Evaluation of association between body size and large intestinal transit time in healthy dogs.

Objective: To compare large intestinal transit time (LITT) in dogs of various body sizes and determine whether fecal quality was correlated with LITT.

Animals: 6 Miniature Poodles, 6 Standard Schnauzers, 6 Giant Schnauzers, and 6 Great Danes.

Procedure: LITT was calculated as the difference between total (TTT) and orocecal transit time (OCTT). Minimum and mean OCTTs were determined by use of the sulfasalazine-sulfapyridine method. Minimum TTT was estimated by use of chromium and ferric oxide as color markers, and mean TTT was calculated from the recovery from feces of ingested colored plastic beads. Fecal moisture content was determined and fecal consistency was scored during the same period.

Results: Large-breed dogs had higher fecal moisture content and more watery fecal consistency. No association between body size and OCTT was detected, but there was a positive correlation between body size and mean TTT. Mean LITT increased significantly with body size, from 9.1 +/- 1.1 hours in Miniature Poodles to 39.4 +/- 1.6 hours for Giant Schnauzers. Significant correlations were detected among mean LITT, mean TTT, and fecal scores, whereas no correlation was observed between fecal moisture content and TTT or LITT.

Conclusions And Clinical Relevance: LITT was correlated with fecal consistency in dogs of various body sizes. Mean LITT can be predicted from values for mean TTT in healthy dogs.