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M J Toscano - One of the best experts on this subject based on the ideXlab platform.
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genetic variation of Keel and long Bone skeletal properties for 5 lines of laying hens
The Journal of Applied Poultry Research, 2020Co-Authors: Laura Candelotto, Sabine G Gebhardthenrich, Ariane Stratmann, Teun Van De Braak, Marc A Stadelmann, D Guggisberg, Philippe K Zysset, M J ToscanoAbstract:Summary Fractures to the Keel Bone is one of the greatest problems facing the laying hen industry. With most severe effects observed in non-cage housing, frequencies are expected to dramatically increase as the industry continues transitioning away from battery cages. Incidences within commercial systems are well documented, where the main cause is believed to be high egg production and the associated need for calcium drawing on endogenous reserves (i.e., Bone) leaving Bone weakened and prone to fracture. The current work sought to characterize various Bone mineral and biomechanical properties of 5 distinct purebred or crossbred laying hen lines (3 commercial: Bovans Brown, Dekalb White, and Institut de Selection Animale Dual Brown; 2 non-commercial: Experimental Brown and Experimental White), following previous work that demonstrated differences in susceptibility to Keel fracture using an ex vivo impact testing apparatus. The Keel was then removed to undergo analysis by computer tomography; the humerus and tibia were also removed for biomechanical testing. The Keel Bone mineral density and moment of area correlated moderately with hen weight and susceptibility to fracture. The biomechanical properties of the tibia, but not the humerus, showed a strong relationship with hen weight. One commercial genetic line (Dekalb White) with a high susceptibility to fracture exhibited a mean tibia strength below the value expected from its mean weight. Our results suggest that for the purebred or crossbred lines other than Dekalb White, rather than properties of Bone, lower mean weight may imply higher levels of activity, higher risk of collisions, and lower soft tissue protection that reflect greater susceptibility to Keel fracture.
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explanations for Keel Bone fractures in laying hens are there explanations in addition to elevated egg production
Poultry Science, 2020Co-Authors: M J Toscano, Stefanie Petow, Kathe Elise Kittelsen, Jens Peter Christensen, I C Dunn, Reiner UlrichAbstract:The current article served to provide the most up-to-date information regarding the causes of Keel Bone fracture. Although elevated and sustained egg production is likely a major contributing factor toward fractures, new information resulting from the development of novel methodologies suggests complementary causes that should be investigated. We identified 4 broad areas that could explain variation and increased fractures independent of or complementing elevated and sustained egg production: the age at first egg, late ossification of the Keel, predisposing Bone diseases, and inactivity leading to poor Bone health. We also specified several topics that future research should target, which include continued efforts to link egg production and Bone health, examination of noncommercial aves and traditional breeds, manipulating of age at first egg, a detailed histological and structural analysis of the Keel, assessment of prefracture Bone condition, and the relationship between individual activity patterns and Bone health.
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radiographic evaluation of Keel Bone damage in laying hens morphologic and temporal observations in a longitudinal study
Frontiers in Veterinary Science, 2020Co-Authors: Sarah Dorothea Baur, M J Toscano, Christina Rufener, Urs GeissbuhlerAbstract:The Keel Bone of commercially kept laying hens is known to be frequently affected by morphologic changes such as fractures and deformations with important implications for animal welfare. To detect morphologic changes, various methods such as palpation, computed tomography and ultrasound are available, though radiography allows for the greatest level of detail in combination with the most ease of use. To explore the benefits of radiography in providing objective data on Keel fractures from the age of 22 to 61 weeks within a single laying period, the Keel Bones of 75 Lohmann Brown and 75 Lohmann Selected Leghorns were radiographed every three to five weeks. Type, location, angulation, dislocation, callus formation, and healing process were assessed descriptively for each lesion. Ninety-nine percent of the animals showed at least one Keel Bone lesion during the study and 97% of the animals had at least one Keel Bone fracture. In 77% of the cases, the caudal third of the Keel Bone was affected. The fracture types were transverse and oblique (88%), comminuted, and butterfly. Further lesions were sclerosis, new Bone formation and angulation. For each Keel Bone, an average of three fractures (3.09 +/- 1.80) was detected at the end of the study. The described radiographic protocol for Keel Bone lesions was suitable for longitudinal, on-site examinations in conscious laying hens. Our results also indicate that Keel Bone fractures are more frequent than reported in earlier studies. The described radiographic examination protocol can be used to perform comparative studies of palpatory findings, or to assess the clinical significance of different fracture types which require a high level of detail.
