Development of eliminative behaviour in piglets

The development of eliminative behaviour in piglets was followed by watching piglets from the day of birth through to 5 weeks of age. Two different environments were used to establish the role of the sow. Six-day-old piglets consistently voided outside their lying area. The sow played no part in influencing where a piglet eliminated. Siblings also did not influence another piglet. When the lying area of the piglets was experimentally fouled, the lying behaviour of the piglets was disrupted. It was concluded that piglets dislike some property(s) of soiled bedding and so avoid soiling their lying area. The conclusion that piglets avoid eliminating in their lying area is contrasted with suggestions that piglets have a preferred elimination site.     

Effect of infrared temperature on thermoregulatory behaviour in suckling piglets

The objective of this study was to investigate the effect of infrared (IR) temperature on thermoregulatory behaviour in suckling piglets in the first 3 weeks after farrowing. A total of 10 piglets from each of the 16 litters were exposed to recommended IR temperature conditions at 1, 2 and 3 weeks of age, with a mild offset (4°C) in IR temperature during the first experiment and a more challenging offset (8°C) during the second experiment. Digital photos were taken when all piglets had settled in the creep area, and the lying posture and huddling behaviour were analysed. A lying posture score and a huddling score was calculated by multiplying the number of piglets in each category with a given value for each category, based on different lying postures and different degrees of huddling behaviour. With a 4°C change in IR temperature, the piglets tended to alter their lying posture, while an 8°C change had a significant effect on lying posture (P < 0.01). A change in IR temperature of 4°C had no effect on the degree of huddling. The huddling score decreased significantly with 8°C change in IR temperature (P < 0.05). Postural changes, rather than changes in degree of huddling were the preferred thermoregulatory strategy for suckling piglets.     

Effect of earth as an additional stimulus on the behaviour of confined piglets

Groups of 8 piglets were housed in flat-deck cages with slatted floors. Experimental cages were provided with a trough of sterilized earth, and the behaviour of focal individuals was recorded for comparison with controls. This replaced an earlier study, with which some of the results were combined. Records were analysed for frequencies and duration of certain activities, and first order sequence analysis was carried out. Experimental piglets rooted in earth for 4 to 8% of observations and also fed for longer. They spent less time sitting or lying. Aggression was reduced and there was a trend for experimental piglets to chew each other less. These differences suggested conditions were more favourable in experimental pens than control pens. However, there were few differences in first order behavioural transitions. Use of earth was not involved in sequences with activities such as feeding, drinking or lying as expected. It seems likely that in these circumstances earth did not act as a stimulus relevant to behavioural organization, but in some other way, with interest declining over time.     

Effect of accommodating sucking and nosing on the behaviour of artificially reared piglets

Neonatal piglets are often used in biomedical research applications that require artificial rearing. Social housing can be problematic because the piglets develop belly nosing, navel and ear sucking that can result in injury. Our objective was to determine the effectiveness of using feeding devices that provide various opportunities for sucking and nosing behaviour on reducing piglet-directed behaviour of group-housed laboratory piglets. Fifteen piglets were used in each of four trials. The piglets nursed their dam for approximately 72 h to obtain passive immunity before transfer to a laboratory facility where they were allotted, five per group, to one of three stainless steel isolator units. Each unit featured a different style of feeding system for the delivery of milk replacer: a plastic trough (T), a nipple (N) mounted on a smooth plexiglass wall, or a nipple mounted on a pliant bag of sterile water (artificial udder [AU]). Each system had five feeding spaces so that all piglets fed simultaneously. Milk was provided at 6-h intervals, and behaviour was recorded on alternate days for 12 days post-weaning. Although trough-fed piglets began to eat much sooner than those piglets fed from nipples, time spent nosing, chewing or sucking on pen-mates and belly nosing were markedly higher in T piglets than in either N or AU, overall (mean: P<0.05) and over time (quadratic: P<0.05). Over time, N piglets developed a stereotypic snout rubbing on the wall behind the nipples, while AU piglets massaged and often fell asleep in contact with the udder from day 2 of the trial. Resting patterns were also affected. N and AU piglets settled down to rest more quickly (P<0.01) and spent significantly more time resting in the hour following feeding than T piglets (P<0.05). A feeding device that accommodates both sucking and massage can significantly reduce piglet-directed behaviour and may facilitate social housing of artificially reared piglets.     

