A novel method for the analysis of social structure allows in-depth analysis of sow rank in newly grouped sows

Greenwood, E. C.; Plush, K. J.; Wettere, W. H. E. J. van; Hughes, Paul E.

doi:10.1016/j.applanim.2017.01.006

Cited by 8 publications

(7 citation statements)

References 32 publications

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“…Displacements and fights were calculated as an overall or ‘global’ rank and not based on resource rank, such as displacements around food, water and space rankings, but rather all displacements in one. Hierarchy was then analyzed using two methods: first, methods from the paper by Greenwood et al (2017) were used [29]. Briefly, the sows were separated into groups; 1D (displacement class 1) or 1F (fight class 1) sows were involved in no fights or displacements, 2D and 2F sows lost more than they won, whereas 3D and 3F sows won more than they lost.…”

Section: Methodsmentioning

confidence: 99%

Provision Point-Source Materials Stimulates Play in Sows but Does Not Affect Aggression at Regrouping

Greenwood

Wettere

Rayner

et al. 2018

Animals

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Simple SummaryIn most intensive pig production systems, pigs are often mixed into new groups. Sows are important to a production system, as they are the driver behind the farms’ productivity. The aggression that results from sows being mixed into new groups and formation of hierarchy can detrimentally affect production and welfare. This study aimed to determine the effect of providing access to materials on aggressive and play behaviors in gestating sows. Play behaviors were observed in the ‘enhanced’ pen and no play was observed in standard housing (without materials present). Aggression measures, salivary free cortisol concentrations, and injury counts were unaffected by treatment. The provision of point-source materials to sows at mixing had no impact on aggression; however, their presence maintained sow interest over the course of the experiment. Additionally, play behavior was observed in their presence, which may suggest that a more positive affect was induced when the materials were provided.AbstractWhen sows are mixed into groups, hierarchies form and resulting aggression and stress can affect production and welfare. This study determined the effect of providing point-source materials on aggressive and play behaviors in gestating sows. Large white cross Landrace sows were mixed after insemination; six pens of 12 sows were housed in ‘standard’ pens, and six pens of 12 sows were housed in ‘enhanced’ pens. The ‘enhanced’ pens each contained two rubber mats, eight strands of 24 mm-thick sisal rope and two yellow plastic disks, suspended from the roof. The sows remained in these pens until pregnancy confirmation. Salivary cortisol concentration, injury counts, and sow behaviors were recorded the day before mixing (day 1), mixing (day 0) and post-mixing day 1, day 4, day 7 and day 20. At farrowing, reproductive outcomes were obtained. Play was observed (including locomotor and object play) in the ‘enhanced’ pen, and percentage of time spent playing was greater on d4 (1.48 ± 0.3 Square root transformed data (2.84% non-transformed adjusted mean)), d7 (1.43 ± 0.3 (2.97%)) and d20 (1.64 ± 0.3 (3.84%)), compared to d0 (0.56 ± 0.3 (0.70%)) and d1 (0.87 ± 0.3 (1.67%) (p < 0.05)). No play was observed in standard housing. Aggression, salivary free cortisol concentrations and injuries were unaffected (p > 0.05). The provision of materials had no impact on aggression, although their presence maintained sow interest and play behavior, suggesting a positive effect.

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Section: Methodsmentioning

confidence: 99%

Provision Point-Source Materials Stimulates Play in Sows but Does Not Affect Aggression at Regrouping

Greenwood

Wettere

Rayner

et al. 2018

Animals

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“…In the line with this hypothesis, Jensen [ 46 ] argued that aggression regulation within groups depends on the ability of subordinate sows to avoid the dominants rather than on the motivation of dominants to attack the subordinates. Social status is often divided in two (e.g., dominant and submissive pigs in Rhim et al [ 47 ]) or three (e.g., low, middle or high social status in Zhao et al [ 48 ]) categories and rare are the studies that divided animals in more than three categories (but see Greenwood et al [ 36 ] and Turner et al [ 49 ]). However, investigating dominance in a large group (up to 91 animals) resulted in the presence of a different category of sows (compared to previous studies with small groups), i.e., a quarter of the sows that did not participate in fighting at all during the observation phase (i.e., the Avoiders).…”

Section: Discussionmentioning

confidence: 99%

Social status and previous experience in the group as predictors of welfare of sows housed in large semi-static groups

