Twelve Threats of Precision Livestock Farming (PLF) for Animal Welfare

Research and development of Precision Livestock Farming (PLF) is booming, partly due to hopes and claims regarding the benefits of PLF for animal welfare. These claims remain largely unproven, however, as only few PLF technologies focusing on animal welfare have been commercialized and adopted in practice. The prevailing enthusiasm and optimism about PLF innovations may be clouding the perception of possible threats that PLF may pose to farm animal welfare. Without claiming to be exhaustive, this paper lists 12 potential threats grouped into four categories: direct harm, indirect harm via the end-user, via changes to housing and management, and via ethical stagnation or degradation. PLF can directly harm the animals because of (1) technical failures, (2) harmful effects of exposure, adaptation or wearing of hardware components, (3) inaccurate predictions and decisions due to poor external validation, and (4) lack of uptake of the most meaningful indicators for animal welfare. PLF may create indirect effects on animal welfare if the farmer or stockperson (5) becomes under- or over-reliant on PLF technology, (6) spends less (quality) time with the animals, and (7) loses animal-oriented husbandry skills. PLF may also compromise the interests of the animals by creating transformations in animal farming so that the housing and management are (8) adapted to optimize PLF performance or (9) become more industrialized. Finally, PLF may affect the moral status of farm animals in society by leading to (10) increased speciesism, (11) further animal instrumentalization, and (12) increased animal consumption and harm. For the direct threats, possibilities for prevention and remedies are suggested. As the direction and magnitude of the more indirect threats are harder to predict or prevent, they are more difficult to address. In order to maximize the potential of PLF for improving animal welfare, the potential threats as well as the opportunities should be acknowledged, monitored and addressed.

Piglets Learn to Use Combined Human-Given Visual and Auditory Signals to Find a Hidden Reward in an Object Choice Task

Although animals rarely use only one sense to communicate, few studies have investigated the use of combinations of different signals between animals and humans. This study assessed for the first time the spontaneous reactions of piglets to human pointing gestures and voice in an object-choice task with a reward. Piglets (Sus scrofa domestica) mainly use auditory signals–individually or in combination with other signals—to communicate with their conspecifics. Their wide hearing range (42 Hz to 40.5 kHz) fits the range of human vocalisations (40 Hz to 1.5 kHz), which may induce sensitivity to the human voice. However, only their ability to use visual signals from humans, especially pointing gestures, has been assessed to date. The current study investigated the effects of signal type (visual, auditory and combined visual and auditory) and piglet experience on the piglets’ ability to locate a hidden food reward over successive tests. Piglets did not find the hidden reward at first presentation, regardless of the signal type given. However, they subsequently learned to use a combination of auditory and visual signals (human voice and static or dynamic pointing gestures) to successfully locate the reward in later tests. This learning process may result either from repeated presentations of the combination of static gestures and auditory signals over successive tests, or from transitioning from static to dynamic pointing gestures, again over successive tests. Furthermore, piglets increased their chance of locating the reward either if they did not go straight to a bowl after entering the test area or if they stared at the experimenter before visiting it. Piglets were not able to use the voice direction alone, indicating that a combination of signals (pointing and voice direction) is necessary. Improving our communication with animals requires adapting to their individual sensitivity to human-given signals.

Effects of group housing on sow welfare: a review

Factors that have been shown to impact the welfare of group-housed sows are discussed in this review. Floor space allowance markedly affects sow welfare. In addition to quantity of floor space, the quality of space is important: spatial separation between sows can be provided with visual or physical barriers and stalls. Whereas 1.4 m/sow is insufficient, further research is required to examine space effects in the range of 1.8 to 2.4 m/sow in more detail. The period immediately after mixing has the most pronounced effects on aggression and stress, and therefore, well-designed mixing pens offer the opportunity to reduce aggression, injury, and stress while allowing the social hierarchy to quickly form. Because hunger is likely to lead to competition for feed or access to feeding areas, strategies to reduce hunger between meals through higher feeding levels, dietary fiber, or foraging substrate should be examined. However, feeding systems, such as full-body feeding stalls, can also affect aggression and stress by providing protection at feeding, but deriving conclusions on this topic is difficult because research directly comparing floor feeding, feeding stalls, and electronic sow feeder systems has not been conducted. Familiar sows engage in less aggression, so mixing sows that have been housed together in the previous gestation may reduce aggression. Although there is evidence in other species that early experience may affect social skills later in life, there are few studies on the effects of early "socialization" on aggressive behavior of adult sows. Genetic selection has the potential to reduce aggression, and therefore, continued research on the opportunity to genetically select against aggressiveness and its broader implications is required. Most research to date has examined mixing sows after insemination and knowledge on grouping after weaning is limited.