Effects of interrupted social contact on the social behaviour of calves and piglets

The use of traditional operant conditioning techniques to assess the behavioural needs of farm animals has been criticised because presenting short rewards repeatedly may interrupt bouts of behaviour and thereby devalue the reward. The two reported experiments (one including 12 calves and one including 12 piglets) aimed to investigate if interruption of social contact affects social behaviour. In both experiments, animals were housed in pairs (one test animal and one companion animal) in large pens with solid sides. The experiment included three periods: a pre-test period, a test period and a post-test period. Animals were separated for 24 h and then reunited for 24 h in each period. In the test period, the first 42 min of contact after reunification comprised 12 successive 3.5 min long periods separated by gaps, whereas in the pre- and post-test periods, the contact was continuous. Calves sniffed and licked each other more when social contact was interrupted (P<0.01), but no effects of interrupting social contact were found for social or locomotor play. In piglets, the test animals performed more flank pushing of the companion (P<0.01), and avoided the companion more (P<0.05), when social contact was interrupted, while no effects of interruption were found for parallel pressing, bites and head knocks, sniffing or locomotor play. The results suggest that if social contact is interrupted in an operant conditioning set up, some elements of aggressive behaviour may be stimulated in piglets.     

Effects of season on the behaviour of early-weaned piglets during and immediately following transport

In North America commercial transport of piglets occurs without supplemental heat, over long durations (24 h) and without feed and water. Scan sampling was used to compare behaviour across seasons (summer, fall, winter) and over representative durations (Control, 6, 12 or 24 h) to help assess welfare. Six groups of 48 Cotswold piglets (17 ± 1 d) were weaned and transported along highways in a van equipped for video and temperature recording. Following transport, piglets were studied in groups of four, in weanling pens with free choice feed and water. Resting during transport increased in frequency from 59.8% (1–12 h) to 91.5% (13–24 h). This pattern was more defined in winter and fall implicating cold as a causal factor. Fatigue, as observed in slaughter hogs, may also be a factor. Higher levels of post-transport resting in transported (81.4%) compared to control piglets (77.5%) supported this interpretation. Habituation to transport conditions may also have affected behaviour as piglet interactions commonly associated with dominance hierarchy establishment, were more frequent, and sitting, a behaviour associated with stress post-weaning decreased in the last 12 h of transport. As the duration of transport increased, post-transport drinking frequency increased, although significance was reached between control (2.4%) and 24 h of transport (3.7%) only. Long transport durations may thus delay hierarchy development, require additional coping strategies with respect to cold and increase the risk for dehydration. However, indications for habituation to some aspects of transport after 12 h are also apparent. During winter transport the frequency of piglet interactions (three piglets) was much lower than in summer (39 piglets) and fall (18 piglets) indicating that the cold temperatures may have affected establishment of a dominance hierarchy. Summer and winter transport differed from fall transport, with less resting (5.5% versus 9.2%) and standing (5.5% versus 9.25%), and more sitting (0.52% versus 0.28%) during the fall, a pattern consistent with increased stress during fall transport. Higher levels of resting for 3 days in winter and 2 days in summer could indicate more post-transport fatigue in these seasons. Transport, irrespective of season, resulted in behaviour indicative of coping strategies. It is important to determine which stressors have the greatest impact in each season and develop strategies to reduce the effects of transport on welfare.     

The behaviour and welfare of sows and piglets in farrowing crates or lactation pens

