T.H. McCallum

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.

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 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.

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.

The effect of design of tether and stall housing on some behavioural and physiological responses related to the welfare of pregnant pigs

Plasma-free corticosteroid concentrations, aggressive behaviour and levels of motivation to socially interact in a standard test were determined in two experiments. The two experiments used 32 and 40 pigs, respectively, and differences between experiments were to take into account the effects of neighbouring pigs between treatments (Experiment 1) and positional effects in the shed (Experiment 2). There were five treatments involving two types of housing (cage-stalls and tetherstalls), two designs of stall division (bars and mesh, that affected the level of aggressive behaviour between neighbouring pigs) and a control treatment of group-housed pigs. Pigs in tether-stalls separated by bars showed evidence of a chronic stress response; free corticosteroid concentrations were 1.28 and 1.21 ng ml−1 in Experiments 1 and 2 compared with 0.63 and 0.54 ng ml−1 for group-housed pigs, respectively (P < 0.01), and these changes were sufficient to affect plasma glucose concentrations (P < 0.01). Separating the tether-stalls with mesh obviated the increase in free corticosteroid concentrations (0.68 and 0.53 ng ml−1 in Experiments 1 and 2, respectively). Pigs housed in cage-stalls separated by bars or mesh showed only slight increases in free corticosteroid concentrations compared with group-housed pigs in Experiment 1 (0.87, 0.81 v. 0.63 ng ml−1, respectively, P 0.05). The increase in free corticosteroid concentrations in Experiment 1 was of insufficient magnitude to affect plasma glucose concentrations. Behaviourally, pigs in the cage-stalls with bars and tether-stalls with bars showed higher levels (P < 0.05) of aggression than pigs in their modified counterpart treatments using mesh divisions, and the proportions of retaliatory and withdrawal behaviours were similar in the two treatments. Pigs in cage-stalls with bars moved backwards and forwards more often (P < 0.05) than pigs in the tether-stalls with bars and this increased movement, possibly in response to aggression, may be a factor affecting the different physiological responses in cage-stall and tether-stall treatments; in cage-stalls aggressive behaviour sequences may be terminated in a manner that does not induce a physiological response. In conclusion, the two experiments confirm that pigs housed in tether-stalls can show evidence of reduced welfare as a consequence of the design of the tether-stall divisions, but show that the design of the cage-stall has no effect on physiological responses. Thus, in this context, cage-stall housing does not appear to pose a risk to welfare.

The Effects of Genotype on Physiological and Behavioural Responses Related to the Welfare of Pregnant Pigs

Abstract Plasma free-corticosteroid concentrations, aggressive behaviour and levels of motivation to socially interact and explore a novel arena were observed in an experiment to examine whether differences previously observed between pigs in neck-tethers and groups are shown by pigs of different genotypes. Thirty-two pregnant gilts of 2 genotypes were housed in either tether stalls or groups. The 2 genotypes were mainly Large White×Landrace stock, but one had been intensively selected on the basis of growth performance. Genotypic differences had previously been observed in protein and energy metabolism, and the present experiment also showed differences in their behaviour (increased activity and a decreased motivation to socially interact in the intensively selected genotype) and free-corticosteroid concentrations (40% lower in the intensively selected genotype). In spite of these differences, the behavioural and physiological responses to housing treatments were similar. In tether stalls, pigs of both genotypes had a higher frequency of retaliation and a lower frequency of withdrawal in response to aggressive interactions than group-housed pigs. There were 50 and 56% increases in free-corticosteroid concentrations in response to tether housing in the 2 genotypes, providing evidence of a chronic stress response of a magnitude sufficient to suggest a risk to welfare in the design of tether stall used in this experiment.