Advances in keeping laying hens in various cage-free systems: part I rearing phase

SUMMARY: Cage-free housing of pullets and laying hens is becoming more and more popular around the world. This paper reviews the literature on the most common cage-free rearing systems for pullets: floor systems with or without elevated structures, multi-tier systems, systems with access to a covered veranda and/or a free-range, and organic systems. The aim is to provide an extensive overview of various aspects of these cage-free systems, such as structure and size and functional elements for the birds. Most research on pullets in cage-free systems focuses on the prevention of health and welfare problems during the later laying period. Investigations on the actual health and welfare status during rearing are rare. There is evidence that pullets should be reared in a system as similar as possible to the later housing system for layers. Particularly for complex multi-tier systems, pullets need to develop sufficient adaptive skills. Effects of providing environmental enrichment during rearing, such as plastic objects, hay or alfalfa bales and pecking blocks, on welfare in early and later life are inconsistent across all alternative pullet housing systems. To prevent feather pecking, other factors like diet and space allowance have to be considered as well. There is a need for further research regarding free-range and organic housing systems for pullets. In addition, environmental-, economic- and food safety aspects of rearing pullets in cage-free systems should be investigated in future research

Tag 'n' Track: Tackling the validation challenge in animal behaviour studies through automated referencing with ArUco markers

Technological advances promise to greatly assist the study of animal behaviour, but the validation of these technologies is often neglected due to its tedious and labour-intensive nature. This paper addresses the challenges of manual annotation in validating technological tools for animal behaviour research. We detail the implementation and effectiveness of a computer vision method that automatically annotates animals within various regions of interest (ROIs). This method uses ArUco markers, open-source visual markers with a grid pattern, fitted onto vests worn by the animals. To validate this method, we used 245 10-minute videos capturing animals’ visits to key resources, using a mobile barn housing twenty-one chickens. Our method generates annotated videos, revealing unique IDs of individuals and timestamps marking their presence in ROIs. Compared with traditional human observation, our method performed excellently: Spearman’s correlation (ρ = 0.96, p < 0.01), 92.83 % sensitivity, 99.93 % specificity, 99.08 % accuracy, 98.77 % precision, and a 95.28 % F1-score. All recordings were annotated automatically in 40.96 h, saving 82.72 % of the time compared to the 222.84 h required for manual annotation. The proposed ArUco marker-based tracking method is easy to set up, based on open-source technology, and accessible to researchers without advanced programming skills. This method has the potential to replace or complement manual annotation, simplifying the validation of new technologies for automated individual tracking

The views of farm animal veterinarians about their roles and responsibilities associated with on-farm end-of-life situations

Farm animal veterinarians are often involved in on-farm end-of-life (EoL) decisions and questions concerning euthanasia. These decisions can be challenging for the veterinarian, particularly if the interests of the animal and owner conflict. Moreover, the challenge is related to fundamental assumptions about roles and responsibilities veterinarians ascribe to themselves in EoL situations. Getting insight into what roles and responsibilities veterinarians perceive in these situations is important to understand the challenges veterinarians face and to explore ways to enable them to manage such situations. Existing literature and professional guidelines do not provide sufficient clarity and guidance in terms of the role conception and responsibilities of veterinarians in on-farm EoL situations. The objective of the current qualitative study was to better understand the views of farm animal veterinarians in the Netherlands regarding their roles and responsibilities associated with on-farm EoL situations. In-depth semi-structured interviews were conducted with 19 farm animal veterinarians. In terms of roles in EoL situations, our analysis shows that 1) seven roles can be distinguished based on the interviews, 2) two contextual dimensions influence role perception: a) the stage in which a veterinarian gets involved at the end of an animal’s life and b) the question of whose interests should be taken into consideration and how to prioritize (conflicting) interests by a veterinarian, 3) veterinarians enact a number of the identified roles and the combination of roles varies between individuals and 4) the individual veterinarian changes between roles depending on contextual aspects. In terms of responsibilities in EoL situations, analyses show that 1) individual veterinarians perceive a combination of five identified responsibilities, and 2) the perception of responsibilities relates predominantly to specific animal sectors. This insight into the roles and responsibility perceptions of veterinarians facilitates understanding the challenges veterinarians face in on-farm EoL situations and creates a starting point for how veterinarians can be supported to deal with potential conflicts of interest. These insights could also be valuable in the training of future veterinarians and lifelong learning of veterinarians as it provides a starting point to reflect on, and discuss, one’s role and responsibility in EoL situations.</p

The views of farm animal veterinarians about their roles and responsibilities associated with on-farm end-of-life situations

