Delaying sexual maturity of pullets by nutrient restriction at the onset of production

Abstract

Two experiments were undertaken to study the effect of delayed sexual maturity of pullets on reproductive performance in the laying house. In the first experiment feed was removed from the pullets for 6 days at the onset of egg production. They were then placed on a regular laying diet. In the second experiment pullets were placed on only wheat bran for a 2-week period at the onset of production, before being placed on a regular diet. Birds on both test treatments lost a significant amount of body weight (17% for exp. 1 and 12% for exp. 2). However, when they were placed on the regular laying diet, egg production rose rapidly so that age at peak production was similar to that of the control birds. Feed intake quickly caught up to that of the control birds, as did egg size. Since birds delayed in sexual maturity are really at a different physiological age from control-fed birds, it was of interest to compare the performance of pullets at similar physiological ages. On this basis, egg production (exp. 2) rose very rapidly for the test birds compared with the control-fed birds, with feed intake and egg weight significantly higher than those of the control-fed birds. With the rapid rise to peak production and enhanced egg size, no loss in egg mass output should be experienced over a normal laying year. Key words: Sexual maturity, limit feeding, pullets, egg size