Skeletal problems in contemporary commercial laying hens

Toscano, Michael J.

doi:10.1016/b978-0-08-100915-4.00008-7

Cited by 6 publications

(4 citation statements)

References 105 publications

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“…Currently, keel bone fractures (KBF) are considered the most important welfare problem for layer hens [1,2]. Within the last 20 years, KBF in egg laying hens have significantly increased in prevalence, globally.…”

Section: Introductionmentioning

confidence: 99%

Keel bone fractures in Danish laying hens: Prevalence and risk factors

2021

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Keel bone fractures (KBF) in commercial poultry production systems are a major welfare problem with possible economic consequences for the poultry industry. Recent investigations suggest that the overall situation may be worsening. Depending on the housing system, fracture prevalences exceeding 80% have been reported from different countries. No specific causes have yet been identified and this has consequently hampered risk factor identification. The objective of the current study was to investigate the prevalence of KBF in Danish layer hens and to identify risk factors in relation to KBF in all major productions systems, including parent stock production. For risk factor identification, production data from the included flocks was used. In total, 4794 birds from 40 flocks were investigated at end-of-lay. All birds were euthanized on farm and underwent inspection and palpation followed by necropsy. All observations were recorded and subsequently analysed using the SAS statistical software package. In flocks from non-caged systems, fracture prevalence in the range 53%-100%, was observed whereas the prevalence in flocks from enriched cages ranged between 50–98%. Furthermore, often multiple fractures (≥4) were observed in individual birds (range 5–81% of the birds with fractures) depending on the flock. The localization of the fractures at the distal end of the keel bone is highly consistent in all flocks (>96%). Macroscopically the fractures varied morphologically from an appearance with an almost total absence of callus, most frequently observed in caged birds, to large callus formations in and around the fracture lines, which was a typical finding in non-caged birds. Despite being housed under cage-free conditions, parent birds had significantly fewer fractures (all flocks were 60 weeks old) per bird, than other birds from cage-free systems. The body weight at end-of-lay had an effect on the risk of having fractures, heavy hens have significantly fewer fractures at end-of-lay. The older the hens were at onset of lay, the lower was the flock prevalence at end-of-lay. Additionally, the daily egg size at onset of lay was of importance for the risk of developing fractures, the production of heavier eggs initially, resulted in higher fracture prevalence at depopulation. The odds ratio of body weight, (+100 g) was 0.97, age at onset of lay (+1 week) was 0.87 and daily egg weight at onset (+1 gram) was 1.03. In conclusion, the study demonstrated a very high prevalence of KBF in hens from all production systems and identified hen size, age at onset of lay and daily egg weight at onset of lay to be major risk factors for development of KBF in the modern laying hen. Further research regarding this is warranted to strengthen the longevity and enhance the welfare of laying hens.

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Section: Introductionmentioning

confidence: 99%

Keel bone fractures in Danish laying hens: Prevalence and risk factors

2021

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“…Bone health has long been a reported problem in commercial laying hens (Warren 1937;Grumbles 1959) with a recent focus in the last 20 years on damage (fractures) to the keel (KBF) (Toscano 2018). In barren battery cages, a lack of exercise and the high calcium requirements of prolific egg production resulted in a severe osteoporotic condition known as "cage layer fatigue" or "cage paralysis" (Grumbles 1959) resulting in brittle bones (including the spine), paralysis and death.…”

Section: Bone Healthmentioning

confidence: 99%

The Ethics of Laying Hen Genetics

Fernyhough

Nicol

Braak

et al. 2019

J Agric Environ Ethics

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Despite societal concerns about the welfare of commercial laying hens, little attention has been paid to the welfare implications of the choices made by the genetics companies involved with their breeding. These choices regarding trait selection and other aspects of breeding significantly affect living conditions for the more than 7 billion laying hens in the world. However, these companies must consider a number of different commercial and societal interests, beyond animal welfare concerns. In this article we map some of the relevant dilemmas faced by genetics companies in order to outline the scope of opportunities to improve welfare under current market conditions. This includes identifying cases where different animal welfare concerns conflict. We discuss the moral responsibility of laying hen genetics companies and the welfare implications that derive from the choices they make and the policies they follow. In addition to evaluating a selection of predominant current practices and breeding goals, we outline different angles from where to assess the moral legitimacy of various industry practices and policies. We discuss specific issues such as injurious pecking, bone health, induced moulting, chick culling and the circumstances of breeding stock.

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“…Osteoporosis is described as a progressive decrease in the amount of mineralized structural bone and leads to bone fragility and susceptibility to fracture ( Kim et al, 2012 ; Toscano, 2018 ). These anomalies can also diminish skeletal calcium reserves and contribute to the seriousness of osteoporosis.…”

Section: Introductionmentioning

confidence: 99%

Effect of the combination of 25-hydroxyvitamin D3 and higher level of calcium and phosphorus in the diets on bone 3D structural development in pullets

2023

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Bone issues such as osteoporosis are major concerns for the laying hen industry. A study was conducted to improve bone-health in pullets. A total of 448 one-day-old Hyline W36 pullets were randomly assigned to four treatments (8 rep; 14 birds/rep) until 17 weeks (wks). Dietary treatments were: 1) vitamin D3 at (2,760 IU/kg) (D), 2) vitamin D3 (2,760 IU/kg)+62.5 mg 25-(OH)D3/ton (H25D), 3) vitamin D3 (2,760 IU/kg) + 62.5 mg 25-(OH)D3/ton + high Ca&P (H25D + Ca/P), and 4) vitamin D3 (2,760 IU/kg) + high Ca&P (D + Ca/P). The high calcium (Ca) and phosphorus (P) diet was modified by increasing both high calcium and phosphorus by 30% (2:1) for the first 12 wks and then only increasing P for 12–17 wks to reduce the Ca to P ratio. At 17 wk, growth performance was measured, whole body composition was measured by dual energy x-ray absorptiometry (DEXA), and femur bones were scanned using Micro-computed tomography (Micro-CT) for bone 3D structure analyses. The data were subjected to a one-way ANOVA using the GLM procedure, with means deemed significant at p < 0.05. There was no significant outcome for growth performance or dual energy x-ray absorptiometry parameters. Micro-computed tomography results indicated that the H25D + Ca/P treatment had lower open pore volume space, open porosity, total volume of pore space, and total porosity in the cortical bone compared to the D + Ca/P. It also showed that a higher cortical bone volume/tissue volume (BV/TV) in the H25D + Ca/P than in the D + Ca/P. Furthermore, the H25D + Ca/P treatment had the lowest trabecular pattern factor and structure model index compared to the other treatments, which indicates its beneficial effects on trabecular structural development. Moreover, the H25D + Ca/P had a higher trabecular percentage compared to the D and 25D, which suggests the additional high calcium and phosphorus supplementation on top of 25D increased trabecular content in the cavity. In conclusion, the combination of 25D with higher levels of high calcium and phosphorus could improve cortical bone quality in pullets and showed a beneficial effect on trabecular bone 3D structural development. Thus, combination of a higher bio-active form of vitamin D3 and higher levels of high calcium and phosphorus could become a potential feeding strategy to improve bone structural integrity and health in pullets.

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Skeletal problems in contemporary commercial laying hens

Cited by 6 publications

References 105 publications

Keel bone fractures in Danish laying hens: Prevalence and risk factors

Keel bone fractures in Danish laying hens: Prevalence and risk factors

The Ethics of Laying Hen Genetics

Effect of the combination of 25-hydroxyvitamin D3 and higher level of calcium and phosphorus in the diets on bone 3D structural development in pullets

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