The influence of straw, cloth tassel, or both on the prepartum behavior of sows

Where is the sow’s nose: RetinaNet object detector as a basis for monitoring the use of rack with nest-building material

Access to nest-building material in the preparturient period is beneficial for sows’ welfare. However, on slatted floors, long-stem forage can drop into the slurry and block the drainage system. As a compromise considering the needs of sows for access to adequate nest-building material, farrowing pens with slatted floors are equipped with dispensers (racks) accessible by sows. In this study, we developed a computer vision method to monitor the use of the racks with nest-building material. In total, 12 sows were included in the experiment from 5 days before farrowing to the end of farrowing. Hay rack use behaviors were labeled for all the sows, i.e., pulling hay, nose close to the rack, exploratory behavior, and bar biting. The object detection algorithm RetinaNet was used to extract centroids of parts of the sow’s body and the hay rack. Several feature variables were estimated from the centroids of detected parts of the sow’s body, and random forest was used for the classification of hay rack use behaviors. The model for the detection of pulling hay behavior had the best performance: 83.5% sensitivity, 98.7% specificity, and 98.6% accuracy. The distance between the sows’ nose and the hay rack was the most important feature variable, which indicated the importance of nose location for the recognition of behaviors in which pigs interact with other objects. The developed models could be applied for automated monitoring of the use of nest-building material in preparturient sows. Such monitoring might be especially important in sows housed on slatted floors.

The effect of hessian and straw as nesting materials on sow behaviour and piglet survival and growth to weaning

Sows are strongly driven to build a nest prior to farrowing, and the performance of this behaviour is linked to the environment in which the animal is housed. The aim of this study was to investigate the impact of two nest-building materials, hessian and straw, on peri-parturient sow behaviour, plasma cortisol concentration and piglet survival and performance in farrowing crates. In the first experiment, sows (parity 1.7 ± 0.1) were allocated to four treatments: (n = 15), straw provided in the lead up to farrowing in an open farrowing pen, with the pen closed after farrowing (STRAW OPEN); (n = 14), straw provided in the lead up to farrowing in a closed farrowing pen (STRAW CLOSED); (n = 15), a closed farrowing pen with hessian sacks provided in the lead up to farrowing (HESSIAN) and; (n = 13), a closed farrowing pen with no nesting materials provided (CONTROL). A second experiment was performed on a separate farm to assess the effect of the same four treatments were applied to sows (parity 2.9 ± 0.1): SRAW OPEN (n = 68), STRAW CLOSED (n = 64), HESSIAN (n = 66) and CONTROL (n = 66), at a commercial level. The first experiment revealed that providing conventionally housed sows with straw or hessian in the lead up to parturition stimulated sows to perform nest-building behaviours similar to sows housed in an open pen with access to straw (nosing events; 16 ± 11 (CONTROL); 169 ± 36 (HESSIAN); 118 ± 29 (STRAW CLOSED); 199 ± 53 (STRAW OPEN); P < 0.05). Additionally, crated sows provided with straw had reduced cortisol levels immediately after farrowing compared to all other treatments (21.9 ± 6.1 ng/ml vs CONTROL; 49.3 ± 8.6 ng/ml; P < 0.01). Piglets born to STRAW CLOSED sows displayed the highest colostrum intake levels (404.8 ± 22.7 g vs CONTROL 361.9 ± 21.9 g; P < 0.01). The second experiment demonstrated a reduced incidence of piglet mortality both prior to fostering (0.7 ± 0.2; P = 0.001) and after fostering (0.7 ± 0.2; P = 0.001) in litters born to sows which were housed in conventional farrowing crates and provided with straw compared to CONTROL (prior to fostering 1.3 ± 0.2, and postfostering 1.1 ± 0.2). In conclusion, straw and hessian sacks are a suitable substrate for stimulating sows to exhibit nest-building behaviour under crated conditions. However, only the provision of straw in the crate environment improved piglet survival and positively affected sow welfare.

