Observations on the pre- and post-weaning behaviour of piglets reared in commercial indoor and outdoor environments

Abstract

A number of behavioural problems are associated with weaning piglets including belly nosing, ear and tail biting, and low intake of solid food. These appear to be less pronounced in piglets reared on outdoor systems, which initially consume more solid food and show less belly nosing and aggression than comparable indoor-reared piglets. The objective of this study was to investigate how these differences in post-weaning behaviour relate to the piglets’ pre-weaning behaviour in the two rearing environments. The study was carried out at a commercial pig unit, where piglets of the same genotype are born into conventional indoor or outdoor farrowing systems. In the intensive system, sows were singly housed prior to farrowing in crates and their piglets received a solid ‘creep’ food prior to weaning. On the outdoor system, sows were allowed to build straw nests in arks for farrowing and both sow and piglets had access to pasture. Indoor and outdoor piglets were weaned at 24 (±3) days of age and mixed in straw-yard housing with access to a solid food. Prior to weaning, teat-directed activity was more common in indoor piglets than outdoor piglets. Outdoor piglets performed more rooting, standing and locomotion and were seen chewing the sows’ roll-nuts. Following weaning, outdoor-reared piglets performed more feeding and rooting, and less fighting than indoor-reared piglets. This study supports previous findings that undesirable activities such as fighting are less common in piglets weaned from outdoor systems, even when mixed with indoor piglets. In addition, outdoor-reared piglets were more likely to exploit solid food even though they did not have access to creep food prior to weaning.

Short-term behavioural effects of weaning age in outdoor-reared piglets

“…Although weaning appears to be less stressful for piglets in outdoor than in confined systems (Cox and Cooper, 2001;Johnson et al, 2001;Hö tzel et al, 2004), this study shows that age at weaning influences the adaptation of outdoor-reared piglets to weaning, and that a considerable improvement can be achieved from the 3rd to the 4th week after birth.…”

“…Furthermore, piglets have the opportunity of experiencing foraging behaviours during lactation through rooting and grazing (Hö tzel et al, 2004;Leite et al, 2008) and of spending time away from the dam (Leite et al, 2008), which has been shown to increase solid-feed consumption after weaning (Weary et al, 1999b;Weary et al, 2002). Indeed, weanling piglets from outdoor systems have higher feeding frequencies compared to indoorhoused piglets (Cox and Cooper, 2001;Hö tzel et al, 2004). Despite all these advantages, in the current study, feeding behaviour was low during the first days after weaning and was lower during the first 3 days in the earlier-than in the later-weaned groups.…”

“…In order to overcome this problem, diets especially designed for the digestive system of very young piglets have been formulated (Dritz et al, 1996). However, because the behaviour of piglets weaned at very young ages indicates distress and suffering (Weary et al, 2008), the age for weaning should not be defined solely based on the performance of the animals.When lactation takes place in enriched, as opposed to conventional housing environments, the piglets' responses to weaning generally involve lower frequencies of aggression and abnormal behaviours, and higher frequencies of playing, feeding and resting behaviours (Webster and -E-mail: mjhotzel@cca.ufsc.br 102 Dawkins, 2000;Cox and Cooper, 2001;Hö tzel et al, 2004), as well as higher growth rates in the post-weaning period (O'Connell et al, 2005). Some factors that may underlie the different behavioural responses to weaning in piglets reared in conventional or outdoor systems are the opportunity to contact piglets of other litters during lactation, which decreases fighting after weaning (Pitts et al, 2000;Weary et al, 2002), and the reduction in suckling frequency, which seems to encourage the piglets to explore solid food and spend time away from the sow (Hö tzel et al, 2004).…”

Does the environmental background (intensive v. outdoor systems) influence the behaviour of piglets at weaning?

“…Similarly, Oostindjer et al (2010) found that outdoor-raised Lau, Pluske and Fleming piglets were more willing to touch the food compared with farrowing shed-raised piglets, whereas Cox and Cooper (2001) recorded greater initial consumption of solid food in piglets reared in an outdoor system compared with indoorreared piglets. Social learning may increase food intake due to the additional stimulus-and substrate-rich environments of outdoor systems, where the mother can show a range of foraging behaviours.…”

“…Previous studies report that, at weaning, undesirable behaviours (e.g. belly nosing, agonistic interactions and low feed consumption) are less frequent in outdoor-raised piglets (Webster and Dawkins, 2000;Cox and Cooper, 2001), which spend more time walking and engage in play activity compared with indoor-reared piglets (Johnson et al, 2001). The environment during rearing can also influence behavioural reactivity towards non-social challenges.…”