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Keel Bone fractures induce a depressive-like state in laying hens
Scientific Reports, 2020Co-Authors: E. A. Armstrong, M J Toscano, V Sandilands, C. Rufener, J. E. Eastham, J. H. Guy, T. Boswell, T. V. SmuldersAbstract:In commercial flocks of laying hens, Keel Bone fractures (KBFs) are prevalent and associated with behavioural indicators of pain. However, whether their impact is severe enough to induce a depressive-like state of chronic stress is unknown. As chronic stress downregulates adult hippocampal neurogenesis (AHN) in mammals and birds, we employ this measure as a neural biomarker of subjective welfare state. Radiographs obtained longitudinally from Lohmann Brown laying hens housed in a commercial multi-tier aviary were used to score the severity of naturally-occurring KBFs between the ages of 21–62 weeks. Individual birds’ transitions between aviary zones were also recorded. Focal hens with severe KBFs at 3–4 weeks prior to sampling (n = 15) had lower densities of immature doublecortin-positive (DCX^+) multipolar and bipolar neurons in the hippocampal formation than focal hens with minimal fractures (n = 9). KBF severity scores at this time also negatively predicted DCX^+ cell numbers on an individual level, while hens that acquired fractures earlier in their lives had fewer DCX^+ neurons in the caudal hippocampal formation. Activity levels 3–4 weeks prior to sampling were not associated with AHN. KBFs thus lead to a negative affective state lasting at least 3–4 weeks, and management steps to reduce their occurrence are likely to have significant welfare benefits.
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Keel Bone fractures are associated with individual mobility of laying hens in an aviary system
Applied Animal Behaviour Science, 2019Co-Authors: Christina Rufener, Ariane Stratmann, Yandy Abreu, Lucy Asher, John Berezowski, Filipe Maximiano Sousa, M J ToscanoAbstract:Abstract Keel Bone fractures (KBF) in laying hens have been shown to cause pain and impair mobility under experimental conditions. However, it is not known how KBF relates to the mobility of individual hens housed in aviary systems. For the current study, 120 focal hens (60 Lohmann Brown (LB) and 60 Lohmann Selected Leghorn (LSL)) were kept in six identical pens equipped with a commercially relevant aviary system (20 LSL focal hens + 205 LB or 20 LB focal hens + 205 LSL per pen, respectively). Data on hen mobility were recorded at 21, 24, 27, 31, 35, 39, 44, 48, 52, 57 and 61 weeks of age. Infrared receivers were attached to the legs of focal hens. They recorded zone-specific codes between five zones (litter, lower tier, nest boxes, top tier, and wintergarden) at a frequency of 1 Hz for six consecutive days per week of age. At the end of each data collection period, hens were radiographed to assess Keel Bone fracture severity. Data were analysed using (generalized) linear mixed effect models. With increasing KBF severity, LB hens spent more time in the top tier (p = 0.005) and less time in the litter zone (p
Stefanie Petow - One of the best experts on this subject based on the ideXlab platform.
