The Influence of Ration Protein Level on the Performance of Floor Reared and Cage Reared Replacement Pullets

Abstract

Two experiments were conducted to determine the effect of protein level fed from 6 to 20 weeks of age on the performance of cage reared and floor reared replacement pullets. The protein level of rations containing 2800 to 3000 kcal. metabolizable energy per kilogram was varied by 2% increments from 18 to 12%, 18 to 12% and 16 to 10% during the periods from 6 to 10, 10 to 14 and 14 to 20 weeks of age, respectively. Data from these two experiments indicate that replacement pullets fed a 20% protein ration to 6 weeks of age require a 14-14-12 or 16-12-12 percent protein level sequence from 6 to 10, 10 to 14 and 14 to 20 weeks of age, respectively, to maximize 20-week weight and efficiency of feed utilization and minimize the days required to reach 50% egg production. Feeding lower protein levels, i.e., 20-14-12-12, 20-12-12-12 and 20-14-12-10 percent protein level sequences resulted in inferior performance of replacement pullets to 20 weeks of age. The data also show that even though feeding a 20-14-12-12 or 20-12-12-12 percent protein level sequence resulted in a smaller bird at 20 weeks of age which required more days to reach 50% egg production, the subsequent production during the following 42-week laying cycle was not significantly reduced. The influence of protein level on the performance of replacement pullets was similar for cage reared and floor reared pullets even though pullets reared in cages were heavier at 20 weeks of age, consumed more feed, were less efficient in the utilization of feed and required fewer days to reach 50% egg production compared to pullets reared on the floor.