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Highlights • A tucked tail worked as a detector of tail damage in finishing pigs. • Tail posture seemed promising as an early detector of tail biting in finishing pigs. • Tail posture was affected by risk factors of tail damage. Abstract The purpose of the current study was to investigate the relation between the tail posture of finishing pigs and tail damage with the aims to use tail posture as (1) a detector of tail damage, (2) an early detector of tail biting to possibly predict and prevent bleeding tail damage. Tails of each individual pig (from 112 finishing pigpens) were scored three times per week for the full study period of 10 weeks. For the first aim, tail posture was observed directly in the stable three times per week, just prior to tail scoring, and pigs with a tucked tail were related to their tail scoring. The odds of being scored with a tail wound (both bleeding and non-bleeding) increased by almost sixfold if the pig was also observed with a tucked tail on the same day. More precisely, 28% of the pigs with a tucked tail were also scored with a tail wound, whereas this was only the case for 5% of the pigs with a different tail posture. This relation between a tucked tail and tail damage was larger than previously found in weaners and suggests that a tucked tail could be used as a detector of tail damage, although with the risk of many false identifications of tail damage. For the second aim, tail posture was observed from video the last 3 days prior to bleeding tail damage for case pens (n = 20; at least one pig with a bleeding tail wound) and their matched controls (n = 20). The number of pigs with lowered tails (below the tail root) was observed by scan sampling during 6 h per day. A generally higher probability of having a lowered tail was seen in the case pens compared to the control pens, but the probability of having a lowered tail did not increase prior to bleeding tail damage. Thus, the results indicate that tail posture is a promising early detector of tail biting in finishing pigs, but observations going further back than 3 days from bleeding tail damage are needed to find out when the difference in tail posture arises. Alternatively, a less severe definition of tail damage could be used. Further, the differences found were relatively small, and thus to be able to predict pens in future risk of tail damage from changes in tail posture would probably demand the development of an automatic recording method for the number of lowered tails at pen level. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate when fouling appears in conventionally housed slaughter pigs and whether stocking density and straw provision are risk factors to fouling. During four batches of a total of 112 pens with slaughter pigs, pens were randomly assigned to one level of each of two treatments: (1) stocking density of 1.21 (low, n = 56) v. 0.73 m 2 /pig (high, n = 56), (2) 150 g of straw provided per pig per day on the solid floor (n = 56) v. no straw provided (n = 56). Fouling was recorded each day, and a pen had an event of fouling if at least half of the solid floor was wet with excreta and/or urine. Only the first event of fouling for each pen was included, and thus results represent whether a pen had a fouling event or not and when it happened. Data was analysed by using a Cox regression assuming proportional hazard and with right censoring of pens that never developed fouling. First event of fouling was mostly seen during the first week after insertion and in the last 3 weeks prior to slaughter (10 week study period). Pens with high stocking density had a 90% higher hazard of fouling compared to pens with low stocking density ( P = 0.016), meaning that pens with a high stocking density had a higher risk of fouling and of developing it earlier. Pens with straw provided had a 49% higher hazard of fouling compared to pens with no straw provided ( P = 0.14 ). No interaction was seen between stocking density and straw provision ( P = 0.80). In conclusion, stocking density was a significant risk factor of fouling, whereas straw provision only indicated this numerically within the used experimental setup and chosen sample size. The results suggest that lowering the stocking density to a level of around 1.21 m 2 /pig could reduce the risk of fouling in slaughter pigs. The relationship between fouling and straw provision needs further investigation. [ABSTRACT FROM AUTHOR]

