Prevention of goitre in new-born lambs from kale-fed ewes

Abstract

Extract

In a previous paper (Sinclair and Andrews, 1954), we showed that goitre in new-born lambs from ewes fed thousand-headed kale (Brassica oleracea var. acephala) was prevented by dosing each ewe during the latter part of pregnancy with potassium iodide at the rate of 140 mg a week for 6weeks. It was pointed out that, while weekly dosing with iodine compounds was impracticable underordinary farming conditions, larger doses, givenat longer intervals and towards the end of pregnancy, might afford an effective and practical method of preventing goitre. The use of iodized licks was also discussed. Under New Zealand conditions, all licks are subject to the disadvantage that many animals will not readily take them, but those containing the commonly-used potassium iodide suffer a special disadvantage because iodine tends to be lost from the mixtures. Because of its greater stability, potassium iodate appeared to be a better choice than potassium iodide as a lick ingredient. Since the iodine in potassium iodate is available to the thyroid glands of sheep (Wright and Andrews, 1955), it seemed probable that potassium iodate given to pregnant ewes should prevent goitre in their lambs.