G. M. Cronin

The effects of the gestation and farrowing environments on sow and piglet behaviour and piglet survival and growth in early lactation

The effects of gestation (individual stall vs. group pen) and farrowing/lactation (conventional crate vs. prototype pair-pen system for two sows) treatments on sow and piglet behaviours considered relevant to piglet survival were examined in a 2 × 2 factorial experiment involving 96 primiparous crossbred (Large White × Landrace) sows and their litters. The pair-pen system provided each sow with an area of about 10 m2 and included a specific farrowing area which contained features important for piglet survival similar to those found in farrowing crates, i.e. small area and heated creep. Sow and piglet behaviour and piglet survival and growth were measured to Day 8 of lactation. While a greater (P < 0.01) proportion of piglets were alive on Day 8 for sows in the gestation stall treatment compared with the gestation pen treatment (88.6 vs. 83.3% of total born (TB)), mean litter size at birth tended to be smaller (P < 0.1) in the former treatment (8.6 vs. 9.4 piglets per sow). Piglet mortality was higher for sows housed in group pens during gestation and crates during farrowing than for sows in the other treatment combinations. Stillbirths occurred at a rate of 8.4 vs. 4.4% of TB and deaths of liveborn piglets in the first 3 days occurred at a rate of 11.0 vs. 6.1% of TB in the gestation pen-farrowing crate treatment compared with the other treatments combined. Sows in the crate treatment compared with those in the pair-pen treatment directed less behaviour to their piglets (e.g. investigation of piglets: Day 1, 7.2 vs. 10.0% of observations, P < 0.01; vocalisation to piglets: Day 1, 9.0 vs. 12.2% of observations, P < 0.05) and were less responsive while feeding at the trough to the loud vocalisations of one of their piglets (e.g. 57 vs. 89% of sows at Day 3 in the crate vs. pair-pen treatments stopped feeding in response to the piglets vocalisations, P < 0.05). The results suggest that the gestation environment had only minimal, or at most short-term, effects on the behaviour of sows and piglets in early lactation. In contrast the farrowing environment had marked effects, particularly on sow behaviour. The present experiment demonstrates that modifying the farrowing environment affected maternal behaviour in sows. However, there is little evidence to support the hypothesis that increased maternal behaviour was associated with improved piglet survival.

The effects of providing sawdust to pre-parturient sows in farrowing crates on sow behaviour, the duration of parturition and the occurrence of intra-partum stillborn piglets

The behaviour of 174 sows (parities 1–10) in commercial farrowing crates was recorded at 10-min intervals around parturition. Approximately half of the sows received regular applications of sawdust on the floor of their crate during the pre-partum period (SD treatment). Control treatment (Con) sows did not receive sawdust. Younger sows (parities 1–3) in the SD treatment spent less (P < 0.01) time belly lying from 24 to 16 h pre-partum, were more (P < 0.05) active in the last 8 h pre-partum and less (P < 0.05) active during parturition than in the Con treatment. More root/nose/paw behaviour occurred during 24 to 16 h (P < 0.01) and the last 8 h (P < 0.005) pre-partum, and more (P < 0.03) feeder-directed behaviour occurred in the last 8 h pre-partum, in the SD than Con treatment. Sows in the SD treatment compared with sows in the Con treatment had a shorter (P < 0.05) mean duration of parturition (159 and 201 min per sow) and a lower (P < 0.01) incidence of piglets that were overlayed during parturition and the subsequent 6 h (2.4% and 21.1% of sows, respectively). While there were no differences in the proportion of litters of younger sows that contained stillborn piglets of the class intra-partum death (IPD: 26.1 and 31.6% of sows), there was a difference (P < 0.02) in the ratio of litters containing 0, 1 or multiple IPD per litter: (SD: 73%, 27% and 0% vs. Con: 68%, 16% and 16% of litters, respectively). As a consequence of the lower occurrence of IPD, litter size born alive was greater (P < 0.03) in the SD than Con treatment (10.5 and 10.0 piglets). Older sows (parities 4 and above) in the SD treatment spent less time sitting (P < 0.05) and more time side lying (P < 0.06), and performed less (P < 0.01) bar biting during the last 8 h pre-partum than older sows in the Con treatment. In conclusion, the application of sawdust during the pre-partum period appeared to stimulate prepartum activity in younger sows, including root/nose/paw behaviour, which may, in turn, positively affect the process of parturition and reduce overlaying of piglets, both of which are relevant to increasing piglet survival. The differing results for older sows suggest that experience with sawdust (for nesting material) is an important determinant of subsequent responses of farrowing sows to this material.