Egg incubation through artificial means is a highly controlled process, where eggs are held at a fixed air temperature of 37.6 °C. Nevertheless, much research has been conducted on alternative temperature profiles to evaluate their influence on production and welfare traits. Most attention has been paid on increasing temperature as this has been shown to improve heat tolerance in later life. Limited research has been conducted on the effects on animal behavior, although the absence of negative emotions such as fearfulness and the presence of social expression is considered crucial for positive animal welfare as stated by the Welfare Quality® Protocol for Poultry. Therefore, the objective of the current study was to investigate the effect of two heat tolerance improving thermal treatments: (T1, +1 °C and T2, +2 °C from embryonic day 15–20) on fearful and social behaviors in later life. A total of 12 pens (4 per treatment) containing 13–14 chickens was reared for 42 days. During this rearing period, post-hatch fearful and social behavior were quantified using seven behavioral tests: an emergence test, a social reinstatement test, an isolation test, a novel arena test, a novel object test, a human stationary and a human approach test. These tests were chosen based on a thorough literature study and repeated 2 or 3 times. The research results showed that social behaviors were affected by the interaction of treatment and gender. Whereas in standard incubation, males have a lower social reinstatement tendency, both treatments changed their behavior. T1 males vocalized more than females during isolation (males: 73 ± 4 calls versus females: 38 ± 2 calls, P < 0.001) and T2 males showed more social motivation during a social reinstatement test compared to C (T2: 121 ± 20 s versus C: 66 ± 25 s, P < 0.05) and T1 (57 ± 27 s, P < 0.05). Finally, an effect of age was found with older birds being less fearful of a novel object and novel environment, but more fearful of an approaching human. Also, they seem more socially driven to contact conspecifics. However, the validity of these age results is questionable as habituation, changing sensory and/or cognitive skills, variance between repeats and possible reduced mobility at an older age could affect the behavioral response over time. In conclusion, increased temperature during incubation conditions can improve heat tolerance in later life, however, sociality is also affected. Both T1 and T2 changed social behaviour. An increased tendency to reinstate contact with conspecifics is found in T2 males than females. • Investigating the effect of heat temperature stimuli on fear and social behavior in broiler chicknes was studied. • Social test results were affected by treatment and gender. • Increased temperature increased social drive of chickens in males. [ABSTRACT FROM AUTHOR]

Temperature is the most influential environmental parameter during egg incubation affecting embryo development, hatchability and post-hatch performance of broilers. Industrial incubation operates to control the temperature and humidity around the eggs closely based on predefined setpoints and keep fluctuations to a minimum. On the other hand, during brooding, the mother hen regularly leaves the nest for self-maintenance resulting in a striking difference between the constant industrial versus fluctuating natural incubation temperature profiles. Previous studies on ducks and laying hens have found fear and/or social behaviours to be affected by temperatures below recommended values during incubation, a similar result could be existing in commercial broilers. Therefore, this study examines the effect of lowering machine temperatures during incubation on behaviour. Three incubation treatments were defined with a constant machine temperature of 37.6 °C on embryonic day (ED) 0–13 and 19–21 with the machine temperature differing on ED 13–18: (1) Control (C ; 37.6 °C), (2) non-optimal Incubation Treatment (IT ; 36.6 °C), (3) Natural Treatment (NT , 30 °C for 30 min per day). Post-hatch fear and social behaviour were quantified using six scientifically accepted behavioural tests: three fear tests (novel object on day (d) 1 and d8, tonic immobility (d40), inversion (d42)), two social tests (isolation (d19) and social reinstatement (25)) and one social/fear test (emergence (d18 and d20)). For the emergence test, wherein the time taken for an individual chick to emerge from a T-shaped box was measured, a treatment effect was found on the latency to emerge (P < 0.05) with C chicks emerging more often and faster than IT chicks. As no differences for IT were found in other social tests, the emergence suggest IT chicks to be more hesitant towards novel environments. No differences were present between NT and C or NT and IT. For the isolation test, where an individual chick is visually and audibly isolated for 3 min and the number of vocalisations was measured, an interaction was found between treatment and sex (P < 0.001). Females vocalised more than males in IT and C, but this was not the case for NT. NT male chicks could thus be considered more sensitive to social separation, which could be explained by the higher impact of early stress, caused by the severe temperature drops in NT, having a stronger impact on the anxiety behaviour of males compared to females in later life. • Investigating the effect of cold temperature stimuli on fear and social behaviour. • More fear of novel environments found in broilers incubated 1 °C lower than advised. • Increased fear of social separation in male broilers incubated such as in nature. [ABSTRACT FROM AUTHOR]

