Skip to main content Accessibility help

Effects of weight, temperature and behaviour on the circadian rhythm of salivary cortisol in growing pigs

  • E. Hillmann (a1), L. Schrader (a2), C. Mayer (a2) and L. Gygax (a3)


In farm animals, salivary cortisol has become a widely used parameter for measuring stress responses. However, only few studies have dealt with basal levels of concentration of cortisol in pigs and its circadian rhythm. The aim of this study was to examine the effects of ambient temperature and thermoregulatory behaviour on the circadian rhythm of salivary cortisol levels in fattening pigs. Subjects were 30 fattening pigs of different weight (60 to 100 kg), kept in six groups in an uninsulated building in pens with partly slatted floors. Saliva samples were taken every 2 h over periods of 24 h at different ambient temperatures at two times in winter and four times in summer. Thermoregulatory behaviour was recorded in the same 24-h time periods. The effect of time of day, body weight, ambient temperature and behaviour on the cortisol level was analysed using a mixed-effects model. Two peaks of cortisol levels per day were found. This circadian pattern became more pronounced with increasing weight and on days where thermoregulatory behaviour was shown. Mean cortisol levels per day were affected by weight but not by thermoregulatory behaviour. From our data, we conclude that long-term variations in cortisol concentration may be influenced by increasing age and weight more than by the respective experimental situation. In assessing animal welfare, it seems more reliable to consider the circadian pattern of cortisol concentration instead of only one value per day.


Corresponding author


Hide All
Bate, LA, Hacker, RR 1985. Effect of cannulation and environmental temperature on the concentration of serum cortisol in pregnant sows. Canadian Journal of Animal Science 65, 399404.
Boon, CR 1981. The effect of departures from lower critical temperature on the group postural behaviour of pigs. Animal Production 33, 7179.
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, 329335.
De Jong, IC, Prelle, TI, 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 and Behavior 68, 571578.
De Leeuw, JA, Ekkel, ED 2004. Effects of feeding level and the presence of a foraging substrate on the behaviour and stress physiological response of individually housed gilts. Applied Animal Behaviour Science 86, 1525.
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 and Behavior 60, 985989.
Ekkel, DE, Spoolder, HAM, Hulsegge, I, Hopster, H 2003. Lying characteristics as determinants for space requirements in pigs. Applied Animal Behaviour Science 80, 1930.
Geverink, NA, Schouten, WGP, Gort, G, Wiegant, VM 2003. Individual differences in behaviour, physiology and pathology in breeding gilts housed in groups or stalls. Applied Animal Behaviour Science 81, 2941.
Griffith, MK, Minton, JE 1991. Free-running rhythms of adrenocorticotropic hormone (ACTH), cortisol and melatonin in pigs. Domestic Animal Endocrinology 8, 201208.
Hillmann, E, Mayer, C, Schrader, L 2004. Lying behaviour and adrenocortical reactions as indicators for the thermal tolerance of pigs of different weight. Animal Welfare 13, 329335.
Hillmann, E, Mayer, C, Gygax, L, Schrader, L 2005. Effects of space allowance on behavioural and adrenocortical reactions to elevated temperatures in fattening pigs. Lanbauforschung Völkenrode 55, 255260.
Huynh, TTT, Aarnink, AJA, Gerrits, WJJ, Heetkamp, MJH, Canh, TT, Spoolder, HAM, Kemp, B, Verstegen, MWA 2005. Thermal behaviour of growing pigs in response to high temperature and humidity. Applied Animal Behaviour Science 91, 116.
Klemcke, HG, Nienaber, JA, Hahn, GL 1989. Plasma adrenocorticotropic hormone and cortisol in pigs: effects of time of day on basal and stressor-altered concentrations. Experimental Biology and Medicine 190, 4253.
Negrao, JA, Porcionato, MA, De Passille, AM, Rushen, J 2004. Cortisol in saliva and plasma of cattle after ACTH administration and milking. Journal of Dairy Science 87, 17131718.
Pinheiro, JC, Bates, DM 2000. Mixed-effects models in S and S-PLUS. Springer, New York.
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 and Behavior 62, 623630.
Schönreiter, S, Zanella, AJ 2000. Assessment of cortisol in swine by saliva: new methodological approaches. Archiv für Tierzucht 43, 165170.
Venables, WN, Ripley, BD 2002. Modern applied statistics with S. Springer, New York.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed