Nicolas Devillers

Assessment of lameness in sows using gait, footprints, postural behaviour and foot lesion analysis

Lameness in sows has an economic impact on pig production and is a major welfare concern. The aim of the present project was to develop methods to evaluate and quantify lameness in breeding sows. Five methods to study lameness were compared between themselves and with visual gait scoring used as a reference: footprint analysis, kinematics, accelerometers, lying-to-standing transition and foot lesion observation. Fifty sows of various parities and stages of gestation were selected using visual gait scoring and distributed into three groups: lame (L), mildly lame (ML) and non-lame (NL). They were then tested using each method. Kinematics showed that L sows had a lower walking speed than NL sows (L: 0.83 ± 0.04, NL: 0.96 ± 0.03 m/s; P < 0.05), a shorter stride length than ML sows (L: 93.0 ± 2.6, ML: 101.2 ± 1.5 cm; P < 0.05) and a longer stance time than ML and NL sows (L: 0.83 ± 0.03, ML: 0.70 ± 0.03, NL: 0.69 ± 0.02 s; P < 0.01). Accelerometer measurements revealed that L sows spent less time standing over a 24-h period (L: 6.3 ± 1.3, ML: 13.7 ± 2.4, NL: 14.5 ± 2.4%; P < 0.01), lay down earlier after feeding (L: 33.4 ± 4.6, ML: 41.7 ± 3.1, NL: 48.6 ± 2.9 min; P < 0.05) and tended to step more often during the hour following feeding (L: 10.1 ± 2.0, ML: 6.1 ± 0.5, NL: 5.4 ± 0.4 step/min standing; P = 0.06) than NL sows, with the ML sows having intermediate values. Visual observation of back posture showed that 64% of L sows had an arched back, compared with only 14% in NL sows (P = 0.02). Finally, footprint analysis and observation of lying-to-standing transition and foot lesions were not successful in detecting significant differences between L, ML and NL sows. In conclusion, several quantitative variables obtained from kinematics and accelerometers proved to be successful in identifying reliable indicators of lameness in sows. Further work is needed to relate these indicators with causes of lameness and to develop methods that can be implemented on the farm.

Effect of age on the behavioral and physiological responses of piglets to tail docking and ear notching1

Neonatal piglets are often subject to potentially painful processing procedures such as tail docking and ear notching during the first few days after birth. However, these procedures may influence the development of suckling behavior and passive transfer of immunoglobulins, especially if done within the first day postpartum. The objective of this experiment was to compare the effects of processing piglets during the first 24 h versus at 3 d of age on suckling and pain-related behavior, the passive transfer of immunoglobulins, and growth. Six piglets per litter from 20 litters (n = 120 piglets) were used in a 3 x 2 complete block design. Piglets were weighed at birth and assigned to 1 of 3 treatments (balanced by birth weight): control (unmanipulated), sham processed (manually manipulated), and processed (tail docked and ear notched) at 1 of 2 ages (1 or 3 d of age). Vocalizations were recorded during the procedures, and piglets were observed after the procedures for pain-related behavior. Suckling behavior was observed for 6 h on each of d 1 to 4. Colostrum samples were collected after the birth of all piglets (before first suck), and blood samples were collected on d 5 to examine concentrations of immunoglobulins (IgA and IgG) and IGF-I. Body weights were measured at birth and on d 5 and 14. During the procedures, processed piglets, regardless of age, vocalized at a greater frequency (P < 0.001) and produced more high frequency calls (P = 0.016) than sham-processed piglets. All piglets on d 1 produced more high frequency calls than all piglets on d 3 (P = 0.047). Immediately after the procedures, sham-processed and processed piglets spent less time lying and more time standing than control piglets (P < 0.001), whereas processed piglets jammed their tail between their legs more than sham-processed or control piglets (P < 0.001). Lying, standing and tail posture were not influenced by age, nor were there age by treatment interactions. Piglets on d 1 trembled more than piglets on d 3 (P < 0.001), and this tended to be exacerbated by processing (P = 0.076). There was no effect of treatment or age of treatment on suckling behavior. Processed piglets had decreased IgG serum concentrations compared with sham-processed and control piglets (P = 0.029), although there was no interaction between treatment and age of treatment (P = 0.67). Whereas tail docking and ear notching do appear to result in short-term pain and modulated immune status, processing on d 1 appears neither better nor worse than processing on d 3.

