A new approach and insights on modelling the impact of production diseases on dairy cow welfare.

Animal welfare is becoming an important consideration in animal health-related decision-making. Integrating considerations of animal welfare into the decision-making process of farmers involves recognising the significance of health disorder impacts in relation to animal welfare. Yet little research quantifies the impact, making it difficult to include animal welfare in the animal health decision-making process. Quantifying the impact of health disorders on animal welfare is incredibly challenging due to empirical animal-based data collection constraints. An approach to circumvent these constraints is to rely on expert knowledge whereby perceived welfare impairment weights are indicative of the negative welfare effect. In this research, we propose an expertise-based method to quantify the perceived impact of sub-optimal mobility (SOM) on the welfare of dairy cows, because of its welfare importance. We first quantified perceived welfare impairment weights of SOM by eliciting expert knowledge using adaptive conjoint analysis (ACA). Second, using the perceived welfare impairment weights, we derived the perceived welfare disutility (i.e., perceived negative welfare effect) of mobility scores 1-5 (1 = optimal mobility, 5 = severely impaired mobility). Third, using the perceived welfare disutility per mobility score, we quantified the perceived welfare impact at case- and herd-level of SOM for different SOM severity. Results showed that perceived welfare disutility increased with each increase in mobility score. However, the perceived welfare impact of SOM cases with lower mobility scores was higher compared to SOM cases with higher mobility scores. This was because of the longer-lasting duration of the SOM cases with lower mobility scores. Moreover, the perceived herd-level welfare impact was largely due to SOM cases with lower mobility scores because of the longer duration and more frequent incidence compared to the SOM cases with higher mobility scores. These results entail that better welfare of dairy cows with respect to SOM can be achieved if lower mobility scores are detected and treated sooner. Our research demonstrates a novel approach that quantifies the perceived impact of health disorders on animal welfare when empirical evidence is limited.

Handling End-of-Life Situations in Small Animal Practice: What Strategies do Veterinarians Contemplate During their Decision-Making Process?

This study researched end-of-life (EoL) decision-making processes in small animal practices in the Netherlands, focusing on strategies veterinarians contemplate during this process. Fourteen veterinarians were interviewed about animal end-of-life decision-making. The results of these interviews show that the decision-making process consists of three steps. The first step is to assess the animal's health and welfare. During the second step, veterinarians consider the position of the owner. Based on steps 1 and 2, veterinarians decide in step 3 whether their advice is to a) euthanize or b) contemplate one or more strategies to come to a decision or potentially alter the decision. These results can support members of the veterinary profession to reflect on their decision-making process. If veterinarians know what strategies their peers use to deal with EoL situations, this can help to reduce the stress they experience in such situations. In addition, veterinarians may find inspiration for new strategies in the study results. For the veterinary profession itself, the current results can be used as a starting point for describing best practices for EoL decision-making in small animal practice.

A multi-suckling system combined with an enriched housing environment during the growing period promotes resilience to various challenges in pigs.

Little is known about the impact of social and environmental enrichment on improving livestock resilience, i.e. the ability to quickly recover from perturbations. We evaluated the effect of an alternative housing system (AHS) on resilience of pigs, as compared to conventional housing (CONV). The AHS consisted of multi-litter housing during lactation, delayed weaning, extra space allowance and environmental enrichment at all times. We assessed recovery to a 2 h-transport challenge, an LPS injection, 2 h-heat stress and a biopsy wound in 96 pigs. Additionally, indicators of long-term "wear and tear" on the body were determined. AHS pigs had better physiological recoveries with quicker returns to baseline in the transport and LPS challenges, showed lower cortisol accumulation in hairs and lower variance in weight gain over the experimental period compared to conventionally-housed (CONV) pigs. They also had higher levels of natural antibodies binding KLH than CONV pigs. Their response to heat stress revealed a different strategy compared to CONV pigs. Taken together, AHS pigs appear to be more resilient and experience less chronic stress. Enhancing welfare by provision of social and environmental enrichment that better meets the behavioural needs of pigs seems to be a promising approach to improve their resilience.

Predicting hatchability of layer breeders and identifying effects of animal related and environmental factors.

