Algers, B, Ekesbo, I, Strömberg, S 1978. Noise measurements in farm animal environments. Acta Veterinaria Scandinavica 68, 1–19.
Boissy, A, Manteuffel, G, Jensen, MB, Moe, RO, Spruijt, B, Keeling, LJ, Winckler, C, Forkman, B, Dimitrov, I, Langbein, J, Bakken, M, Veissier, I, Aubert, A 2007. Assessment of positive emotions in animals to improve their welfare. Physiology & Behavior 92, 375–397.
Bolker, BM, Brooks, ME, Clark, CJ, Geange, SW, Poulsen, JR, Stevens, MHH, White, J-SS 2009. Generalized linear mixed models: a practical guide for ecology and evolution. Trends in Ecology & Evolution 24, 127–135.
Bushong, DM, Friend, TH, Knabe, DA 2000. Salivary and plasma cortisol response to adrenocorticotropin administration in pigs. Laboratory Animals 34, 171–181.
Chrousos, GP 1995. The hypothalamic-pituitary-adrenal-axis and immune-mediated inflammation. The New England Journal of Medicine 332, 1351–1363.
Clark, LS, Cowan, DF, Pfeiffer, DC 2006. Morphological changes in the Atlantic bottlenose dolphin (Tursiops truncatus) adrenal gland associated with chronic stress. Journal of Comparative Pathology 135, 208–216.
Cook, NJ, Schaefer, AL, Lepage, P, Morgan Jones, S 1996. Salivary vs. serum cortisol for the assessment of adrenal activity in swine. Canadian Journal of Animal Science 76, 329–335.
Cordoni, G 2009. Social play in captive wolves (Canis lupus): not only an immature affair. Behaviour 146, 1363–1385.
de Jong, IC, Prelle, IT, van de Burgwal, JA, Lambooij, E, Korte, SM, Blokhuis, HJ, Koolhaas, JM 2000. Effects of environmental enrichment on behavioral responses to novelty, learning, and memory, and the circadian rhythm in cortisol in growing pigs. Physiology & Behavior 68, 571–578.
de Jong, IC, Ekkel, ED, Van de Burgwal, JA, Lambooij, E, Korte, SM, Ruis, MAW, Koolhaas, JM, Blokhuis, HJ 1998. Effects of strawbedding on physiological responses to stressors and behavior in growing pigs. Physiology & Behavior 64, 303–310.
defra 2003. Economic evaluation of the pig industry restructuring scheme. Agra CEAS Consulting in association with the Department of Agricultural Sciences, Imperial College, University of London.
defra 2007. Welfare of farmed animals (England) regulations (SI 2007 No 2078) Section 8: codes of recommendation for the welfare of livestock: pigs.
Done, SH, Chennells, DJ, Gresham, ACJ, Williamson, S, Hunt, B, Taylor, LJ, Bland, V, Jones, P, Armstrong, D, White, RP, Demmers, TGM, Teer, N, Wathes, CM 2005. Clinical and pathological responses of weaned pigs to atmospheric ammonia and dust. The Veterinary Record 157, 71.
Drummond, JG, Curtis, SE, Simon, J, Norton, HW 1980. Effects of aerial ammonia on growth and health of young pigs. Journal of Animal Science 50, 1085–1091.
Ekkel, ED, Dieleman, SJ, Schouten, WGP, Portela, A, Cornelissen, G, Tielen, MJM, Halberg, F 1996. The circadian rhythm of cortisol in the saliva of young pigs. Physiology & Behavior 60, 985–989.
Foury, A, Geverink, NA, Gil, M, Gispert, M, Hortós, M, Font i Furnols, M, Carrion, D, Blott, SC, Plastow, GS, Mormède, P 2007. Stress neuroendocrine profiles in five pig breeding lines and the relationship with carcass composition. Animal 1, 973–982.
Golden, RN, Gaynes, BN, Ekstrom, RD, Hamer, RM, Jacobsen, FM, Suppes, T, Wisner, KL, Nemeroff, CB 2005. The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence. The American Journal of Psychiatry 162, 656–662.
Greenwood, PI, Shutt, DA 1992. Salivary and plasma cortisol as an index of stress in goats. Australian Veterinary Journal 69, 161–163.
Groot Koerkamp, PWG, Metz, JHM, Uenk, GH, Phillips, VR, Holden, MR, Sneath, RW, Short, JL, White, RPP, Hartung, J, Seedorf, J, Schröder, M, Linkert, KH, Pedersen, S, Takai, H, Johnsen, JO, Wathes, CM 1998. Concentrations and emissions of ammonia in livestock buildings in Northern Europe. Journal of Agricultural Engineering Research 70, 79–95.
Gustin, P, Urbain, B, Prouvost, JF, Ansay, M 1994. Effects of atmospheric ammonia on pulmonary hemodynamics and vascular permeability in pigs: interaction with endotoxins. Toxicology and Applied Pharmacology 125, 17–26.