The Way Humans Behave Modulates the Emotional State of Piglets.

The emotional state can influence decision-making under ambiguity. Cognitive bias tests (CBT) proved to be a promising indicator of the affective valence of animals in a context of farm animal welfare. Although it is well-known that humans can influence the intensity of fear and reactions of animals, research on cognitive bias often focusses on housing and management conditions and neglects the role of humans on emotional states of animals. The present study aimed at investigating whether humans can modulate the emotional state of weaned piglets. Fifty-four piglets received a chronic experience with humans: gentle (GEN), rough (ROU) or minimal contact (MIN). Simultaneously, they were individually trained on a go/no-go task to discriminate a positive auditory cue, associated with food reward in a trough, from a negative one, associated with punishments (e.g. water spray). Independently of the treatment (P = 0.82), 59% of piglets completed the training. Successfully trained piglets were then subjected to CBT, including ambiguous cues in presence or absence of a human observer. As hypothesized, GEN piglets showed a positive judgement bias, as shown by their higher percentage of go responses following an ambiguous cue compared to ROU (P = 0.03) and MIN (P = 0.02) piglets, whereas ROU and MIN piglets did not differ (P > 0.10). The presence of an observer during CBT did not modulate the percentage of go responses following an ambiguous cue (P > 0.10). However, regardless of the treatment, piglets spent less time in contact with the trough following positive cues during CBT in which the observer was present than absent (P < 0.0001). This study originally demonstrates that the nature of a chronic experience with humans can induce a judgement bias indicating that the emotional state of farm animals such as piglets can be affected by the way humans interact with them.

Colostrum production in swine: from the mammary glands to the piglets

An early and high intake of colostrum is a major determinant of survival during the early suckling period, when most losses occur. Indeed, piglets are born devoid of body fat and are dependent on colostrum as their sole energy source. Colostrum also has other essential roles for the developing piglet; most importantly, it provides passive immunity and nutrients to the piglet and permits thermoregulation. It also stimulates gastrointestinal development, muscle protein synthesis and the development of active immunity. Neonatal swine can efficiently use colostrum since they have a remarkable capacity to deposit large amounts of fat and can also absorb intact immunoglobulins for 24 h postnatally. The production of colostrum, however, is very variable between sows and the factors affecting this variability are not well known. Such studies are most difficult to carry out since it is not easy to estimate colostrum yield. Indeed, the various methods that can be used to measure colostrum yield all have several drawbacks. The endocrine status of the sow undoubtedly affects the process of colostrogenesis and the underlying mammary changes associated with it. The composition of sow colostrum is well known, yet it is only recently that the presence of numerous bioactive compounds which can either protect piglets from infection or modulate their metabolism was detected in colostral secretions. There are indications that the composition of colostrum can be altered by some management components but further studies are necessary in that area.

Effects of a new housing system and temperature on sow behaviour during lactation

Abstract The objective of this study was to evaluate the adaptation of sows to housing in interaction with ambient temperature. Seventy primiparous sows were used to compare the effect of housing sows in a standard farrowing crate (STD) or a modified farrowing pen system (MOD) on sow activity, space use and nursing behaviour at 21 °C or 29 °C. The MOD pen consisted of a STD crate with a back area where the sows could access by backing up into. This area was equipped with rubber mats, a feeder and a water nipple which they could use to moisten the floor. Sows in the MOD pens spent more than 85% of their time in the back area, were more active and had fewer non-productive nursings in late lactation than the sows in STD crates. This new farrowing pen design improved the behavioural expression of the sows irrespective of temperature.

Behaviour of piglets weaned at three or six weeks of age.

Abstract The objective of this experiment was to compare behaviour of piglets weaned and mixed at 21±1 (W21, n=81) or 43±1 (W43, n=70) days of age. Piglets were observed two days before weaning (D-2), just after weaning and mixing (D0) and 24 hours later (D1). Time spent feeding was lower on D0 compared to D1 in both treatment, but was lower in W21 than in W43 piglets (P<0.05). On D0, W21 piglets were less active than W43 piglets (P<0.001). Accordingly, between D-2 and D0, W43 piglets increased (P<0.001) time spent in aggression, exploration and locomotion. Conversely, W21 piglets were more active than W43 piglets on D1 (P<0.01). Timing of behaviour relative to weaning day differed between treatments; W21 piglets were more apathetic than W43 piglets just after weaning indicating a delay in the reaction of younger piglets to weaning and mixing. W21 piglets also had a greater and longer decrease in post-weaning eating incidence than W43 piglets, which is likely due to both older age and previous creep feed experience.