In this study, a data driven approach was used by applying linear regression and machine learning methods to understand animal related and environmental factors affecting hatchability. Data was obtained from a parent stock and grand-parent stock hatchery, including 1,737 batches of eggs incubated in the years 2010-2018. Animal related factors taken into consideration were strain (white vs. brown strain), breeder age, and egg weight uniformity at the start of incubation, whereas environmental factors considered were length of egg storage before incubation, egg weight loss during incubation and season. Effects of these factors on hatchability were analyzed with 3 different models: a linear regression (LR) model, a random forest (RF) model and a gradient boosting machine (GBM) model. In part one of the study, hatchability was predicted and the performance of the models in terms of coefficient of determination (R2) and root mean square error (RMSE) was compared. The ensemble machine learning models (RF: R2 = 0.35, RMSE = 8.41; GBM: R2 = 0.31, RMSE = 8.67) appeared to be superior than the LR model (R2 = 0.27, RMSE = 8.92) as indicated by the higher R2 and lower RMSE. In part 2 of the study, effects of these factors on hatchability were investigated more into detail. Hatchability was affected by strain, breeder age, egg weight uniformity, length of egg storage and season, but egg weight loss didn't have a significant effect on hatchability. Additionally, four 2-way interactions (breeder age × egg weight uniformity, breeder age × length of egg storage, breeder age × strain, season × strain) were significant on hatchability. It can be concluded that hatchability of parent stock and grand-parent stock layer breeders is affected by several animal related and environmental factors, but the size of the predicted effects varies between the methods used. In this study, 3 models were used to predict hatchability and to analyze effects of animal related and environmental factors on hatchability. This opens new horizons for future studies on hatchery data by taking the advantage of applying machine learning methods, that can fit complex datasets better than LR and applying statistical analysis.

Gregarious nesting in relation to floor eggs in broiler breeders.

Gregarious nesting has often been observed in laying hens, where hens prefer to visit a nest already occupied by other hens over empty nests. This may result in overcrowding of the nests which is considered a welfare issue and, moreover, can increase the economic issue of floor eggs. This study aimed to describe gregarious nesting and spatial behavior in broiler breeders and how this relates to genetic background, fearfulness and mating behavior. Five commercially available genetic lines of broiler breeders were housed in 21 pens of 550 females and 50 males (six pens for lines 1 and 2, five pens for line 3 and two pens for lines 4 and 5) during the ages 20-60 weeks. Every 10 weeks, the plumage condition and wounds were assessed of 50 random hens per pen. Avoidance distance and novel object tests were performed to assess fearfulness at four time points. Distribution of eggs over nests was observed for 6 weeks at the onset of egg production at 26 weeks of age, and use of space was recorded at four time points, while (floor) egg production was noted daily per pen. We found differences between genetic lines over time in plumage condition and prevalence of wounds. Fear of humans was highest at the earliest age tested and did not correlate with general fearfulness as assessed by the novel object test. The distribution of eggs over nests was related to genetic background and was more uneven at the earliest age compared to later ages, and a more uneven distribution was correlated with an increased percentage of floor eggs. Distribution of birds over the litter area differed between the genetic lines, and less use of the litter area was correlated with an increased fear of humans and presence of wounds, suggesting an association with aggressive mating behavior. This difference in distribution of the birds could also explain the correlation between increased presence of wounds and decreased percentage of floor eggs. It is concluded that broiler breeders do show gregarious nesting, which is affected by genetic background. Both increased gregarious nesting and wounds are related to increased floor egg percentage, which should be studied further in broiler breeder research. Genetic selection for even use of the available nests and of the litter and slatted area would therefore support both broiler breeder welfare and performance.

Influence of a raised slatted area in front of the nest on leg health, mating behaviour and floor eggs in broiler breeders.