Harris, RBS, Gu, H, Mitchell, TD, Endale, L, Russo, M, Ryan, DH 2004. Increased glucocorticoid response to a novel stress in rats that have been restrained. Physiology & Behavior 81, 557–568.
Hötzel, MJ, Lopez, EJC, de Oliveira, PAV, Guidoni, AL 2009. Behaviour and performance of pigs finished on deep bedding with wood shavings or rice husks in summer. Animal Welfare 18, 65–71.
Hyun, Y, Ellis, M, Riskowski, G, Johnson, RW 1998. Growth performance of pigs subjected to multiple concurrent environmental stressors. Journal of Animal Science 76, 721–727.
Janssens, C, Helmond, FA, Wiegant, VM 1994. Increased cortisol response to exogenous adrenocorticotropic hormone in chronically stressed pigs – influence of housing conditions. Journal of Animal Science 72, 1771–1777.
Janssens, CJ, Helmond, FA, Loyens, LW, Schouten, WG, Wiegant, VM 1995. Chronic stress increases the opioid-mediated inhibition of the pituitary-adrenocortical response to acute stress in pigs. Endocrinology 136, 1468–1473.
Jasnow, AM, Drazen, DL, Huhman, KL, Nelson, RJ, Demas, GE 2001. Acute and chronic social defeat suppresses humoral immunity of male Syrian Hamsters (Mesocricetus auratus). Hormones and Behavior 40, 428–433.
Jones, JB, Burgess, LR, Webster, AJF, Wathes, CM 1996. Behavioural responses of pigs to atmospheric ammonia in a chronic choice test. Animal Science 63, 437–445.
Kanitz, E, Otten, W, Tuchscherer, M 2005. Central and peripheral effects of repeated noise stress on hypothalamic-pituitary-adrenocortical axis in pigs. Livestock Production Science 94, 213–224.
Kanitz, E, Tuchscherer, M, Puppe, B, Tuchscherer, A, Stabenow, B 2004. Consequences of repeated early isolation in domestic piglets (Sus scrofa) on their behavioural, neuroendocrine, and immunological responses. Brain, Behavior and Immunity 18, 35–45.
Kenward, MG, Roger, JH 1997. Small sample inference for fixed effects from restricted maximum likelihood. Biometrics 53, 983–997.
Korte, SM, Olivier, B, Koolhaas, JM 2007. A new animal welfare concept based on allostasis. Physiology & Behavior 92, 422–428.
Littell, RC, Milliken, GA, Stroup, WW, Wolfinger, RD, Schabenberger, O 2006. SAS for mixed models. SAS Institute Inc., Cary, NC, USA.
Miller, GE, Chen, E, Zhou, ES 2007. If it goes up, must it come down? Chronic stress and the hypothalamic-pituitary-adrenocortical axis in humans. Psychological Bulletin 133, 25–45.
Monjan, AA, Collector, MI 1977. Stress-induced modulation of the immune response. Science 196, 307–308.
Mormede, P, Andanson, S, Auperin, B, Beerda, B, Guemene, D, Malnikvist, J, Manteca, X, Manteuffel, G, Prunet, P, van Reenen, CG, Richard, S, Veissier, I 2007. Exploration of the hypothalamic-pituitary-adrenal function as a tool to evaluate animal welfare. Physiology & Behavior 92, 317–339.
Muller-Schwarze, D, Stagge, B, Muller-Schwarze, C 1982. Play behavior: persistence, decrease, and energetic compensation during food shortage in deer fawns. Science 215, 85–87.
Newberry, RC, Wood-Gush, DGM, Hall, JW 1988. Playful behaviour of piglets. Behavioural Processes 17, 205–216.
Otten, W, Kanitz, E, Puppe, B, Tuchscherer, M, Brüssow, KP, Nürnberg, G, Stabenow, B 2004. Acute and long term effects of chronic intermittent noise stress on hypothalamic-pituitary-adrenocortical and sympatho-adrenomedullary axis in pigs. Animal Science 78, 271–283.
Palagi, E, Paoli, T 2007. Play in adult Bonobos (Pan paniscus): modality and potential meaning. American Journal of Physical Anthropology 134, 219–225.
Parker, MO, O'Connor, EA, McLeman, MA, Demmers, TGM, Lowe, JC, Owen, RC, Davey, EL, Wathes, CM, Abeyesinghe, SM 2010. The impact of chronic environmental stressors on growing pigs, Sus scrofa (Part 2): social behaviour. Animal, doi:10.1017/S1751731110001084.
Partonen, T, Lonnqvist, J 2000. Bright light improves vitality and alleviates distress in healthy people. Journal of Affective Disorders 57, 55–61.