Farm animal veterinarians are often involved in on-farm end-of-life (EoL) decisions and questions concerning euthanasia. These decisions can be challenging for the veterinarian, particularly if the interests of the animal and owner conflict. Moreover, the challenge is related to fundamental assumptions about roles and responsibilities veterinarians ascribe to themselves in EoL situations. Getting insight into what roles and responsibilities veterinarians perceive in these situations is important to understand the challenges veterinarians face and to explore ways to enable them to manage such situations. Existing literature and professional guidelines do not provide sufficient clarity and guidance in terms of the role conception and responsibilities of veterinarians in on-farm EoL situations. The objective of the current qualitative study was to better understand the views of farm animal veterinarians in the Netherlands regarding their roles and responsibilities associated with on-farm EoL situations. In-depth semi-structured interviews were conducted with 19 farm animal veterinarians. In terms of roles in EoL situations, our analysis shows that 1) seven roles can be distinguished based on the interviews, 2) two contextual dimensions influence role perception: a) the stage in which a veterinarian gets involved at the end of an animal’s life and b) the question of whose interests should be taken into consideration and how to prioritize (conflicting) interests by a veterinarian, 3) veterinarians enact a number of the identified roles and the combination of roles varies between individuals and 4) the individual veterinarian changes between roles depending on contextual aspects. In terms of responsibilities in EoL situations, analyses show that 1) individual veterinarians perceive a combination of five identified responsibilities, and 2) the perception of responsibilities relates predominantly to specific animal sectors. This insight into the roles and responsibility perceptions of veterinarians facilitates understanding the challenges veterinarians face in on-farm EoL situations and creates a starting point for how veterinarians can be supported to deal with potential conflicts of interest. These insights could also be valuable in the training of future veterinarians and lifelong learning of veterinarians as it provides a starting point to reflect on, and discuss, one’s role and responsibility in EoL situations.</p

Considering life and death:a qualitative vignette study among farm animal veterinarians in the Netherlands on considerations in end-of-life decision-making

Farm animal veterinarians are frequently involved in animals’ end-of-life (EoL) situations. Existing literature found that the decision-making process to end an animal’s life can be experienced as complex and stressful by veterinarians. The complexity of the process may find its origin in the multiple medical and non-medical aspects that veterinarians consider coming to their decision. Although research provides insight into what considerations are at stake, the literature does not provide information on how these aspects affect the decision-making process. This study explores how different considerations affect the decision-making process of farm animal veterinarians in EoL situations. Semi-structured interviews were conducted with nineteen farm animal veterinarians in the Netherlands. During the interviews, case scenarios in the form of vignettes were used to identify and explore the considerations that play a role for these veterinarians in EoL decision-making. Based on the analysis of the interview data, we discovered that farm animal veterinarians consider EoL situations using one of three identified frames: function, prospect, and duty. These frames illustrate one’s perspective on the interplay of medical and non-medical aspects. Whereas veterinarians for whom the function frame is dominant focus on the human-centred function that an animal fulfils, veterinarians for whom the prospect frame is dominant focus on an animal’s prospects based on the animal’s living conditions and the influence of the owner. Veterinarians for whom the duty frame is dominant focus on the owner’s legal position towards the animal, illustrating a clear distinction between the veterinarian’s professional duties towards the animal and the duty of care of the animal owner. As such, the key contributions of this study are the discovery of the importance of the interplay between considerations in EoL decision-making and the frame-specific approach of veterinarians. The identified frames may relate to the coping strategies of veterinarians dealing with the complexity of EoL situations.</p

Considering life and death:a qualitative vignette study among farm animal veterinarians in the Netherlands on considerations in end-of-life decision-making

Farm animal veterinarians are frequently involved in animals’ end-of-life (EoL) situations. Existing literature found that the decision-making process to end an animal’s life can be experienced as complex and stressful by veterinarians. The complexity of the process may find its origin in the multiple medical and non-medical aspects that veterinarians consider coming to their decision. Although research provides insight into what considerations are at stake, the literature does not provide information on how these aspects affect the decision-making process. This study explores how different considerations affect the decision-making process of farm animal veterinarians in EoL situations. Semi-structured interviews were conducted with nineteen farm animal veterinarians in the Netherlands. During the interviews, case scenarios in the form of vignettes were used to identify and explore the considerations that play a role for these veterinarians in EoL decision-making. Based on the analysis of the interview data, we discovered that farm animal veterinarians consider EoL situations using one of three identified frames: function, prospect, and duty. These frames illustrate one’s perspective on the interplay of medical and non-medical aspects. Whereas veterinarians for whom the function frame is dominant focus on the human-centred function that an animal fulfils, veterinarians for whom the prospect frame is dominant focus on an animal’s prospects based on the animal’s living conditions and the influence of the owner. Veterinarians for whom the duty frame is dominant focus on the owner’s legal position towards the animal, illustrating a clear distinction between the veterinarian’s professional duties towards the animal and the duty of care of the animal owner. As such, the key contributions of this study are the discovery of the importance of the interplay between considerations in EoL decision-making and the frame-specific approach of veterinarians. The identified frames may relate to the coping strategies of veterinarians dealing with the complexity of EoL situations.</p

A two-step Bayesian network approach to identify key SNPs associated to multiple phenotypic traits in four purebred laying hen lines

