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

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.

High-throughput phenotyping to characterise range use behaviour in broiler chickens.

A key characteristic of free-range chicken farming is to enable chickens to spend time outdoors. However, each chicken may use the available areas for roaming in variable ways. To check if, and how, broilers use their outdoor range at an individual level, we need to reliably characterise range use behaviour. Traditional methods relying on visual scans require significant time investment and only provide discontinuous information. Passive RFID (Radio Frequency Identification) systems enable tracking individually tagged chickens' when they go through pop-holes; hence, they only provide partial information on the movements of individual chickens. Here, we describe a new method to measure chickens' range use and test its reliability on three ranges each containing a different breed. We used an active RFID system to localise chickens in their barn, or in one of nine zones of their range, every 30 seconds and assessed range-use behaviour in 600 chickens belonging to three breeds of slow- or medium-growing broilers used for outdoor production (all <40 g daily weight gain). From those real-time locations, we determined five measures to describe daily range use: time spent in the barn, number of outdoor accesses, number of zones visited in a day, gregariousness (an index that increases when birds spend time in zones where other birds are), and numbers of zone changes. Principal Component Analyses (PCAs) were performed on those measures, in each production system, to create two synthetic indicators of chickens' range use behaviour. The first two PCA axes represented over 90% of the variance of the five measures and were both consistent over time and correlated with independent visual scans. Contributions of the five measures to the PCAs were similar among breeds, except for the correlation between the number of outdoor accesses and the four other measures. PC1 correlated with time spent inside the barn and zone changes frequency, whilst PC2 was explained by exploration of the range. Taken together, PC1 and PC2 indicators showed that range use increased with age, outdoor temperature (in spring), and did not differ between males and females. Importantly, daily scores for both indicators were repeatable among individuals - particularly in PC1 - showing inter-individual variability on range-use. The characterisation of broiler behaviour around their range with these reliable and repeatable indicators provides novel tools to help understand individual variations of range-use in free-range farming.

Effects of group size on agonistic interactions in dairy cows: a descriptive study.

Group-housed cattle may engage in agonistic interactions over resources such as feed, which can negatively affect aspects of welfare. Little is known about how contextual factors such as group size influence agonistic behaviour. We explored the frequency of agonistic interactions at the feeder when cattle were housed in different-sized groups. We also explored the consistency of the directionality of agonistic interactions in dyads and of the number of agonistic interactions initiated by individuals across the group sizes. Four replicates of 50 cows each were assessed in two group-size phases. In Phase 1, cows were kept in one group of 50. In Phase 2, these same cows were divided into five groups of 10, maintaining stocking density (i.e., ratio of animals to lying stalls and feed bunk spaces). We measured agonistic replacements (i.e., interactions that result in one cow leaving the feed bin and another taking her place) at an electronic feeder using a validated algorithm. We used these data from Phase 1 to calculate individual Elo-ratings (a type of dominance score). Cows were then categorised into five dominance categories based upon these ratings. To ensure a consistent Elo-rating distribution between phases, two cows from each dominance category were randomly assigned to each small group of 10 cows. The mean ± SE number of replacements per cow was similar regardless of whether the cows were housed in groups of 50 (34.1 ± 2.4) or 10 (31.1 ± 4.5), although the groups of 10 were more variable. Further, 81.6 ± 7.7% (mean ± SD) of dyads had the same directionality across group sizes (i.e., the same individual won the majority of interactions in the dyad) and individuals were moderately consistent in the number of replacements they initiated (intraclass correlation coefficient = 0.62 ± 0.11; mean ± SD). These results indicate that the relationship between group size and agonistic behaviour is complex; we discuss these challenges and suggest new avenues for further research.

Feed form and perch design do not interact to production performance, gastrointestinal tract traits, behaviour and welfare of laying hens reared in enriched cages.

