LAYING HEN PRODUCTION RESPONSES TO LEAST-COST RATIONS FORMULATED WITH STOCHASTIC-PROGRAMMING OR LINEAR-PROGRAMMING WITH A MARGIN OF SAFETY

An experiment with 480 DeKalb DK laying hens was conducted to study the effect of rations formulated with stochastic programming (STCH) or linear programming with a margin of safety (LPMS) over 12, 28-d periods. Rations were formulated to guarantee the requirement of methionine and lysine greater-than-or-equal-to 69%, in all rations, and Ca and P greater-than-or-equal-to either 69 or 90%. The four rations were: LPMS69 with Ca and P greater-than-or-equal-to 69%, LPMS90 with Ca and P greater-than-or-equal-to 90%, STCH69 with Ca and P greater-than-or-equal-to 69%, and STCH90 with Ca and P greater-than-or-equal-to 90%. Rations formulated with STCH were lower in cost than LPMS rations for respective probability levels. Costs per metric ton for LPMS69, LPMS90, STCH69, and STCH90 were $155.70, $157.71, $155.00, and $156.30, respectively. Compared to STCH rations, LPMS rations were overformulated in nutrients. There was no difference (P > .05) in performance for hen-housed egg production, hen-day egg production, feed er dozen eggs, mortality, egg weight, or eggshell percentage.