The effect of mixing entire male pigs prior to transport to slaughter on behaviour, welfare and carcass lesions

PLoS One. 2015 Apr 1;10(4):e0122841. doi: 10.1371/journal.pone.0122841. eCollection 2015.

Abstract

Research is needed to validate lesions recorded at meat inspection as indicators of pig welfare on farm. The aims were to determine the influence of mixing pigs on carcass lesions and to establish whether such lesions correlate with pig behaviour and lesions scored on farm. Aggressive and mounting behaviour of pigs in three single sex pens was recorded on Day -5, -2, and -1 relative to slaughter (Day 0). On Day 0 pigs were randomly allocated to 3 treatments (n = 20/group) over 5 replicates: males mixed with females (MF), males mixed with males (MM), and males unmixed (MUM). Aggressive and mounting behaviours were recorded on Day 0 at holding on farm and lairage. Skin/tail lesions were scored according to severity at the farm (Day -1), lairage, and on the carcass (Day 0). Effect of treatment and time on behaviour and lesions were analysed by mixed models. Spearman rank correlations between behaviour and lesion scores and between scores recorded at different stages were determined. In general, MM performed more aggressive behaviour (50.4 ± 10.72) than MUM (20.3 ± 9.55, P < 0.05) and more mounting (30.9 ± 9.99) than MF (11.4 ± 3.76) and MUM (9.8 ± 3.74, P < 0.05). Skin lesion scores increased between farm (Day -1) and lairage (P < 0.001), but this tended to be significant only for MF and MM (P = 0.08). There was no effect of treatment on carcass lesions and no associations were found with fighting/mounting. Mixing entire males prior to slaughter stimulated mounting and aggressive behaviour but did not influence carcass lesion scores. Carcass skin/tail lesions scores were correlated with scores recorded on farm (rskin = 0.21 and rtail = 0.18, P < 0.01) suggesting that information recorded at meat inspection could be used as indicators of pig welfare on farm.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aggression
  • Animal Husbandry / methods
  • Animal Welfare
  • Animals
  • Female
  • Housing, Animal
  • Hydrocortisone / blood
  • Male
  • Random Allocation
  • Skin / injuries*
  • Stress, Psychological
  • Sus scrofa / blood
  • Sus scrofa / injuries*
  • Sus scrofa / psychology
  • Tail / injuries*
  • Transportation

Substances

  • Hydrocortisone

Grants and funding

This study was part of the PIGWELFIND project funded by the Department of Agriculture, Food and the Marine (DAFM), Ireland. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.