European farms for broiler breeders often have raised slatted areas in front of the nests, but in other regions of the world no raised slatted areas are provided. This study aimed to investigate the effects of a raised slatted area on leg health, mating behaviour and floor laying behaviour. Ten groups of 33 broiler breeder hens and three males were housed in two pen types: with or without a raised slatted area in front of the nests. Each pen had one plastic and one wooden nest. Between 25 and 31 weeks of age, ten marked hens per pen were weighed and assessed weekly on foot pad dermatitis, hock burn and wounds. At the end of week 31, animals were euthanized and bone strength of the tibia and humerus of these individuals was assessed. At 24, 27 and 30 weeks of age, mating behaviour was observed for an hour per pen, noting both numbers of successful and unsuccessful copulations. The number of eggs laid in the nests and on the floor was recorded daily between 20 and 31 weeks of age. Foot pad dermatitis scores were affected by age, but not by pen type. Generally, there were only minor issues with foot pad dermatitis (scores <11 on a 0-100 scale), probably due to the young age of the hens. Body weight was not affected by pen type, while the prevalence of hock burns was too low to analyse and no difference in bone strength was found for the tibia and the humerus. Overall, mating behaviour was less frequent in pens with raised slats than in pens without raised slats (29 ±â€¯2 vs 35 ±â€¯3 times/h) and more frequent at 27 weeks of age than at 24 and 30 weeks of age (38 ±â€¯1 vs 31 ±â€¯4 and 27 ±â€¯2 times/h). The pens with raised slats had a lower percentage of floor eggs than pens without raised slats (11.2 ±â€¯0.4 vs 19.3 ±â€¯0.5%). The wooden nest was preferred over the plastic nest as on average 63% of the eggs were laid in the wooden nest. This study shows that providing raised slats decreases mating behaviour and percentage of floor eggs, although its effects on leg health remain inconclusive.

Assessing keel bone damage in laying hens by palpation: effects of assessor experience on accuracy, inter-rater agreement and intra-rater consistency.

Accurate assessment is essential when evaluating keel bone damage. Palpation is commonly used to assess keel bone damage in living hens. However, there is little information on the accuracy of assessment of deviations and fractures on different parts of the keel, and on the consistency within, and agreement between, assessors. Crucially, although the importance of experience is commonly emphasized, knowledge on its effect is scarce. Ten assessors with or without prior experience palpated the same 50 75-wk-old hens for deviations, medial fractures, and caudal fractures (scored as present/absent). Accuracy, sensitivity, specificity, precision, and negative predictive value were determined by comparing palpation scores to post-dissection assessment, and then compared between experienced and inexperienced assessors. To determine the effect of the experience gained during the experiment, hens were subsequently re-assessed. Consistency within, and agreement between, assessors were also determined. Assessors with prior experience were more accurate (proportion of accurately assessed deviations: experienced 0.83 vs. inexperienced 0.79±0.01, P = 0.04; medial fractures: 0.82 vs. 0.68±0.03 in session 1 only, P = 0.04; caudal fractures: 0.41 vs. 0.29±0.03, P = 0.03), and inexperienced assessors classified medial fractures more accurately in session 2 (session 1: 0.68 vs. session 2: 0.77±0.04, P = 0.04). However, effect sizes were small for deviations and even experienced assessors lacked accuracy when assessing caudal fractures. Unexpectedly, deviations tended to be assessed more accurately in session 1 than in session 2, regardless of assessor status (1: 0.83 vs. 2: 0.79±0.01, P = 0.06), suggesting that prolonged assessment contributes to errors. Prior experience decreased specificity and precision of fracture assessment (more unfractured keels were classified as fractured) even though overall accuracy was greater. Intra-rater consistency was fair to good (0.55 to 0.67) for deviations and medial fractures, but poor to fair (0.36 to 0.44) for caudal fractures, and unaffected by prior experience (P = 0.49 to 0.89). In conclusion, experience improves accuracy to a limited extent but does not guarantee high accuracy for all types of damage. Future research should determine if other training methods (e.g., comparison to post-dissection scores or to radiographs) improve accuracy.

Effects of dark brooders and overhangs on free-range use and behaviour of slow-growing broilers.