Pig–human interactions: Creating a positive perception of humans to ensure pig welfare

Domestic pig fear of humans is common, certainly because a lot of the human interactions are aversive and the current intensive pig husbandry systems do not leave much place for positive interactions. However, the situation may change because the quality of human–animal relationship is being included in many welfare evaluation systems. The development of the relationship with humans involves different sensory channels (acoustic, visual, tactile or chemical). Memory is central in the relationship, and it leads pigs to discriminate and even recognise individual humans. The nature of the relationship matters as it will modulate not only pig health and welfare but also productivity and product quality as well as stockpeople work quality and job satisfaction. Future research aiming at improving the human–pig relationship will have to focus on the pigs’ sensorial capacities and social behaviour, as well as stockperson training.

A preliminary study of the effects of individual response to challenge tests and stress induced by humans on learning performance of weaned piglets (Sus scrofa).

This study investigated whether individual behavioural characteristics of piglets and stress induced by experience with humans can influence learning performance. After weaning, piglets received a chronic experience with humans to modulate their emotional state: rough (ROU), gentle (GEN), or minimal (MIN) experience. Simultaneously, they were trained on a discrimination task. Afterward, their behaviour during challenge tests was assessed. The first learning step of the task involved associating a positive sound cue with a response (approach a trough) and success of piglets depended mostly on motivation to seek for reward. Although the experience with humans did not have direct effect, the degree of fear of handler, measured based on their reactivity to a human approach test, was related to motivation to seek rewards and learning speed of this first step in stressed ROU piglets, but not in MIN and GEN piglets. In contrast, the second learning step was more cognitively challenging, since it involved discrimination learning, including negative cues during which piglets had to learn to avoid the trough. Locomotion activity, measured during an open-field test, was associated with performance of the discrimination learning. To conclude, fearfulness towards humans and locomotion activity are linked with learning performance in relation to task complexity, highlighting the necessity to take into account these factors in animal research and management.

On-farm evaluation of methods to assess welfare of gestating sows

The objectives were to evaluate quantitative animal-based measures of sow welfare (lameness, oral stereotypies and reactivity to humans) under commercial farm conditions, and to estimate the influence of housing, sow parity and stage of gestation on the outcome of these measures. Across 10 farms, 311 sows were used. Farms differed in terms of housing design (pen v. stall), space allowance, floor type in stalls (partially v. fully slatted), and feeding system in pens (floor v. trough). Lameness was assessed in terms of gait score, walking speed, stride length, stepping behaviour, response to a stand-up test and latency to lie down after feeding. The presence of oral stereotypies and saliva foam were recorded. Reactivity to humans was assessed by approach (attempt to touch the sow between the ears) and handling tests (exit of the stall for stall-housed sows, or isolation of the animal for pen-housed sows). Only stride length and walking speed were associated with lameness in stall-housed sows (P<0.05 and P<0.01). In stalls, the probability that a sow was lame when it presented a short stride length (<83 cm) or a low speed (<1 m/s) was high (69% and 72%, respectively), suggesting that these variables were good indicators of lameness, but were not sufficient to detect every lame sow in a herd (sensitivity of 0.39 and 0.71, respectively). The stage of gestation and parity also influenced measures of stride length and walking speed (P<0.05). Saliva foam around the mouth was associated with the presence of sham chewing and fixture biting (P<0.05). The probability that a sow presents sham chewing behaviour when saliva foam around her mouth was observed was moderate (63%) but was not sufficient to detect all sows with stereotypies (41%). A high discrimination index was obtained for behavioural measures (aggressions, escapes) and vocalisations during the approach test (stalls: 78.0 and 64.0; pens: 71.9 and 75.0, respectively), the number of interventions needed to make the sow exit the stall during the handling test for stall-housed sows (74.9), and attempts to escape during the handling test for pen-housed sows (96.9). These results suggest that these measures have a good power to discriminate between sows with low and high reactivity to humans. Finally, the outcome of several measures of lameness, stereotypies and reactivity to humans were influenced by the housing characteristics, sow parity and stage of gestation. Therefore, these factors should be considered to avoid misinterpretations of these measures in terms of welfare.