Comprehensive evaluation of well-being in pigs: Environmental enrichment and pen space allowance

An experiment was conducted to provide comparative scientific evidence for the well-being or ill-being of pigs while residing in different environments under intensive housing conditions. Four categories of indices--viz., productivity, including growth and feed-efficiency performance and health; physiology; immunology; and behavior were used for assessing the well-being of the animals involved. Productive, health, physiologic, immunophysiologic, and behavioral traits related to indicators of well-being were measured in 512 growing-finishing pigs in a 2 x 2 factorial experiment, the two factors being environmental enrichment and pen size.The results with respect to productive performance indicated that pigs' body-weight gain and feed conversion efficiency were similar regardless of treatment. However, lesion scores throughout the experiment were consistently higher in the enriched pens as compared to the barren. Based on the results for the productivity indicators it is suggested that the enriched environment did not improve pig well-being as compared to that of conspecifics in the relatively barren confinement environment.The results with respect to the physiologic traits--viz., gastric ulceration, adrenal weight, basal cortisol concentration, and ACTH challenge--as well as the immunophysiologic traits--viz., intradermal response to phytohemagglutinin and delayed-type hypersensitivity reaction to sheep red blood cells did not differ due to treatment variables. Based on these indicators it was concluded that pig well-being was similar across treatments.Results with respect to behavioral indicators--viz., general behavior patterns, use of manipulanda, reaction to novelty, and defecation patterns revealed only few differences due to the treatment variables imposed. However, a test of the pigs' reaction to a novel situation indicated that animals in the enriched pens were less fearful than those in the barren. Although most of the indicators did not differ across treatments, the results did suggest that provision of enrichment features might have rewarded the pigs in a positive way and led to improved psychological well-being as compared to that experienced by conspecifics in the nonenriched environment.U of I OnlyETDs are only available to UIUC Users without author permissio