Cyclic changes in plasma phosphorus of laying turkeys

Plasma phosphorus of laying turkeys measured at 0, 6, 18, and 24 hr after oviposition showed a cyclic pattern similar to that reported for laying chickens. Plasma phosphorus was lowest at oviposition and remained relatively low until 6 hr postoviposition; values at 18 and 24 hr postoviposition were higher. Plasma phosphorus was higher (P less than .05) 24 hr postoviposition than 0 or 6 hr postoviposition. The changes were assumed to be associated with egg shell calcification and bone resorption. Plasma phosphorus values of turkey toms measured during a 24-hr period remained constant and were not significantly (P less than .05) different from each other.