Sow communication with piglets while being active is a good predictor of maternal skills, piglet survival and litter quality in three different breeds of domestic pigs (Sus scrofa domesticus)

Maternal care behaviour is crucial for offspring quality and survival in pigs. Defining care is therefore essential for ensuring the welfare of pigs and sustainability of pig production. The aim of the present study was to investigate the relationship between sow nest building, communication with piglets (sniffing, nudging, grunting) during resting and activity, and piglet survival in three different sow breeds: a maternal line selected for high weaned pig production (Landrace), a paternal line selected for meat traits (Duroc), and a crossbred line (Landrace and Yorkshire). We predicted that a higher frequency of nest building and sow communication would have a positive impact on piglet survival. Secondly, we predicted that a high level of maternal care outside the time of nursing (nest building and communication) would increase the quality of the litter (weight at weaning). We also predicted that nest building activity and sow communication would be more pronounced in maternal sow lines selected for maternal traits than in a non-selected, paternal line, and that primiparous sows would perform more nest building behaviour and communicate more than multiparous sows due to high investment in their first litter. Finally, an impaired condition around farrowing (i.e. low body condition score and presence of shoulder lesions) was predicted to be negatively correlated to care behaviours. Data was collected on 38 sows with 511 born piglets. Sows with their litters, were loose-housed in individual farrowing pens until weaning. Nest building activity can be partly considered as maternal care behaviour as it prepares the sows for motherhood and is associated with a lower proportion of stillborn piglets (P < 0.001), starved piglets (P = 0.004), and overlaid piglets (P = 0.034). As predicted, sows that communicated more while being active had lower postnatal piglet mortality (starvation (P < 0.001), less overlying (P < 0.001), overlying with (P < 0.001), and without the milk in the stomach (P < 0.001) and fewer that died of other causes (P < 0.001), higher piglet survival (P < 0.001) and litter weight (P < 0.001) at weaning irrespective of the breed. A higher level of communication while active was associated with more pronounced shoulder lesions in sows (P = 0.010), suggesting a positive association between good maternal care and prevalence of shoulder lesions. We also found that resting sows that communicated more with piglets outside the time of nursing, had higher postnatal piglet mortality (P < 0.001) due to starvation (P < 0.001), overlying (P < 0.001), overlying with (P < 0.001), or without milk (P < 0.001). Communication during resting was more pronounced with increasing litter size at birth (P < 0.001), especially for thin sows (P < 0.001). Communication during resting was more pronounced in the non-selected Duroc line (P < 0.001). Our results suggest that sow communication while being active is a good predictor of good maternal care, piglet survival and litter quality in three different breeds of domestic pigs.

Influence of housing system during gestation on the behaviour and welfare of gilts in farrowing crates

There is some evidence to show that loose housing during gestation has a negative influence on the welfare of sows subsequently in farrowing crates. However, little is known about the effects of the gestation housing on the initial responses of gilts to the farrowing crate or of the effects on gilt welfare throughout lactation. The objective of this experiment was to evaluate three gestation housing systems (1) stalls (ST); (2) loose-bedded (LB) and (3) loose-unbedded (LU) pens for their effect on behaviour, heart rate and skin lesion scores of gilts in farrowing crates. During the 1st h in the farrowing crate, LB gilts were more active, while ST gilts were more vocal. Although heart rates during the 1st h did not differ significantly between treatments, LB and LU gilts had significantly higher mean heart rates during the first 5 min in the crate, compared with 35 min later. Posture changes during the first 24 h did not differ between treatments. However, there was a significant reduction in the number of posture changes made by ST gilts but not LB or LU gilts by day 8. Increases in the skin lesion score of gilts in all three treatments were observed after 24 h in the crate, further increases were observed post farrowing in both loose treatments. Although no significant differences in the skin lesion score were observed during lactation, LB gilts were weaned with lower lesion scores than LU or ST gilts. Gilts from both loose treatments experienced greater distress at first introduction to the farrowing crate. However, the change in environment also had an adverse affect on the welfare of ST gilts. Skin damage and continuing discomfort of the loose-housed gilts post farrowing suggests that they experienced more stress at parturition. Bedding during gestation had a beneficial effect on skin health in the farrowing crate that persisted until weaning.