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie [grant number 812777].When purebred laying hen chicks hatch, they remain at a rearing farm until approximately 17 weeks of age, after which they are transferred to a laying farm. Chicks or pullets are removed from the flocks during these 17 weeks if they display any rearing abnormality. The aim of this study was to investigate associations between single nucleotide polymorphisms (SNPs) and rearing success of 4 purebred White Leghorns layer lines by implementing a Bayesian network approach. Phenotypic traits and SNPs of four purebred genetic White Leghorn layer lines were available for 23,000 rearing batches obtained between 2010 and 2020. Associations between incubation traits (clutch size, embryo mortality), rearing traits (genetic line, first week mortality, rearing abnormalities, natural death, rearing success, pullet flock age, and season) and SNPs were analyzed, using a two-step Bayesian Network (BN) approach. Furthermore, the SNPs were connected to their corresponding genes, which were further explored in bioinformatics databases. BN analysis revealed a total of 28 SNPs associated with some of the traits: ten SNPs were associated with clutch size, another 10 with rearing abnormalities, a single SNP with natural death, and seven SNPs with first week mortality. Exploration via bioinformatics databases showed that one of the SNPs (ENAH) had a protein predicted network composed of 11 other proteins. The major hub of this SNP was CDC42 protein, which has a role in egg production and reproduction. The results highlight the power of BNs in knowledge discovery and how their application in complex biological systems can help getting a deeper understanding of functionality underlying genetic variation of rearing success in laying hens. Improved welfare and production might result from the identified SNPs. Selecting for these SNPs through breeding could reduce stress and increase livability during rearing.Peer reviewe

Estimation of Resilience Parameters Following LPS Injection Based on Activity Measured With Computer Vision

Resilience could be referred to as the animal’s ability to successfully adapt to a challenge. This is typically displayed by a quick return to initial metabolic or activity levels and behaviors. Pigs have distinct diurnal activity patterns. Deviations from these patterns could potentially be utilized to quantify resilience. However, human observations of activity are labor intensive and not feasible in practice on a large scale. In this study, we show the use of a computer vision tracking algorithm to quantify resilience based on activity individual patterns following a lipopolysaccharide (LPS) challenge, which induced a sickness response. We followed 121 individual pigs housed in barren or enriched housing systems, as previous work suggests an impact of housing on resilience, for eight days. The enriched housing consisted of delayed weaning in a group farrowing system and extra space compared with the barren pens and environmental enrichment. Enriched housed pigs were more active pre-injection of LPS, especially during peak activity times, than barren housed pigs (49.4 ± 9.9 vs. 39.1 ± 5.0 meter/hour). Four pigs per pen received an LPS injection and two pigs a saline injection. LPS injected animals were more likely to show a dip in activity than controls (86% vs 17%). Duration and Area Under the Curve (AUC) of the dip were not affected by housing. However, pigs with the same AUC could have a long and shallow dip or a steep and short dip. Therefore the AUC:duration ratio was calculated, and enriched housed pigs had a higher AUC:duration ratio compared to barren housed pigs (9244.1 ± 5429.8 vs 5919.6 ± 4566.1). Enriched housed pigs might therefore have a different strategy to cope with an LPS sickness challenge. However, more research on this strategy and the use of activity to quantify resilience and its relationship to physiological parameters is therefore needed

Hair Cortisol in Service Dogs for Veterans with Post-traumatic Stress Disorder Compared to Companion Dogs (Canis Familiaris)

Service dogs are trained to assist humans. This assistance potentially exposes them to stressors To investigate if service dogs are exposed to more stressors than companion dogs we questioned whether hair cortisol levels differed between both groups. We studied this by cutting a tuft of hair from the neck of 19 companion and 11 service dogs. Cortisol levels were subsequently analyzed via immunoassay and compared via a simple linear regression model. The influence of coat color, season, sex, other dogs, pets, or mental health diagnoses in the household was also checked . Results showed that cortisol values did not differ between service and companion dogs. Furthermore, none of the additional variables had an influence on cortisol levels. This lead to the conclusion that the service dogs in this study did not have higher hair cortisol levels than companion dogs Further study should be conducted as to why no difference did occur between groups and if this difference is persistent over time given that we only studied a period of up to two months' worth of hair cortisol

Genetics of rearing success in four pure laying hen lines during the first 17 weeks of age

This study aimed to investigate the genetics of rearing success (RS) in laying hens. Four rearing traits: clutch size (CS), first week mortality (FWM), rearing abnormalities (RA), and natural death (ND), were included as factors determining RS. Pedigree, genotypic, and phenotypic records of 4 purebred genetic lines of White Leghorn layers were available for 23,000 rearing batches obtained between 2010 and 2020. FWM and ND showed little or no variation amongst the 4 genetic lines over the years 2010-2020, whereas an increase was observed for CS and a decrease for RA. To determine whether these traits were heritable, genetic parameters for each trait were estimated, using a Linear Mixed Model. Heritabilities within lines were low (0.05-0.19 for CS, 0.01-0.04 for FWM, 0.02-0.06 for RA, 0.02 -0.04 for ND, and 0.01-0.07 for RS). Additionally, genome wide association study was done to scan the genomes of the breeders to reveal single nucleotide polymorphisms (SNPs) associated with these traits. Manhattan plots indicated the existence of 12 differ-ent SNPs having a significant effect on RS. Thus, the identified SNPs will increase the understanding of the genetics of RS in laying hens