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Causes of mortality in laying hens in different housing systems in 2001 to 2004

BACKGROUND: The husbandry systems for laying hens were changed in Sweden during the years 2001 – 2004, and an increase in the number of submissions for necropsy from laying hen farms was noted. Hence, this study was initiated to compare causes of mortality in different housing systems for commercial...

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Autores principales: Fossum, Oddvar, Jansson, Désirée S, Etterlin, Pernille Engelsen, Vågsholm, Ivar
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2652464/
https://www.ncbi.nlm.nih.gov/pubmed/19146656
http://dx.doi.org/10.1186/1751-0147-51-3
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author Fossum, Oddvar
Jansson, Désirée S
Etterlin, Pernille Engelsen
Vågsholm, Ivar
author_facet Fossum, Oddvar
Jansson, Désirée S
Etterlin, Pernille Engelsen
Vågsholm, Ivar
author_sort Fossum, Oddvar
collection PubMed
description BACKGROUND: The husbandry systems for laying hens were changed in Sweden during the years 2001 – 2004, and an increase in the number of submissions for necropsy from laying hen farms was noted. Hence, this study was initiated to compare causes of mortality in different housing systems for commercial laying hens during this change. METHODS: Based on results from routine necropsies of 914 laying hens performed at the National Veterinary Institute (SVA) in Uppsala, Sweden between 2001 and 2004, a retrospective study on the occurrence of diseases and cannibalism, i.e., pecking leading to mortality, in different housing systems was carried out. Using the number of disease outbreaks in caged flocks as the baseline, the expected number of flocks with a certain category of disease in the other housing systems was estimated having regard to the total number of birds in the population. Whether the actual number of flocks significantly exceeded the expected number was determined using a Poisson distribution for the variance of the baseline number, a continuity correction and the exact value for the Poisson distribution function in Excel 2000. RESULTS: Common causes of mortality in necropsied laying hens included colibacillosis, erysipelas, coccidiosis, red mite infestation, lymphoid leukosis and cannibalism. Less common diagnoses were Newcastle Disease, pasteurellosis and botulism. Considering the size of the populations in the different housing systems, a larger proportion of laying hens than expected was submitted for necropsy from litter-based systems and free range production compared to hens in cages (P < 0.001). The study showed a significantly higher occurrence of bacterial and parasitic diseases and cannibalism in laying hens kept in litter-based housing systems and free-range systems than in hens kept in cages (P < 0.001). The occurrence of viral diseases was significantly higher in indoor litter-based housing systems than in cages (P < 0.001). CONCLUSION: The results of the present study indicated that during 2001–2004 laying hens housed in litter-based housing systems, with or without access to outdoor areas, were at higher risk of infectious diseases and cannibalistic behaviour compared to laying hens in cages. Future research should focus on finding suitable prophylactic measures, including efficient biosecurity routines, to reduce the risk of infectious diseases and cannibalism in litter-based housing systems for laying hens.
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spelling pubmed-26524642009-03-07 Causes of mortality in laying hens in different housing systems in 2001 to 2004 Fossum, Oddvar Jansson, Désirée S Etterlin, Pernille Engelsen Vågsholm, Ivar Acta Vet Scand Research BACKGROUND: The husbandry systems for laying hens were changed in Sweden during the years 2001 – 2004, and an increase in the number of submissions for necropsy from laying hen farms was noted. Hence, this study was initiated to compare causes of mortality in different housing systems for commercial laying hens during this change. METHODS: Based on results from routine necropsies of 914 laying hens performed at the National Veterinary Institute (SVA) in Uppsala, Sweden between 2001 and 2004, a retrospective study on the occurrence of diseases and cannibalism, i.e., pecking leading to mortality, in different housing systems was carried out. Using the number of disease outbreaks in caged flocks as the baseline, the expected number of flocks with a certain category of disease in the other housing systems was estimated having regard to the total number of birds in the population. Whether the actual number of flocks significantly exceeded the expected number was determined using a Poisson distribution for the variance of the baseline number, a continuity correction and the exact value for the Poisson distribution function in Excel 2000. RESULTS: Common causes of mortality in necropsied laying hens included colibacillosis, erysipelas, coccidiosis, red mite infestation, lymphoid leukosis and cannibalism. Less common diagnoses were Newcastle Disease, pasteurellosis and botulism. Considering the size of the populations in the different housing systems, a larger proportion of laying hens than expected was submitted for necropsy from litter-based systems and free range production compared to hens in cages (P < 0.001). The study showed a significantly higher occurrence of bacterial and parasitic diseases and cannibalism in laying hens kept in litter-based housing systems and free-range systems than in hens kept in cages (P < 0.001). The occurrence of viral diseases was significantly higher in indoor litter-based housing systems than in cages (P < 0.001). CONCLUSION: The results of the present study indicated that during 2001–2004 laying hens housed in litter-based housing systems, with or without access to outdoor areas, were at higher risk of infectious diseases and cannibalistic behaviour compared to laying hens in cages. Future research should focus on finding suitable prophylactic measures, including efficient biosecurity routines, to reduce the risk of infectious diseases and cannibalism in litter-based housing systems for laying hens. BioMed Central 2009-01-15 /pmc/articles/PMC2652464/ /pubmed/19146656 http://dx.doi.org/10.1186/1751-0147-51-3 Text en Copyright © 2009 Fossum et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Fossum, Oddvar
Jansson, Désirée S
Etterlin, Pernille Engelsen
Vågsholm, Ivar
Causes of mortality in laying hens in different housing systems in 2001 to 2004
title Causes of mortality in laying hens in different housing systems in 2001 to 2004
title_full Causes of mortality in laying hens in different housing systems in 2001 to 2004
title_fullStr Causes of mortality in laying hens in different housing systems in 2001 to 2004
title_full_unstemmed Causes of mortality in laying hens in different housing systems in 2001 to 2004
title_short Causes of mortality in laying hens in different housing systems in 2001 to 2004
title_sort causes of mortality in laying hens in different housing systems in 2001 to 2004
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2652464/
https://www.ncbi.nlm.nih.gov/pubmed/19146656
http://dx.doi.org/10.1186/1751-0147-51-3
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