SIFT-MS data, and OPLS-DA was found to be best at discriminating
between the groups, particularly with SIFT-MS data acquired using the H3O+ precursor ion. Analysis of these data
also show the significance of ammonia as a discriminating ion. These results show that SIFT-MS may potentially be used
on the headspace of horse faecal samples for detecting altered microbial fermentation associated with acute intestinal disease
of the colon.