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Litter size and kit mortality are both relatively high in the production of farm mink, with the vast majority of deaths occurring around parturition and during the first days of life. Maternal care is crucial to ensure the survival of the vulnerable kits. This subject has received little attention and the objective of the present study was to describe periparturient behaviour and the course of parturition in mink, aiming to identify key factors related to early kit mortality. We video recorded the parturitions of 39 1-year-old primiparious mink dams of the brown colour-type ‘wild’ kept under identical conditions, and sampled data on the progress of parturition for descriptive analysis. In addition, a detailed behavioural analysis was performed on a subset of the sample comparing low mortality (‘SURV’, n = 8) and high mortality (‘MORT’, n = 8) females with equally sized litters. MORT females lost more than 70% of their live-born kits from the day of parturition (Day 0) until Day 7, whereas SURV females lost none. Several types of behaviour in mink females around parturition are described for the first time. SURV females spent more time in kit-directed behaviour, such as circling, carrying, sniffing/licking the kit, and moving the kit to the udder, and kits from their litters were alone for shorter periods during the first 24 h after the birth of the first kit compared to MORT dams. The majority of kit deaths occurred during the first day postpartum, and deliveries with high variation in inter-birth intervals were related to increased kit mortality ( P = 0.025). MORT females spent more time sniffing/licking their genital region prior to parturition ( P = 0.004). The duration of parturition was markedly longer in MORT than in SURV dams (607 (125) min versus 309 (72) min, P = 0.034). The inter-birth intervals increased as parturition progressed ( P = 0.032), with different level (MORT > SURV, P = 0.002), but the same slope (N.S.), for SURV and MORT litters. In conclusion, our results point to birth problems as important contributors to suboptimal maternal behaviour and early kit mortality in farmed mink.

It has previously been shown that when sows lie down in the open there is a much greater risk of piglet crushing than when they lie down alongside a wall, probably because the wall provides support and/or a piglet escape zone. Therefore, walls in farrowing pens should be attractive to the sow, so that she chooses to use them when lying down. EU-regulations state that farrowing pens must be given “some means of protecting the piglets, such as farrowing rails”. Walls with farrowing rails may, however, not be the most appropriate option as they may be unattractive to the sows. We tested sow preferences for lying down alongside a plain wall, a sloping wall or a wall with a farrowing rail. Beforehand, we tested preferences for three sloping wall designs (plain, curved and multiple bars) in order to use the preferred one in the later choice experiment. In both experiments, 4 × 6 pregnant second–seventh parity individually housed sows were used over a 3-day training and a 4-day testing period. In both experiments, the three types of walls were balanced on position in the pen. In both tests, the sows predominantly lay down alongside the walls (on average, 80 ± 4 and 86 ± 3% of lying down events, respectively). In the test of the three sloping wall designs, the sows had no significant preferences for wall designs. For practical reasons the plain sloping wall was used in the subsequent test. Here, there was a significant effect of wall type (on average, 16 ± 5% of lying down events alongside the wall with the farrowing rail, 48 ± 8% alongside the plain wall and 36 ± 8% alongside the plain sloping wall (P In conclusion, walls with farrowing rails appear to be less attractive to lie down against than other wall designs. Although farrowing rails provide piglets with escape zones they may not be optimal for piglet survival because they do not encourage the sow to lie down alongside a wall, rather than in the open. Moreover, they may not be optimal from a sow welfare perspective due to lack of support for the sow when lying down.

The aim of this study was to determine whether provision of nest materials in a form and amount that could be handled in a commercial Danish pig farm with modified Schmid pens would affect the environment for sows and piglets to an extent that could be detected in sow behaviour and parameters relevant both for production and piglet welfare, i.e. piglet mortality and growth. Three-hundred twenty-six farrowings were included in the study and the sows in the treatment group were provided with 2.5 kg long-stemmed barley straw from 2 days prior to expected farrowing until 4 days after farrowing in addition to the 4 kg chopped straw that was given both at treatment ( n = 163) and control farrowings ( n = 163). The median mortality rates (and interquartile ranges) due to still-birth were 6.7 (0–17.6) and 6.3 (0–13.3)% for the treatment and control group, respectively. The median mortality rates within the first 3 weeks after birth for live-born piglets that remained with their biological mother, i.e. piglets that were not cross fostered, were 18.2 (6.3–30.8)% and 20.0 (7.7–30.8)% for the treatment and control group, respectively. On average, the live-born piglets that had remained by their biological mother died 0.76 ± 0.05 days after birth in the treatment group and 0.74 ± 0.06 days after birth in the control group. The primary mortality causes were still-birth and piglet crushing, but 72% of all the live-born piglet which died had also not received colostrum. The mortality rates, the distribution on specific mortality causes and the time of death did not differ between treatments. The results indicate that 2.5 kg long-stemmed straw in addition to the chopped straw provided to both groups was insufficient to achieve the positive effect on maternal behaviour suggested possible in previous more fundamental studies of provision of nest materials to sows. This conclusion was supported by behavioural observation on a randomly selected subset sample (27 treatment farrowings and 20 control farrowings). The observations revealed no significant differences between treatment and control group in frequency of nest building or lying in lateral recumbency without changing posture from 4 h prepartum until 6 h postpartum. There was also no difference in the inter birth intervals or percentage of the litter that was suckling during the first 8 h after birth of the first piglet. The results emphasise the need for further studies of the amounts and types of nest materials that should be given in order to fulfil the intention of the EU requirement for nesting materials to periparturient sows, and to obtain the effects on behaviour and production that have been suggested possible by previous more fundamental studies on nesting materials to loose housed sows.