A note on the relationship between the behavioural response of lactating sows to humans and the survival of their piglets

Abstract The objective of this study was to examine the relationships, based on unit averages, between the behavioural responses of lactating sows to humans and the performance of sows in 25 farrowing units at a large commercial farm. The behavioural responses of 25 sows in each farrowing unit were observed at 2–4 and 16–18 days of lactation and a correlation analysis, using unit averages, was used to examine the behaviour–productivity relationships. Moderate and significant between-unit correlations were found between the behavioural response of lactating sows at days 16–18 to an approaching experimenter and the percentage of stillborn piglets. Units in which test sows were quicker to withdraw in the presence of the experimenter had a higher stillbirth rate than those units in which a reduced withdrawal response was displayed. The withdrawal response of sows in the close presence of the experimenter accounted for about 18% of the variance in percentage of stillborn piglets. While this study was a preliminary one examining the potential for the human–animal relationship to affect the performance of sows in the farrowing shed, the results indicate that high levels of fear of humans by sows may affect the survival of their piglets. The possible mechanisms whereby fear may affect piglet survival are considered. Clearly further research is warranted because of the important practical implications of this negative fear–productivity relationship on animal performance and welfare.

Effects of grouping unfamiliar adult pigs after dark, after treatment with amperozide and by using pens with stalls, on aggression, skin lesions and plasma cortisol concentrations

The effects of methods, previously shown to reduce aggression, were determined on the number of aggressive interactions, skin lesions and plasma cortisol concentrations following grouping of four unfamiliar, adult ovariectomised pigs. There were four treatments involving 24 pigs in six replicates: (i) Control; (ii) Stall, in which there were four partial stalls used for feeding; (iii) Amperozide, an anti-aggression drug; (iv) Dark in which the pigs were grouped 30 min after sunset. All treatments were in rectangular pens providing a space allowance of 1.4 m2 per pig. Aggressive interactions were observed for 90 min following grouping and for 40-min periods around feeding on the day following grouping and 9 days later. Skin lesions were assessed 3 days after grouping. The spatial use of the pens was determined during a 60 min period between 14:00 and 16:00 h on the day following grouping and 9 days later. Total cortisol concentrations were determined from samples collected during a 75 min period commencing 90 min and 24 h after the start of grouping and total and free cortisol concentrations were determined from nine blood samples collected at hourly intervals on days 8 and 10. Fewer aggressive interactions (P 0.05). However, there were significant positive regressions between aggressive interactions and the number and length of lesions (P < 0.05). There was an acute stress response in the Amperozide treatment 90–165 min after grouping compared with all other treatments (0.001 < P < 0.01) and the magnitude of this stress response raises some welfare concerns on the use of amperozide. Animals in the Stall treatment showed a lower (P < 0.01) total cortisol concentration on day 10 than animals in the other treatments and this indicates a welfare benefit from the provision of stalls.

The behaviour of primiparous sows around farrowing in response to restraint and straw bedding

Abstract The behaviour of 24 primiparous sows around parturition was examined from continuous video-records to investigate the effects of accommodation type (farrowing crate vs pen) and substrate (straw vs no straw), in a factorial experiment, on sow behaviours that may influence piglet survival. The experiment was part of a larger experiment involving 64 sows and litters, which examined the effects of the farrowing/lactation environment on sow behaviour, and piglet survival and growth to weaning. During the 24 h pre-partum, sows spent less time side lying (29.3 vs 42.3% of observations; P P P The occurrence of pawing at the bare floor was greater in crates than in pens (0.6 vs 0.3% of observations; P P P P P P The data suggest that factors in the environment of the peri-parturient sow affect the quantity of pre-partum nesting-like behaviour, such as root/nose/paw behaviours and manipulation of straw. However, the fact that environments that elicited more maternal behaviour did not promote piglet survival, suggested that piglet survival may be more affected by the structural/thermal environment than by the sows behaviour.

The welfare of pigs in two farrowing/lactation environments: cortisol responses of sows

Abstract Plasma free cortisol concentrations were measured in 24 primiparous sows housed from Day 104 after mating up to Day 2 after parturition. Concentrations were measured in 22 of these sows, from Days 2–29 of lactation, housed in either commercial farrowing crates (Crate treatment) or farrowing pens with straw added (Pen treatment). The mortality and growth data of litters from the time of birth to weaning were also recorded. The mean plasma free cortisol concentration was higher in sows housed in the Crate treatment, compared with sows housed in the Pen treatment, on the first day of treatment (8.2 and 5.8 nmol l−1, respectively, P The data suggest that housing treatment around parturition and during lactation may have only limited effects on the welfare of sows, providing that lactation is no longer than 28 days. On Days 21 and 24, there were no effects of treatment on free cortisol concentrations and no response to the exogenous adrenocorticotrophic hormone (ACTH), respectively. However, on Day 28, there were mean increases in the concentrations of free cortisol of approximately 150% and approximately 60%, respectively; these may have been the result of unavoidable attention of the piglets to the sows.

Scientific assessment of animal welfare

Abstract Animal welfare is a state within the animal and a scientific perspective provides methodologies for evidence-based assessment of an animals welfare. A simplistic definition of animal welfare might be how the animal feels now. Affective experiences including emotions, are subjective states so cannot be measured directly in animals, but there are informative indirect physiological and behavioural indices that can be cautiously used to interpret such experiences. This review enunciates several key science-based frameworks for understanding animal welfare. The biological functioning and affective state frameworks were initially seen as competing, but a recent more unified approach is that biological functioning is taken to include affective experiences and affective experiences are recognised as products of biological functioning, and knowledge of the dynamic interactions between the two is considered to be fundamental to managing and improving animal welfare. The value of these two frameworks in understanding the welfare of group-housed sows is reviewed. The majority of studies of the welfare of group-housed sows have employed the biological functioning framework to infer compromised sow welfare, on the basis that suboptimal biological functioning accompanies negative affective states such as sow hunger, pain, fear, helplessness, frustration and anger. Group housing facilitates social living, but group housing of gestating sows raises different welfare considerations to stall housing, such as high levels of aggression, injuries and stress, at least for several days after mixing, as well as subordinate sows being underfed due to competition at feeding. This paper highlights the challenges and potential opportunities for the continued improvement in sow management through well-focused research and multidisciplinary assessment of animal welfare. In future the management of sentient animals will require the promotion of positive affective experiences in animals and this is likely to be a major focus for animal welfare science activity in the early twenty-first century.

Effects of pen size/shape and design on aggression when grouping unfamiliar adult pigs

The effects of space allowance/pen shape (small square or small rectangular pens providing a space allowance of 1.4 m2 per pig and a large pen providing a space allowance of 3.4 m2 per pig) and pen design (partial stalls, 0.44 m wide×0.74 m long, or no stalls) on aggression when grouping four unfamiliar adult ovariectomized pigs were examined in an experiment involving 24 pigs that was replicated five times. Aggression was observed for 90 min immediately following grouping and for 40-min periods, around feeding, on the day following grouping and 9 days later. Social behaviour and spatial use of the pens were also determined during a 60-min period between 14:00 and 16:00 h on the day following grouping and 9 days later. Aggressive interactions and the consequent retaliations were significantly lower during the period of 15–90 min after grouping in the small rectangular pens (P 0.05). Treatment significantly affected social behaviour and spatial use of the pen during a ‘rest period’. On the day following grouping in small rectangular pens lying alone behaviour and standing were reduced, and concurrent lying and use of stalls (when present) were increased. In conclusion, this experiment has shown that there may be potential advantages to the welfare of adult pigs in reducing aggression around grouping by grouping unfamiliar pigs in rectangular pens with a space allowance of 1.4 m2 per pig compared with similar sized square pens or pens with a larger space allowance.

