The foetal thyroid of the dromedary: its relation to body weight and dimensions and to the weight of the Dam's thyroid.

Growth and iodine content of the thyroid glands in relation to body weight, length [total (BCVRT), crown-rump (CR), and curved crown-rump (CVR)], chest circumference (CC), and age were investigated in 83 camel foetuses from 70 to 355 days of gestation (mean gestation length 390 days). Weight and iodine content of the dam's thyroid were also studied. Highly significant (P less than 0.01) correlations of 0.883, 0.797, 0.798, 0.792, and 0.813 were obtained between foetal thyroid weights on the one hand and body weight, BCVRT, CR, CVR, and CC on the other hand. A significant (P less than 0.05) correlation of 0.345 was obtained between weights of the foetal thyroid and dam's thyroid. The relative weight of the foetal thyroid to body weight was 0.045% at 70-99 days of gestation, but decreased to 0.028 (0.023 to 0.036%) in the subsequent stages. Iodine trapping by the foetal thyroid was first detected at 100-129 days of gestation. Total iodine then increased until 310 days, but decreased thereafter. The foetal thyroid has 4 to 25 times higher avidity to iodine accumulation than that of the dam.