Piglet crushing remains a problem in crated sows and it is even more of a problem in loose housing systems. Most piglets are crushed when the sow moves from standing to lying or when she rolls over while already lying. This paper reviews lying down and rolling behaviours in sows and their association with piglet crushing in loose housing environments. Only little is known of the rolling behaviour, but the frequency of rolling may be affected by floor properties and fast rolling seems to be more riskful for the piglets than slower rolling. There is substantially more knowledge of the lying down behaviour. The lying down sequence is commonly divided into five stages. The speed of performance of these stages may be related to the risk of piglet crushing, e.g. flopping (the hindquarter drops quickly to the floor) is the most dangerous way the sow can lie down. In contrast, lying down by leaning against a surface rather than lying down in the open reduces the risk of piglet crushing, as does the performance of pre-lying behaviour and adequate sow responsiveness to piglets. The factors that may affect the speed and way of lying down (domestication, breed, muscular control, previous and current housing), pre-lying behaviour (piglet stimuli and space) and responsiveness to piglets (piglet stimuli, timing in relation to parturition, space and bedding) are discussed. The presented knowledge could be used in design and management of farrowing pens in order to reduce piglet crushing. However, several areas still require investigation. The aim of these investigations should be to encourage sows to use support when lying down, but also to make the few very riskful unsupported lying events as well as rolling safer for the piglets. This may be achieved though, e.g. increased knowledge of the motivational context of the various ways of lying down and rolling, development of attractive support features that sows will willingly use and determination of space requirements for the entire lying down and rolling complexes (i.e. pre-lying/-rolling, actual lying/rolling and responsiveness to overlain piglets).

The success of pens which provide pigs with a bedded resting area and an area for feeding, elimination and other activities depends on pigs' ability to show discrimination in elimination behaviour and thereby keep the resting area dry and clean. The eliminative behaviour of 16 gilts was studied during the last day of gestation when motivation for prepartum nest-building was high. During gestation the gilts had been housed in stalls (n=8) or in pens (n=8). Before parturition the animals were moved to farrowing pens with a peat and straw bedded resting area and a solid floor activity area. The gilts urinated and defecated significantly more in the activity area than in the resting area (P

The aim of the present study was to identify characteristics of sow behaviour and parturition related to early piglet mortality in loose-housed farrowing sows. Data from 152 farrowings that originated from three different herds with loose-housed sows during parturition were used. Graphical chain models were used to model the relationships between perinatal behaviour, periparturient individual conditions (time of day of parturition, rectal temperature 1–3 days postpartum) and causes of early piglet mortality. Modelling was based on the correlation between variables within herd and farrowing batch. The analysis showed that different causes of mortality were linked to different behavioural variables during the periparturient period and that they grouped into three independent categories. The first category was associated with stillbirth and death due to other causes. Stillbirth was positively related to the variation of the inter-birth interval and negatively related to the percentage of piglets that suckled during the first 8 h after birth of first piglet (BFP). Death due to other causes was negatively related to the suckling activity during the post-partal period (9–24 h after BFP). The second category was associated with piglet crushing, which was positively related to much lateral lying the last 4 h before BFP. Finally, the third category was associated with death due to lack of colostrums ingestion of colostrum, which was linked to the time of parturition and sow rectal temperature on days 1 and 2 after farrowing. Sows that gave birth during the morning compared to evening/night had more dead piglets due to lack of colostrums ingestion. Death due to lack of colostrums ingestion was also higher in sows with high rectal temperature on the day after BFP. The results further showed that litter size not only influenced mortality but also behavioural variables. High litter size was related to high nest building activity before BFP, low but more variable inter-birth intervals, and much lateral lying after BFP. The study points towards several areas of interest for further research that can help understand early piglet mortality. These include causes of variation in the progress of parturition, causes of individual differences in sow activity and responsiveness to piglets, and early management of farrowing. In addition, the study suggests possible indicators of problematic farrowings rendering liveborn piglets at risk. These include prepartum lateral lying in the sow, low suckling activity and rate of stillbirth.

In Lorenz's 'psychohydraulic model', behaviour is regulated by performance: the motivation to perform a behaviour builds up with time and can be reduced only by performance itself. However, a convincing example of Lorenzian regulation has been lacking. We studied dustbathing in featherless and feathered chicks, Gallus gallus domesticus, the latter trained to dustbathe on glass with sand underneath. In both cases the function, that is, plumage cleaning, was eliminated. In both featherless and feathered chicks dustbathing increased with time since the last performance as found in normal dustbathing, and there was a compensatory adjustment when the amount of previous dustbathing was artificially reduced. We suggest that the amount of dustbathing performed at any one time may be controlled by the cooperative action of a deprivation or timer mechanism and a counter mechanism. The timer mechanism responds to the time since the last performance, whereas the counter mechanism records the number of elements during that last dustbathing. Alternatively, there may be a single mechanism that continually records the deficit in the amount of dustbathing performed. Lorenz's model may be valid not only for dustbathing in fowl but also for other comfort behaviours. Our results suggest the existence of behavioural needs that can be satisfied only by performance. Copyright 1999 The Association for the Study of Animal Behaviour.