Anticipation and frequency of feeding affect heart reactions in domestic pigs

Measuring heart reactions has become a widely used method for the assessment of emotions. Heart rate and its variability, which can quite easily be noninvasively recorded, reflect the inputs of the sympathetic and parasympathetic branches of the autonomous nervous system. We tested the hypothesis that frequent anticipation of a positive event results in an increased state of welfare in pigs, expressed as positive arousal in anticipation of announced feeding as well as lowered heart rate and augmented heart rate variability during resting periods. We used a controlled paradigm with 3 groups of young domestic pigs (Sus scrofa domestica). We compared frequent acoustic announcement of feed delivery (group 1: 3 feedings between 0730 h and 1030 h plus 3 feedings between 1200 h and 1530 h) with the same number of feedings as in group 1 but without a temporal relation to the sound (group 2) and with a fixed-schedule feeding (group 3: 2 feedings at 0600 h and 1500 h). Specific cardiac and behavioral reactions indicated short-term (1 min) anticipation in the conditioned group. In this group, heart rate increased (P < 0.001) mainly through vagal withdraw and behavior became more active (P < 0.001). Only the conditioned group displayed changing heart rate characteristics during the sound. Pigs in the frequent unpredictable feed group reacted to feed delivery with increased heart rates (P < 0.001), whereas the heart-rate characteristics of pigs with the fixed schedule were unchanged during the sound and while the other 2 treatment groups were feeding. Clear evidence for long-term anticipation (over the course of hours) was not present in the data. Comparisons between the 3 treatment groups suggested that in housing conditions where pigs cannot obtain feed by their actions but must wait for feed delivery, feeding at 2 fixed times would be preferred. Animals in this treatment group presented lower resting heart rates at the end of the experiment than animals in the other 2 groups (P < 0.01). Therefore, merely announcing a positive stimulus without giving control to its access is apparently not suitable for increasing welfare.

Aggression and cortisol levels in three different group housing routines for lactating sows

BACKGROUND

Lactating sows in Swedish organic piglet production are commonly group-housed with piglets in a multi-suckling pen within 14 days after farrowing. Nursing behaviour may be disturbed when lactating sows are moved to a new environment and mixed with other sows, as they spend more time fighting with other sows and exploring the new surroundings. This can disrupt the inhibitory effect of suckling on ovarian activity and increase the risk of lactational oestrus, making efficient reproductive management difficult. Therefore this study evaluated aggression and levels of the stress hormone cortisol in lactating sows group-housed together with their piglets at one (W1), two (W2) or three (W3) weeks post farrowing.

RESULTS

There was no significant difference (P > 0.05) between the three management routines (W1, W2, W3) regarding number of attacks initiated or received in the mixed group. After mixing, W2 sows had a lower number of shoulder scratches (P < 0.05) than W3 sows. Among the W3 sows, there was a lower (P < 0.01) cortisol concentration in saliva when sows were group housed compared to when they were individually housed. The cortisol response, measured as variation in cortisol concentration in saliva, was also lower (P < 0.05) in group-housed W3 sows compared with W1 sows. For all management routines, sows already living in the new environment (resident sows) initiated more attacks (P < 0.001) and received fewer attacks (P < 0.01) than sows entering the new environment (intruder sows). Overall, multiparous sows initiated more attacks and received fewer attacks than primiparous sows (P <0.001).

CONCLUSIONS

Overall, the results suggest that mixing and group housing sows at three weeks post farrowing is less stressful than mixing and group housing sows at one week post farrowing. The results also indicate that parity and whether a sow is a resident or intruder in the group housing environment may have an effect on aggression levels when sows are group-housed.

Effects of cognitive enrichment on behavioural and physiological reactions of pigs

Cognitive enrichment, a special form of environmental enrichment, addresses the cognitive abilities of animals in captivity. Through cognitive interaction with the environment, the animals regain a certain control over their environment, and essential resources, such as food or water, act as a reward for successful coping. It is assumed that this process has important implications for animal welfare, especially in the intensive housing systems of farm animals. This study investigates the effects of cognitive enrichment on welfare-relevant behaviour (agonistic interactions and behavioural reactivity in a repeated open-field test) and autonomic control (heart rate variability during feeding, resting and in a repeated open-field test) in domestic pigs. A total of forty-eight pigs, Sus scrofa, were housed in groups of four. In six replicates, an experimental group was compared with a conventionally fed control group. The pigs in the experimental group were confronted with a cognitive challenge that was integrated into their familiar housing environment. Pigs were rewarded with food after they successfully mastered the discrimination of an individual acoustical signal followed by an operant task. The pigs in both groups reacted with sympathetic arousal to feeding announcement (increased heart rate (HR)). During feeding, the experimental pigs' HR decreased, and heart rate variability (HRV) increased, while the control pigs' HR stayed highly elevated and HRV decreased. These results are supported by a considerably larger number of agonistic interactions during feeding in the control group. During resting, the basal HRV of the experimental pigs increased (during operant conditioning) compared to the control. In the repeated open-field test, the experimental pigs displayed less locomotion and elimination as well as more contact with the wall and an unknown object compared to the control group. We conclude that cognitive enrichment leads to relaxed feeding and evokes longer lasting positive emotions. Moreover, the pigs displayed more explorative and less fearful behaviour in stressful situations. These findings support the use of cognitive enrichment to improve animal welfare.