Influence of environmental stimuli on nursing and suckling behaviour in domestic sows and piglets

The influence of environmental stimuli considered biologically relevant for nest building sows, on nursing and suckling behaviour and piglet growth was investigated. Effects of floor type (beach sand v. concrete) and substrate type (straw feeder v. no straw feeder) were examined in a 2 × 2 factorial experiment with nine replicates of four multiparous sows. The sows were kept individually in roofed 7·6 m2 ‘get-aw ay-pens’ from 1 week pre-partum until 13 to 15 days post-partum. The behaviour of sows and piglets were video recorded for 24 h on days 0, 3, 6 and 12 post-partum.

The latency from termination of farrowing until perceptible milk ejection tended to be shorter for experienced sows (parity 4 to 5) kept on sand than on concrete floors (1207 (s.e. 109) min; no. = 7 v. 1725 (s.e. 123) min; no. = 6, respectively; F2,8 = 3·93, P < 0·07) and for experienced sows with access to a straw feeder than without access to a straw feeder (1257 (s.e. 113) min; no. = 8 v. 1666 (s.e. 132) min; no. = 5, respectively; F2,8 = 3·56, P < 0·08). On days 3 and 6 a longer duration of suckling was found for sows on sand v. concrete floors (384 (s.e. 20) v. 327 (s.e. 16) s on day 3; F1,19 = 5·6, P < 0.03 and 377 (s.e. 14) v. 318 (s.e. 13) on day 6; F1,21 = 9·09; P < 0·01, respectively) and with straw feeder v. without straw feeder (385 (s.e. 20) v. 326 (s.e. 18) s on day 3; F1,19 = 5·11, P < 0.04 and 372 (s.e. 14) v. 323 (s.e. 13) on day 6; F1,21 = 6·21; P < 0·03, respectively). On day 3, a tendency for a sand × straw feeder interaction (F11,8 = 3·58, P < 0.08), showed that sows without environmental stimuli terminated more sucklings than sows with access to a straw feeder and sows kept on sand (32 (s.e. 7) %, 16 (s.e. 4) % and 13 (s.e. 5) %, respectively). Similarly, on day 6 a significant sand × straw feeder interaction (F316 = 7·15, P < 0·01) led to increased frequency of foreleg rowing for sows without environmental stimuli compared with the three other treatments (14 (s.e. 2) v. 7 (s.e. 1), 5 (s.e. 1) and 6 (s.e. 1) foreleg rowings per h, respectively). During the stay in the experimental pens, the growth rate of piglets kept on sand tended to be higher than for piglets kept on concrete floors (261 (s.e. 33) v. 240 (s.e. 30) g per piglet per day; F1,25 = 3·38; P < 0·08).

The results of the present experiment indicate that provision of biologically relevant stimuli affect the nursing and suckling behaviour of sows and piglets. The reduced termination of sucklings, the reduced frequency of foreleg rowing, the increased duration of suckling as well as the earlier development of suckling behaviour might have been advantageous for the early milk intake of the piglets.

Benefits of Prepartum Nest-building Behaviour on Parturition and Lactation in Sows - A Review

It is well known that prepartum sows have an innate motivation to build a nest before parturition. Under commercial conditions, however, the farrowing crate, which is widely used in modern pig husbandry, inhibits this innate behaviour through the lack of space, materials, or both. Thus, restriction of nest-building behaviour could generate increased stress, resulting in a decrease in maternal endogenous hormones. Hence, it could lead to detrimental effects on farrowing and lactating performance. Here we review interactions between prepartum nest-building behaviour, stress and maternal endogenous hormone levels, and discuss their effects on parturition, lactation, and welfare of sows and offspring.