1. It was hypothesised that perch material and design may affect utility and maintenance energy demand in laying hens, affecting their feed form preferences and daily feed consumption. Accordingly, perch design and feed form on hen performance, gastrointestinal tract functions and some behavioural and welfare-related traits were studied in laying hens (ATAK-S) reared in enriched colony cages from 24 to 40 weeks of age.2. The experiment was a 2 × 2 factorial investigating two perch materials and design (circular steel or mushroom-shaped plastic) and feed form (mash or crumble). A total of 396 hens were randomly assigned to one of the four treatment groups with nine replicates each (11 birds per replicate).3. Except for feeding behaviour and prevalence of foot pad dermatitis at 40 weeks of age, the modification of the perch design did not have a significant effect on the traits examined. Mushroom-shaped plastic perches reduced feeding behaviour (p < 0.01) and the incidence of foot pad dermatitis at 40 weeks of age (p < 0.001).4. Performance traits were not affected by feed form. Intake, final body weight and FCR for crumble-fed laying hens were greater than those fed mash (p < 0.01).5. Hens fed mash had higher (p < 0.01) relative gizzard weights along with lower (p < 0.05) pH values, pancreatic chymotrypsin, amylase and lipase activities (p < 0.05), and duodenal absorption surface areas (p < 0.01). Ultimately, this gave higher protein digestibility (p < 0.05) compared to those receiving crumble.6. In conclusion, in enriched cage rearing systems, mashed feed was preferred over crumble to efficiently maintain productive performance. Compared to circular steel, plastic mushroom-shaped perches were associated with better footpad health and welfare.

MouseVUER: video based open-source system for laboratory mouse home-cage monitoring.

Video monitoring of mice in the home-cage reveals behavior profiles without the disruptions caused by specialized test setups and makes it possible to quantify changes in behavior patterns continually over long time frames. Several commercial home-cage monitoring systems are available with varying costs and capabilities; however there are currently no open-source systems for home-cage monitoring. We present an open-source system for top-down video monitoring of research mice in a slightly modified home-cage. The system is designed for integration with Allentown NexGen ventilated racks and allows unobstructed view of up to three mice, but can also be operated outside the rack. The system has an easy to duplicate and assemble home-cage design along with a video acquisition solution. The system utilizes a depth video camera, and we demonstrate the robustness of depth video for home-cage mice monitoring. For researchers without access to Allentown NexGen ventilated racks, we provide designs and assembly instructions for a standalone non-ventilated rack solution that holds three systems for more compact and efficient housing. We make all the design files, along with detailed assembly and installation instructions, available on the project webpage ( https://github.com/NIH-CIT-OIR-SPIS/MouseVUER ).

Environmental enrichment promotes adaptive responding during tests of behavioral regulation in male heterogeneous stock rats.

Organisms must regulate their behavior flexibly in the face of environmental challenges. Failure can lead to a host of maladaptive behavioral traits associated with a range of neuropsychiatric disorders, including attention deficit hyperactivity disorder, autism, and substance use disorders. This maladaptive dysregulation of behavior is influenced by genetic and environmental factors. For example, environmental enrichment produces beneficial neurobehavioral effects in animal models of such disorders. The present study determined the effects of environmental enrichment on a range of measures related to behavioral regulation using a large cohort of male, outbred heterogeneous stock (HS) rats as subjects. Subjects were reared from late adolescence onwards either in pairs in standard housing with minimal enrichment (n = 200) or in groups of 16 in a highly enriched environment consisting of a large multi-level cage filled with toys, running wheels, and shelters (n = 64). Rats were subjected to a battery of tests, including: (i) locomotor response to novelty, (ii) light reinforcement, (iii) social reinforcement, (iv) reaction time, (v) a patch-depletion foraging test, (vi) Pavlovian conditioned approach, (vii) conditioned reinforcement, and (viii) cocaine conditioned cue preference. Results indicated that rats housed in the enriched environment were able to filter out irrelevant stimuli more effectively and thereby regulate their behavior more efficiently than standard-housing rats. The dramatic impact of environmental enrichment suggests that behavioral studies using standard housing conditions may not generalize to more complex environments that may be more ethologically relevant.

Effects of Salvinia as a broiler litter material on growth performance, behavior, welfare parameters, litter characters, and ammonia emission.