• Optical flow was used to monitor pig movement before an outbreak of tail-biting. • There was increased group movement in the three days prior to tail-biting. • However, there was no difference between outbreak pens and matched nooutbreak pens. • Outbreak and nooutbreak pens were highly synchronized, suggesting mutual influence. Videos of pigs were analysed using an optical flow algorithm to measure group movement in the four days leading up to and including an outbreak of tail-biting. 8 pens in which tail-biting occurred (Outbreak) were retrospectively matched with 8 similar pens in which no tail-biting occurred over the lifetime of the pigs (NoOutbreak) and videos analysed for the same four days. Results showed an increase in movement over the four days in both groups and no difference between Outbreak pens and their matched NoOutbreak pens. On the contrary, Outbreak and NoOutbreak matched pens showed similar changes in behaviour, suggesting that the pigs were influencing each other or responding to common external circumstances. Such a tendency to "match" the behaviour of pigs in neighbouring pens makes it difficult to identify which pens will show tail biting. [ABSTRACT FROM AUTHOR]

Simple Summary: Tail biting is a major animal welfare issue within modern pig production, and tail biting should be prevented whenever possible. If the farmer could get an alarm when a pen of pigs is at high risk of developing tail damage, the farmer would be able to take timely action to prevent tail damage in specific pens. In the current investigation, a method for prediction of tail biting events was developed and tested in a real-life setting. The method used changes in pigs' drinking behaviour and in the temperature of the pen. The method was able to alarm the farmer about 12 of the 14 tail biting events prior to serious tail damage. However, the farmer did also get false alarms on 30% of the days without tail biting events, which is not optimal. Thus, the farmer could use the alarms as indications of which pens to pay greater attention to. The next step could be to expand the method to include behavioural changes that are more specific to tail biting such as changes in the pigs' tail posture. Tail biting in pigs is an animal welfare problem, and tail biting should be prevented from developing into tail damage. One strategy could be to predict events of tail biting so that the farmer can make timely interventions in specific pens. In the current investigation, sensor data on water usage (water flow and activation frequency) and pen temperature (above solid and slatted floor) were included in the development of a prediction algorithm for tail biting. Steps in the development included modelling of data sources with dynamic linear models, optimisation and training of artificial neural networks and combining predictions of the single data sources with a Bayesian ensemble strategy. Lastly, the Bayesian ensemble combination was tested on a separate batch of finisher pigs in a real-life setting. The final prediction algorithm had an AUC > 0.80, and thus it does seem possible to predict events of tail biting from already available sensor data. However, around 30% of the no-event days were false alarms, and more event-specific predictors are needed. Thus, it was suggested that farmers could use the alarms to point out pens that need greater attention. [ABSTRACT FROM AUTHOR]

Thermosensation is crucial for the survival of any organism. In animals, changes in brain temperature are detected via sensory neurons, their cell bodies are located in the trigeminal ganglia. Transient receptor potential (TRP) ion channels are the largest temperature sensing family. In mammals, 11 thermoTRPs are known, as in poultry, there are only three. This research further elucidates TRP mRNA expression in the brain of broiler embryo's. Three incubation treatments were conducted on 400 eggs each: the control (C) at 37.6 °C; T1 deviating from C by providing a + 1 °C heat stimuli during embryonic day (ED) 15–20 for 8 h a day; and T2 , imposing a + 2 °C heat stimuli. After each heat stimuli, 12 eggs per treatment were taken for blood sampling from the chorioallantoic membrane and brain harvesting. Incubation parameters such has residual yolk (free embryonic) weight, chick quality and hatch percentage were collected. After primer optimization, 22 target genes (13 TRPs and 9 non-TRPs) were measured on mRNA of the brain using a nanofluidic biochip (Fluidigm Corporation). Four target genes (ANO2, TRPV1, SCN5A, TRAAK) have a significant treatment effect - independent of ED. Another four (TRPM8, TRPA1, TRPM2, TRPC3) have a significant treatment effect visible on one or more ED. Heat sensitive channels were increased in T2 and to a lesser degree in T1, which could be part of an acclimatisation process resulting in later life heat tolerance by increased heat sensitivity. T2, however, resulted in a lower hatch weight, quality and hatchability. No hormonal differences were detected. [Display omitted] • IFC of 13 TRP and 9 non-TRP ion channels in the brain of broiler chicken embryos. • Design of 16 new primer pairs. • Heat stimuli during embryonic incubation by +1 °C and + 2 °C for 8 h/day, ED15–20. • Incubation treatment affected 8 target genes • ANO2, SCN5A, TRPA1, and TRAAK are potentially crucial for acclimatisation to temperature. [ABSTRACT FROM AUTHOR]

