Technical Note: Plastic mats prevent footpad injuries in rabbit does

In the Netherlands, welfare regulations indicate that rabbits should be housed on 3 mm wire floors. In a pilot study, 3 mm wire floors did not decrease footpad injuries as expected, whereas a plastic mat fixed to the 3 mm wire did improve footpad quality. However, more data were necessary to support this finding. To this end, footpad injuries were studied in does housed on 3 mm wire floors (NOMAT) and 3 mm wire floors with a plastic mat (MAT) on five rabbit farms. On each farm, 25 cages were used for each floor type and footpad quality was measured during 5 successive reproductive cycles. Footpad quality was scored once every production cycle of 42 or 49 d, using a scale from 0 (= intact footpads) to 4 (=wounds). The total number of does in the experiment declined at later parity, due to relocation within the farm and mortality. The percentage of does with intact footpads on NOMAT declined from 96.4% to 13.3% from the first to the fifth parity, respectively. On MAT, 81.3% of the does still had intact footpads at the fifth parity. Results indicated that on NOMAT footpads became injured after the second parity, with a negative effect on the welfare of the does. The average footpad score was significantly lower for the does on MAT as compared to the does on NOMAT (average scores ± SD were 0.17 ± 0.43 and 0.32 ± 0.54, respectively; P < 0.05). Fewer injuries were observed on MAT. Thus, plastic mats have a positive effect on prevention of footpad injuries.Rommers, J.; De Jong, IC. (2011). Technical Note: Plastic mats prevent footpad injuries in rabbit does. World Rabbit Science. 19(4):233-237. doi:10.4995/wrs.2011.868SWORD23323719

Immunity in barren and enriched housed pigs differing in baseline cortisol concentration

It was shown recently that barren housed pigs (small pens, no substrate) have a blunted circadian rhythm of salivary cortisol as compared to enriched housed pigs (large pens with daily fresh bedding). In the light period, enriched housed pigs showed significantly higher concentrations of cortisol in saliva than barren housed pigs, whereas in the dark period, cortisol concentrations were low in both enriched and barren housed pigs. In the present study, the immunological consequences of the difference in baseline salivary cortisol concentration in the light period were evaluated. It appeared that leukocyte and lymphocyte distributions, and in vitro lymphocyte proliferation following ConcanavalineA (ConA) stimulation in the assay using purified lymphocytes were not affected. However, barren and enriched housed pigs did show a different proliferation response to ConA in the whole blood assay. At day 2 of culture, proliferation was higher in barren housed pigs than in enriched housed pigs, whereas at day 4 of culture, proliferation was higher in enriched housed pigs than in barren housed pigs. Lymphocyte proliferation at day 2 of culture in the whole blood assay correlated negatively with plasma cortisol levels, which might thus explain the higher proliferation in barren housed pigs at day 2 of culture. The in vivo humoral and cellular (delayed type hypersensitivity, DTH) immune response to KLH was not affected by housing conditions. We conclude that, although baseline salivary cortisol concentrations differ between enriched and barren housed pigs, immune function appears to be relatively unaffected.

Personalities in female domesticated pigs: behavioural and physiological indications

