Effects of feed-back from the nest on maternal responsiveness and postural changes in primiparous sows during the first 24 h after farrowing onset

Analysis of image-based sow activity patterns reveals several associations with piglet survival and early growth

An activity pattern describes variations in activities over time. The objectives of this study are to automatically predict sow activity from computer vision over 11 days peripartum and estimate how sow behavior influences piglet's performance during early lactation. The analysis of video images used the convolutional neural network (CNN) YOLO for sow detection and posture classification of 21 Large White and 22 Meishan primiparous sows housed in individual farrowing pens. A longitudinal analysis and a clustering method were combined to identify groups of sows with a similar activity pattern. Traits under study are as follows: (i) the distribution of time spent daily in different postures and (ii) different activities while standing. Six postures were included along with three classes of standing activities, i.e., eating, drinking, and other, which can be in motion or not and root-pawing or not. They correspond to a postural budget and a standing-activity budget. Groups of sows with similar changes in their budget over the period (D-3 to D-1; D0 and D1-D7) were identified with the k-means clustering method. Next, behavioral traits (time spent daily in each posture, frequency of postural changes) were used as explanatory variables in the Cox proportional hazards model for survival and in the linear model for growth. Piglet survival was influenced by sow behavior on D-1 and during the period D1-D7. Piglets born from sows that were standing and doing an activity other than drinking and eating on D-1 had a 26% lower risk of dying than other piglets. Those born from sows that changed posture more frequently on D1-D7 had a 44% lower risk of dying. The number of postural changes, which illustrate sow restlessness, influenced piglet growth in the three periods. The average daily gain of piglets born from sows that were more restless on D1-D7 and that changed posture more frequently to hide their udder on D0 decreased by 22 and 45 g/d, respectively. Conversely, those born from sows that changed posture more frequently to hide their udder during the period of D1-D7 grew faster (+71 g/d) than the other piglets. Sow restlessness at different time periods influenced piglet performance.

Light from heat lamps affects sow behaviour and piglet salivary melatonin levels

The light environment regulates animal physiology and behaviour. As widely used supplementary heat sources in creep areas, the effect of visible light radiated by infrared heat lamps on pigs is worth investigating. To investigate the effects of light from heat lamps on the behaviour of sows and piglets and possible endocrine mechanisms, 24 primiparous sows were randomly assigned to three supplementary heat source treatments: (1) 250 W non-luminous ceramic heat lamps (CE, n = 8), (2) 175 W red heat lamps (RL, n = 8), and (3) 175 W transparent heat lamps (TL, n = 8). All heat lamps were turned off on Day 15 postpartum. Piglets were weighed on days 3 and 21 postpartum. The number and duration of suckling within 24 h were analysed via video recordings on days 4, 8, and 16 postpartum. Sow posture changes during the day and night were detected using the YOLOv4 target detection network model. One marked piglet from six litters randomly selected from each treatment was used for saliva collection. Saliva samples were collected at 0800, 1400, 2000, and 0200 (+1 d) on days 10 and 20 postpartum. The results showed that the mean postural change frequency of TL sows was higher than that of CE sows (P < 0.05), while that of RL sows was not different from that of CE and TL sows. However, the duration of the sows being in each posture was not affected by the treatment. The total suckling duration of TL piglets was significantly longer than that of CE piglets, but there was no significant difference in the performance of the piglets. The melatonin concentrations in the saliva of piglets at 10 and 20 days of age in the three treatments showed different diurnal rhythms, but there was no significant difference in the levels of melatonin in TL piglets between night and day. Differences in salivary cortisol levels only appeared between the CE and RL groups at 20 days of age. Based on the present results, the illuminance and spectrum of the transparent heat lamps were sufficient to stimulate sow activity and inhibit melatonin levels in piglets. However, the stimulating effect on suckling was not sufficient to significantly improve the performance of piglets. Exposure to red heat lamps, rather than ceramic lamps, resulted in the strongest circadian rhythm of salivary melatonin in piglets.

Effect of Enrichment Items on the Physiology and Behavior of Sows in the Third Trimester of Pregnancy

Modern intensive pig breeding harms animal welfare, which is especially noticeable for pregnant sows kept in confinement stalls. This study aimed to evaluate the effects of enrichment items on the movement and physiological parameters of sows in the third trimester of pregnancy. A total of 30 large white pregnant sows were randomly divided into three equal treatment groups (n = 10): control, pine wood, and scented wood groups. Interestingly, compared with the control group, the sows in the pine wood or scented wood groups showed less ventral lying and more lateral lying behavior (p < 0.01), coupled with significant reduction in the frequency of scratching and sham-chewing (p < 0.01), but with no significant difference in the degree of preference for these enrichment items (p > 0.05). Additionally, the sows in the pine wood or scented wood groups also decreased significantly in the concentration of immunoglobulin A (IgA) (p < 0.01) and the concentration of tumor necrosis factor-α (TNF-α) (p < 0.05) throughout the late pregnancy period. Overall, adding enrichment items to confinement stalls can alleviate the chronic stress and the stereotypic behavior of sows, suggesting their potential to reduce welfare compromise.

