A Model for the Stratification of Dairy and Mutton Sheep Breeds in Middle Eastern Deserts

than any of the other grass mixtures when collected in the cured stage. Since aphosphorosis did not occur during the winter blood sampling period, phosphorus accumulated during the growing period on winter and alpine ranges may influence blood phosphorus during the winter when forage phosphorus is in short supply. At this time it is not known to what degree a free-ranging animal can accumulate phosphorus (April to October) nor the ease with which it is mobilized from storage depots. Simesen (1963) states, “Bone mineral is readily mobilized to maintain the level of serum calcium, but less readily to maintain that of phosphorus, so that a low serum inorganic phosphate level is the first. sign of a deficiency of phosphorus.” Hays and Swenson (1970) suggest that bone phosphorus is readily mobilized. Serum inorganic phosphorus levels of my sheep did not indicate a state of deficiency. They were above 4 mg/lOO ml, the minimum level set by the National Research Council (1964) and Watkins and Knox (1945).