The Withdrawal Feed of Broilers: Carcass Responses to Dietary Phosphorus

During the period of three to six weeks, broiler males received growing feeds that were either adequate or deficient in phosphorus (P). This regimen was followed by withdrawal feeds during weeks six and seven, either including or excluding dicalcium phosphate (CaP). Birds were then caught, cooped, livehauled, on-line processed, and cone deboned to stress the skeletal system as would occur in practice. Consequences to product yield, meat quality, and leg bone integrity were examined. Low P growing feed decreased live performance, and superimposing a withdrawal feed without CaP did not accentuate problems nor did its inclusion enable recovery. Processing revealed reduced abdominal fat and reduced percentage carcass yield attributable to low P during week's three to six, but the subsequent omission of CaP had no influence. Carcass bruising decreased whenever P was low; however, a corresponding increase in skeletal problems balanced total defects, and similar proportions of grade A's occurred among treatments.