Journal of Veterinary and Animal Sciences

Abstract

Postnatal development of thyroid gland in the Kuttanad duck was studied using 104 female birds from day-old to 24 weeks of age. The material was collected from eight birds in each group at fortnightly intervals. The paired thyroid glands in the day-old Kuttanad duckling were placed at the base of the neck between the common carotid artery and the jugular vein. Mean weight of the thyroid gland increased gradually upto four weeks of age. Between four and six weeks there was a sharp increase in the weight of thyroid gland. Thereafter, from six weeks onwards, the increase was slow upto 20 weeks of age. Length, breadth and thickness of the thyroid increased by 3.5, 3.6 and 4.5 times, respectively from day-old to 24th week of age and showed more correlation with the age than the weight of the gland. Weight of the thyroid was more correlated with the body weight than with the age. Histological parameters of thyroid gland such as thickness of capsule and number of total, large, small, active and inactive follicles showed greater correlation with age than with the body weight.