Broiler chickens often make limited use of the free-range area. Range use is influenced by type of shelter available. Range use may possibly be improved by a more gradual transition from the house to the range and by using dark brooders (secluded warm, dark areas in the home pen) that mimic aspects of a broody hen and possibly reduce fearfulness. The aim of this study was to assess effects of dark brooders on fearfulness, free-range use and behaviour later in life. Another aim was to test the chickens' preference for shelter type and the effects of overhangs outside of the pop holes to provide a gradual transition to the range. Three production rounds, each with 440 Sasso broiler chickens (110/group), were completed. Chicks were housed indoors from days 0 to 25; per round, two groups had access to a dark brooder, whereas the other two groups had conventional IR lamps. Fearfulness was assessed by the open field (OF) and tonic immobility (TI) tests on days 22 to 24 on 25 chicks/group per round. Birds were then moved to four mobile houses from which they could access both grassland with artificial shelter (AS) and short rotation coppice (SRC). Two of the houses had overhangs extending from the pop holes; these were switched between the four houses weekly. Free-range use and behaviour were observed three times daily from Monday to Friday. Dark brooders did not affect results from the OF or TI test, except for jumps in the OF test which tended to occur less often in brooded chicks. Neither dark brooders (34.9% without v. 31.7% with brooder) nor overhangs (32.5% without v. 34.1% with overhangs) influenced the percentage of chickens outside. Chickens showed a clear preference for SRC, range use increased over time in SRC, and more birds ranged farther from the house in SRC. Behaviours of chickens observed outside were mainly influenced by shelter type, age of the birds and distance from the house. Locomotion tended to occur more in the presence of overhangs. Overall, these results could not confirm the hypothesis that dark brooders would decrease fearfulness and thereby increase free-range use. Overhangs also did not improve free-range use, and neither brooders nor overhangs had considerable impact on behaviour of chickens outside. Chickens clearly preferred dense natural vegetation over AS and ranged farther in it, indicating that this type of shelter is more suitable for slow-growing free-range broilers.

Animal Board Invited Review: Comparing conventional and organic livestock production systems on different aspects of sustainability.

To sustainably contribute to food security of a growing and richer world population, livestock production systems are challenged to increase production levels while reducing environmental impact, being economically viable, and socially responsible. Knowledge about the sustainability performance of current livestock production systems may help to formulate strategies for future systems. Our study provides a systematic overview of differences between conventional and organic livestock production systems on a broad range of sustainability aspects and animal species available in peer-reviewed literature. Systems were compared on economy, productivity, environmental impact, animal welfare and public health. The review was limited to dairy cattle, beef cattle, pigs, broilers and laying hens, and to Europe, North America and New Zealand. Results per indicators are presented as in the articles without performing additional calculations. Out of 4171 initial search hits, 179 articles were analysed. Studies varied widely in indicators, research design, sample size and location and context. Quite some studies used small samples. No study analysed all aspects of sustainability simultaneously. Conventional systems had lower labour requirements per unit product, lower income risk per animal, higher production per animal per time unit, higher reproduction numbers, lower feed conversion ratio, lower land use, generally lower acidification and eutrophication potential per unit product, equal or better udder health for cows and equal or lower microbiological contamination. Organic systems had higher income per animal or full time employee, lower impact on biodiversity, lower eutrophication and acidification potential per unit land, equal or lower likelihood of antibiotic resistance in bacteria and higher beneficial fatty acid levels in cow milk. For most sustainability aspects, sometimes conventional and sometimes organic systems performed better, except for productivity, which was consistently higher in conventional systems. For many aspects and animal species, more data are needed to conclude on a difference between organic and conventional livestock production systems.

Effects of shelter type, early environmental enrichment and weather conditions on free-range behaviour of slow-growing broiler chickens.

Free-range use by broiler chickens is often limited, whereas better use of the free-range area could benefit animal welfare. Use of free-range areas could be stimulated by more appropriate shelter or environmental enrichment (by decreasing birds' fearfulness). This study aimed to assess the effects of shelter type, early environmental enrichment and weather conditions on free-range use. Three production rounds with 440 slow-growing broiler chickens (Sasso T451) were carried out. Birds were housed indoors in four groups (two with males, two with females) from days 0 to 25, during which two of the groups received environmental enrichment. At day 23 birds' fearfulness was assessed with a tonic immobility (TI) test (n=100). At day 25 all birds were moved (in mixed-sex groups) to mobile houses, and provided with free-range access from day 28 onwards. Each group could access a range consisting for 50% of grassland with 21 artificial shelters (ASs, wooden A-frames) and for 50% of short rotation coppice (SRC) with willow (dense vegetation). Free-range use was recorded by live observations at 0900, 1300 and 1700 h for 15 to 21 days between days 28 and 63. For each bird observed outside the shelter type (AS or SRC), distance from the house (0 to 2, 2 to 5, >5 m) and its behaviour (only rounds 2 and 3) were recorded. Weather conditions were recorded by four weather stations. On average, 27.1% of the birds were observed outside at any given moment of observation. Early environmental enrichment did not decrease fearfulness as measured by the TI test. It only had a minor effect on the percentage of birds outside (0.4% more birds outside). At all distances from the house, SRC was preferred over AS. In AS, areas closer to the house were preferred over farther ones, in SRC this was less pronounced. Free-range use increased with age and temperature and decreased with wind speed. In AS, rainfall and decreasing solar radiation were related to finding more birds outside, whereas the opposite was true in SRC. Behaviour of the birds depended on shelter type, distance from the house, early environmental enrichment, time of day and age. Chickens ranged more and farther in SRC, possibly because this provided a greater sense of safety because of the amount of cover and/or better protection against adverse weather conditions. These results indicate that SRC with willow is a more appropriate shelter for slow-growing broiler chickens than A-frames.

