EXPERIMENTAL REPRODUCTION OF IODINE DEFICIENCY IN CATTLE

The role of iodine deficiency in stillbirth/perinatal weak calf syndro me was investigated in pregnant heifers, Five heifers were fed an iodi ne deficient diet (mean [sd] iodine concentration 0.06 [0.01] mg/kg dr y matter [DM]) and six received an iodine sufficient diet (mean [sd] i odine concentration 1.45 [0.27] mg/kg DM). The diets consisted of whea t and soyabean meal with added minerals and vitamins (with or without iodine) and were fed to the heifers over the final four to five months of pregnancy. The iodine deficient diet produced clinicopathological changes and pathological changes in the thyroid glands of both the hei fers and their offspring. However, all the calves in the iodine defici ent group were born clinically normal.