Water is a vital nutrient for mammals, including the pig. Despite this, the use of drinkers and water have not yet been explicitly quantified across the finisher period. The current study aimed at gaining greater insight into finisher pigs' drinker use and its relation to drinker location, age, time of day, stocking density, enrichment provision and tail damage. The experiment included 110 pens of finisher pigs over a 9-week period, with two drinker cups per pen. Pens had a stocking density of either 0.73 m 2 /pig ( n = 54 pens, 18 pigs per pen) or 1.21 m 2 /pig ( n = 56 pens, 11 pigs per pen), were either provided with straw ( n = 54, 150 g per pig and day) or not ( n = 56), and had pigs with either undocked ( n = 50) or docked tails ( n = 60). Drinker use was recorded automatically by water-flow meters and summed to L and number of activations per hour and pig. Pens never experiencing a tail damage event (at least one pig in the pen with a bleeding tail) were used to investigate the normal drinker use of finisher pigs ( n = 56). The water use of pigs increased from 3.7 to 8.2 L per pig and day during the 9 weeks, and this increase was mainly seen during the two large peaks of the diurnal pattern within the pigs' active period (06:00-18:00 h). No such increase was seen in the activation frequency at average 50 activations per pig and day. A decrease in stocking density increased both water use and activation frequency during the active period, suggesting that pigs at the standard space allowance and pig:drinker ratio could be restricted in their access to the drinking cups. The pigs also seemed to prefer to use the drinking cup closest to the feeder. Water use and activation frequency did not change the last 3 days prior to an event of tail damage, but general differences were seen between pens with and without a tail damage event. The current results may explain the success of previous studies in classifying tail damage pens from pens without tail damage using sensor data on drinker use., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Larsen and Pedersen.)

Pen fouling, where the pigs choose to rest in their designated excretion area (the slatted floors) and excrete in their designated resting area (the solid floors), is an undesired behaviour and should be prevented when possible. One strategy to prevent fouling is early detection by means of either animal or environmental measures changing prior to fouling. The aim of the present study was to investigate whether the lying pattern of pigs and the temperature in the pen changed the last 5 days prior to an event of fouling and whether this differed from pens without an event of fouling (controls). Fouling events was recorded at pen level when at least half of the solid floor was wet with excreta and/or urine (day0). Each fouling pen was paired with a control pen that had not been scored as a fouling pen prior to or at least 1 week after the fouling event. Fouling and control pens were either not provided with straw or provided daily with 150 g of straw per pig. Percentage of pigs lying on the solid floor and the slatted floor (36 events) as well as pen temperature above the solid and slatted floor (24 events) was analysed using four linear mixed effects models. The percentage of pigs lying on the solid floor decreased (40-24%; P < 0.05) while the number of pigs lying on the slatted floor increased (14-24%; P < 0.05) from day-2 to day0 only in the fouling pens, with differences seen between fouling and control pens on the same days ( P < 0.01). However, these changes and differences was only seen in pens without straw. Also only in pens without straw did pen temperature above the solid floor decrease from day-2 to day0 (18.6-17.6°C; P < 0.001), with differences seen between fouling and control pens only on day0 ( P < 0.05). In contrast, pen temperature measured above the slatted floor did not change, independent of whether the pen was provided with straw or not. Thus, in pens not provided with straw, both the lying pattern of pigs and pen temperature above the solid floor have potential as early detectors of pen fouling.