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explanations for Keel Bone fractures in laying hens are there explanations in addition to elevated egg production
Poultry Science, 2020Co-Authors: M J Toscano, Stefanie Petow, Kathe Elise Kittelsen, Jens Peter Christensen, I C Dunn, Reiner UlrichAbstract:The current article served to provide the most up-to-date information regarding the causes of Keel Bone fracture. Although elevated and sustained egg production is likely a major contributing factor toward fractures, new information resulting from the development of novel methodologies suggests complementary causes that should be investigated. We identified 4 broad areas that could explain variation and increased fractures independent of or complementing elevated and sustained egg production: the age at first egg, late ossification of the Keel, predisposing Bone diseases, and inactivity leading to poor Bone health. We also specified several topics that future research should target, which include continued efforts to link egg production and Bone health, examination of noncommercial aves and traditional breeds, manipulating of age at first egg, a detailed histological and structural analysis of the Keel, assessment of prefracture Bone condition, and the relationship between individual activity patterns and Bone health.
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radiographic examination of Keel Bone damage in living laying hens of different strains kept in two housing systems
PLOS ONE, 2018Co-Authors: Beryl Katharina Eusemann, Ulrich Baulain, Lars Schrader, Antonia Patt, Christa Thonereineke, Stefanie PetowAbstract:A high prevalence of deviations and fractures of the Keel Bone is a widespread welfare problem in laying hens. The aim of this study was to experimentally investigate this multifactorial problem throughout the laying period and to compare the prevalence and severity in different layer lines and different housing systems. High performing white (WLA) and brown (BLA) pure bred layer lines and low performing white (R11, G11) and brown layer lines (L68) were kept in both single cages and a floor housing system. A total of 97 hens (19 or 20 from each line, respectively) were repeatedly radiographed in the 35th, 51st and 72nd week of age. Fracture prevalence increased with age (p<0.001). The proportion of deviated Keel Bone area increased only for caged BLA, WLA and R11 hens (p<0.05) and was significantly higher for caged WLA and R11 hens compared to floor-housed WLA and R11 hens in the 72nd week of age (p<0.05). In the 72nd week of age hens in the floor housing system showed significantly more fractures than hens kept in cages (p<0.05). Prevalence of Keel Bone deviations was significantly higher in the white layer line R11 but significantly lower in the white layer line G11 compared to both brown layer lines and WLA (p<0.05). Brown layers showed significantly more fractures than white layers (p<0.05) in the 51st and 72nd week of age. Within the brown layers there was a significantly lower prevalence of deviations (p<0.05) and fractures (p<0.05) in the low performing (L68) compared to the high performing line (BLA). Our results show a different development of Keel Bone damage in caged compared to floor-housed hens under experimental conditions. Additionally, they indicate genetic effects on Keel Bone damage.
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A deviated Keel Bone.
2018Co-Authors: Beryl Katharina Eusemann, Ulrich Baulain, Lars Schrader, Christa Thöne-reineke, Antonia Patt, Stefanie PetowAbstract:The Keel Bone surface area is circumscribed with blue color; the area of deviation is circumscribed with red color. The blue-red line marks the straight line between the start and end point of thedeviated outline.
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Radiographic examination of Keel Bone damage in living laying hens of different strains kept in two housing systems
2018Co-Authors: Beryl Katharina Eusemann, Ulrich Baulain, Lars Schrader, Christa Thöne-reineke, Antonia Patt, Stefanie PetowAbstract:A high prevalence of deviations and fractures of the Keel Bone is a widespread welfare problem in laying hens. The aim of this study was to experimentally investigate this multifactorial problem throughout the laying period and to compare the prevalence and severity in different layer lines and different housing systems. High performing white (WLA) and brown (BLA) pure bred layer lines and low performing white (R11, G11) and brown layer lines (L68) were kept in both single cages and a floor housing system. A total of 97 hens (19 or 20 from each line, respectively) were repeatedly radiographed in the 35th, 51st and 72nd week of age. Fracture prevalence increased with age (p
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Fracture prevalence.