The type of litter material has direct impacts on production, behavioral, and welfare parameters of broilers. The price of conventionally-used litter materials is increasing. Salvinia molesta is a fast-growing aquatic plant which has become an environmental issue in some areas. This study assessed the suitability of air-dried Salvinia plants (SAL) as an alternate litter material to paddy husk (PH). Resulting in a completely randomized experiment, a total of 240 broilers was raised in 12 floor-pens each provided with either PH or SAL as litter materials, from 11 to 36 d. Scan sampling technique was employed to record the birds' engagement in 15 predetermined behaviors. Foot pad dermatitis (FPD), hock burn damage (HBD) and plumage cleanliness (PC) were assessed using Welfare Quality Scoring System. Litter samples were analyzed for pH, dry matter%, water holding capacity, porosity, N%, tapped-density and ammonia emission rate. The litter material had no significant effect (P > 0.05) on mortality, growth performance parameters, dressing % and visceral organ weight. The scores for FPD and PC were unaffected by the litter materials. SAL litter reported significantly lower (P < 0.05) HBD scores. The percentages of birds engaged in eating and wing flapping behaviors were significantly lower on SAL. Litter type had no significant influence on the color, aroma, flavor, texture and overall acceptability of breast meat. Air-dried Salvinia plants reported acidic pH. SAL litter gave a significantly higher tapped-density. Ammonia emission rate of SAL litter was significantly lower than that of PH. However, the final litter N content was higher for PH (3.7%) than SAL (3.2%). The study proposes air-dried Salvinia plants as a litter material for broilers since it gives growth performance comparable to PH with reduced hock burn damage incidences. Effects of SAL on behavior and the fertilizer value of the spent litter are to be studied further.

Influence of keel impacts and laying hen behavior on keel bone damage.

Keel bone damage, which presents as fractures and/or deviations of the keel, has been detected in laying hens housed in all types of systems. Factors leading to keel bone damage in hens housed with limited vertical space, such as those housed in furnished systems, are not well understood, and are the topic of this study. Ten focal hens from each of 12 furnished cages (4 rooms of 3 cages) were fitted with keel mounted tri-axial accelerometers. Their behavior was video recorded continuously over two 3-wk trials: the first when the hens were between 52 and 60 wk of age, and the second approximately 20 wk later. The integrity of each hen's keel was evaluated at the start and end of each 3-wk trial using digital computed tomography. We identified predominant behaviors associated with acceleration events sustained at the keel (collisions, aggressive interactions and grooming) by pairing accelerometer outputs with video data. For each recorded acceleration event we calculated the acceleration magnitudes as the maximum summed acceleration recorded during the event, and by calculating the area under the acceleration curve. A principle components analysis, which was used as a data reduction technique, resulted in the identification of 4 components that were used in a subsequent regression analysis. A key finding is that the number of collisions a hen has with structures in her environment, and the number of aggressive interactions that a hen is involved, each affect the likelihood that she will develop 1 or more fractures within a 3-wk time span. This relationship between hen behavior and keel fracture formation was independent of the magnitude of acceleration involved in the event. Observed behavior did not have an impact on the formation of keel bone deviations, further supporting reports that the mechanisms underlying the 2 types of keel bone damage are different.

A systematic review of potential productivity, egg quality, and animal welfare implications of extended lay cycles in commercial laying hens in Canada.