The inconclusive evidence so far on the existence of distinct personality types in domesticated pigs, led us to perform the present experiment. A total of 128 gilts from 31 sows were systematically studied from birth to slaughter in two identical trials. Intra-test consistency in individual behavioural andror physiological reactions was studied in three different tests. We were not able to show consistencies in reactions of gilts over time to a backtest (at 2–4 days and 4 weeks of age) and to a novel environment test (at 10 and 24 weeks of age). Individual aggression, however, as measured in a group-feeding competition test in stable groups (at 10 and 24 weeks of age), proved to be highly consistent. Explanations for these discrepancies in intra-test consistencies are critically discussed. Inter-test consistencies were determined by relating the individual reactions of gilts to the backtest to various characteristics and responses to tests at a later age. The highest correlations were found when resistance in the first backtest was involved. No evidence was found for the existence of specific isolated categories of animals with respect to this resistance. For further analysis, extreme responding gilts in the first backtest (roughly the top and bottom 25% of the distribution) were classified as low resistant (LR; <3 escape attempts; n=31) or high resistant (HR; >4 escape attempts; n=45). By comparisons of mean responses of LR and HR gilts within groups, we have established a relationship between the backtest and several other variables. Behaviourally, the HR gilts showed more aggression in the group-feeding competition tests. Also, in the competition for the most productive teats at the anterior, a predominant position of HR piglets at this site was observed during the suckling period. The latter piglets also gained more weight during this period than LR ones. Compared to HR pigs, in the first novel environment test LR pigs hesitated longer to leave their home pens and to contact a human, but no difference in their locomotory behaviour was observed. Contrasts between LR and HR pigs in the second novel environment test were reduced or absent. Physiologically, when compared to HR gilts, LR ones had a higher reactivity of the hypothalamic–pituitary–adrenocortical (HPA) system. This was shown by higher cortisol responses to the first novel environment test, to routine weighing at 25 weeks of age, and to administration of a high dose of ACTH. It is discussed that these findings for LR and HR gilts, may provide support for the existence of behavioural and physiological responses in pigs, resembling those of proactive and reactive rodents.

Effects of environmental enrichment on behavioral responses to novelty, learning, and memory, and the circadian rhythm in cortisol in growing pigs

Previously we showed that pigs reared in an enriched environment had higher baseline salivary cortisol concentrations during the light period than pigs reared under barren conditions. In the present experiment, it was investigated whether these higher baseline salivary cortisol concentrations were a real difference in cortisol concentration or merely represented a phase difference in circadian rhythm. The effects of different cortisol concentrations on the behavioral responses to novelty and learning and long-term memory in a maze test were also studied in enriched and barren housed pigs. At 9 weeks of age enriched and barren housed pigs did not differ in baseline salivary cortisol concentrations nor in circadian rhythm, but at 22 weeks of age barren housed pigs had a blunted circadian rhythm in salivary cortisol as compared to enriched housed pigs. The differences in baseline salivary cortisol concentrations between enriched- and barren-housed pigs are age-dependent, and become visible after 15 weeks of age. Enriched- and barren-housed piglets did not differ in time spent on exploration in the novel environment test. Barren-housed pigs had an impaired long-term memory in the maze test compared to enriched-housed pigs; however, no differences in learning abilities between enriched- and barren-housed pigs were found. Because blunted circadian cortisol rhythms are often recorded during states of chronic stress in pigs and rats or during depression in humans, it is suggested that the blunted circadian rhythm in cortisol in barren-housed pigs similarily may reflect decreased welfare.

Description of nestbox visits and suckling events in a group housing system for rabbit does as compared to individual cages

[EN] Research was conducted to study nursing associated events of lactating rabbit does. Nest box visits and suckling events were investigated using 6 group pens (8 does/pen) and 12 enriched individual cages. Each group pen and individual cage was observed by video for one day per week until weaning at 35 d of lactation, with exception of the third week of lactation. In the first 2 wk of lactation, videotapes were analysed for the frequency and duration of nest box visits per day. The fourth and fifth week of lactation, suckling events on the floor of the group pens and nest box visits in the individual cages were analysed for one day per week. The first 2 wk of lactation, does visits to the nest boxes were less frequent (respectively 1.9±0.2 vs. 2.6±0.3, P24 h between nest box visits. In the cages, all does visited the nest boxes at least once a day. In the last 2 wk of lactation, in the group pens suckling duration (mean±standard deviation) was 89±49 and 92.2±37 s in respectively week 4 and 5. In 79% of the suckling events a mix of the does¿ own and other kits were suckled. No difference was found in suckling duration between litters consisting of own and/or other kits. Thirty-two per cent of the does in week 4 and 62% of the does in week 5 did not suckle kits on the floor of the pen, whereas all the does in the cages still visited the nest boxes at least once every 24 h. Based on this study, it can be concluded that in group housing less frequent and shorter nest box visits as well as suckling events were found as compared to individual housing.Rommers, JM.; Kemp, B.; Houwers, H.; Gunnink, H.; De Jong, IC. (2012). Description of nestbox visits and suckling events in a group housing system for rabbit does as compared to individual cages. World Rabbit Science. 20(4):231-240. doi:10.4995/wrs.2012.1231SWORD23124020

