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Erik Jørgensen

Effects of thermal environment on HPA-axis hormones, oxytocin and behavioral activity in peri-parturient sows

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  • Biostatistik
  • Department of Genetics and Biotechnology
  • Department of Animal Health and Bioscience
  • Behaviour and stressbiology
  • Disease Mechanisms, -Markers and -Prevention
Provision of additional floor heating (33 to 34C) at birth and during the early postnatal hours is favorable for newborn piglets of domestic sows (Sus scrofa). We investigated whether this relatively high temperature influenced sow behavior and physiology around farrowing. Half of 28 second-parity pregnant sows were randomly chosen to be exposed to floor heating 12 h after onset of nest building and until 48 h after birth of the first piglet (treatment =
HEAT), whereas the rest of the sows entered the control group (treatment = CONT) with no floor heating. Hourly blood sampling from 8 h before and until 24 h after the birth of the first piglet was used for investigation of temporal changes in plasma concentrations of oxytocin, cortisol, and ACTH. In addition, occurrence and duration of sow postures were recorded -8 h to +48 h relative to the birth of first piglet. There was a clear temporal development in sow behavior and hormone concentrations (ACTH, cortisol, and oxytocin) across parturition (P < 0.001), independent of treatment. In general, the hormonal level increased from start to the end of farrowing. The observed oxytocin increase and peak late in farrowing coincided with the passive phase where sows lie laterally with an overall low activity. Floor heating increased the mean concentration of cortisol (P = 0.02; estimated as 29% greater than in controls) and tended
to increase the mean concentration of ACTH (P = 0.08; estimated as 17% greater than in controls), but we did not find any treatment effect on mean oxytocin concentrations, the course of parturition, or the behavior of sows. Behavioral thermoregulation may, however, have lost some function for the sows, because the floor was fully heated in our study. In addition, exposure to heat decreased the between-sow variation of plasma oxytocin (approximately 31% lower
relative to control) and ACTH (approximately 46% lower relative to control). Whether this decreased variation may be indicative of acute stress or linked to other biological events is unclear. In conclusion, inescapable floor heating (around 33.5C) may be considered a stressor for sows around farrowing, giving rise to elevated plasma concentrations of cortisol, but without concurrent changes in oxytocin or behavioral activity.
Original languageEnglish
JournalJournal of Animal Science
Pages (from-to)2796-2805
Publication statusPublished - 2009

    Research areas

  • behavior, Sus scrofa, parturition, oxytocin, hypothalamic-pituitary-adrenal axis

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