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We investigated effects of loose housing of the sow during lactation and enrichment of the pen pre- and postweaning on performance of newly weaned piglets. Before weaning, piglets (n = 320) were housed in an enriched (straw, wood shavings, peat, and branches) or barren pen with a confined or loose-housed sow (n = 32). Loose-housed sows and their piglets could eat together from a family feeder, whereas confined sows and piglets had separate feeding troughs. Piglets (n = 256) were mixed postweaning, and 4 piglets from each litter were relocated to a barren pen (n = 32 pens) and 4 other piglets were housed in an enriched pen (n = 32 pens). Growth from d 15 until weaning was greater for piglets from enriched pens (4.38 [+ or ] 0.29 vs. 4.71 [+ or ] 0.21 kg/pig, P < 0.05) and tended to be greater for piglets with a loose-housed sow compared with piglets with a confined sow (4.41 [+ or ] 0.26 vs. 4.67 [+ or ] 0.24 kg/pig, P = 0.10). Preweaning feed intake was not affected by preweaning conditions (P > 0.25). Piglets from enriched preweaning pens ate more in the first 2 d postweaning than piglets from barren pens (first 48 h, barren 0.45 [+ or ] 0.05 kg/pig, enriched 0.53 [+ or ] 0.04 kg/ pig, P < 0.05). Piglets relocated to an enriched pen after weaning showed a greater growth in the 2 wk after weaning (barren 5.5 [+ or ] 0.2 kg/pig, enriched 6.2 [+ or ] 0.2 kg/pig, P < 0.0001), had a profoundly reduced diarrhea prevalence than piglets housed in barren pens after weaning (barren 2.4 [+ or ] 0.4 d, enriched 1.0 [+ or ] 0.3 d, P < 0.0001), and had a greater feed efficiency (barren 0.81 [+ or ] 0.03, enriched 0.85 [+ or ] 0.02, P < 0.05). Enrichment of the preweaning environment likely stimulates development of feeding behaviors and consequently increases feed intake immediately after weaning. Providing piglets with an enriched environment after weaning positively affected postweaning growth, feed efficiency, and incidence of diarrhea, which may be caused by decreased stress or increased gut health. Enrichment of the pre- and postweaning environment seems important in improving performance and health of newly weaned pigs. Key words: environmental enrichment, learning, piglet, sow housing, weaning doi: 10.2527/jas.2010-2940

The purpose of this paper is twofold. First, it discusses in general terms how animal production can be affected by the animals' cognitive abilities; secondly, it aims to introduce our work on pig cognition. The extent to which farm animals are positively or negatively affected by their housing and husbandry environments depends (amongst other things) on their cognitive abilities. It has long been known that predictability of and control over the variable aspects of their environment reduce the physiological symptoms of stress in animals. For the environment to be predictable, it must have some predictable properties, and the animal must realize that it does. To have control over its environment, the animal must learn and understand how the environment works and how it can be changed to its benefit. To this end, the animal must be able to perceive, store and use appropriately the pertinent environmental information. Research at Bristol investigates cognition in domestic pigs, particularly social cognition. An improved understanding of how much pigs understand about the behaviour and intentions of others may help reduce welfare and productivity problems. For example, being grouped and re-grouped with unfamiliar individuals is a common experience for domestic pigs at various stages in their lives. This often leads to high aggression levels in the new groups with negative consequences for production. Research has shown that aggression levels are higher when unfamiliar pigs of the same (high or low) aggressiveness are mixed than when pigs of different aggressiveness are mixed. This implies that some social assessment and recognition takes place between individuals that allows them to judge each other's aggressiveness and to avoid fighting. Re-grouping of previously familiar pigs can also lead to high aggression levels. This suggests that pigs may be able to form only short-term social memories, or that their social memory is disrupted before re-grouping. Our research to date has focused on the memory abilities of pigs and their disruption by stressful husbandry procedures, on the pigs' ability to adjust their food-searching behaviour when paired with a competing co-forager, and on their ability to understand what others can and cannot see. Key Words: Animal Cognition, Animal Production, Swine