Temporary confinement during parturition and early postpartum may provide an intermediary step preceding loose housing that offers improvement in sow and piglet welfare. Three experiments were conducted to investigate the implications of replacing farrowing crates (FCs) with an alternative housing system from 3 days postpartum until weaning. In each experiment sows farrowed in FCs and were randomly allocated at day 3 of lactation to either a FC or a pen with increased floor space (lactation pen (LP)) until weaning. In experiment 1, piglet growth and sow and piglet skin injuries were recorded for 32 sows and 128 focal piglets in these litters. Behaviour around nursing and piglet behavioural time budgets were also recorded for 24 of these litters (96 focal piglets for time budgets). In experiment 2, measures of skin injury and behavioural time budgets were conducted on 28 sows and 112 focal piglets. The behavioural response of sows to piglet vocalisation (maternal responsiveness test (MRT)) was also assessed. In experiment 3, piglet mortality from day 3 of lactation until weaning was recorded in 672 litters over 12 months. While housing did not affect piglet weight gain in experiment 1, or piglet skin injuries in experiments 1 or 2, sows in both experiments sustained more injuries in LP than FC (experiment 1, 2.9 v. 1.4; experiment 2, 2.5 v. 0.8 lesions/sow; P<0.05). Sow–piglet interactions were more frequent in LP than FC at days 11 and 18 postpartum in both experiment 1 (day 11, 1.4% v. 1.2%; day 18, 1.7% v. 1.0% of observations; P=0.05) and 2 (day 11, 1.0% v. 0.3%; and at day 18 were 1.0% v. 0.6% of observations; P<0.01), and LP sows were more responsive in the MRT in experiment 2 (2 v. 0 median number of tests in which sows react, P<0.01). In experiment 1 piglets played more (0.7% v. 0.3% of observations, P=0.05) and manipulated others less (0.3% v. 0.7% of observations, P=0.04) in LP, but more piglets missed nursing bouts (0.2 v. 0.1 piglets/bout, P<0.01) compared with FC. There was no effect of housing on piglet mortality from day 3 of lactation until weaning in experiment 3 (0.63 and 0.64 deaths/litter for LP and FC, respectively, P>0.05). Thus, housing sows and litters in LP from day 3 of lactation minimises piglet mortality while improving maternal behaviour in sows and social behaviour in piglets.     

Short communication: insoluble fibres in supplemental pre-weaning diets affect behaviour of suckling piglets

We investigated the effect of offering supplementary dietary fibres to suckling piglets on their behaviour and performance before weaning. From 5 to 22 days of age, suckling piglets were offered a high-fibre diet (HF; 5% cellulose; n=5 litters), or a control low-fibre diet (n=5 litters). Piglets were housed with the sows in individual farrowing pens, and had access to maternal milk until weaning, at 23 days of age. Behaviours of six focal piglets per pen were scored at 6, 16 and 21 days of age. All piglets were individually weighed at 5, 15 and 20 days of age and feed intake was measured daily at the pen level. Piglets on the HF diet were more active than controls (P=0.05), and spent more time suckling or massaging the udder (P=0.01) and interacting with pen mates (P=0.008). Time spent manipulating pen mates, which may reflect re-directed foraging activity in the absence of substrate, accounted for most of the time spent interacting with pen mates (⩾73% of total time spent interacting). Dietary fibres had no effect on BW and feed intake. In conclusion, inclusion of cellulose in the supplemental diet of suckling piglets affects behaviour, with no deleterious effects on performance before weaning.     

Impact of general injection anaesthesia and analgesia on post-castration behaviour and teat order of piglets

Injection anaesthesia with a combination of ketamine and azaperone (K/A) is discussed as a painless alternative to commonly used non-anaesthetized castration. To protect anaesthetized piglets from being crushed, they have to be separated from the sow for 3 h following castration. The aim of this study was to test if this separation and the different treatments would affect short-term behaviour after castration (3 to 6 h after castration) as well as weight gain. Piglets were 5 to 7 days old. Treatment Group 1 received a combination of anaesthesia and analgesia (n = 29, ketamine: 25 mg/kg BW; azaperone: 2 mg/kg BW; meloxicam: 0.4 mg/kg BW), Group 2 received only analgesia (n = 24) and Group 3 received no medication (n = 29). Behaviour and suckling order were compared for a 3 h period the day before castration and after castration. A significantly higher number of teats used by anaesthetized piglets (P = 0.004) suggests a decrease in suckling order stability. There were significant treatment effects between all three groups in the time spent at the sow's teat, with an increase in Group 2 (+69%), decrease in Group 1 (−28%), whereas the control Group 3 (+2%) almost remained unchanged. The anaesthetized piglets showed an increase in the time spent active away from the sow after castration of almost 200% (Groups 2 and 3: ∼50%, P < 0.001). However, no significant treatment effect was seen for weight gain. The results suggest that analgesia has an effect on behaviour, perhaps due to less post-castration pain. This advantage is not apparent for animals receiving additional anaesthesia, probably because of impaired coordination. Although the behavioural changes did not affect weight gain significantly, a decrease in suckling order stability indicates a certain degree of stress due to fighting over teat positions as a consequence of separation. Thus, post-castration behaviour must be taken into account when evaluating alternative castration methods.     

