Alternative farrowing systems: design criteria for farrowing systems based on the biological needs of sows and piglets

The effect of farrowing environment and previous experience on the maternal behaviour of sows in indoor pens and outdoor huts

Outdoor farrowing huts facilitate a less restricted maternal behaviour in sows compared with sows kept indoors in farrowing pens. The aim of our study was to investigate whether there are behavioural differences between primiparous sows kept outdoors in farrowing huts and indoors in pens, and whether the maternal behaviour during the second parity, when all sows were kept outdoors in farrowing huts, would differ between sows that have experienced the indoor or the outdoor environment, respectively, during their first parturition. A total of 26 Yorkshire×Swedish Landrace sows were studied. Of these, 11 sows were housed outdoors in farrowing huts during both parturitions (group=OUTOUT). The other 15 sows were kept indoors in a barn with single farrowing pens during their first parturition. During their second parturition, sows were kept outdoors in farrowing huts (group=INOUT). The behaviour was video recorded from 2 h prepartum to 48 h postpartum. The sows' responsiveness to playbacks of a piglet's screams was tested on days 2 to 3 postpartum. Parity 1: during the last 2 h prepartum, OUTOUT sows had a higher proportion of observations in the sternal lying position (P<0.01). During parturition, OUTOUT sows changed posture more often (P<0.05) and were lying less (P<0.05) than INOUT sows. All sows in both groups responded with 'lifting head' towards the playback of piglet scream, whereas 100% of OUTOUT sows and only 43% of INOUT sows thereafter were 'getting up' (P <0.01). Parity 2: There were no behavioural differences between INOUT and OUTOUT sows. In conclusion, it is not problematic for a second parity sow with initial maternal experience from an indoor farrowing pen to be kept outdoors in farrowing huts during its following farrowing.

A review of sow and piglet behaviour and performance in group housing systems for lactating sows

Commercial use of group housing systems for lactating sows is limited, but the recent transition to group housing during gestation in the EU may result in a renewed interest in such systems. Therefore, this review aims to identify key factors that may contribute to the success or failure of group housing of lactating sows in comparison with individual housing by describing the variety in group housing systems and discussing animal behaviour and performance compared with individual housing. Group housing systems can be divided in multi-suckling (MS) systems, in which sows are grouped with their litters, and get-away (GA) systems, which include a separate communal area accessible to sows only. These systems differ in many aspects regarding management and layout but, compared with individual housing, generally provide more environmental complexity, more freedom of movement for the sows and more freedom to express behaviours related to, for example, maternal care and social interactions. Group housing poses several risks, such as disrupted nursing and an increased level of crushing during the MS phase, and in the GA systems there is a risk for early cessation of nursing. On the other hand, pre-weaning mingling of litters clearly benefits piglet social development and may improve adaptation to the post-weaning situation. In addition, group-housed sows may show lactational ovulation, which provides opportunities for insemination during an extended lactation period, which benefits the piglets. Gradual transitions in social and physical environment around gestation, farrowing, grouping and weaning seem to be key success factors for group housing systems during lactation. In addition, selection of suitable sows and quality of stockmanship seem important.

Sow postural changes, responsiveness to piglet screams, and their impact on piglet mortality in pens and crates

Free farrowing pens (pens) improve the welfare of sows but may increase sow activity and negatively influence piglet production. The aim of this study was to assess the effect of pens and crates on sow postural changes, piglet trapping, sow responses to piglet screams, piglet mortality, and piglet BW gain. It was predicted that provision of greater space (in pens) would increase not only the frequency of sow postural changes and the probability of trappisng but also sow responses to the screams of piglets; thus, the outcome would be no differences in fatal piglet crushing or overall mortality between the housing systems. Sows were randomly moved to either a farrowing pen (n = 20) or farrowing crate (n = 18). Sow behavior was recorded and analyzed for 72 h from the birth of the first piglet (BFP). Sow postural changes included rolling from a ventral to lateral position and vice versa and going from standing to sitting, standing to lying, and sitting to lying. Occurrences of piglet trapping and sow responsiveness to real crushing situations were analyzed. Sow responsiveness was assessed in response to audio playbacks (PB) of piglet screams on d 3 postpartum (48 to 72 h after BFP; PB crush calls) and real piglet crushing during the first 72 h after BFP (real crush calls). Piglet BW gain was estimated 24 h after BFP, piglet BW was recorded at weaning, and piglet crushing and piglet mortality were recorded during the 72 h after BFP. Data were analyzed using PROC MIXED and PROC GENMOD of SAS. Sows in pens showed more postural changes (P = 0.04) and tended to have greater incidences of piglet trapping (P = 0.07) than those in crates. Sow response to PB crush calls was greater in pens (P = 0.04) but did not differ for real crush calls between pens and crates (P = 0.62). There was no effect on the probability of piglet crushing (P = 0.38) and mortality (P = 0.41) during the 72 h after BFP nor in piglet mortality at weaning (P = 0.81) between pens and crates. Piglet BW gain at 24 h after BFP (P = 0.01) and piglet BW at weaning (P = 0.02) were greater in pens. Sows in pens showed more postural changes and tended to trap more piglets; however, the response to real crush calls did not differ between the two housing systems. Despite this, there was no increase in piglet crushing or mortality in pens, which might be influenced by the better piglet body condition observed in pens, which in turn could influence their ability to avoid crushing by the sow.

