Ultrasonographic evaluation of gastrointestinal wall thickness in Korean raccoon dogs (Nyctereutes procyonoides koreensis)

Importance: Ultrasonographic reference values for evaluating the gastrointestinal (GI) tract in Korean raccoon dogs (Nyctereutes procyonoides koreensis) have not yet been established. Objective: This study aimed to establish baseline ultrasonographic parameters for GI wall thickness and assess differences based on sex, gastric distension, body weight, and the presence of GI symptoms. Methods: A retrospective analysis was conducted on 42 Korean raccoon dogs (35 healthy, seven symptomatic). Total and individual layer thicknesses (mucosa, submucosa, muscularis, and serosa) were measured for the stomach, duodenum, jejunum, ileum (folded and interfolded regions), and colon. Statistical analyses were performed to assess the effects of sex, body weight, gastric distension, and GI symptoms on wall thickness. Results: All Korean raccoon dogs exhibited a five-layer GI wall and echogenicity similar to that of domestic dogs. Mean total wall thickness values were: stomach (2.77 ± 0.74 mm), duodenum (2.19 ± 0.31 mm), jejunum (2.06 ± 0.35 mm), ileum (folded, 1.75 ± 0.35 mm, interfolded, 2.31 ± 0.24 mm), and colon (1.06 ± 0.37 mm). Stomach wall thickness was greater in collapsed (3.31 ± 0.37 mm) than in distended (2.15 ± 0.52 mm) states. No statistically significant differences in GI wall thickness were observed based on sex or body weight. Symptomatic Korean raccoon dogs exhibited significant thickening of the duodenum, jejunum, and colon, along with increased mucosal echogenicity, loss of normal wall layering, and intestinal corrugation. Conclusions and Relevance: These findings provide essential reference values for GI ultrasonographic evaluation in Korean raccoon dogs, with implications for diagnostic accuracy.