EDUCATION AND PRODUCTION The Efficacy of Using Prelay and Early-Lay Rations

ABSTRACT Experiments were conducted using two brown-egg strains to determine whether additional calcium or CP is required by these pullets prior to sexual maturity (prelay) and whether increased CP during the early part of production (early lay) would improve overall performance. In Experiment 1, the prelay treatments were arranged as a 2 x 3 factorial arrangement with two levels of CP (15 or 17%) and three levels of calcium (.9,1.8, or 3.5%) and given to the pullets from 18 to 20 wk of age. From 20 to 26 wk of age, pullets were given either a 17 or 19 % CP ration with 3.5 % calcium, resulting in a total of 12 treatments. There were no significant effects of the prelay or early-lay rations on eggs per hen housed, hen-day percentage production (HDP), or feed efficiency. Egg weight was significantly improved using the 17 % prelay ration at 26, 28, and 31 wk of age, but adversely affected by the higher levels of CP in the early-lay ration at 28 and 31 wk of age. Increasing calcium in the prelay ration had only minimal effects on egg size distribution. Experiment 2 consisted of a 3 x 2 factorial arrangement of treatments with three levels of prelay CP (15,17, or 19%) and two levels of early-lay CP (17 or 19%) and given to the pullets from 18 to 20 and 20 to 41 wk of age, respectively. There was a significant improvement in HDP from 30 to 41 wk of age using the 19 % CP prelay ration. Egg size distribution was not significantly affected by either the prelay or the early-lay rations at 35 wk of age. (Key words: calcium, protein, prelay rations, early-lay rations, brown-egg pullets