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Aggression is one of the major welfare concerns among group-housed sows, especially during feeding and regrouping. There are no simple solutions, but any attempt to reduce aggression should be considered. Therefore, the aim was to reduce aggression among group-housed gestating sows by feeding sows different dietary fiber using individual feeding places made from either short- or long-length partitions. Five blocks (n = 36 sows/block) of primiparous and multiparous sows were fed a dietary treatment of either 30% wheat middlings and 15% soybean hulls (MIDD-SY) or 30% distillers dried grains and 30% corn germ meal (DDGS-GM) and housed in pens (9 sows/pen) with individual feeding partitions that were either shoulder (short) or full-body (long) in length. Sow behavior, skin lesions, immune status, and performance were measured. Sow behavior, including aggression and lesion severity scores, were mainly affected by partition length. Aggressive encounters were greater and remained elevated among sows in pens with short partitions until 9 weeks post-grouping but were reduced among sows in pens with long partitions by 3 weeks. During feeding, sows in pens with short ones were more likely to be displaced than were those in pens with long ones. Percentages of time spent lying, standing, eating, and oral–nasal–facial behaviors were also differentially influenced by partition length. Dietary fiber differentially influenced immune status and productivity. For example, sows fed MIDD-SY had higher lymphocyte proliferation and increased neutrophils, while those fed DDGS-GM had deeper backfat and weaned heavier piglets. Overall, the length of the feeding partitions influenced the aggressive encounters, other behaviors, and lesion scores; in turn, the fibrous source differentially influenced several immune measures and sow productivity.

Aggression is one of the major welfare concerns among group-housed sows, especially during feeding and regrouping. There are no simple solutions, but any attempt to reduce aggression should be considered. Therefore, the aim was to reduce aggression among group-housed gestating sows by feeding sows different dietary fiber using individual feeding places made from either short- or long-length partitions. Five blocks (n = 36 sows/block) of primiparous and multiparous sows were fed a dietary treatment of either 30% wheat middlings and 15% soybean hulls (MIDD-SY) or 30% distillers dried grains and 30% corn germ meal (DDGS-GM) and housed in pens (9 sows/pen) with individual feeding partitions that were either shoulder (short) or full-body (long) in length. Sow behavior, skin lesions, immune status, and performance were measured. Sow behavior, including aggression and lesion severity scores, were mainly affected by partition length. Aggressive encounters were greater and remained elevated among sows in pens with short partitions until 9 weeks post-grouping but were reduced among sows in pens with long partitions by 3 weeks. During feeding, sows in pens with short ones were more likely to be displaced than were those in pens with long ones. Percentages of time spent lying, standing, eating, and oral–nasal–facial behaviors were also differentially influenced by partition length. Dietary fiber differentially influenced immune status and productivity. For example, sows fed MIDD-SY had higher lymphocyte proliferation and increased neutrophils, while those fed DDGS-GM had deeper backfat and weaned heavier piglets. Overall, the length of the feeding partitions influenced the aggressive encounters, other behaviors, and lesion scores; in turn, the fibrous source differentially influenced several immune measures and sow productivity. [ABSTRACT FROM AUTHOR]

Group-housing systems for pregnant sows are considered a welfare-promoting alternative to the individual stall. A major concern associated with pregnant sows housed in group pens is increased aggression at mixing and at feeding, which may cause chronic stress among some of the sows in the group due to low feed intake and social stress. Prolonged activation of the stress axis, based on elevated cortisol levels, may inhibit or impair reproductive success via disruption of the reproductive axis. Mixing sows into groups shortly after insemination evokes a stress response, which may affect fertilization and implantation due to sustained, elevated cortisol levels that disrupt reproductive processes. Yet, most studies reported minimal effects of group housing sows during pregnancy on reproduction or cortisol-related stress response. Differences between housing systems-in terms of group size, floor-space allowance, feeding system, and genetics-could account for these unexpected results. Indeed, interrupted feed intake, especially in early pregnancy, and sustained aggression in late pregnancy are two unfavorable social stresses that deserve special attention in order to achieve good reproductive performance. Unfortunately, most studies do not consider other factors, such as social rank and parity, which may interactively affect reproductive success and aggressive behavior of sows, especially in group-pen systems., (© 2017 Wiley Periodicals, Inc.)