Equipping Farrowing Pens with Straw Improves Maternal Behavior and Physiology of Min-Pig Hybrid Sows

Simple Summary

This study used different sow breeds combined with an enriched environment to relieve stress and to improve the welfare level of sows. Both groups of sows were in loose-housed pens. Sows living in a barren environment (BE) without straw were compared with sows in farrowing crates that received 3.5 kg of straw daily (enriched environment (EE)). Compared with BE sows, EE sows showed more nest-building behavior prior to farrowing, more nursing behavior, and less ventral recumbency behavior during the first three days postpartum. Furthermore, compared with BE sows, EE sows tended to have higher concentrations of serum oxytocin and prolactin, while the concentration of cortisol was lower, suggesting an increase in maternal behavior and a reduction of stress in this group. In addition, the concentration of oxytocin and both the frequency and duration of prepartum nest-building behavior were higher in Duroc × Min and Landrace × Min sows compared with Landrace × Yorkshire sows. However, the concentration of prolactin was significantly lower in both Duroc × Min and Landrace × Min sows than in Landrace × Yorkshire sows, indicating that hybrid sows of Min-pig inherited good maternal characteristics. Based on these results, straw enrichment improved Min-pig hybrid sow welfare during farrowing and lactation.

Abstract

This study investigated the effects of two factors, enriched environment (EE) and different crossbreeds, on the maternal behavior and physiology of Min-pig hybrid sows. The analysis was performed on a total of 72 multiparous sows, including Duroc × Min pig (DM), Landrace × Min pig (LM), and Landrace × Yorkshire (LY) sows, using a total of 24 sows per cross. The sows were housed in two different farrowing pens, one with straw (EE) and one without straw (barren environment (BE)). The results showed that nest-building behavior, including the frequency, total duration, and bout duration, was significantly higher in EE sows than in BE sows (p < 0.01). The frequency and duration of prepartum nest-building behavior were higher in DM and LM sows than in LY sows (p < 0.0001). During the first three days postpartum, EE sows spent a shorter time in ventral recumbency compared with BE sows (p < 0.05). The oxytocin (p < 0.05) and prolactin (p < 0.01) concentrations of EE sows were significantly higher than in BE sows; however, the concentration of cortisol followed the opposite (p < 0.01). The concentration of oxytocin was significantly higher in DM and LM sows than in LY sows (p < 0.01). In conclusion, both EE increased the expression of hormones related to parental behaviors and prenatal nesting and nursing behavior of sows. Furthermore, an EE can also reduce stress in sows. Min-pig hybrids may inherit highly advantageous characteristics of maternal behavior of Min-pig sows.

Effect of different parities on reproductive performance, birth intervals, and tail behavior in sows

A goal for swine farming is the improvement in the number of live-born and weaned piglets per sow. Hence, the effect of parities should consider the correlation between the component traits of reproductive performance, weaning, and duration. Sows were housed in farrowing pens (W 2.2 × D 1.8 × H 1.2 m) on a partially slatted plastic floor. Twenty sows used in this study were between the first and sixth parity in gilts (P1), parity 2–5 (P3), and parity 6–9 (P6). Data collection by parity was classified into three categories: (1) reproduction performance (gestation length, total number of piglets born, number of piglets live born, number of piglets stillborn, total piglet birth weight; (2) weaning traits (weaning period, number of piglets weaning, total piglets weaning weight); (3) duration traits (farrowing duration, placenta expulsion duration, time from last piglet to first placenta, average birth interval, and tail wagging behavior). Gestation length was higher in P6 than P1 and P3 of different parity sows. The maximum value in P1 and P3 was 117 days, but the median value in P6 was 117 days (p < 0.05). The total number of piglets born (p = 0.113), number of piglets live born (p = 0.118), number of still piglets born (p = 0.151), and total piglet birth weight (p = 0.117) were not affected by parity. The number of live piglets was higher than the other parities by an average of 15.6 ± 2.1 in P1. The duration of farrowing was the lowest at 22.2 min in P6, but the maximum value was 42.2 min more than other parities (p = 0.355). Weaning traits of sows also did not differ significantly (p > 0.05), but the weaning period from P1 was lower than that of the other parities (p = 0.170). The number of piglets weaned was 10 heads on average in P1, P3, and P6 (p < 0.05). However, the mean values of the total piglet weaning weight (p = 0.377) of P6 (62.0 10.4 kg) were higher than those of P1 (54.9 10.2 kg) and P3 (58.4 13.6 kg). The placenta expulsion duration was higher in P6 than that in P1 and P3 (p = 0.447). The time from the last piglet to first placenta was be lower in P3 than that of the other parities (p = 0.206). The average birth interval was higher in P3 than that of the other parities (p = 0.156). Tail wagging (count) behavior was higher in P6 than in the other parities (p = 0.065). The data showed that the reproduction performance, total piglets born, and weight were higher in the gilts group, and higher in the weaning trait than that in the P6 group. This study examined the relationship between reproductive performance, birth interval and tail motion according to sow parity. Regarding duration, farrowing duration was lower in P6 than that in the other parities, but placenta expulsion and tail wagging were higher in P6 than in the other parities. Therefore, it is possible that the results from these sows could be used as basic data for effective farm management.