Lay cycle lengths in the Canadian egg industry are currently 50 to 52 wk (68-70 wk of age). In light of increased productivity in commercial laying hens over the last few decades, the much longer lay cycle lengths already implemented in other countries, extending lay cycle lengths in Canada, should be considered with careful attention to potential environmental, economic, and animal welfare implications. However, there is a lack of information in the public domain that provides robust evidence of performance levels and potential trade-offs to support comprehensive consideration of the desirability of extending lay cycles beyond current Canadian norms. Hence, a systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was undertaken. Data collection focused primarily on information related to feed-, flock management-, and hen genetics/physiology-related interventions that were studied in literature to support extension of lay cycles (review objective 1), and compiling and analyzing productivity, egg quality, and animal welfare outcomes reported at 70 wk of age or beyond (review objective 2). Several feed-related interventions such as high-protein diets, and probiotics supplements, and flock management interventions such split-feeding were found to potentially improve productivity, and especially egg quality, outcomes in the late laying phase. More studies with bigger flock sizes and in commercial lay facilities need to be undertaken before any of these interventions can be definitively recommended for commercial egg production. Under objective 2, productivity was found to be at acceptable levels well beyond 70 wk of age. Performance on most egg quality traits and animal welfare indicators were also at acceptable levels past 70 wk of age but increased variability was observed beyond ∼80 wk of age. There were also inconclusive indications on how hens in caged housing and white laying hens fare relative to hens in noncaged housing and brown-type layers during the late laying phase. Economic data were limited but suggested that lay cycle lengths beyond 90 wk might not generated net economic benefits.

Effects of socialising piglets on sow and piglet performance and behaviour of entire male piglets.

Entire male pigs show more aggressive behaviour and mounting than female pigs. By sorting growing pigs into male and female pens, at least half of the pigs are protected from the aggressive behaviour and mounting of the entire males. Mixing of unknown pigs provokes them to perform such behaviours which increase the risk for injuries. The idea behind socialising piglets is to create groups of piglets from several litters that become familiar with each other and thus show less aggressive behaviour and mounting later, when housed together after weaning. The effect of socialising piglets on animal welfare was studied on 24 sows and their 235 piglets. Male piglets were not castrated. Sows were housed in individual farrowing pens without crates. A small door was opened between two adjacent pens at a piglet age of two weeks for half of the litters (12 litters), and the other half was regarded as a control (12 litters). At weaning, control piglets were kept in groups of eight litter mates whereas socialised piglets were kept in groups of either eight entire males or eight females from two litters. Sow weight, body condition and health were recorded together with nursing events and social behaviour of piglets (aggressive, mounting, contact). There was no effect of socialisation on udder lesions or sows' relative change in body reserves. Socialised and control piglets did not differ in daily weight gain before weaning, but socialised piglets tended to have higher growth rate during the week after weaning (P = 0.07). The day after opening between pens, skin lesions were more common among socialised piglets (as compared to control piglets at the same age, P = 0.02) but at weaning, skin lesions were more common among control piglets than socialised piglets (P = 0.01). Almost all lesions were mild. No aggressive behaviour of sows towards piglets was observed. No difference between control and socialised piglets in social behaviour was seen before weaning. The frequency of aggressive and mounting behaviours was low after weaning for both socialised and control piglets, but socialised piglets showed more contact behaviour (P = 0.02). Socialised entire males showed as little aggressive and mounting behaviour as females. Nursing frequency was not affected by piglet socialisation and cross-suckling was rare. Based on the performance of piglets and sows, nursing frequency, and health of piglets and sows, we conclude that socialising entire male piglets (and their sisters) improve piglet welfare without any negative effect on the sows.

The impact of cage dividers on mouse aggression, dominance and hormone levels.

Home cage aggression in group-housed male mice is a major welfare concern and may compromise animal research. Conventional cages prevent flight or retreat from sight, increasing the risk that agonistic encounters will result in injury. Moreover, depending on social rank, mice vary in their phenotype, and these effects seem highly variable and dependent on the social context. Interventions that reduce aggression, therefore, may reduce not only injuries and stress, but also variability between cage mates. Here we housed male mice (Balb/c and SWISS, group sizes of three and five) with or without partial cage dividers for two months. Mice were inspected for wounding weekly and home cages were recorded during housing and after 6h isolation housing, to assess aggression and assign individual social ranks. Fecal boli and fur were collected to quantify steroid levels. We found no evidence that the provision of cage dividers improves the welfare of group housed male mice; The prevalence of injuries and steroid levels was similar between the two housing conditions and aggression was reduced only in Balb/c strain. However, mice housed with cage dividers developed less despotic hierarchies and had more stable social ranks. We also found a relationship between hormone levels and social rank depending on housing type. Therefore, addition of cage dividers may play a role in stabilizing social ranks and modulating the activation of hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes, thus reducing phenotypic variability between mice of different ranks.

