Relative phosphorus requirements of three strains of White Leghorn cockerels

Three strains of White Leghorn Cockerels were fed a degerminated corn meal diet supplemented with graded levels of phosphorus. The basal diet which contained .30% phosphorus and .21% calcium was adjusted to contain added phosphorus levels of 0, .05, .10, or .15%, with calcium levels of .49, .47, .57 and .61%, respectively. At the end of a 21-day trial period, birds were group weighed by replicate, and four birds from each replicate sacrificed for bone ash determinations. The experiment was repeated one time. Maximum body weights of Babcock B-300 and Hyline W-36 chicks was attained at the .10% supplemental phosphorus level; whereas Kimber K-137 chick body weight data indicated a response beyond this point to the .15% level. Bone ash data indicated that there may be a difference in phosphorus requirement and/or utilization among the three strains. There was no significant response beyond the .10% supplemental phosphorus level when tibia ash values of the B-300 and W-36 chicks were analyzed. A significant response in ash values was noted, however, to the .15% supplemental phosphorus level with K-137 chicks.