Ultrasonographic evaluation of thyroid glands and comparative hormonal analysis of domestic cats and neotropical wild felids

ABSTRACT This study aimed to determine the morphological and metric of the thyroid gland, and Total T4 and Free T4 hormonal values among domestic and wild felids without thyroid diseases. Thirty-three felids without thyroid diseases were evaluated, being 13 felids, one Panthera onca, three Pumas concolor, three small wild cats, three Pumas yagouaroundi, two Leopardus pardalis and one Leopardus wiedii, and 20 domestic felines. The animals were submitted to ultrasonography of the thyroid gland and to hormonal serum dosage of Total T4 and Free T4 by the technique of chemiluminescence. Subsequently, they were divided into groups according to weight, sex, and age. The mean volume of thyroid lobe was 0.11cm³ for domestic cats, 0.18cm³ for the mixed wild feline group (Leopardus pardalis, Leopardus tigrinus, Leopardus wiedii and Pumas yagouaroundi) and 1.57cm³ for the jaguar group (Panthera onca e Pumas concolor). The mean Total T4 and Free T4 were 2.55µg/dL and 1.23ng/dL for domestic cats, 1.46µg/dL and 1.89ng/dL for the mixed feline group and 0.68µg/dL and 0.82ng/dL for the jaguar group, respectively. Animals over 10 years old presented higher Free T4 values.