The effects of modifying the farrowing environment on sow behaviour and survival and growth of piglets

The effect of modifying the farrowing environment on maternal behaviour of sows and survival and growth of piglets was studied. Sixteen sows farrowed in standard crates (CC) or in the same crates modified (MC) by addition of straw on the floor and a hessian cover over the farrowing stall. About 6 h after farrowing was completed, the environments were made similar by removing the hessian cover in the MC treatment and adding straw to the CC treatment. The MC sows performed more (P<0.05) nesting behaviour before farrowing, were more (P<0.05) responsive to the distress vocalizations of their piglets throughout lactation and tended to perform more (P<0.07) piglet-directed investigation/vocalization than CC sows. The incidence of piglet mortality was lower (P<0.01) in the MC than CC treatment. It was concluded that modifications to the farrowing environment can affect maternal behaviour, with apparent consequent advantages for piglet survival.     

Pain behaviour after castration of piglets; effect of pain relief with lidocaine and/or meloxicam

Behavioural responses and the effect of lidocaine and meloxicam on behaviour of piglets after castration were studied. A total of 144 piglets of 2 to 5 days of age were allocated to one of six treatments: castration (CAST), castration with lidocaine (LIDO), castration with meloxicam (MELO), castration with lidocaine and meloxicam (L + M), handling (SHAM) and no handling (NONE). Behaviour was observed for 5 days after the procedure, growth until weaning was recorded and characteristics of the castration wound noted. MELO piglets showed significantly (P < 0.05) more no pain-related behaviour than CAST and LIDO at the afternoon after castration, and were not significantly different from SHAM and NONE. LIDO piglets showed an increase (P < 0.001) in tail wagging, lasting for 3 days. This increase was not seen in L + M piglets. The occurrence of several behaviours changed with age, independent of treatment. A treatment effect on growth was not found. Wound healing was rapid in all treatments, but thickening of the heal was observed in several piglets, suggesting perturbation in the cicatrization process. Our study showed a pain-relieving effect of meloxicam after castration. Local anaesthesia resulted in piglets performing more tail wagging during the first few days after castration, which was prevented by administering meloxicam in combination with local anaesthesia.     

The automated analysis of clustering behaviour of piglets from thermal images in response to immune challenge by vaccination

An automated method of estimating the spatial distribution of piglets within a pen was used to assess huddling behaviour under normal conditions and during a febrile response to vaccination. The automated method was compared with a manual assessment of clustering activity. Huddling behaviour was partly related to environmental conditions and clock time such that more huddling occurred during the night and at lower ambient air temperatures. There were no positive relationships between maximum pig temperatures and environmental conditions, suggesting that the narrow range of air temperatures in this study was not a significant factor for pig temperature. Spatial distribution affected radiated pig temperature measurements by IR thermography. Higher temperatures were recorded in groups of animals displaying huddling behaviour. Huddling behaviour was affected by febrile responses to vaccination with increased huddling occurring 3 to 8 h post-vaccination. The automated method of assessing spatial distribution from an IR image successfully identified periods of huddling associated with a febrile response, and to changing environmental temperatures. Infrared imaging could be used to quantify temperature and behaviour from the same images.     

The effect of providing shredded paper or ropes to piglets in farrowing crates on their behaviour and health and the behaviour and health of their dams

The objective of this study was to evaluate the effect of providing paper or rope, alternative enriching substrates to straw, to piglets in farrowing crates on piglet and sow welfare.Sixty multiparous sows and their litters were housed in crates that were either barren (BARREN), enriched with shredded paper (PAPER) or natural fibre rope (ROPE). Enriching substrates were introduced when piglets were 10 days old. The proportion of sows with udder and teat lesions before parturition and at weaning was recorded. Piglet facial lesions were scored according to severity on days 11, 18 and 27. Sow and piglet behaviour was recorded using scan sampling on days 14, 18, 22 and 26. Furthermore, the behaviour of one male and one female focal piglet per litter was recorded continuously for 10 min twice per day on days 14, 18, 22 and 26. On day 27 post-partum, focal piglets were observed for 5 min in a novel arena and for a further 5 min after a novel object was introduced.On day 27, there was a tendency for more BARREN sows to have teat lesions (P = 0.07). PAPER litters tended to have a smaller proportion of piglets with facial lesions (P = 0.06). ROPE piglets were active in the enriched area of the crate in more observations than BARREN and PAPER piglets (P < 0.01). PAPER piglets spent less time inactive (P < 0.01), less time exploring the pen-fittings (P < 0.01) and more time interacting with the enriching substrate (P < 0.001) than piglets in the other two treatments. In the first 5 min in the novel arena BARREN piglets froze more than PAPER and ROPE piglets (P = 0.05).In conclusion, shredded paper improved piglet welfare and was easily incorporated into the farrowing crates.     

