​Comparative Gross Anatomical and Biometrical Studies on Thyroid Gland of Buffalo, Sheep and Goat

Abstract

Background: The thyroid gland is vital endocrine gland which secretes three hormones i.e. thyroxin (T4), triiodothyronine (T3) and Calcitonin hormones. The thyroxin (T4) and triiodothyronine (T3) hormones are biologically active and are required for maintenance of normal levels of metabolic activity. The thyroid also produces calcitonin from the parafollicular cells which act directly on osteoclast to decrease the bone resorption which lower the blood calcium level. Deficient or excessive production of thyroid hormones may lead to serious pathological states with outward symptoms. Methods: The gross anatomical and biometrical studies were conducted on thyroid gland of buffalo, sheep and goat (n=12) collected immediately after slaughtering from slaughter house and local meat shop. The weight of thyroid gland was measured by weighing balance, volume by water displacement method, length and width of lateral lobes and isthmus by calibrated scale and inelastic thread and thickness of lateral lobes and isthmus was measured by digital vernier calliper. The data was analysed statistically. Result: The lateral lobes were roughly triangular in buffalo and elongated in sheep and oval in goat. The surfaces were granular and rough in buffalo but smooth in sheep and goat. It extended from thyroid cartilage to 2nd tracheal ring in buffalo, 1st to 6th tracheal ring in sheep and 1st to 7th tracheal ring in goat. The left lobe was larger than the right lobe in all the three species studied. The thyroid gland was biggest in buffalo followed by goat and smallest in sheep. The density of isthmus was more than the lobes in sheep and goat but not in buffalo.