Loose farrowing systems: challenges and solutions

The use of farrowing crates is increasingly questioned from an animal welfare point of view. Even so, since a number of attempts to develop loose farrowing systems have been unsuccessful, leading to high levels of piglet mortality due in the main to crushing, many farmers remain sceptical as to whether or not alternative systems can be viable. On the other hand, several European countries have introduced legislation requiring loose farrowing systems, thus promoting research into this type of housing and allowing for performance studies based on large samples of commercial farms. As a consequence of these recent developments, we think it timely to reconsider the evidence available on loose farrowing systems. In our review, we first address the normal peri-parturient behaviour of domestic pigs, as well as studies comparing behaviour and stress physiology in sows kept in both crates and loose systems during farrowing. We then review approaches taken to develop alternative farrowing systems in different countries, and focus lastly on pen, piglet and sow characteristics that contribute to piglet survival in loose farrowing systems. Taking scientific evidence as well as practical experience into account, we conclude that piglet mortality in loose farrowing systems need not exceed that of crate systems. To obtain good performance results, sows due to farrow should be kept individually in sufficiently large pens, structured for preference into a nest area and an activity area. Furthermore, both management and breeding aspects, resulting in high piglet viability and good maternal behaviour, are essential to achieve high production in loose farrowing systems.

BOARD-INVITED REVIEW: The ethical and behavioral bases for farm animal welfare legislation

Concerns about farm animal welfare vary among individuals and societies. As people increasingly consider the values underlying current farm animal production methods, farm animal welfare policy debates have escalated. Recent food animal protection policies enacted in the European Union have fueled highly contentious discussions about the need for similar legislative activity in the United States. Policymakers and scientists in the United States are apprehensive about the scientific assessment, validation, and monitoring of animal welfare, as well as the unforeseen consequences of moving too hastily toward legislating farm animal welfare. The potential impact of such legislation on producers, food prices, animals, and concerned citizens must also be considered. Balancing the interests of all stakeholders has therefore presented a considerable challenge that has stymied US policymaking. In this review, we examine the roles of ethics and science in policy decisions, discuss how scientific knowledge relative to animal behavior has been incorporated into animal welfare policy, and identify opportunities for additional refinement of animal welfare science that may facilitate ethical and policy decisions about animal care.

Pituitary-Adrenal Activation in Pre-Parturient Pigs (Sus Scrofa) is Associated with Behavioural Restriction Due to Lack of Space Rather than Nesting Substrate

Previous research has shown that pre-parturient primiparous pigs (gilts) housed in behaviourally restrictive farrowing crates without straw redirect their nest-building behaviour to non-manipulable substrates such as the bars of the crate. These gilts also show elevated plasma adrenocorticotropic hormone (ACTH) and Cortisol levels, particularly around the peak of nest-building activity, when compared to gilts in larger pens that have been provided with a manipulable substrate (straw). It remains unclear whether these behavioural and physiological responses to crating result from the lack of a suitable nesting substrate or from the restricted space. This study investigated the effects of space (crate [C] versus pen [P] and straw (straw [S] versus no straw [NS]) using a 2 × 2 factorial design. Thirty-four gilts were implanted with an indwelling jugular catheter at around 12 days before parturition. They were moved to one of the four environments five days before parturition, and blood sampling and recording of behaviour were carried out during the pre-parturient period. Penned gilts (P), irrespective of straw availability, spent more time standing and walking and performed more total substrate-directed behaviour than crated (C) gilts. When straw was not available to penned gilts, a large proportion of their substrate-directed behaviour was redirected to the floor. Space also had an effect on ACTH and Cortisol levels across the entire pre-parturient phase, with C gilts having higher levels than P gilts irrespective of straw availability, but particularly so at the peak of nest-building activity. There was no effect of straw on ACTH or Cortisol levels. Overall, it appears that increased space, perhaps through allowing locomotion, increases substrate-directed behaviour of pre-parturient gilts. When space is available but straw is absent, pre-parturient gilts redirect their nest-building behaviour to the floor. The ability to express substrate-directed behaviour as a result of increased space is reflected in lower levels of indicators of physiological stress.

Evidence of a limited role for prolactin in the preparturient activity of confined gilts

