The aim of this study was to describe maternal behaviour in the pig and to investigate the effect of endogenous opioids on maternal responsiveness. The behaviour of 16 Large White x Landrace female pigs was recorded around farrowing. The pig's posture and her response when piglets were present at her nose were described. To determine the role of endogenous opioids, sows were injected (i.m.) with either naloxone (1 mg/kg body weight, 8 pigs) or saline (8 pigs) at 3.75 h after the birth of the first piglet. Generally the initial period following the birth of the first piglet seemed to be the most active after which the sows spent almost all of the time in lateral recumbency. Farrowing sows were generally unresponsive to their piglets during farrowing. Sows receiving naloxone became more responsive towards their piglets. The changes seen in posture and responsiveness to piglets were delayed in sows with a longer parturition and it is suggested that there is some involvement of cumulative piglet births on passivity. It is proposed that opioid-mediated passivity in the pig, characterised by lateral lying and unresponsiveness to piglets, may be helpful in maximizing suckling opportunities and reducing the risk of crushing piglets.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Animal Biology Division, SAC Edinburgh, West Mains Rd, Edinburgh, EH9 3JG, UK.|
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