Piccoli, B, Parazzoli, S, Zaniboni, A, Demartini, G, Fraschini, F 1991. Non-visual effects of light mediated via the optical route: review of the literature and implications for occupational medicine. La Medicina del Lavoro 82, 213–232.
Reiter, RJ 1991. Pineal gland interface between the photoperiodic environment and the endocrine system. Trends in Endocrinology & Metabolism 2, 13–19.
Ruis, MAW, te Brake, JHA, Engel, B, Buist, WG, Blokhuis, HJ, Koolhaas, JM 2001. Adaptation to social isolation – acute and long-term stress responses of growing gilts with different coping characteristics. Physiology & Behavior 73, 541–551.
Ruis, MAW, Te Brake, JHA, Engel, B, Ekkel, ED, Buist, WG, Blokhuis, HJ, Koolhaas, JM 1997. The circadian rhythm of salivary cortisol in growing pigs: effects of age, gender, and stress. Physiology & Behavior 62, 623–630.
Sapolsky, RM, Romero, LM, Munck, AU 2000. How do glucocorticoids influence stress responses? Integrating permissive, suppressive, stimulatory, and preparative actions. Endocrine Reviews 21, 55–89.
Seedorf, J, Hartung, J 1999. Survey of ammonia concentrations in livestock buildings. The Journal of Agricultural Science 133, 433–437.
Selye, H 1936. A syndrome produced by diverse nocuous agents. Nature 138, 32.
Siviy, S, Panksepp, J 1985. Energy balance and play in juvenile rats. Physiology & Behavior 35, 438–441.
Siviy, SM, Atrens, DM 1992. The energetic costs of rough and tumble play in the juvenile rat. Developmental Psychobiology 25, 137–148.
Smith, JH, Wathes, CM, Baldwin, BA 1996. The preference of pigs for fresh air over ammoniated air. Applied Animal Behaviour Science 49, 417–424.
Sorrells, AD, Eicher, SD, Scott, KA, Harris, MJ, Pajor, EA, Lay, DCJ, Richert, BT 2006. Postnatal behavioral and physiological responses of piglets from gilts housed individually or in groups during gestation. Journal of Animal Science 84, 757–766.
Stombaugh, DP, Teague, HS, Roller, WL 1969. Effects of atmospheric ammonia on the pig. Journal of Animal Science 28, 844–847.
Sutherland, MA, Niekamp, SR, Rodriguez-Zas, SL, Salak-Johnson, JL 2006. Impacts of chronic stress and social status on various physiological and performance measures in pigs of different breeds. Journal of Animal Science 84, 588–596.
Talling, JC, Waran, NK, Wathes, CM, Lines, JA 1996. Behavioural and physiological responses of pigs to sound. Applied Animal Behaviour Science 48, 187–202.
Talling, JC, Lines, JA, Wathes, CM, Waran, NK 1998. The acoustic environment of the domestic pig. Journal of Agricultural Engineering Research 71, 1–12.
Taylor, N, Prescott, N, Perry, G, Potter, M, Sueur, CL, Wathes, C 2006. Preference of growing pigs for illuminance. Applied Animal Behaviour Science 96, 19–31.
Ulrich-Lai, YM, Figueiredo, HF, Ostrander, MM, Choi, DC, Engeland, WC, Herman, JP 2006. Chronic stress induces adrenal hyperplasia and hypertrophy in a subregion-specific manner. American Journal of Physiology-Endocrinology and Metabolism 291, E965–E973.
UK Health and Safety Executive 2001. EH40/2001 Occupational Exposure Limits.
Vanderschuren, LJMJ, Niesink, RJM, Ree, JM 1997. The neurobiology of social play behavior in rats. Neuroscience & Biobehavioral Reviews 21, 309–326.
Veissier, I, Boissy, A 2007. Stress and welfare: two complementary concepts that are intrinsically related to the animal’s point of view. Physiology & Behavior 92, 429–433.
von Borell, E 2000. Stress and coping in farm animals. Archiv Tierzucht/Archives Animal Breeding 43, 144–152.
von Borell, E, Özpinar, A, Eslinger, KM, Schnitz, AL, AZhao, Y, Mitloehner, FM 2007. Acute and prolonged effects of ammonia on hematological variables, stress responses, and behavior of nursery pigs. Journal of Swine Health and Production 15, 137–145.
Wathes, CM, Demmers, TGM, Teer, N, White, RP, Taylor, LL, Bland, V, Jones, P, Armstrong, D, Gresham, ACJ, Hartung, J, Chennells, DJ, Done, SH 2004. Production responses of weaned pigs after chronic exposure to airborne dust and ammonia. Animal Science 78, 87–97.
Yoshioka, G, Imaeda, N, Ohtani, T, Hayashi, K 2005. Effects of cortisol on muscle proteolysis and meat quality in piglets. Meat Science 71, 590–593.