In semi-natural environments sows often select a protected nest site at farrowing. Investigations of nest site selection under indoor conditions are scarce but suggest that sows prefer to nest and farrow under a covered area. Since feed-back from a functional nest may improve maternal behaviour and thus piglet survival we investigated if access to a covered area and ad libitum access to straw would improve maternal behaviour of importance for piglet survival.We used forty-four primiparous sows housed in large individual pens from approximately 2 weeks prior to expected parturition. The sows were randomly distributed to four treatment groups of +/- ad libitum access to straw combined with +/- access to a covered area in the pen. The sows' position in the pen (left or right side) was observed from 24 h prior to birth of the first piglet until 24 h after using 10-min interval scan sampling and the temporal pattern of sow position in relation to position of the cover (left or right side of the pen) was studied. Furthermore, postural and nest-building behaviours were observed, as well as situations where the piglets were either at risk of being crushed or were crushed.The results showed no significant influence of cover on sow position. Odds-ratio for choosing the covered farrowing position was 1.4 (95% creditability interval (0.4-5.1)). The temporal pattern of sow position showed that the probability of observing the sows in the part of the pen classified as the farrowing position increased from close to 0.5 to 1 as parturition approached and stayed high during the 24 h observation period after birth of the first piglet, except for a small drop around 12 h after birth of the first piglet. However, the tendency to stay in the nest during farrowing was not increased neither by cover nor by ad libitum access to straw. Access to cover significantly increased prepartum nest-building behaviour (F1,29 = 4.27, P = 0.05) whereas there was no significant influence of access to straw. However, it should be taken into account that all sows had access to sawdust on the floor, which may also serve as a nesting material.The number of crushing and near crushing situations within 24 h after birth of first piglet (BFP) was significantly decreased in pens with access to straw (F1,25 = 4.50, P = 0.04), whereas there was no significant influence of cover on this variable. Neither the number of scan intervals with lateral lying nor the number of postural changes were significantly influenced by cover or straw.In conclusion, the sows did select a specific nest site within the farrowing pen, but neither the choice of nest site nor the temporal consistency of staying in the nest were significantly affected by cover or ad libitum access to straw. Access to a covered area increased the occurrence of nest-building behaviour whereas access to straw reduced the number of near crushing situations.

In Denmark we have about 1.2 million sows that produce about 21 million pigs per year for slaughter or export. While the number of pigs produced for slaughter per sow year when Denmark entered the EU in 1972 was 11–12 it is now more than doubled [1]. Behind this development lie highly focussed efforts within breeding, housing and management. The goals have been achieved with particular attention to two factors – the reduction of space used per pig and increase in production per man hour [1]. To illustrate this, a gestating sow in tethers – a much used housing system in the 1980'ies, but now phased out due to legislative demands – took only 52 min per year to care for, i.e. an average of only 9 seconds per day [2]. The incentive of using as little space and as little time as possible, have lead to a number of welfare problems for sows, either directly or indirectly. One example is the use of mechanical slurry systems and extensive use of slatted floors that are difficult to combine with straw or other kinds of bedding and/or rooting materials, and that pigs do not like to walk or lie on. Through EU and national legislation it has been attempted to alleviate several of the welfare problems for pigs (e.g. [3,4]). But even within the framework of recent welfare regulations, many of the old problems continue to exist and a range of new challenges emerges, because the restraints of using as little space and as little time as possible prevail. The very limited use of time per animal also in loose housing gestation systems is illustrated by reports of time use ranging between 0.14 – 0.38 min per "sow space" on weekdays and 0.06–0.15 min on weekend days [2,5], i.e. a few seconds per animal per day. A large amount of scientific knowledge of sow behaviour and welfare exists now, but the restraints of using very little time and very little space make it very challenging to put the knowledge to good use. Many suggestions are bound to take a few seconds and utilise some cm2, which relatively speaking will increase use of space and time greatly. The explanation of the continued emphasis on using very little space and very little time per animal is of course the industry's desire to keep its high competition ability, which will become clear in other presentations at this meeting. The first example, I will present, where the incentive of using as little time and as little space as possible is demonstrated very clearly is the predominant farrowing accommodation for sows in Denmark and other EU countries. In intensive pig production the use of the farrowing crate is almost exclusive, and real alternatives with loose housing are very difficult to get established in practise. Secondly, I will briefly present two of the loose housing systems for gestating sows that are now among the predominant ones in Danish pig production. Using the two systems as a starting point, I will then discuss some variants of the systems where sow welfare is very poor. These examples demonstrate how even in the better loose housing systems, there is a constant challenge of securing sow welfare due to the forces pulling in the direction of using as little space and time per animal as possible.