Seasonal serum copper variation in sheep and measurement of copper, molybdenum and sulfur concentrations in pasture grass and soil in Mahabad, West Azarbaijan Province

200 blood samples along with siol and pasture sample, for copper molybdenum and sulfur were taken at the end of each season from sheep grazing at the pastures around Mahabad in WestAzarbaijan province. Chemical analysis of samples showed that copper content of the blood was lowerthan normal in all seasons except for spring. The ratio of Cu/ Mo in pasture grass was lower than 2.Also the concentration of grass sulfur was about1000 ppm which was higher than normal (400ppm). The low level of copper in serum and high content or molybdenum and sulfur in the pasture grass, advocate the probable of a risk of secondary copper deficiency in sheep in Mahabad.