2018Co-Authors: Beryl Katharina Eusemann, Ulrich Baulain, Lars Schrader, Christa Thöne-reineke, Antonia Patt, Stefanie PetowAbstract:Each bar represents the total amount of radiographed and evaluated hens of one layer line within one housing system. The grey part of a bar shows the part of hens with a fractured Keel Bone, the white part those without any fracture. The numbers written in the bars show the total numbers of affected or non-affected hens, respectively. Fracture prevalence was affected by layer line (p
Sabine G Gebhardthenrich - One of the best experts on this subject based on the ideXlab platform.
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genetic variation of Keel and long Bone skeletal properties for 5 lines of laying hens
The Journal of Applied Poultry Research, 2020Co-Authors: Laura Candelotto, Sabine G Gebhardthenrich, Ariane Stratmann, Teun Van De Braak, Marc A Stadelmann, D Guggisberg, Philippe K Zysset, M J ToscanoAbstract:Summary Fractures to the Keel Bone is one of the greatest problems facing the laying hen industry. With most severe effects observed in non-cage housing, frequencies are expected to dramatically increase as the industry continues transitioning away from battery cages. Incidences within commercial systems are well documented, where the main cause is believed to be high egg production and the associated need for calcium drawing on endogenous reserves (i.e., Bone) leaving Bone weakened and prone to fracture. The current work sought to characterize various Bone mineral and biomechanical properties of 5 distinct purebred or crossbred laying hen lines (3 commercial: Bovans Brown, Dekalb White, and Institut de Selection Animale Dual Brown; 2 non-commercial: Experimental Brown and Experimental White), following previous work that demonstrated differences in susceptibility to Keel fracture using an ex vivo impact testing apparatus. The Keel was then removed to undergo analysis by computer tomography; the humerus and tibia were also removed for biomechanical testing. The Keel Bone mineral density and moment of area correlated moderately with hen weight and susceptibility to fracture. The biomechanical properties of the tibia, but not the humerus, showed a strong relationship with hen weight. One commercial genetic line (Dekalb White) with a high susceptibility to fracture exhibited a mean tibia strength below the value expected from its mean weight. Our results suggest that for the purebred or crossbred lines other than Dekalb White, rather than properties of Bone, lower mean weight may imply higher levels of activity, higher risk of collisions, and lower soft tissue protection that reflect greater susceptibility to Keel fracture.
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improving intra and inter observer repeatability and accuracy of Keel Bone assessment by training with radiographs
Poultry Science, 2019Co-Authors: Sabine G Gebhardthenrich, Christina Rufener, Ariane StratmannAbstract:Assessing Keel Bone damage reliably and accurately is a requirement for all research on this topic. Most commonly, assessment is done on live birds by palpation and is therefore prone to bias. A 2-day Training School of the COST Action "Identifying causes and solutions of Keel Bone damage in laying hens" with 16 participants of variable experience was held where palpation of live hens was followed by consulting corresponding radiographic images of Keel Bones. We hypothesized that the inter-observer and intra-observer repeatabilities as well as the agreement between palpation and assessment from the radiograph (considered as the accuracy) would increase from day 1 to 2. Repeatability estimates were calculated using the R-package rptR and the change in level of accuracy on day 1 and 2 was analyzed with generalized linear models. As predicted, the inter-observer repeatabilities of the assessments of the fractures and deviations were improved by training, but this improvement differed for fractures and deviations between the cranial, middle, and caudal parts of the Keel Bone. Intra-observer repeatabilities before training also differed between the different parts of the Keel Bone and were highest for fractures at the caudal part of the Keel Bone. The training affected the accuracy of palpation to different degrees for the different parts of the Keel Bone. A training effect was found for the caudal part of the Keel Bone in regard to fractures and deviations, but for fractures the training effect was missing for the cranial part and for deviations it was missing for the middle part of the Keel Bone. In conclusion, the training school involving radiographs improved inter-observer repeatabilities in the diagnosis of fractures and deviations of Keel Bones and thus had the potential to lead to more comparable results among research groups.
