Few observations about prevalence and features of gastrointestinal (GI) signs in hypothyroid dogs (hypoT-dogs) are available.The study aimed (1) to evaluate concurrent GI signs in hypoT-dogs; (2) to analyze clinico-pathological and ultrasound features ofhypoT-dogs with and w/out GI signs, and (3) to analyzed GI signs follow-up after thyroid hormone replacement therapy (THRT).Medical records of hypoT-dogs from two Veterinary Teaching Hospitals were retrospectively reviewed. Dogs were classified ashypothyroid if TT4 or fT4 were low/normal with normal/high TSH or inadequate TSH-stimulation test response. Clinical history, GIsigns (vomiting, diarrhea, constipation), hematobiochemical parameters and abdominal ultrasound were collected. HypoT-dogs were divided based on the presence of at least one GI signs (GI group and not-GI group). Twenty-seven GI dogs had 3-4 weeks recheck from the beginning of THRT and information on GI signs were recorded. A total of 166 dogs were included (GI group, n=45, 27%; not-GI group, n=121, 73%). GI dogs showed nausea (42%), vomiting(40%), constipation (22%), large bowel diarrhea (40%), small bowel diarrhea (4%) and aspecific diarrhea (40%). No significant difference between GI and not-GI groups on hematobiochemical parameters was found. GI group had significantly higherfrequency (20%) of large intestine involvement than not-GI group at the ultrasound (P = 0.03; Chi-square test). Twenty-one out of27 GI dogs had a resolution of GI signs at recheck (P = 0.0001; McNemar test). Most of hypoT-dogs had concurrent GI signs mainly due to large bowel involvement. After THRT beginning the concurrent GI signs in hypoT-dogs seem to be reduce