Effects of food and time of day on aggression when grouping unfamiliar adult pigs

Abstract The effects of manipulating bioschedules on the number of aggressive interactions and skin lesions following grouping of four unfamiliar, adult ovariectomized pigs were examined in an experiment involving 24 pigs in five replicates. There were six treatments: food present at the time of grouping in the morning or the afternoon (Food-am and Food-pm), food present ad libitum for either 24 or 48 h (Food-24h and Food-48h), pigs grouped 30 min after sunset (Dark) and a Control. The latter treatment pigs were introduced into the pen in the morning after feeding. All treatments were in rectangular pens providing a space allowance of 1.4 m 2 per pig. Aggressive interactions were observed for 90 min immediately following grouping and for 40 min periods around feeding on the day following grouping and 9 days later. Skin lesions were assessed 3 days after grouping. Social behaviour and spatial use of the pens were also determined during a 60 min period between 14:00 and 16:00 h on the day following grouping and 9 days later. Fewer ( P P > 0.05). There were no effects of treatment on the number or length of lesions, or the spatial use of the pen during a rest period ( P > 0.05). However, the number of aggressive interactions during the initial 15 and 90 min of grouping were significantly regressed with the length of lesions measured 3 days after grouping (0.01

Effects of design of individual cage-stalls on the behavioural and physiological responses related to the welfare of pregnant pigs

This experiment describes the effects of two designs of individual cage-stalls on the behavioural and physiological responses of pregnant pigs. There was a total of 32 experimental pigs housed in two designs of cage-stalls, vertical or horizontal bars, and two control treatments, tether-stalls (vertical bars) and group housing. Video recordings taken of individually housed pigs (over 3 consecutive days) for 60 min day−1 (commencing 10 min after the start of feeding) after 14 and 49 days in treatments were used to determine the time pigs spent in three areas of the stalls (0–31, 32–63 and more than 63 cm from the front of the stall), number of movements between these areas, the duration that four neighbouring (within a treatment) pigs were concurrently in the front area of the stall and the number and duration of aggressive interactions. The duration of head-to-head contact of four focal pigs per individual housing treatment was also determined. Plasma-free cortisol concentrations were determined after 30 and 57 days in the treatments. The design of the stall division in the individual cage-stalls affected both the spatial use of the stall, aggressive behaviour and cortisol concentrations. Pigs in the horizontal stall treatment spent more time in the back area of the stall (618 s vs. 388 s; P < 0.01) and spent less time concurrently (four neighbouring pigs) in the front area of the stall (55 s vs. 193 s; P < 0.05) than animals in the vertical stall treatment. Duration of aggressive interactions was less in the horizontal stall treatment (11.1 s v. 20.3 s; P < 0.05) and there were fewer pigs (2 vs. 8; P < 0.05) involved in aggressive interactions than in the vertical stall treatment. Head-to-head contact (of focal pigs) while standing was also less in the horizontal stall treatment (171 s vs. 374 s; P < 0.05). There was evidence of a chronic stress response in the horizontal stall treatment (mean free cortisol concentrations in the horizontal and vertical stall treatments were 6.6 nmol l−1, respectively; P < 0.05). The behavioural data suggest that pigs in the horizontal stall treatment were actively avoiding their neighbours. In conclusion, this experiment has shown that the design of cage-stalls can affect the welfare of pigs. Pigs housed in stalls comprised of horizontal bars showed evidence of a chronic stress response of a magnitude sufficient to adversely affect welfare, and active avoidance by neighbouring. Pigs housed in stalls comprised of vertical bars showed cortisol concentrations similar to group-housed pigs (and lower than pigs in tether-stalls) and they also showed the highest levels of aggression of all treatments. Across the individual housing treatments, the hormone data were not correlated with measures of aggressive behaviour and thus the relationship (s), if any, between aggressive behaviour and physiological responses are unclear and remain a subject for further research.