To investigate the role of peripheral prolactin in stimulating the preparturient activity of pigs, 12 cross-bred gilts housed in standard farrowing crates either received orally 10mg of bromocriptine three times per day from day 110 of gestation or served as controls. Jugular blood samples were collected on days 107 and 113 and assayed for prolactin, while the gilts' behaviour was recorded during the last 24h before parturition. Bromocriptine eliminated the preparturient rise in prolactin concentrations (P=0.002). As parturition approached all gilts initially spent less time laying down and more time standing or sitting. The frequency of posture changes also increased as did the incidence of oro-nasal behaviours. These trends were reversed during the final 5-8h before parturition, when the gilts began to lay down for longer periods. The mean concentrations of prolactin on day 113 were correlated with the frequency of posture changes (r=0.70,P=0.015) but not with any other behavioural measure (P>0.10). Bromocriptine had no overall effect on any of the preparturient behaviours (P>0.10) but did reduce the frequency of posture changes 13-16h before parturition (P=0.05). There was a significant interaction between time until parturition and bromocriptine treatment for time spent lying down (P=0.013): bromocriptine delayed the time when the gilts began lying down again as parturition approached. The results suggest that peripheral prolactin plays only a limited role in the preparturient activity of pigs and throws some doubt on its importance in the motivation of nest building in this species.

The effect of parity and environmental restriction on behavioural and physiological responses of pre-parturient pigs

There is increasing evidence that restriction of pre-parturient behaviour in pigs is stress-inducing, characterised by an elevation in hypothalamic-pituitary-adrenal (HPA) activity in gilts. To determine whether pigs adapt to behavioural restriction, through modification of nest-building behaviour, we studied pre-parturient pigs in either farrowing crates (no bedding, n=7) or straw-bedded pens (n=7) in their first (gilts) and second (sows) parity, with physiological measurements being taken in the second parity. Observations and blood sampling were carried out during the pre-parturient phase. Crated pigs changed posture more often than penned pigs (F(1,12)=7.06, P<0.05), with the number of posture changes reducing across parities in both environments. The reduction in posture changing was more apparent in the crated sows which may indicate that attempted nest-building behaviour of sows with prior experience of farrowing crates is less fragmented. The crated pigs spent a greater proportion of time sitting across both parities (F(1,12)=9.4, P<0.01), and spent less time manipulating available substrates (F(1,12)=10.67, P<0.05). There was a tendency for penned pigs to spend a greater proportion of time standing (F(1,12)=3.77, P=0.076) with peak nesting behaviour occurring earlier in relation to parturition than in crated pigs. In addition penned sows performed more floor-directed behaviour than penned gilts, and at an earlier stage in relation to parturition. However, crated sows also performed peak nest-building earlier than crated gilts. Plasma cortisol profiles indicated elevated HPA activity in crated sows during the pre-parturient period (F(42,303)=1.43, P<0.05) suggesting increased physiological stress, however, the difference between crated and penned sows was less than that previously seen in gilts. The increased range of pre-parturient behaviours seen in the penned sows suggests that experience may result in an 'improvement' in their nest-building behaviour: earlier preparation of the nest site and then subsequent manipulation of substrates. The crated sows appeared to show some behavioural adaptation to the crate environment; earlier peak in floor directed behaviour and total substrate directed behaviour, reduced posture changing. In conclusion the nest-building behaviour of pigs is modified over parities with adaptation to the behavioural restrictions imposed by the farrowing crate. However, this adaptation, through prior experience, does not completely reduce the elevation in HPA activity previously reported in pre-parturient crated gilts.

Effects of prostaglandin F2alpha treatment on the behavior of pseudopregnant pigs in an extensive environment

In seminatural environments, prepartum sows leave the herd and construct a maternal nest (a dug out hollow lined with vegetation) prior to the birth of their piglets. The endocrine drives motivating this behavior are not understood, but may involve prostaglandin (PG) F2alpha. This study examined the effect of PGF2alpha treatment on the behavior of pseudopregnant gifts housed in a large enclosure. Pseudopregnancy was induced using 5 mg/ml estradiol valerate/day im from days 11 to 15 of the estrous cycle (first day of estrus = day 0). The gifts' behavior was recorded on a control day, during which no treatment was given, and a test day (= 45.9 +/- 0.42 days of pseudopregnancy) when gilts received either 15 mg PGF2alpha (dinoprost: Lutalyse, Upjohn, Crawley, UK, n = 11) or 0.9% saline (n = 10) im at 11.00 h. PGF2alpha-treated gilts traveled further and were more frequently >10 m from the nearest pig than saline-treated animals. In the hour following injection, PGF2alpha-treated animals also showed increased frequencies of rooting and pawing the ground and stood for longer than saline-treated animals. However, gathering and carrying nest materials were not increased. These results suggest that PGF2alpha, given as a single dose to extensively housed gilts, initiated many, but not all, of the behaviors characteristic of prepartum nest building. The dose and duration of PGF2alpha treatment may have limited the observed behaviors. In addition, environmental feedback is likely to affect the degree to which some nest building behaviors are expressed.