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susceptibility to Keel Bone fractures in laying hens and the role of genetic variation
Poultry Science, 2017Co-Authors: Laura Candelotto, Sabine G Gebhardthenrich, Christina Rufener, Ariane Stratmann, Teun Van De Braak, M J ToscanoAbstract:ABSTRACT Keel Bone fractures are a well-known welfare problem in modern commercial laying hen systems. The present study sought to identify genetic variation in relation to Keel Bone fracture susceptibility of 4 distinct crossbred and one pure line, and by extension, possible breeding traits. Susceptibility to fractures were assessed using an ex vivo impact testing protocol in combination with a study design that minimized environmental variation to focus on genetic differences. The 5 crossbred/pure lines differed in their susceptibility to Keel Bone fractures with the greatest likelihood of fracture in one of the 3 commercial lines and the lowest susceptibility to fractures in one of the experimental lines. Egg production at the hen-level did not differ between the crossbred/pure lines (P > 0.05), though an increased susceptibility to Keel Bone fractures was associated with thinner eggshells and reduced egg breaking strength, a pattern consistent among all tested crossbred/pure lines. Our findings suggest an association between egg quality and Bone strength which appeared to be independent of crossbred/pure line. The findings indicate the benefit of the impact methodology to identify potential breeding characteristics to reduce incidence of Keel fracture as well as the potential relationship with eggshell quality.
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limited associations between Keel Bone damage and Bone properties measured with computer tomography three point bending test and analysis of minerals in swiss laying hens
Frontiers in Veterinary Science, 2017Co-Authors: Sabine G Gebhardthenrich, Ernst K F Frohlich, S Kappeli, Andreas Pfulg, Dominik Guggisberg, Annette Liesegang, Michael Hubert StoffelAbstract:Keel Bone damage is a wide-spread welfare problem in laying hens. It is unclear so far whether Bone quality relates to Keel Bone damage. The goal of the present study was to detect possible associations between Keel Bone damage and Bone properties of intact and damaged Keel Bones and of tibias in end-of-lay hens raised in loose housing systems. Bones were palpated and examined by peripheral quantitative computer tomography (PQCT), a three-point bending test, and analyses of Bone ash. Contrary to our expectations, PQCT revealed higher cortical and trabecular contents in fractured than in intact Keel Bones. This might be due to structural Bone repair after fractures. Density measurements of cortical and trabecular tissues of Keel Bones did not differ between individuals with and without fractures. In the three-point bending test of the tibias, ultimate shear strength was significantly higher in birds with intact vs. fractured Keel Bones. Likewise, birds with intact or slightly deviated Keel Bones had higher mineral and calcium contents of the Keel Bone than birds with fractured Keel Bones. Calcium content in Keel Bones was correlated with calcium content in tibias. Although there were some associations between Bone traits related to Bone strength and Keel Bone damage, other factors such as stochastic events related to housing such as falls and collisions seem to be at least as important for the prevalence of Keel Bone damage.
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genetic selection to increase Bone strength affects prevalence of Keel Bone damage and egg parameters in commercially housed laying hens
Poultry Science, 2016Co-Authors: Ariane Stratmann, Sabine G Gebhardthenrich, Ernst K F Frohlich, Alexandra Harlandermatauschek, Hanno Wurbel, M J ToscanoAbstract:The prevalence of Keel Bone damage as well as external egg parameters of 2 pure lines divergently selected for high (H) and low (L) Bone strength were investigated in 2 aviary systems under commercial conditions. A standard LSL hybrid was used as a reference group. Birds were kept mixed per genetic line (77 hens of the H and L line and 201 or 206 hens of the LSL line, respectively, per pen) in 8 pens of 2 aviary systems differing in design. Keel Bone status and body mass of 20 focal hens per line and pen were assessed at 17, 18, 23, 30, 36, 43, 52, and 63 wk of age. External egg parameters (i.e., egg mass, eggshell breaking strength, thickness, and mass) were measured using 10 eggs per line at both 38 and 57 wk of age. Body parameters (i.e. tarsus and third primary wing feather length to calculate index of wing loading) were recorded at 38 wk of age and mortality per genetic line throughout the laying cycle. Bone mineral density (BMD) of 15 Keel Bones per genetic line was measured after slaughter to confirm assignment of the experimental lines. We found a greater BMD in the H compared with the L and LSL lines. Fewer Keel Bone fractures and deviations, a poorer external egg quality, as well as a lower index of wing loading were found in the H compared with the L line. Mortality was lower and production parameters (e.g., laying performance) were higher in the LSL line compared with the 2 experimental lines. Aviary design affected prevalence of Keel Bone damage, body mass, and mortality. We conclude that selection of specific Bone traits associated with Bone strength as well as the related differences in body morphology (i.e., lower index of wing loading) have potential to reduce Keel Bone damage in commercial settings. Also, the housing environment (i.e., aviary design) may have additive effects.