Invited review: piglet mortality: management solutions

Preweaning mortality varies greatly among herds and this is partly attributed to differences in farrowing house management. In this review, we describe the various management strategies than can be adopted to decrease mortality and critically examine the evidence that exists to support their use. First, we consider which management procedures are effective against specific causes of death: intrapartum stillbirth, hypothermia, starvation, disease, crushing, and savaging. The most effective techniques include intervention to assist dystocic sows, measures to prevent and treat sow hypogalactia, good farrowing house hygiene, providing newborn piglets with a warm microenvironment, early fostering of supernumerary piglets, methods that assist small and weak piglets to breathe and obtain colostrum, and intervention to prevent deaths from crushing and savaging. The provision of nest-building material and modifications to the pen to assist the sow when lying down may also be beneficial, but the evidence is less clear. Because most deaths occur around the time of farrowing and during the first few days of life, the periparturient period is a particularly important time for management interventions intended to reduce piglet mortality. A number of procedures require a stockperson to be present during and immediately after farrowing. Second, we consider the benefits of farrowing supervision for preweaning mortality in general, focusing particularly on methods for the treatment of dystocia and programs of piglet care that combine multiple procedures. Third, we discuss the need for good stockmanship if farrowing supervision is to be effective. Stockmanship refers not only to technical skills but also to the manner in which sows are handled because this influences their fearfulness of humans. We conclude that piglet survival can be improved by a range of management procedures, many of which occur in the perinatal period and require the supervision of farrowing by trained staff. Although this incurs additional labor costs, there is some evidence that this can be economically offset by improved piglet survival.

Reproductive issues in welfare-friendly housing systems in pig husbandry: a review

In Europe, housing conditions of sows are currently changing, related with a larger emphasis on pig welfare. As a result, sows are and will be less kept in crates, but more so in loose housing systems (farrowing, lactation) and group housing systems (pregnancy, lactation, weaning-to-oestrus interval). These changes in housing conditions may affect reproductive functioning of the sows. Group housing of sows may decrease farrowing rate and litter size when stress levels rise or when feed intake in early pregnancy is not fully secured. Loose housing during farrowing results in an improved farrowing process, but may increase piglet mortality by crushing during early lactation. Further, group housing during lactation may increase the risk of lactational oestrus. Thus, new - welfare friendly - housing systems require increased attention to management to ensure optimal reproductive performance.

Confinement of lactating sows in crates for 4 days after farrowing reduces piglet mortality

To reduce mortality among suckling piglets, lactating sows are traditionally housed in farrowing crates. Alternatively, lactating sows can be housed in farrowing pens where the sow is loose to ensure more behavioural freedom and consequently a better welfare for the sow, although under commercial conditions, farrowing pens have been associated with increased piglet mortality. Most suckling piglets that die do so within the first week of life, so potentially lactating sows do not have to be restrained during the entire lactation period. Therefore, the aim of the current study was to investigate whether confinement of the sow for a limited number of days after farrowing would affect piglet mortality. A total of 210 sows (Danish Landrace × Danish Yorkshire) were farrowed in specially designed swing-aside combination farrowing pens measuring 2.6 m × 1.8 m (combi-pen), where the sows could be kept loose or in a crate. The sows were either: (a) loose during the entire experimental period, (b) crated from days 0 to 4 postpartum, (c) crated from days 0 to 7 postpartum or (d) crated from introduction to the farrowing pen to day 7 postpartum. The sows and their subsequent litters were studied from introduction to the combi-pen ∼1 week before expected farrowing and until 10 days postpartum. Confinement period of the sow failed to affect the number of stillborn piglets; however, sows that were crated after farrowing had fewer live-born mortality deaths (P < 0.001) compared with the sows that were loose during the experimental period. The increased piglet mortality among the loose sows was because of higher mortality in the first 4 days after farrowing. In conclusion, the current study demonstrated that crating the sow for 4 days postpartum was sufficient to reduce piglet mortality.