Effects of litter provision during early rearing and environmental enrichment during the production phase on feather pecking and feather damage in laying hens.

Feather pecking is a multi-factorial behavioral disorder and a serious welfare issue in the poultry industry. Several studies report early life experience with litter to be a major determinant in the development of feather pecking. The current study aimed to test the large-scale on-farm efficiency of a simple and cheap husbandry procedure applied during the rearing period with the ultimate goal of reducing the incidence of feather pecking and plumage damage during the production stage in laying hens. Five laying hen-rearing farmers from across Norway participated in the study. These farmers were asked to create divisions within their hen rearing houses and to separate their chicks into 2 groups: one reared with access to a paper substrate from the first d of age, the other a control group without access to paper substrate during rearing. All flocks were visited at the production farms at 30 wk of age and observed for pecking behavior and feather damage. Birds in the control group had higher odds of having more feather damage compared to the birds from the treatment group. In addition, flocks provided with environmental enrichment at the production farms had a reduced incidence of feather pecking, irrespective of the treatment. These results indicate that husbandry procedures during both rearing and production stages have the potential to alleviate feather pecking and increase laying hen welfare.

Ramps and hybrid effects on keel bone and foot pad disorders in modified aviaries for laying hens.

Non-cage systems provide laying hens with considerable space allowance, perches and access to litter, thereby offering opportunities for natural species-specific behaviors. Conversely, these typical characteristics of non-cage systems also increase the risk of keel bone and foot pad disorders. The aim of this study was twofold: 1) to investigate if providing ramps between perches (housing factor) reduces keel bone and foot pad disorders and 2) to test for genetic predisposition by comparing 2 different layer hybrids. In a 2 × 2 design, 16 pens were equipped either with or without ramps between perches and nest boxes (8 pens/treatment), and housed with either 25 ISA Brown or Dekalb White birds per pen (in total 200 birds/hybrid). Keel bone injuries and foot health were repeatedly measured via palpation and visual assessment between 17 and 52 wk of age and daily egg production was recorded. The relationships between the dependent response variables (keel bone and footpad disorders, egg production) and independent factors (age, ramps, hybrid) were analyzed using generalized linear mixed models and corrected for repeated measures. Ramps reduced keel bone fractures (F1,950 = 45.80, P < 0.001), foot pad hyperkeratosis (F1,889 = 10.40, P = 0.001), foot pad dermatitis (F1,792 = 20.48, P < 0.001) and bumble foot (F1,395 = 8.52, P < 0.001) compared to pens without ramps. ISA Brown birds sustained more keel bone fractures (F1,950 = 33.26, P < 0.001), had more foot pad hyperkeratosis (F1,889 = 44.69, P < 0.001) and laid more floor eggs (F1,1883 = 438.80, P < 0.001), but had fewer keel bone deviations (F1,1473 = 6.73, P < 0.001), fewer cases of foot pad dermatitis (F1,792 = 19.84, P < 0.001) and no bumble foot as compared to Dekalb White birds. Age, housing and hybrid showed several interaction effects. Providing ramps proved to be very effective in both reducing keel bone and foot pad problems in non-cage systems. Keel bone and foot pad disorders are related to genetic predisposition. These results indicate that adaptation of the housing systems and hybrid selection may be effective measures in improving laying hen welfare.

Heritability of body surface temperature in hens estimated by infrared thermography at normal or hot temperatures and genetic correlations with egg and feather quality.

