Dry matter concentration, particle size distribution and sand presence in faeces from horses with and without colic

A study comprising 74 colic and 74 control horses admitted to an animal hospital was performed. Faecal samples were collected and analysed for dry matter concentration, particle size distribution using wet-sieving, and sand presence through a sand sedimentation test. Data on horse breed, age, gender and basic feeding variables was collected and analysed using χ²-tests. Faecal dry matter concentration, particle size distribution and sand score was compared between colic and non-colic horses, and between horses with different colic types, using one-way ANOVA. Results showed that colic and non-colic horse groups were similar in breed, age, gender and basic feeding variables. Faecal dry matter concentration, particle size distribution and sand score were similar among colic and non-colic horses. Horses diagnosed with "unknown colic cause" had higher proportion of particles >0.5 <1.0 mm size compared to horses with colic due to impactions in caecum or colon, torsion or gas accumulation (P<0.05), but this difference was very small and most likely not of biological importance. Faecal dry matter concentration and sand score were similar among horses with different types of colic. Increased knowledge of the composition of particles of different size in equine faeces may enhance our understanding of digesta passage rate in colic and non-colic horses, which is needed to develop preventative measures of certain types of colic.