et al. 2021

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Mixing gestating sows implies hierarchy formation and has detrimental consequences on welfare. The effects of social stress on the most vulnerable individuals may be underestimated and it is therefore important to evaluate welfare between individuals within groups. This study aimed at investigating the impact of social status and previous experience in the group on well-being of sows housed in large semi-static groups. We assessed aggression (d0 (mixing), d2, d27, d29), body lesions (d1, d26, d84) and feeding order on 20 groups of 46–91 animals. Social status was based on the proportion of fights won during a 6-hr observation period between d0 and d2. Dominants (29%) were those who won more fights than they lost, Subdominants (25%) won fewer fights than they lost, Losers (23%) never won any fight in which they were involved while Avoiders (23%) were never involved in fights. Resident sows (70%) were already present in the group in the previous gestation while New sows (30%) were newly introduced at mixing. Subdominants and Dominants were highly involved in fights around mixing but this was more detrimental for Subdominants than Dominants, Losers and Avoiders since they had the highest body lesion scores at mixing. Avoiders received less non-reciprocal agonistic acts than Losers on d2 (P = 0.0001) and had the lowest body lesion scores after mixing. However, Avoiders and Losers were more at risk in the long-term since they had the highest body lesions scores at d26 and d84. They were followed by Subdominants and then Dominants. New sows fought more (P<0.0001), tended to be involved in longer fights (P = 0.075) around mixing and had more body lesions throughout gestation than Resident sows. Feeding order from one-month post-mixing was influenced both by the previous experience in the group and social status (P<0.0001). New sows, especially with a low social status, are more vulnerable throughout gestation and could serve as indicators of non-optimal conditions.

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“…In the line with this hypothesis, Jensen (45) argued that aggression regulation within groups depends on the ability of subordinate sows to avoid the dominants rather than on the motivation of dominants to attack the subordinates. Social status is often divided in two (e.g., dominant and submissive pigs in Rhim et al (46)) or three (e.g., low, middle or high social status in Zhao et al (47)) categories and rare are the studies that divided animals in more than three categories (but see Greenwood et al (36) and Turner et al (48)). However, investigating dominance in a large group (up to 91 animals) resulted in the presence of a different category of sows (compared to previous studies with small groups), i.e., a quarter of the sows that did not participate in fighting at all during the observation phase (i.e., the Avoiders).…”

Section: Discussionmentioning

confidence: 99%

“…Behaviours recorded as non-reciprocal agonistic acts were threats (the perpetrator suddenly stretches the neck toward a recipient and provokes the recipient avoidance or escape without physical contact), bites and knocks (the perpetrator bites or gives a head knock to the recipient) and bullying (the perpetrator gives a series of three or more threats, bites and/or knocks to the recipient). Fight occurrence and duration were also recorded and were defined as a reciprocal act of at least three bites or knocks where each opponent bites or gives a head knock at least once and for a total duration of at least 3 sec (21,36). The aggressive pattern was investigated by classifying sows in four categories according to their propensity to initiate and receive a fight: Sows not involved in fights: sows which were never involved in fights; Systematically aggressed sows: sows which never initiated a fight but received at least one fight; Intermediate sows: sows which initiated fewer fights than they received; Predominantly aggressor sows: sows which initiated more fights than they received.…”

Section: Methodsmentioning

confidence: 99%

Social status and previous experience in the group as predictors of long-term welfare of sows housed in large semi-static groups

Brajon

Ahloy‐Dallaire

Devillers

et al. 2020

Preprint

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Mixing gestating sows implies hierarchy formation and has detrimental consequences on welfare. The effects of social stress on the most vulnerable individuals may be underestimated and it is therefore important to evaluate welfare between individuals within groups. This study aimed at investigating the impact of social status and previous experience in the group on well-being of sows housed in large semi-static groups (20 groups of 46-91 animals). We assessed aggression (d0 (mixing), d2, d27, d29), body lesions (d1, d26, d84) and feeding order. Social status was based on the proportion of fights won during a 6-hr observation period between d0 and d2. Dominants (29%) were those who won more fights than they lost, Subdominants (25%) won fewer fights than they lost, Losers (23%) never won any fight in which they were involved while Avoiders (23%) were never involved in fights. Resident sows (70%) were already present in the group in the previous gestation while New sows (30%) were newly introduced at mixing. Subdominants and Dominants were highly involved in fights around mixing but this was more detrimental for Subdominants than Dominants, Losers and Avoiders since they had the highest body lesion scores at mixing. Avoiders received less non-reciprocal agonistic acts than Losers on d2 (P=0.0001) and had the lowest body lesion scores after mixing. However, Avoiders and Losers were more at risk in the long-term since they had the highest body lesions scores at d26 and d84. They were followed by Subdominants and then Dominants. New sows fought more (P<0.0001), tended to be involved in longer fights (P=0.075) around mixing and had more body lesions throughout gestation than Resident sows. Feeding order from one-month post-mixing was influenced both by the previous experience in the group and social status (P<0.0001). New sows, especially with a low social status, are more vulnerable throughout gestation and could serve as indicators of non-optimal conditions.

show abstract

A novel method for the analysis of social structure allows in-depth analysis of sow rank in newly grouped sows

Cited by 8 publications

References 32 publications

Provision Point-Source Materials Stimulates Play in Sows but Does Not Affect Aggression at Regrouping

Provision Point-Source Materials Stimulates Play in Sows but Does Not Affect Aggression at Regrouping

Social status and previous experience in the group as predictors of welfare of sows housed in large semi-static groups

Social status and previous experience in the group as predictors of long-term welfare of sows housed in large semi-static groups

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