CALCIUM REQUIREMENTS OF TWO BREEDS OF CHICKENS AS INFLUENCED BY LEVEL OF DIETARY PHOSPHORUS

Abstract

Two factorial experiments were conducted to compare the dietary calcium requirements of two breeds of chickens and to determine the relationship between breed, dietary phosphorus level, and dietary calcium levels. Both experiments used two breeds of chickens (broiler crossbreds and Single Comb White Leghorns), two levels of added dietary phosphorus (0.18 and 0.36%), and six levels of added dietary calcium (experiment 1: 0.2, 0.4, 0.6, 0.8, 1.2, and 1.4%; experiment 2: 0.0, 0.3, 0.6, 0.9, 1.2, and 1.5%). Criteria observed included body weight (4-week), feed efficiency, mortality, and percent bone-ash. Breed and calcium level had a consistent significant effect on body weight, feed efficiency, and percent bone-ash. The breed × calcium interaction was significant for all the criteria measured, indicating that the Leghorn and broiler-type chickens differ in their dietary calcium requirements.