Impact of body weight at 19 weeks of Embrapa 051 layers on performance, nest utilization, and egg quality throughout the laying cycle.

ABSTRACT: A total of 860 Embrapa 051 pullets were allocated into three groups based on their 19-week body weights (heavy: 1.48 kg ± 0.01 SD, N= 172 birds, medium: 1.32 kg ± 0.039 SD, N= 516 birds, light: 1.19 kg ± 0.019 SD, N=172 birds) and housed in floor pens with nests for a 65-week production period. Heavy-weight birds exhibited higher egg production during weeks 24-28, while medium-weight hens surpassed heavy-weight counterparts between weeks 41-46, and light-weight hens outperformed heavy-weight birds in weeks 61-65. From weeks 57-65, no significant egg production differences were noted between heavy and medium-weight hens. Body weight at 19 weeks affected floor eggs, cracked eggs, and double-yolk eggs (P < 0.05) during weeks 22-34. Heavy-weight hens laid fewer floor eggs, medium-weight hens had fewer cracked eggs (0.3%), and light-weight hens produced fewer double-yolk eggs (1.1%). No significant impact of weight grouping on egg weight was observed. Results indicated that body weight at 19 weeks influences the laying cycle, with heavy, medium, and light-weight hens exhibiting distinct egg production patterns, nest use and egg quality traits at different phases of the cycle. Key words: cracked eggs, double-yolk eggs, egg production, floor eggs, laying rate, nests. RESUMO: Oitocentas e sessenta frangas Embrapa 051 foram alocadas em três grupos de peso corporal às 19 semanas (pesadas: 1,48 kg ± 0,01 DP, N= 172 aves, médias: 1,32 kg ± 0,039 DP, N= 516 aves, leves: 1,19 kg ± 0,019 DP, N=172 aves) e alojadas em piso com ninhos por 65 semanas. As aves pesadas apresentaram maior produção de ovos nas semanas 24-28, enquanto as médias superaram as pesadas nas semanas 41- 46, e as leves superaram as pesadas nas semanas 61-65. Nas semanas 57 a 65, não houve diferenças significativas na produção de ovos entre as aves pesadas e médias. O peso às 19 semanas afetou ovos no chão, ovos trincados e ovos duplos (P < 0,05) nas semanas 22-34. As aves pesadas botaram menos ovos no chão, as médias tiveram menos ovos trincados (0,3%), e as leves produziram menos ovos com duas gemas (1,1%). Não houve impacto significativo do peso inicial no peso dos ovos. Em conclusão, o peso às 19 semanas influencia o ciclo de postura, com aves pesadas, médias e leves exibindo padrões distintos de produção de ovos, uso do ninho e características de qualidade em diferentes fases do ciclo.