In this study, the male merino lambs which were clinically healthy, at the same age and similar body weight were used. The animals were divided into 5 groups as Control, Group 1A, Group 1-B, Group 2-A and Group 2-B.

During the first 3.5 month, hypothyroidism was induced except the control animals all the other by administration of thiourea at the different dose levels. Then, thiourea administration was lasted and potassium iodide (Kl) was given to the animals in the Group 1-B and Group 2-B for 3.5 month.

In the animals which were given thiourea, because of hypothyroidism. urea-N and total cholesterol levels in the blood serum increased (25.58 mg/dl and 83.78 mg/dl respectively). However, glucose levels in the blood serum decreased (40.34 mg/dl). While the parameters of the animals those were given Kl, reached at the levels of control ones (mean blood serum urea-N 17.40 mg/dl, total cholesterol 55.84 mg/dl, glucose 59.00 mg/dl). it was determined that, in the lams not given Kl. the levels of those parameters were different values in proportion to the control ones (mean blood serum urea-N 23.57 mg/dl, total cholesterol 78.48 mg/dl, glucose 41.25 mg/dl). During the experiment, no s(af/s(;ca//y important differences were found among total protein levels of all groups.