Resource choice during ontogeny enhances both the short- and longer-term welfare of laying hen pullets.

We hypothesised that resource choice during early life contributes to both current and longer-term beneficial effects on animal welfare. We investigated this hypothesis in a longitudinal cross-over experiment with laying hen pullets (Gallus gallus domesticus) reared in pens with one or four litter and perch types, respectively (n = 8 pens/treatment, all providing ample and identical litter and perch space). After 4 weeks (chick period), half the pens were modified to provide the opposite treatment (juvenile period). After 11 more weeks, all groups were moved to novel, identical laying pens (adult period; Week 16-27). In support of our hypothesis, the opportunity to choose between multiple litter and perch variants was associated with higher levels of positively-valenced behaviours, including play as chicks and dustbathing as juveniles and adults, and lower levels of negatively-valenced behaviours, including feather pecking as chicks and juveniles and aggressive pecking as adults. Resource choice in the juvenile period also led to better juvenile and adult plumage condition, and greater growth as adults. We conclude that the opportunity to choose among different litter and perch types, instead of having only one type of each, had both short- and longer-term positive effects on the birds' affective states and physical condition.

Environmental enrichments and data-driven welfare indicators for sheltered dogs using telemetric physiological measures and signal processing.

Shelters are stressful environments for domestic dogs which are known to negatively impact their welfare. The introduction of outside stimuli for dogs in this environment can improve their welfare and life conditions. However, our current understanding of the influence of different stimuli on shelter dogs' welfare is limited and the data is still insufficient to draw conclusions. In this study, we collected 28 days (four weeks) of telemetry data from eight male dogs housed in an Italian shelter for a long period of time. During this period, three types of enrichment were introduced into the dogs' pens for one week each: entertaining objects, intraspecific, and interspecific social enrichment, by means of the presence of female conspecifics and the presence of a human. To quantify their impact, we introduce novel metrics as indicators of sheltered dogs' welfare based on telemetry data: the variation of heart rate, muscle activity, and body temperature from an average baseline day, quality of sleep, and the regularity for cyclicity of the aforementioned parameters, based on the day-night cycle. Using these metrics, we show that while all three stimuli statistically improve the dogs' welfare, the variance between individual dogs is large. Moreover, our findings indicate that the presence of female conspecific is the best stimulus among the three explored options which improves both the quality of sleep and the parameters' cyclicity. Our results are consistent with previous research findings while providing novel data-driven welfare indicators that promote objectivity. Thus, this research provides some useful guidelines for managing shelters and improving dogs' welfare.

Partially divided caging reduces overall aggression and anxiety which may indicate improved welfare in group housed male C57BL/6J mice.

Deciding which environmental enrichment is used in mouse caging is often subjective, with cost frequently prevailing over welfare benefits, including aggression and anxiety. While many devices introduced to encourage natural behaviors and reduce aggression show mixed results, we have previously demonstrated significant reductions in aggressive behavior between group-housed male mice housed in partially divided caging. To further assess behavior, we have raised male C57BL/6J mice in either partially divided caging or in standard caging with no divider. Animal behavior was tested on rotarod, open field, novel object recognition, elevated plus maze, and Y maze. Body weights were taken weekly beginning at weaning and bite wounds were counted weekly beginning at 133 days old. Aggressive behavior was recorded weekly beginning at 133 days old. Results indicated significantly less anxiety in the elevated-plus maze, statistically fewer bite wounds, and a statistically significant decrease in aggressive behaviors of mice in partially divided caging compared to mice in standard cages. We conclude that reductions in anxiety, aggressive behavior, and bite wounds may indicate improved overall welfare for non-sibling, group housed male mice.

Impact of housing system on intestinal microbiota of laying hens - A systematic review.

