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Research article - Peer-reviewed, 2022

Integument, mortality, and skeletal strength in extended production cycles for laying hens - effects of genotype and dietary zinc source

Wall, H.; Boyner, M.; de Koning, D. J.; Kindmark, A.; McCormack, H. A.; Fleming, R. H.; Pinto, F. Lopes; Tauson, R.

Abstract

1. This study on long-life layers, covering the period 20-100 weeks of age, investigated longitudinal effects on mortality, layer integument, and skeletal properties in Bovans White (BoW) and Lohmann Selected Leghorn Classic (LSL), with or without supplementation with dietary organic zinc (Zn). 2. Two experiments, using 1440 layers in furnished small group cages (FC) and 1836 layers in a traditional floor housing system (Floor), were run in parallel. Each replicate consisted of five adjacent cages containing eight hens in each FC, or a pen with 102 layers in the Floor group. 3. Mortality was recorded daily. Integument and keel bone condition were scored at 35, 55, 85, and 100 weeks of age on 20% of the layers. Tibial strength was recorded from 933 layers at 100 weeks. Statistical analyses were performed on replicate means, with four to five and nine replicates per combination of hybrid and diet in Floor and FC groups, respectively. 4. Cumulative mortality was 9.6% and 16.3% in FC and Floor, respectively, and increased in the latter part of the production cycle, particularly in the Floor group. 5. In FC, LSL had inferior feather cover, less keel bone deviation, and shorter claws than BoW. In Floor, LSL had superior feather cover, less severe vent wounds, more bumble foot, and cleaner plumage than BoW. In both production systems, claws grew longer and keel bone deviation became more severe with age. 6. In FC, layers fed organic Zn had lower body weight and less keel bone deviation at 100 weeks of age. 7. In conclusion, keel bone integrity, claw length, and mortality rate are potential threats to welfare in long-life layers. Feather pecking is a problem that needs addressing at an early stage in the production period. On the whole, organic Zn did not improve welfare conditions in long-life layers.

Keywords

Feather cover; keel bone damage; bone strength; long life layer; organic zinc; hybrid

Published in

British Poultry Science
2022, volume: 63, number: 2, pages: 115-124
Publisher: TAYLOR AND FRANCIS LTD

Authors' information

Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Swedish University of Agricultural Sciences, Department of Animal Breeding and Genetics
Kindmark, A.
Uppsala University Hospital
McCormack, H. A.
University of Edinburgh
Fleming, R. H.
UK Research and Innovation (UKRI)
Lopes Pinto, Fernando A
Swedish University of Agricultural Sciences, Department of Animal Breeding and Genetics
Tauson, Anne-Helene
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management

UKÄ Subject classification

Animal and Dairy Science

Publication Identifiers

DOI: https://doi.org/10.1080/00071668.2021.1955329

URI (permanent link to this page)

https://res.slu.se/id/publ/113676