Location: ESQRUTitle: Laying hen strain influences skeletal morphology and keel fracture prevalence in multi-tier aviary system
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2017
Publication Date: 7/17/2017
Citation: Regmi, P., Jones, D.R., Gast, R.K., Karcher, D. 2017. Laying hen strain influences skeletal morphology and keel fracture prevalence in multi-tier aviary system. Poultry Science Association Meeting Abstract. 96:35.
Technical Abstract: The change in US laying hen housing system means that the focus has been shifted from conventional cages to more extensive systems. A great deal of literature exists on nutrition, management, and breed performance in the conventional cages but not so much in the newer systems. Larger colony size and extensive opportunities of vertical and lateral movement associated with newer systems such as the multi-tier aviary (AV) system pose unique challenges to hen well-being, production, and management. The objective of this study was to evaluate the skeletal properties of brown and white egg strain of layers in the AV system. Floor reared pullets of 4 different strains – Hy-Line Brown, Bovan Brown, Dekalb White, and Hy-Line W36 were transferred to AV system at 16 wk. Hens were randomly distributed in 4 sections per room of 4 AV rooms at 144 birds per section. At 72 wk, 14 hens from each section were euthanized and tibia and keel bones were collected. Bone weight was measured and bones were scanned using a laser imaging system (Volscan ProfilerÒ) for measurement of volume and surface area. Tibia ash content was measured on a dry bone basis whereas keel fractures and deviations were scored on a binary scale. Data were analyzed with mixed ANOVA model including fixed effect of strain and random effect of AV rooms. Brown egg strains will be referred to as A and B whereas white egg strains will be referred to as C and D here onwards. Bone volume, surface area, length, dry bone weight, and ash weight were greater in brown hens than white hens (P < 0.05). Among the white hens, C had longer heavier tibia with bigger volume and surface area than D (P < 0.05) whereas dry bone weight and ash weight were not different. Keel surface area and volume was greater in brown hens than white hens with values lowest for D and intermediate for C (P < 0.05). All strains of hens suffered high incidences of keel fracture (90%) and deviations (51%). The prevalence of fracture occurrence was lowest in A (78.6%) compared to B (92.9%), C (96.2%) and D (92.9%) (P < 0.05). Keel deviation was lower in A and D hens compared to B and C hens (P < 0.05). The results indicate that strain influences the skeletal parameters and fracture prevalence in AV systems.