Plasma Inorganic Phosphate, Calcium, and Magnesium Levels of Hens Which Laid Soft-Shelled or Shell-Less Eggs

A total of 564 plasma samples was collected from Leghorn hens to determine if inorganic phosphate, calcium, and magnesium concentrations differed in birds which had just laid soft-shelled (SS) or shell-less (SL) eggs when compared to control hens. Four groups, 141 observations per group, were used. Group 1 consisted of hens which had just laid SS or SL eggs. Group 2 contained hens with SS or SL eggs in their uteri. Group 3 consisted of hens with hard-shelled (HS) eggs in their uteri. Group 4 represented those hens which had just laid HS eggs. In general, a lower concentration of plasma calcium and magnesium was found in hens which laid either SS/SL or HS eggs (Groups 1 and 4, respectively) when compared to hens with SS/SL or HS eggs in their uteri (Groups 2 and 3, respectively). Likewise, a lower concentration of plasma inorganic phosphate was observed in hens which laid HS eggs (Group 4) when compared to hens with HS eggs in their uteri (Group 3). However, a greater concentration of plasma phosphate was found in hens which laid SS/SL eggs (Group 1) when compared to hens with SS/SL eggs in their uteri (Group 2). It is concluded that hens which laid SS/SL eggs had plasma calcium and magnesium concentrations comparable to hens which produced HS eggs. However, birds which laid SS/SL eggs had higher plasma phosphate levels than those which laid HS eggs.