Canine hypothyroidism is one of the common endocrinopathies in dogs. Clinical signs are variable as it's a multi-systemic disease. This study was carried out to investigate epidemiology of hypothyroidism in dogs regarding to clinical signs under effect of age, sex, season and breed and confirmation with evaluation of TT4. A total number of 441 dogs admitted to a private clinic in Cairo Governorate during the period of 2018 till 2020 were subjected to comprehensive clinical examination of which 82 hypothyroid dogs were recorded and incidence of different hypothyroidism features was evaluated.
Hypothyroidism showed higher incidence in middle aged dogs (1-5 years), in males compared to females, in autumn than other seasons, and in large dog breeds. TT4 levels in this study ranged between 0.5-1 μg/dl with mean 0.8 ± 0.017. TT4 should be put in consideration during diagnosis of suspected cases related to dermatological, gynecological, otitis, CNS, tumors, dwarfism, cardiac, GIT, low BCS, obesity, eye and mixed signs. Special care should be associated with sharp decrease in TT4 in cases of CNS. The obtained data should be put under consideration in diagnosing of canine hypothyroidism and evaluation of clinical signs associated with it and therapeutic regimen to be applied for correction of such dysfunctions.