Exposure of laying hens to chronic heat stress results in loss of egg production. It should be possible to improve hen resilience to chronic heat stress by genetic selection but measuring their sensitivity through internal temperature is time consuming and is not very precise. In this study we used infrared thermography to measure the hen's capacity to dissipate heat, in a commercial line of laying hens subjected to cycles of neutral (N, 19.6°C) or high (H, 28.4°C) ambient temperatures. Mean body temperatures (BT) were estimated from 9355 infrared images of wing, comb and shank taken from 1200 hens. Genetic parameters were estimated separately for N and H temperatures. Correlations between BT and plumage condition were also investigated. Wing temperature had low heritability (0.00 to 0.09), consistent with the fact that wing temperature mainly reflects the environmental temperature and is not a zone of heat dissipation. The heritability of comb temperature was higher, from 0.15 to 0.19 in N and H conditions, respectively. Finally, the shank temperature provided the highest heritability estimates, with values of 0.20 to 0.22 in H and N conditions, respectively. Taken together, these results show that heat dissipation is partly under genetic control. Interestingly, the genetic correlation between plumage condition and shank and comb temperatures indicated that birds with poor condition plumage also had the possibility to dissipate heat through featherless areas. Genetic correlations of temperature measurements with egg quality showed that temperatures were correlated with egg width and weight, yolk brightness and yellowness and Haugh units only under H conditions. In contrast, shell colour was correlated with leg temperature only at thermo-neutrality.

Risk factors associated with keel bone and foot pad disorders in laying hens housed in aviary systems.

Aviary systems for laying hens offer space and opportunities to perform natural behaviors. However, hen welfare can be impaired due to increased risk for keel bone and foot pad disorders in those systems. This cross-sectional study (N = 47 flocks) aimed to assess prevalences of keel bone and foot pad disorders in laying hens housed in aviaries in Belgium to identify risk factors for these disorders and their relation to egg production. Information on housing characteristics and egg production were obtained through questionnaire-based interviews, farm records, and measurements in the henhouse. Keel bone (wounds, hematomas, fractures, deviations) and foot pad disorders (dermatitis, hyperkeratosis) were assessed in 50 randomly selected 60-week-old laying hens per flock. A linear model with stepwise selection procedure was used to investigate associations between risk factors, production parameters, and the keel bone and foot pad disorders. The flock mean prevalences were: hematomas 41.2%, wounds 17.6%, fractures 82.5%, deviations 58.9%, hyperkeratosis 42.0%, dermatitis 27.6%, and bumble foot 1.2%. Identified risk factors for keel bone disorders were aviary type (row vs. portal), tier flooring material (wire mesh vs. plastic slats), corridor width, nest box perch, and hybrid. Identified risk factors for foot pad disorders were aviary type (row vs. portal), free-range, and hybrid. Percentage of second-quality eggs was negatively associated with keel bone deviations (P = 0.029) at the flock level. Keel bone and foot pad disorders were alarmingly high in aviary housing. The identification of various risk factors suggests improvements to aviary systems may lead to better welfare of laying hens.

Robustness to chronic heat stress in laying hens: a meta-analysis.

Chronic heat is a major stress factor in laying hens and many studies on the effect of heat stress have been published. It remains difficult, however, to draw general conclusions about the effect of chronic heat stress on performance and its relationship with genetic and environmental factors, as these studies have been done under varying experimental conditions and using various experimental designs. A meta-analysis enabled us to make a quantitative review of the results from 131 published papers. The relative effects of four factors (genotype, age, group size, and amplitude of temperature variation) and their interactions with temperature were analyzed for 13 traits. After pre-correcting the data for a random study effect, the best model for each trait was selected in a stepwise procedure based on its residual sum of squares. Shell strength, daily feed intake, egg mass, and hen-day egg production were found to be more sensitive to heat stress than the other traits as they dropped by 9.0 to 22.6% between thermo-neutrality (15 to 20°C) and heat stress (30 to 35°C) while yolk and albumen proportions or Haugh units showed nearly no variation with temperature (<1.2% between thermo-neutrality and heat stress). Many interactions (17) were found between temperature and one or more factors in the 13 traits studied here, which reinforces the interest of using a meta-analysis to summarize data from the literature. This study highlighted that the impact of heat stress in laying hens depends on the genotype, age, and group size, some of which have rarely been investigated.

Effects of roughage source, amount, and particle size on behavior and gastrointestinal health of veal calves.