A Scientific Conception of Animal Welfare that Reflects Ethical Concerns

Scientific research on ‘animal welfare’ began because of ethical concerns over the quality of life of animals, and the public looks to animal welfare research for guidance regarding these concerns. The conception of animal welfare used by scientists must relate closely to these ethical concerns if the orientation of the research and the interpretation of the findings is to address them successfully.

At least three overlapping ethical concerns are commonly expressed regarding the quality of life of animals: (1) that animals should lead natural lives through the development and use of their natural adaptations and capabilities, (2) that animals should feel well by being free from prolonged and intense fear, pain, and other negative states, and by experiencing normal pleasures, and (3) that animals should function well, in the sense of satisfactory health, growth and normal functioning of physiological and behavioural systems. Various scientists have proposed restricted conceptions of animal welfare that relate to only one or other of these three concerns. Some such conceptions are based on value positions about what is truly important for the quality of life of animals or about the nature of human responsibility for animals in their care. Others are operational claims: (1) that animal welfare research must focus on the functioning of animals because subjective experiences fall outside the realm of scientific enquiry, or (2) that studying the functioning of animals is sufficient because subjective experiences and functioning are closely correlated. We argue that none of these positions provides fully satisfactory guidance for animal welfare research.

We suggest instead that ethical concerns about the quality of life of animals can be better captured by recognizing three classes of problems that may arise when the adaptations possessed by an animal do not fully correspond to the challenges posed by its current environment. (I) If animals possess adaptations that no longer serve a significant function in the new environment, then unpleasant subjective experiences may arise, yet these may not be accompanied by significant disruption to biological functioning. Thus, a bucket-fed calf may experience a strong, frustrated desire to suck, even though it obtains adequate milk. (2) If the environment poses challenges for which the animal has no corresponding adaptation, then functional problems may arise, yet these may not be accompanied by significant effects on subjective feelings. Thus, a pig breathing polluted air may develop lung damage without appearing to notice or mind the problem. (3) Where animals have adaptations corresponding to the kinds of environmental challenges they face, problems may still arise if the adaptations prove inadequate. For example, an animal's thermoregulatory adaptations may be insufficient in a very cold environment such that the animal both feels poorly and functions poorly. We propose that all three types of problems are causes of ethical concern over the quality of life of animals and that they together define the subject matter of animal welfare science.

Behavioural Observations of Peri-Parturient Sows and the Development of Alternative Farrowing Accommodation: A Review

A number of alternative farrowing systems have recently been developed, some of which have been more successful at improving welfare and productivity than others. It is argued that for a system to be successful it should meet with the behavioural requirements of the sow at this time. A number of studies have been carried out to observe the natural behaviour patterns of the peri-parturient sow in a wide range of environmental conditions. These studies have shown that during each phase of peri-parturient behaviour there are a number of key environmental features and conditions which are important to the sow. These include the social environment, shelter, nesting material and offspring interaction. This information can be useful in the design of farrowing systems. A review of the literature indicated that the more these conditions are met, the more readily the sow can adapt to the system, leading to improvements in maternal behaviour and piglet production.

The Effect of Bedding on the Behaviour and Welfare of Pigs

Straw bedding provides a number of functions which affect the behaviour and welfare of pigs including comfort, recreation and diet. It has been suggested that the importance of these different functions will vary depending on the life/production stage of the pig. The available literature indicates that all of the above functions are relevant to all the different stages except newly born piglets. The occupational value of straw appears to be highly important. The actual mechanisms by which straw affects the pig's motivation systems are still poorly understood. It is therefore uncertain whether suitable alternatives to bedding exist or even if straw bedding in itself is completely satisfactory. Until satisfactory alternatives are available straw bedding should continue to be recommended in terms of pig behaviour and welfare.