The present article discussed the relationships between thyroidal hormonal changes, rumen functions and
metabolism, serum biochemicals assays, electrolytes and blood pictures in sheep in Egypt either before or after potassium
iodide (KI) adding to their rations through long term study extended for successive 65 days. The study was
conducted on fattening Osimi sheep (n=19) with ages ranging between 6-11 months. Animals were supplied with KI
salts dissolved in distilled water in the morning with a dose of 0.15 mg/kg in addition to 0.093 mg iodine /kg DM/
day for successive 65 days. The examined sheep were undergoing thorough investigations included clinically, laboratory,
rumen functions and body gain estimation according to the following schedule; zero, 15th, 30th and 65th days. The
study reported significant changes in rumen metabolic functions through the remarkable improvement in each of the
protozoal ciliate density and TVFAs, and reduced ruminal ammonia as well as maintaining normal pH. Most of blood
picture indices showed clear improvement particularly red blood corpuscles and haemoglobin concentration. Thyroid
functions were clearly affected with long-term 65 days KI supplementation as thyroid hormones were significantly
reduced in their concentrations and reached their lowest values at day 65, however, they were still not lower than their
reference values. Serum biochemicals showed no changes except for glucose that showed significant improvement.
Long-term KI supplementation had a great impact on serum blood urea nitrogen and alkaline phosphatase through
their significant serum concentrations reduction. A significant improvement in body weight gain was reported in treated
sheep during the current study with a reported highest body weight gain at the 65th day. In Conclusion, long-term
65 days KI supplementation induced variable significant changes in sheep mainly rumen metabolic functions, blood
picture indices, thyroid hormones functions and body weight gain.