Group level and individual activity of broiler chickens hatched in 3 different systems

Information on the behavior of chickens hatched in different systems is limited and inconsistent across different studies. Changes in broiler activity can be measured automatically and continuously. The aim of this study was to assess the effects of 3 hatching systems on flock activity using a commercial tracking system, and to compare these findings to individual activity measured under experimental conditions. As this experiment was part of a larger study, it was possible to investigate the effects of vaccination on individual activity. In study 1, flock activity was measured in chickens that hatched either conventionally in the hatchery (HH), in a system which provided nutrition in the hatcher (HF), or on-farm (OH). Chickens were reared in 2 batches, in 12 pens/batch (1,155 animals/pen). One camera recorded top-view images of each pen. A daily activity index (moved pixels/total pixels × 100) was calculated by automated image analysis. In study 2, individual activity was measured under experimental conditions using an ultra-wideband (UWB) system. Chickens from the 3 hatching systems were reared in 3 pens (1 pen/treatment, 30 animals/pen). At d14, UWB-tags were attached to 5 chickens/pen, which tracked the distances moved (DM). In study 1, group level activity showed a significant age × hatching system interaction (F 8,752= 5.83, P < 0.001). HH and HF chickens showed higher activity levels than OH chickens in wk 1, 4, and 5. In wk 3, higher activity levels were measured in HH compared to HF, and in HF compared to OH pens. In contrast, HH chickens in small groups in study 2 showed lower DM than HF and OH chickens in wk 3 (P < 0.001). DM did not differ between treatments before vaccination, however, thereafter, HH chickens showed longer DM, whereas HF and OH chickens moved less. The results indicate that hatching system affected broiler activity at specific ages. Effects found at flock level could not be reproduced by individual measurements in study 2, although stocking density was comparable

Individuality of a group: detailed walking ability analysis of broiler flocks using optical flow approach

Impaired walking ability is one of the most important factors affecting broiler welfare. Routine monitoring of walking ability provides insights in the welfare status of a flock and assists farmers in taking remedial measures at an early stage. Several computer vision techniques have been developed for automated assessment of walking ability, providing an objective and biosecure alternative to the currently more subjective and time-consuming manual assessment of walking ability. However, these techniques mainly focus on assessment of averages at flock level using pixel movement. Therefore, the aim of this study was to investigate the potential of optical flow algorithms to identify flock activity, distribution and walking ability in a commercial setting on levels close to individual monitoring. We used a combination of chicken segmentation and optical flow methods, where chicken contours were first detected and were then used to identify activity, spatial distribution, and gait score distribution (i.e. walking ability) of the flock via optical flow. This is a step towards focusing more on individual chickens in an image and its pixel representation. In addition, we predicted the gait score distribution of the flock, which is a more detailed assessment of broiler walking ability compared to average gait score of the flock, as slight changes in walking ability are more likely to be detected when using the distribution compared to the average score. We found a strong correlation between predicted and observed gait scores (R2 = 0.97), with separate gait scores all having R2 > 0.85. Thus, the algorithm used in this study is a first step to measure broiler walking ability automatically in a commercial setting on a levels close to individual monitoring. These validation results of the developed automatic monitoring of flock activity, distribution and gait score are promising, but further validation is required (e.g. for chickens at a younger age, with very low and very high gait scores)

Effects of hatching system on chick quality, welfare and health of young breeder flock offspring

