Effect of Calcium, Phosphorus, and Energy on the Incidence of Weak Legs in Heavy Male Broilers

Abstract

Two feeding trials were conducted to study the effects of calcium, phosphorus, and energy on the incidence of weak legs in broilers grown to 8 weeks of age. Chicks with a stilted gait and those reluctant to move or refusing to walk were considered to have weak legs. Trial 1 consisted of three treatments in which chicks were fed corn-soybean meal-based diets containing different levels (Treatment 1 < 2 < 3) of available phosphorous (aP) and calcium (Ca). No differences occurred in body weights and feed efficiency through 6 weeks. During the 6 to 8-week period, chicks in Treatment 1 gained less (P < .05) than chicks in Treatments 2 and 3. Percentage bone ash and circumference of the middle of the bone shaft were not different among treatments. Normal chicks had longer (P < .05) bones than chicks with weak legs. Chicks with weak legs had greater bone volume (P < .05) and a higher percentage of crooked bones (P < .50) than normal chicks. A deficiency of aP and Ca was not the cause of the weak legs in these heavy male broilers.Trial 2 consisted of three treatments in which chicks were fed diets containing varying levels of metabolizable energy (ME)/kg during the starting and growing periods. Body weight and feed efficiency were unaffected by any treatment during any period of the trial. The number of chicks with weak legs at 8 weeks was unaffected by diet. Chicks with weak legs had a greater bone volume (P < .06) and a higher percentage of crooked bones (P < .05) than normal chicks.