The European Union 1997 Directive, stipulating that veal calves should be fed a minimum of 50 to 250 g of fibrous feed from 8 to 20 wk of age, is vague. A fibrous feed ration maximum of 250 g has been implicated in welfare issues, namely the occurrence of abnormal oral behaviors and poor gastrointestinal health. Past research suggests that this amount is insufficient to prevent the development of abnormal oral behaviors and enabling good rumen development. Different sources and particle sizes of roughage could lead to very different welfare outcomes. In a 3×2 × 2 factorial design, 240 group-housed calves (10±1 d; 46.1±0.1 kg) were fed different roughage sources (straw, maize silage, or maize cob silage; the latter 2 were dried and provided no extra moisture compared with straw) in 2 amounts (250 or 500 g of dry matter per day), and 2 particle sizes (chopped or ground). Roughage was supplemented to milk replacer (MR) from 2 wk after arrival. In addition, 60 calves were fed 1 of 3 additional control treatments: MR only (n=20), MR plus an iron supplement (n=20), or MR plus ad libitum hay (n=20). Oral behaviors were recorded using instantaneous scan sampling at 2-min intervals for 2 h in 3 periods per day, at 12 and 22 wk of age. Calves were slaughtered at 24 wk of age and rumen and abomasal health parameters were recorded. Limited provision of straw resulted in behavior comparable with that from unlimited provision of hay, with reduced tongue playing and oral manipulation of the environment, as well as increased chewing compared with diets with no roughage supplement. Straw prevented ruminal hairballs, but impaired rumen development and increased abomasal damage. A higher ration of roughage increased chewing (12 wk), decreased oral manipulation of the trough (12 and 22 wk) and the pen (22 wk), and increased rumen weight. However, more roughage led to increased abomasal damage for certain parameters. Longer feed particles had no obvious benefits for behavior, but decreased hairball prevalence. Overall, unlimited hay had the highest benefit for both behavior and gastrointestinal health. Adding iron to the MR did not alter behavior or gastrointestinal health compared with MR without iron supplement. This study demonstrated that different roughage sources, amounts, and particle sizes have different effects on veal calf behavior and gastrointestinal health, and hence on veal calf welfare.

Fear, stress, and feather pecking in commercial white and brown laying hen parent-stock flocks and their relationships with production parameters.

Little is known about the relationship between welfare traits and production in laying hen parent stock (PS). In commercial laying hens and pure lines, it is known that aspects associated with reduced welfare such as high fear, stress, and feather pecking can have negative effects on production. Because PS hens are housed under different conditions than commercial laying hens, the relationship between welfare traits and production may differ. We therefore studied the fear response to a stationary person (SP) and novel object (NO), basal plasma corticosterone (CORT) and whole-blood serotonin levels (5-HT), and feather damage as a proxy for feather pecking in 10 Dekalb White (DW) and 10 ISA Brown (ISA) commercial PS flocks and related these to production data. Because the relationship between welfare traits and production may differ by genetic origin and group size, we also assessed genotype and group size effects. Dekalb White birds were more fearful of a SP, and had more feather damage and lower 5-HT levels than ISA birds. Genotypes did not differ in CORT. A large group size (n > 5,000) was associated with low feed intake and better feed conversion for ISA flocks. For DW flocks, high fear of the NO was associated with low BW, low egg weight, and low feed intake. For ISA flocks, high fear of the SP was associated with high mortality. For both lines, high CORT was related to low egg weight. This is the first study to associate levels of fear and CORT to production in commercial PS flocks. Management of PS flocks should take into account breed differences, group size effects, and effects of human-bird interactions. Further research is needed to determine the effects of fear, CORT, 5-HT, and feather damage in commercial PS flocks on the development of their offspring.

Backtest and novelty behavior of female and castrated male piglets, with diverging social breeding values for growth.