Studies on the housing system's impact on laying hens' intestinal microbiota were retrieved from the Web of Science, PubMed, and Scopus (between 2017 and 2022). Inclusion criteria were studies that discussed measurable effects related to the topic written in English, Portuguese, and Spanish. Of 3281 articles in the identification stage, 12 studies were used in the systematic review. Asia developed most research relating to the subject. Most studies compared the intestinal microbiota of laying hens from conventional cages versus Cage-Free or Free-Range. However, no study has evaluated the intestinal microbiota of laying hens maintained in an organic system. Greengene and Silva were the most used reference in the studies. According to the results observed in the studies included in the systematic review, there is greater alpha diversity in the alternative system and a high dissimilarity between the conventional and alternative systems. Exposure to environmental factors such as soil, vegetation, natural lighting, access to pastures, and ingesting fibrous foods can lead to changes in the intestinal microbiota. A brief outline of published scientific evidence demonstrates that the housing system can change the gut microbiome of hens. This study summarises the relationship between the housing system and the intestinal microbiome of laying hens and provides a roadmap for future research regarding the gut microbiome of hens.

Ethnic networks in neighborhoods affect mental health: Evidence from a quasi-random assignment of applicants in the public social housing system.

This paper examines the impact of residence-based ethnic networks on mental health; such networks are defined as the concentration of residents from the same country of origin in a neighborhood. To estimate the effect, we utilize administrative registry data, together with data on quasi-random assignment of apartments to non-Western households with housing needs to various neighborhoods. After controlling for individual characteristics, time-invariant neighborhood characteristics, and general practitioners (GP) fixed effects, we find that a 1-percentage-point increase in the concentration of residence-based co-ethnics (RBCEs) increases the probability of being treated with psychiatric medications by 0.7-percentage point over a 5-year period after the assignment. With 19% of the population being treated with psychiatric medications the year before assignment, the result translates into an effect size of 3.7%. The results indicate that relatively high concentrations of co-ethnics treated with psychiatric medications increase the probability of being treated with psychiatric medications. The positive impact on treatment with psychiatric medication reflects an increase in the demand for these drugs when moving into a neighborhood with neighbors of the same ethnicity. If new residents are in good mental health condition when moving, these results suggest that moving into a neighborhood with a high co-ethic concentration worsens mental health status. However, as the population in this study is a vulnerable group an increase in treatment with psychiatric medications likely reflects that untreated mental health problems are treated, and the mental health status improved. The group of non-Western immigrants in this study differs significantly from the population in general, thus, results may not be generalized to all non-Western immigrants.

Conditioner application improves bedding quality and bacterial composition with potential beneficial impacts for dairy cow's health.

Recycled manure solids (RMS) is used as bedding material in cow housing but can be at risk for pathogens development. Cows spend several hours per day lying down, contributing to the transfer of potential mastitis pathogens from the bedding to the udder. The effect of a bacterial conditioner (Manure Pro, MP) application was studied on RMS-bedding and milk qualities and on animal health. MP product was applied on bedding once a week for 3 months. Bedding and teat skin samples were collected from Control and MP groups at D01, D51, and D90 and analyzed through 16S rRNA amplicon sequencing. MP application modified bacterial profiles and diversity. Control bedding was significantly associated with potential mastitis pathogens, while no taxa of potential health risk were significantly detected in MP beddings. Functional prediction identified enrichment of metabolic pathways of agronomic interest in MP beddings. Significant associations with potential mastitis pathogens were mainly observed in Control teat skin samples. Finally, significantly better hygiene and lower Somatic Cell Counts in milk were observed for cows from MP group, while no group impact was observed on milk quality and microbiota. No dissemination of MP strains was observed from bedding to teats or milk. IMPORTANCE: The use of Manure Pro (MP) conditioner improved recycled manure solids-bedding quality and this higher sanitary condition had further impacts on dairy cows' health with less potential mastitis pathogens significantly associated with bedding and teat skin samples of animals from MP group. The animals also presented an improved inflammation status, while milk quality was not modified. The use of MP conditioner on bedding may be of interest in controlling the risk of mastitis onset for dairy cows and further associated costs.

