Analysis of genotype-environment interactions between layer lines and housing systems for performance traits, egg quality and bone breaking strength - 1st communication: Performance traits

Performance traits of white layers (Lohmann Selected Leyhorn, LSL) and brow n layers (Lohmann Tradition LT) were comparatively analysed in three differ ent housing systems, battery cages, aviary and intensive free range housing . In each housing system 750 LSL and 750 LT-layers were kept on the same gr ound area. All laying hens had identical feeding, management and health car e management. The same staff was responsible for all laying hens. The egg l aying period started in April 1999 and ended in March 2000. The objective o f this investigation was to analyse performance traits for significant inte ractions among layer lines and housing systems. The LSL-layer line showed s ignificantly higher performances compared to the LT-layer line in the trait s egg number (82.10% per hen housed and 87.26% per average hen housed), egg mass (49.89 g per lien housed and 53.12 g per average hen housed), food co nsumption (2.05 kg food per kg egg mass), and a lower proportion of floor e ggs (2.38 %) as well as of cracked and broken eggs (1.23 %). However, the m ortality rate (3.91 %) and the proportion of dirty eggs (3.65%) was lower i n the LT-layer line as well as the egg weight (62.47 g) was higher than in the LSL-layer line. The LSL-hens reached the highest performance in the tra its egg number (79.15% per hen housed and 81.84% per average hen housed), e gg mass (51.95 g per lien housed and 53.63 g per average hen housed) and fo od consumption (2.03 kg food per kg egg mass) in the aviary. The highest mo rtality (13.29%) rate was registered for LSL-hens in battery cages. The LT- hens showed the highest performance in battery cages in the traits egg numb er (75.04% per hen housed and 77.77% per average hen housed), egg mass (51. 10 g per hen housed and 52.87 g per average hen housed) and egg weight (62. 70 g). The highest mortality rate (5.52%) was recorded in the intensive fre e range system for LT-hens. The highest proportion of cracked and broken eg gs for both layer lines was registered in battery cages. Food consumption p er kg egg mass increased in the intensive free range system compared to the other housing systems. The highest proportion of floor eggs and cracked an d broken eggs was registered in the aviary for both layer lines. Genotype-environment interactions between layer lines and housing systems w ere significant. Both layer lines differed in their ability to be used for alternative housing systems. Therefore, conclusions on lien housing systems have to consider which layer lines were used and generalizations have to b e taken with care for other layer lines.