Pigs housed together in a group influence each other's growth. Part of this effect is genetic and can be represented in a social breeding value. It is unknown, however, which traits are associated with social breeding values. The aim of this study was, therefore, to investigate whether personality and response to novelty could be associated with social breeding values for growth in piglets. Female and castrated male piglets from 80 litters, with either an estimated relative positive or negative social breeding value (+SBV or -SBV) for growth, were individually tested in a backtest and novel environment test, and group-wise in a novel object (i.e., a feeder with feed) test and human approach test. All tests were performed during the suckling period. No differences between +SBV and -SBV piglets were found for the frequency and latency of struggling and vocalizing in the backtest (at least, P > 0.30). In the novel object test, piglets with a +SBV for growth touched the feeder faster than piglets with -SBV for growth (P = 0.01) and were more frequently present near the person in the human approach test (P < 0.01). No behavioral differences between +SBV and -SBV piglets were found in the novel environment test (at least, P > 0.40), but piglets that struggled more in the backtest walked more in this test (P = 0.02). Behavior was affected by gender in each test. Female piglets were faster than castrated male piglets to start struggling in the backtest (P = 0.047). In the novel object test, females were faster than males to touch the feeder and sample the feed. In the human approach test, they were also faster than male piglets to touch a person (all, P < 0.001). Females were also more frequently present near the feeder (P < 0.001) and person (P = 0.03). In the novel environment test, female piglets explored the floor more (P = 0.046), produced less low- (P = 0.04) and high-pitched vocalizations (P = 0.02), and defecated (P = 0.08) and urinated less than male piglets (P < 0.01). It was concluded that +SBV and -SBV piglets do not differ in their response to the backtest, and only subtle differences were found in their response to novelty. More research is warranted to identify the traits underlying SBV for growth in pigs. Moreover, castrated male piglets seemed to react more fearfully to each test than female piglets.

Effects of maternal care and selection for low mortality on tyrosine hydroxylase concentrations and cell soma size in hippocampus and nidopallium caudolaterale in adult laying hen.

Feather pecking and cannibalism in farm-kept laying hens are damaging behaviors both in terms of animal welfare and economic loss, and a major challenge in modern poultry farming. Both rearing with a foster hen and genetic selection have been demonstrated to reduce feather pecking in laying hens. We examined the effects of rearing with a foster hen, genetic selection for low mortality from cannibalism, and interactions between both, using cellular morphology and levels of the rate-limiting enzyme in dopamine production, tyrosine hydroxylase, in the hippocampus and nidopallium caudolaterale (NCL) as a potential measure for laying hen welfare. Hens from the second generation of a sib-selection scheme line derived from a pure-bred White Leghorn line, selected for low mortality and for production characteristics, or their control line (CL) selected only for production characteristics, were housed with or without a foster Silky hen for the first 7 wk of life. Aside from the presence or absence of a foster Silky hen during the first 7 wk of life, housing conditions were identical for all hens. The hens were then sacrificed and brains were removed at 52 wk of age. Brains were sectioned and stained using a Nissl staining to reveal cell soma morphology, or using immunocytochemistry for tyrosine hydroxlase. A greater degree of lateralization in the hippocampus was observed in hens reared without a foster hen, as measured by absolute difference in cell soma size between hemispheres (P<0.05). The low mortality line showed decreased concentrations of tyrosine hydroxylase in the NCL compared with the CL (P<0.005). Our results indicate that morphological changes in brain induced in very early life can be detected in adult hens, and that genetic selection against mortality due to cannibalism impacts tyrosine hydroxylase in the NCL of laying hens. These observations strengthen the notion that brain measures may be useful as potential readouts for animal welfare.

Effects of genetic origin and social environment on behavioral response to manual restraint and monoamine functioning in laying hens.

Purebred laying hen lines of White Leghorn (WL) origin have been found to be more flighty and to show more feather pecking than lines of Rhode Island Red (RIR) origin. It has been found, however, that when RIR birds were housed together with WL birds, RIR birds became more flighty and those mixed groups developed more feather damage than pure-line cage-housed groups. It is unknown, however, whether this effect of social environment is accompanied by changes in stress-related behavior and neurophysiological activity, which are assumed to be associated with increased feather damage. The objective of this study was therefore to investigate the effects of genetic origin (WL or RIR) and social environment (mixed or pure groups) on behavioral response to manual restraint and monoamine functioning. Monoamine functioning was measured by brain serotonin (5-HT) and dopamine turnover. Furthermore, correlations between 5-HT turnover in the brain and peripheral measures of 5-HT in the blood were calculated. Experimental birds, housed either with other birds from the same genetic origin (pure groups) or with both RIR and WL birds (mixed groups) from hatching onward, were subjected to a manual restraint test at 47 wk of age. The WL birds struggled less during restraint and had higher dopamine and 5-HT turnover levels after restraint than did RIR birds. The WL birds also showed higher levels of platelet 5-HT uptake than did RIR birds. No effects of social environment were found. Blood and brain 5-HT measures were found to be correlated, with correlations ranging from 0.34 to 0.57, which seems to offer opportunities for less invasive peripheral indicators of 5-HT activity. In conclusion, genetic origin, but not social environment, affected the behavioral response to manual restraint and monoamine functioning in laying hens.