Some relations between stereotyped suckling in piglets and exploratory behaviour and discrimination reversal learning in adult swine

The relationship of stereotyped suckling positions in artificially fed and sow-fed infant swine to the behaviour of adult animals was investigated. Suckling behaviour was observed, and four animals from each feeding condition exhibiting low suckling stereotypy and four from each feeding condition exhibiting high suckling stereotypy were selected. Animals were tested at five months of age in exploratory situations and on a two-window position discrimination and reversals.Low suckling stereotypy and artificially reared animals made fewer errors on the first discrimination reversals than high stereotypy and sow-fed animals. They were also less emotional on the first reversals. Over nine reversals artificially reared animals made significantly fewer errors than sow-fed subjects and low stereotype sow-fed animals made fewer errors than high stereotypy sow-reared animals. Low stereotypy subjects explored more objects and over a longer period of time than high stereotypy subjects. It was concluded that stereotyped suckling in piglets is related to behaviour exhibited by the adult in problem-solving situations.     

Effect of radiant heat at the birth site in farrowing crates on hypothermia and behaviour in neonatal piglets

It has been documented that floor heating of the farrowing area in loose housed sows improves survival of piglets significantly. However, today, the majority of farrowing pens are designed with crating of sows and slatted floor at the birth site. The aim of this study was to investigate whether providing radiant heat at the birth site to new-born piglets in pens with crated sows reduced hypothermia, time to first milk intake and growth of the piglets during the 1^st week. Second parity Danish Landrace×Yorkshire sows (n=36) were randomly divided into two groups: Control (CG) and heat (HG). In the area behind the sow (zone 1), two radiant heat panels were mounted above the slatted floor in the HG. The farrowings were attended, and the heaters were turned on at birth of first piglet and turned off 12 h after. Birth time, time to leave zone 1, time to first contact with udder and time to first suckling were registered by direct observation. The piglet’s rectal temperature (RT) was measured 15, 30, 60, 120, 180, 240 min after birth and 12, 14 and 24 h after birth of first piglet. Piglets were weighed at birth, 24 and 48 h and 7 days after birth. Data were analysed in a mixed model in SAS. The drop in RT was lower in HG compared with CG (P=0.002), and the RT in HG remained higher than in CG from 30 to 240 min after birth (P<0.05), whereas no difference was found at 12 h after birth of first piglet (P=0.92). Piglets in HG stayed longer in zone 1 than those in CG (P=0.01), whereas time to reach udder (P=0.35) and to first suckling (P=0.56) did not differ. No difference in weight gain was found between piglets in HG and CG at 24 h (P=0.23), 48 h (P=0.28) and 7 days after birth (P=0.44). Birth weight had a positive effect on RT (P<0.001) and reduced time to leave zone 1 (P<0.01), reach udder (P<0.001) and time to first suckling (P<0.001). The results showed that radiant heating behind the sows reduced hypothermia in new-born piglets and indicate that providing heat during the first half hour after birth is important.     

The lying behaviour of sows and piglets during early lactation in relation to the position of the creep heater

In modern farrowing pens, side creep areas are sometimes so narrow that the heated portion overlaps with the sow's lying area, possibly increasing the danger of piglets being crushed. In two experiments the behaviour of sows and litters was studied during the first week of lactation in relation to the position of the creep heater. With a side creep area, the amount of time the piglets lay inactive or semi-active against the sow declined from between 30 and 40% on the first day of life to between 5 and 20% on days 3 to 7. With the heater at the front of the pen, the young showed an increased tendency to lie well away from the sow on days 3 to 7 (P < 0.05), but there was no effect on days 1 and 2. In both studies the sows tended to lie with the udder facing a side creep heater, but not a heater at the front, particularly on day 2 post partum (P < 0.01).     