Alternative hatching systems have been developed for broiler chickens to provide immediately feed and water after hatch and reduce the number or severity of early life stressors. Besides beneficial effects of these alternative hatching systems on chick quality and performance, broiler health and welfare may be positively affected as well. Especially offspring from young broiler breeder flocks may benefit, as they have been shown to be more sensitive to preturbations than offspring from older breeder flocks. This study evaluated effects of hatching systems on chick quality, health and welfare of young breeder flock offspring, using 3 different hatching systems: conventional hatchery-hatched (HH), hatchery-fed (HF), and on-farm hatching (OH). A total of 24 pens were used in a completely randomized block design, with 8 pens per hatching system and 30 chickens per pen. Chick quality at hatch and performance until 35 d of age was improved in the HF and OH compared to HH treatment, but only minor effects were found on the welfare indicators: footpad dermatitis, hock burn, cleanliness, skin lesion and gait score. No effect was observed on the dynamics of a humoral immune response after NCD vaccination, given at d 0 and 14 of age, as no differences between NCD titers were found at d 18. Animals were vaccinated with a live attenuated infectious bronchitis vaccine virus (IBV) at d 28 to address treatment related differences to disease resilience. The expressions of inflammation and epithelial integrity related genes in the trachea and histo-pathological changes in the trachea were examined at 3 d after vaccine administration. No differences between treatment groups were observed. Although beneficial effects of HF and OH systems were found for young breeder flock offspring on chick quality at hatch and body weight posthatch, only one effect of alternative hatching systems on welfare and health indicators were found. No effect of hatching system on humoral immune response or disease resilience was found

Seeing is caring – automated assessment of resource use of broilers with computer vision techniques

Routine monitoring of broiler chickens provides insights in the welfare status of a flock, helps to guarantee minimum defined levels of animal welfare and assists farmers in taking remedial measures at an early stage. Computer vision techniques offer exciting potential for routine and automated assessment of broiler welfare, providing an objective and biosecure alternative to the current more subjective and time-consuming methods. However, the current state-of-the-art computer vision solutions for assessing broiler welfare are not sufficient to allow the transition to fully automated monitoring in a commercial environment. Therefore, the aim of this study was to investigate the potential of computer vision algorithms for detection and resource use monitoring of broilers housed in both experimental and commercial settings, while also assessing the potential for scalability and resource-efficient implementation of such solutions. This study used a combination of detection and resource use monitoring methods, where broilers were first detected using Mask R-CNN and were then assigned to a specific resource zone using zone-based classifiers. Three detection models were proposed using different annotation datasets: model A with annotated broilers from a research facility, model B with annotated broilers from a commercial farm, and model A+B where annotations from both environments were combined. The algorithms developed for individual broiler detection performed well for both the research facility (model A, F1 score > 0.99) and commercial farm (model A+B, F1 score > 0.83) test data with an intersection over union of 0.75. The subsequent monitoring of resource use at the commercial farm using model A+B for broiler detection, also performed very well for the feeders, bale and perch (F1 score > 0.93), but not for the drinkers (F1 score = 0.28), which was likely caused by our evaluation method. Thus, the algorithms used in this study are a first step to measure resource use automatically in commercial application and allow detection of a large number of individual animals in a non-invasive manner. From location data of every frame, resource use can be calculated. Ultimately, the broiler detection and resource use monitoring might further be used to assess broiler welfare

Prevalence and influence of cys407* Grm2 mutation in Hannover-derived Wistar rats:mGlu2 receptor loss links to alcohol intake, risk taking and emotional behaviour

AbstractModulation of metabotropic glutamate 2 (mGlu2) receptor function has huge potential for treating psychiatric and neurological diseases. Development of drugs acting on mGlu2 receptors depends on the development and use of translatable animal models of disease. We report here a stop codon mutation at cysteine 407 in Grm2 (cys407*) that is common in some Wistar rats. Therefore, researchers in this field need to be aware of strains with this mutation. Our genotypic survey found widespread prevalence of the mutation in commercial Wistar strains, particularly those known as Han Wistar. Such Han Wistar rats are ideal for research into the separate roles of mGlu2 and mGlu3 receptors in CNS function. Previous investigations, unknowingly using such mGlu2 receptor-lacking rats, provide insights into the role of mGlu2 receptors in behaviour. The Grm2 mutant rats, which dominate some selectively bred lines, display characteristics of altered emotionality, impulsivity and risk-related behaviours and increased voluntary alcohol intake compared with their mGlu2 receptor-competent counterparts. In addition, the data further emphasize the potential therapeutic role of mGlu2 receptors in psychiatric and neurological disease, and indicate novel methods of studying the role of mGlu2 and mGlu3 receptors