Early human contact and housing for pigs - part 2: resilience to routine husbandry practices

Authors: LUCAS, MEGAN - University Of Melbourne; HEMSWORTH, LAUREN - University Of Melbourne; BUTLER, KYM - University Of Melbourne; MORRISON, REBECCA - Rivalea Australia; TILBROOK, ALAN - University Of Queensland; Marchant, Jeremy; RAULT, JEAN-LOUP - University Of Veterinary Medicine; GALEA, RUTU - University Of Melbourne; HEMSWORTH, PAUL - University Of Melbourne

Submitted to: Animal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2024
Publication Date: 4/18/2024
Citation: Lucas, M.E., Hemsworth, L.M., Butler, K.L., Morrison, R.S., Tilbrook, A.J., Marchant, J.N., Rault, J., Galea, R.Y., Hemsworth, P.H. 2024. Early human contact and housing for pigs - part 2: resilience to routine husbandry practices. Animal. https://doi.org/10.1016/j.animal.2024.101165.
DOI: https://doi.org/10.1016/j.animal.2024.101165

Interpretive Summary: Farm animal production is under increasing pressure to change some of the close confinement housing systems such as battery cages, veal crates and sow gestation and farrowing crates. With those changes, come new experiences for the animals contained within them. In the farrowing system, piglets in different systems will be exposed to different environments from birth and these environments may have long-lasting impacts on piglets' behaviors, responses to stress and resilience. We carried out a study examining 2 different farrowing housing systems (traditional crates and larger, open pens) and 2 different levels of human handling (normal, routine husbandry and increased positive contact) on piglets' subsequent responses to some routine management tasks, such as vaccinating, tail docking, weaning and moving out of the home pen. We found that pigs that were positively handled showed fewer escape behaviors than control pigs when handled during routine management tasks and lower concentrations of cortisol, a stress hormone, after weaning. Pigs from farrowing crates showed fewer escape attempts than loose pen pigs, lower cortisol after weaning and less baulking when removed from the home pen at the end of the study. Overall, positively handled pigs and pigs from farrowing crates coped better with stressful situations than control handled pigs and pigs from loose farrowing pens.

Technical Abstract: This paper is the second of three in a series on early experiences and stress resilience in pigs, and reports on the effects of early human contact and housing on the behavioural and physiological responses of pigs to routine husbandry practices. Using a 2 × 2 factorial design, 48 litters of pigs were reared in either a standard farrowing crate (FC) or a loose farrowing pen (LP) which was larger, more physically complex and allowed the sow to move freely. Piglets were provided with either routine contact from stockpeople (C), or routine contact plus regular opportunities for positive human contact (+HC) involving 5 min of scratching, patting and stroking imposed to the litter from 0-4 weeks of age. At 4 days of age after only 3 bouts of the handling treatment, +HC pigs showed less escape behaviour than C pigs during capture by a stockperson for vaccinations and tail docking, and shorter durations of vocalising throughout the procedures. +HC pigs also showed less escape behaviour during capture by a stockperson at 3 weeks of age. FC pigs showed less escape behaviour than LP pigs during capture by a stockperson at 4 days of age but not at 3 weeks of age. Serum cortisol concentrations were lower in FC pigs than LP pigs 2 h after weaning but not at 49 h after weaning, whereas serum cortisol concentrations were lower in +HC pigs than C pigs at 49 h after weaning but not at 2 h after weaning. In the period from 0-1 h after weaning, C pigs from LP performed the most escape attempts, although overall escape attempts were rare. Effects of the treatments on other pig behaviours after weaning, such as activity, aggression and nosing pen mates were sometimes contradictory and difficult to interpret in terms of stress resilience. When being moved out of the home pen by a stockperson at 21 weeks of age, FC pigs showed less baulking compared to LP pigs. There were no detected effects of human contact treatment on the behaviour of pigs when being moved at 21 weeks of age. Overall, +HC and FC pigs appeared to cope better with routine husbandry practices compared to C and LP pigs, based on lower biological responses indicative of stress including escape behaviour, vocalisations and cortisol concentrations.