Effects of early contact between non-littermate piglets and of the complexity of farrowing conditions on social behaviour and weight gain

In this study we tested if contact possibilities between non-littermate piglets and complexity of farrowing conditions affect the pre- and post-weaning behaviour, weight gain and skin lesions of piglets. Suckling sows were either kept in a group housing system (GH), in a single pen loose housing system (LH), or in conventional farrowing crates (FC). In the single pen systems a piglet door to the adjacent pen was opened on d 10 after farrowing in half of the pens so that piglets were able to enter the neighbouring pen (LH+ and FC+). For control, in the other half of single pens no piglet doors were opened (LH− and FC−). In the group housing system piglets also were allowed to freely move within the whole system on d 10 after farrowing. After weaning on d 28 piglets were kept in littered rearing pens in an open stable holding 20 piglets each. Piglets from contact pens were mixed with those they previously had contact to whereas piglets from control pens were mixed with unfamiliar litters. Data were obtained from 230 litters (113 sows with 1935 farrowed piglets). All piglets were scored for skin lesions immediately before and 4 days after opening the piglet doors, as well as immediately before and 4 days after moving into rearing pens. Behaviour (biting, fighting, drinking and laying) of piglets was recorded in the rearing pens in a 48-h period after weaning for 2 × 4 h. Treatments did not affect the level of skin lesions in the rearing period (H = 8.72, df 4, ns) nor daily weight gain until weaning (F_4,216 = 1.21, ns). In the 48 h after moving to rearing pens, less intensive agonistic behaviour (fighting and biting) was observed in contact piglets (H = 53.36, df 4, P < 0.0001). Four days after weaning control piglets showed significantly higher numbers and more severe skin lesions than contact piglets and, in addition, lesion scores of piglets from the larger single farrowing pens with straw bedding were significantly lower compared to the single farrowing crate (H = 33.86, df 4, P < 0.0001). The latency for lying in the new rearing pen was decreasing (F_4,93 = 25.76, P < 0.001) and the latency for drinking (F_4,81 = 3.43, P = 0.01) was increasing with decreasing complexity and space allotment of the housing system but were not related to whether the piglets have had contact to other litters before weaning. Five weeks after weaning weight gain (F_4,204 = 7.01, P < 0.0001) and BW (F_4,207 = 5.34, P < 0.001) were higher in treatments offering contact. Our results show that familiarising piglets from different litters 10 day post partum by establishing contact possibilities through a piglet door reduces social stress at weaning and increases weight gain after weaning. Farrowing pens with straw bedding and enlarged space as offered in the farrowing pens and the group housing system can further decrease the level of harmful agonistic interactions after mixing unacquainted litters at weaning and can improve the adaptation of piglets towards the new environment of the rearing pen.     

Confinement of sows for different periods during lactation: effects on behaviour and lesions of sows and performance of piglets

Alternatives to farrowing crates with continuous confinement of the sow are urgently needed because the animal welfare is negatively impacted. Given the increase of herd sizes, practical experience with loose-housing is needed to force the implementation of these systems in the field. Next to aspects of labour efficiency, detrimental piglet mortality rates that may occur during the first days postpartum (pp) is a major criticism. Therefore, loose-housing after a crating period limited to the first days pp might be a feasible alternative to improve welfare under intensive production conditions. The aim was to investigate the effect of crating sows during lactation for different periods on their behaviour and integument alterations and on piglets’ performance. Gilts from a commercial herd were observed from 5 to 26 days pp and housed in farrowing crates (1.85×2.50 m) that could be altered between confinement crates and loose-housing pens. Animals were divided into three groups, that were either crated continuously from birth until weaning (Group A, n=55), until 14 days pp (Group B; n=54) or 7 days pp (Group C, n=59). The behaviour of six randomly selected gilts per group was video recorded from 5 to 26 days pp and analysed by time sampling technique. Lesions on the legs, shoulder and lumbar vertebra were scored on days 7, 14 and 25 pp. Piglets were weighed weekly, causes of losses recorded and weight losses of gilts measured. Not different between groups (P>0.05), animals spent 72 to 76% lying laterally, 14 to 17% lying in abdominal or semi-abdominal position, 9 to 10% standing and 1 to 3% sitting. B-sows were lying longer in week 3 and 4 of lactation compared to A- and C-sows (P<0.05). The incidence of slight shoulder lesions rose from <1% on day 7 to 4% on day 14 and 14% on day 25 pp. On day 25 pp, 5% of all studied gilts showed moderate shoulder lesions. Piglet mortality rates were 11.4%, 12.9% and 13.3% for groups A, B and C, respectively (P>0.05), whereas almost 90% of the losses occurred in the first week pp. In conclusion, loose-housing of lactating gilts after a reduced postnatal crating period of 7 days affected neither the activity level of the gilts and lesions on the integument nor pre-weaning mortality. Therefore, it is recommended to allow sows to move around to some extent during the later lactation period.