Jens Peter Christensen - One of the best experts on this subject based on the ideXlab platform.
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a descriptive study of Keel Bone fractures in hens and roosters from four non commercial laying breeds housed in furnished cages
Open Access Journal, 2020Co-Authors: Kathe Elise Kittelsen, Jens Peter Christensen, Ingrid Toftaker, Randi Oppermann Moe, Tone Beate Hansen, Guro VasdalAbstract:The presence of Keel Bone fractures (KBF) in laying hens has been documented and discussed by several authors, nevertheless the causative factors behind KBF remain uncertain. High prevalence of KBF have been reported in all commercial egg production systems, in different genetic lines and at different ages. Several of the proposed causal mechanisms behind KBF are linked to selection for efficient production. It is, therefore, of interest to explore whether less selected breeds have a lower occurrence of Keel Bone fractures compared to reports from highly selected, modern laying hen breeds. Thus, the aim of the current study was to investigate Keel Bones of hens from four non-commercial layer breeds. Birds were housed in furnished cages and Keel Bones examined at 30 and 63 weeks of age, using a portable X-ray equipment. The results from this descriptive study indicate a low prevalence of KBF at both ages in all four breeds, with only five KBF detected in 213 X-ray pictures taken from 126 birds. Of these, four of the KBF were observed in the most genetically selected breed, with an early onset of lay. None of the roosters examined exhibited KBF. The overall low numbers of KBF found indicate that genetic factors may be involved in KBF and, thus that selective breeding may help to reduce the susceptibility to KBF. Finally, this study highlights the importance of poultry conservation to secure genetic diversity, which may be an important resource in future selection schemes.
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prevalence of Keel Bone damage in red jungle fowls gallus gallus a pilot study
Open Access Journal, 2020Co-Authors: Kathe Elise Kittelsen, Per Jensen, Jens Peter Christensen, Ingrid Toftaker, Randi Oppermann Moe, Guro VasdalAbstract:Keel Bone damage (KBD) is a highly prevalent problem in commercial egg production. KBD consists of two different conditions affecting the Keel: Keel Bone deviation and Keel Bone fractures (KBF). Deviations are linked to pressure on the Keel, e.g., from perching. The causative factors for KBF are not clear; however, selection for efficient egg production has been suggested as a major contributing factor. An important step to shed light on the role of selective breeding as an underlying cause of KBF in modern laying hens is to evaluate the Keel Bones of the ancestor, the red jungle fowl. To the authors' knowledge, this has never previously been published. The aim of this study was therefore to describe the prevalence of KBD in a study group of red jungle hens and roosters housed in an aviary system. The present study examined 29 red jungle fowls 112 weeks of age post-mortem; 12 hens and 17 roosters. Keel Bones were evaluated by external palpation for deviations and fractures. Palpation was followed by autopsy. No fractures were detected in the 17 roosters; one had a very slight deviation. Of the 12 red jungle hens in this pilot study, one had a single fracture and 10 hens had a very slight deviation.
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explanations for Keel Bone fractures in laying hens are there explanations in addition to elevated egg production
Poultry Science, 2020Co-Authors: M J Toscano, Stefanie Petow, Kathe Elise Kittelsen, Jens Peter Christensen, I C Dunn, Reiner UlrichAbstract:The current article served to provide the most up-to-date information regarding the causes of Keel Bone fracture. Although elevated and sustained egg production is likely a major contributing factor toward fractures, new information resulting from the development of novel methodologies suggests complementary causes that should be investigated. We identified 4 broad areas that could explain variation and increased fractures independent of or complementing elevated and sustained egg production: the age at first egg, late ossification of the Keel, predisposing Bone diseases, and inactivity leading to poor Bone health. We also specified several topics that future research should target, which include continued efforts to link egg production and Bone health, examination of noncommercial aves and traditional breeds, manipulating of age at first egg, a detailed histological and structural analysis of the Keel, assessment of prefracture Bone condition, and the relationship between individual activity patterns and Bone health.
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pathological characterization of Keel Bone fractures in laying hens does not support external trauma as the underlying cause
PLOS ONE, 2020Co-Authors: Ida Thofner, Hans Petter Hougen, Chiara Villa, Niels Lynnerup, Jens Peter ChristensenAbstract:Keel Bone fractures in laying hens have been described with increasing prevalence from several countries over the last twenty years and are considered one of the greatest welfare problems to the layer industry. In Denmark we have observed fracture prevalence in the range of 53% to 100% in flocks from cage-free systems whereas flock prevalences in birds from enriched cages ranged between 50–98%. Previous research have speculated that the underlying reason for the development of Keel Bone fractures is trauma in relation to impact of the bird with furniture, other equipment etc. However, little evidence of this theory has been provided. Predisposing factors have also been suggested including genetics of the bird, lack of specific feedstuff components, high egg production, management factors and layer fatigue. This study has addressed the possible pathogenesis of these fractures by pathological characterization of fractures in birds from different production systems. More than 60 Keel Bones with fractures have been characterized histo-pathologically and by CT scan. This included an assessment of damage to muscles and soft tissues, the Bone and the healing process including callus formation. This investigation has shown that high energy collisions cannot be responsible for the majority of fractures, located at the caudal tip of the Keel Bone, observed in laying birds as markers associated trauma were not observed in the majority of the cases just as few recognized healing processes were observed. These results suggest an alternative pathogenesis to trauma.
T. V. Smulders - One of the best experts on this subject based on the ideXlab platform.
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Keel Bone fractures induce a depressive-like state in laying hens
Scientific Reports, 2020Co-Authors: E. A. Armstrong, M J Toscano, V Sandilands, C. Rufener, J. E. Eastham, J. H. Guy, T. Boswell, T. V. SmuldersAbstract:In commercial flocks of laying hens, Keel Bone fractures (KBFs) are prevalent and associated with behavioural indicators of pain. However, whether their impact is severe enough to induce a depressive-like state of chronic stress is unknown. As chronic stress downregulates adult hippocampal neurogenesis (AHN) in mammals and birds, we employ this measure as a neural biomarker of subjective welfare state. Radiographs obtained longitudinally from Lohmann Brown laying hens housed in a commercial multi-tier aviary were used to score the severity of naturally-occurring KBFs between the ages of 21–62 weeks. Individual birds’ transitions between aviary zones were also recorded. Focal hens with severe KBFs at 3–4 weeks prior to sampling (n = 15) had lower densities of immature doublecortin-positive (DCX^+) multipolar and bipolar neurons in the hippocampal formation than focal hens with minimal fractures (n = 9). KBF severity scores at this time also negatively predicted DCX^+ cell numbers on an individual level, while hens that acquired fractures earlier in their lives had fewer DCX^+ neurons in the caudal hippocampal formation. Activity levels 3–4 weeks prior to sampling were not associated with AHN. KBFs thus lead to a negative affective state lasting at least 3–4 weeks, and management steps to reduce their occurrence are likely to have significant welfare benefits.