Desempenho comparativo entre duas linhagens de roedeiras comerciais debicadas em diferentes idades na fase de recria

the present experiment was conducted to compare the performance between two commercial laying hens strains beak trimmed at dijferent ages during growing phase. two hundred andfifty birds oflohmam (lsl.) stram an？ two hundred andfifty birds of isa babcock (ib) stram were beak trimmed at dijferent ages. the first trimmed was accomplished in the 8th day of age and second one at 8th , 10th, 12th or 14th week of age. a group of32 birds from each strain was left with beaks intact and the other was not submitted to the second beak trimmed. the data were analyzed as 2 x 6 (stram x beak trimmimg age) factorial arrangement m a randomised block design. the produclive parameters studied were not significantiy affected by beak trimming age, except the egg production. the lsl strain showed better results for sexual maturity, egg weight, egg production, percentage of broken eggs and feed conversion than ib strain. the results revealed that analywd productive performance were more influenced by laying stram than beak trimming age. the relative benefits of beak trimming could vary among laying strains.