Growth performance, carcass, and meat quality traits in broiler chickens reared on plastic-grid flooring, wood shavings, and zeolite-supplemented wood shavings.

This study aimed to assess the growth performance, carcass characteristics, and meat quality traits of broiler chickens raised on plastic-grid floors, traditional wood shavings, and wood shavings enriched with zeolite. The experimental design included the allocation of 504-day-old chicks to three different bedding materials, namely wood shavings, plastic-grid floors, and zeolite litter, each with four replications (42 birds per replicate). The chicks were individually weighed at birth and grouped according to their average body weights. An experiment involving 504 chicks was conducted, with each replicate consisting of 42 male chicks of similar body weight. At the end of the experiment, a total of 120 chickens were slaughtered with 10 chickens selected from each replicate for processing carcass and meat quality traits. The effects of different bedding materials on mortality (P = 0.812), body weight (P = 0.565), and body weight gain (P = 0.569) were not significant. The ANOVA test was conducted to compare the main effects of performance, carcass, and meat quality characteristics. The feed intake was significantly affected in the 2nd, and 3rd weeks (P = 0.001; 0.023); in addition, the feed conversion ratio was significant in the 2nd, 4th, and overall period (P = 0.003; P = 0.026; P = 0.038) by the bedding materials. The breast yield (P = 0.001), thigh yield (P = 0.028), and wing yield (P = 0.023) were significant. The type of bedding material used in broiler production significantly influenced the pH24 (P = 0.030), L* (P = 0.037), a* (P = 0.000), and CL (P = 0.028). It was concluded that both a plastic-grid floor and zeolite supplementation to wood shaving litter did not significantly affect overall growth performance in broiler chickens. However, the plastic-grid floor showed superior effects on breast meat yield and quality characteristics, particularly reducing cooking loss, when compared to zeolite supplementation in wood shaving litter. The plastic-grid floor led to a slight increase in the feed conversion ratio. Consequently, adopting a plastic grid floor emerges as a viable alternative to traditional wood shavings in broiler farming.

Effect of housing system on carcass composition, meat quality, digestive morphometry, and leg bone dimensions of Ross 308 parent broilers.

The aim of the present study was to compare the effects of 2 Ross 308 parent broiler housing systems (SLS-slat-litter system vs. LS-litter-based system) in terms of carcass composition, meat quality traits (chemical composition, texture, physicochemical properties), as well as biometric traits of the digestive system and leg bones. The weight of the eviscerated carcass and the proportion of carcass components were determined at the end of the reproductive period (60 wk of life) following slaughter. The lengths and diameters of the individual intestinal segments, the weight of selected internal organs, the acidity (pH24) and electrical conductivity (EC24), as well as the color (L*, a*, b*) of breast and thigh muscles were assessed. The basal chemical composition of the breast and thigh muscles was also determined, texture analysis of the pectoralis major muscle and measurements of the femur and tibia of parent broilers were also carried out. The housing system differentiated the birds in terms of percentage of breast muscle (SLS-27.4% vs. LS-26.0%) and intramuscular fat content in the breast muscle (SLS-1.1% vs. LS-0.7%), spleen weight pH of the breast and thigh muscles and EC of the thigh muscles (SLS-9.3 mS/cm vs. LS-7.0 mS/cm). Differences were also found between the study groups in the color of the breast and thigh muscles. The housing system affected the results of the texture analysis of the pectoralis major muscle. The birds differed significantly (P < 0.05) in terms of gumminess (SLS-11.1 N vs. LS-16.0 N), springiness, chewiness (SLS-17.6 N × cm vs. LS-23.4 N × cm) and cohesiveness parameters. The housing system did not affect the lengths and diameters of the individual intestinal segments, except for the length of the terminal intestine. There was no significant effect of the housing system on the tibia and femur dimensions analyzed. This study provided information about differences in certain carcass characteristics, meat quality, and the digestive system of Ross 308 parent broilers in relation to the maintenance system.