Maternal Behavior, Posture Change, and Production Performance of Lactating Sows Housed in an Enriched Environment

This study aimed to evaluate whether adding straw to a loose-farrowing house promotes maternal functions and production. Forty-eight sows (Landrace× Large White) were housed in either a farrowing pen without straw (C, n = 24) or with straw (S, n = 24). Behaviors were observed using video recordings and were statistically analyzed. Lateral recumbency was higher and standing was lower in S compared with C (p = .034 and p = .020, respectively), and lateral recumbency to other postures, ventral to lateral recumbency and standing to lying were markedly lower in S than C (p = .014, p = .025 and p = .023, respectively) on Day 1 postpartum. However, except piglet losses during the first three days postpartum (p = .032), piglet weight on Day 21 (p = .037), and piglet weaning weight (p = .020), other production performances were not significantly different between the two groups during the whole experimental period (p ˃.05). The results suggest the enrichment of a farrowing pen with straw has important beneficial effects on sow and piglet welfare and improves piglet survival rates.

Impact of sow prepartum behavior on maternal behavior, piglet body weight gain, and mortality in farrowing pens and crates

In the 24-h period prior to parturition, sows are active and motivated to perform nest-building behavior. The aim of this study was to investigate whether prepartum activity (nesting and postural changes) could predict maternal behavior 24 h postpartum, piglet mortality, and BW gain 24 h postpartum in farrowing pens and crates. Sows were randomly moved either to a farrowing pen ( = 20) or a farrowing crate ( = 18). Prepartum nest-building behavior (PRE-nesting) and prepartum postural changes (prepartum postural changes) were analyzed 24 h before the birth of the first piglet (BFP) and were divided into twelve 2-h intervals. Latency of the first suckling from the litter was observed after the birth of the last piglet. Udder accesses and piglet suckling were noted at 5-min intervals, using 1/0 sampling, during the first 24 h after BFP were counted. Piglet trapping, crushing, and total live-born mortality were measured during the first 72 h after BFP. Piglet BW gain was estimated 24 h after BFP. Increased PRE-nesting observed 2 h before BFP were associated with fewer suckling intervals in crates but not in pens ( < 0.01) as well as an increase in postural changes during parturition ( < 0.001) in both housings. A link between housing and PRE-postural changes was evident. An increase in the number of PRE-postural changes 2 h prior to BFP was associated with lower incidences of udder access in crates but not in pens ( < 0.05). A higher probability of piglet trapping was associated with increased PRE-nesting in the 2 to 4 h before BFP. No significant relationship between either PRE-nesting and postural changes and piglet BW gain and mortality was detected. Our results suggest that increased prepartum activity 2 h before parturition is associated with less suckling and less udder access in farrowing crates but not in farrowing pens. This suggests that the same sow behavior can have different consequences in pens vs. in crates. Future research should focus on nest-building activity, its relationship to endocrine indicators (e.g., oxytocin, cortisol) before parturition, and its potential long-lasting effects on subsequent maternal behaviors and piglet production.

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 influence of the thermal environment and other early life events on growth rate of piglets during lactation

The effects of early life events on average daily weight gain from birth to day 21 (ADG) of suckling pigs kept at different room temperatures (15°C, 20°C and 25°C) from birth to weaning were investigated. Data were collected from litters born by 61 sows in a loose housing system. The ADG for piglets with low birth weight (estimated for birth weights below the 10% percentile) was estimated to be 20 to 30 g higher per day at room temperature 20°C to 25°C compared with 15°C. In contrast, the ADG during the lactation period decreased for larger piglets (estimated for birth weights above the 10% percentile) by 28 g/day at room temperature 25°C compared with 15°C. Thus, high ambient temperatures (20°C to 25°C) are favourable for the growth in smaller piglets during lactation. Neither latency to first suckle nor birth-induced hypoxia, measured as concentration of umbilical cord lactate, affected the growth rate of the piglets. Lowest rectal temperature during the first 24 h after birth had a long-term negative effect on ADG (P<0.05), so that piglets with a lowest rectal temperature of 32.8°C (10% percentile) had an ADG which was on average 19 g lower per day than piglets with a rectal temperature of 37.3°C (90% percentile). Our results showed that hypothermia at birth, low birth weight and high number of suckling piglets lead to reduced ADG during the suckling period. The results suggest that keeping the room temperature at 20°C during lactation to some extent could compensate for the otherwise negative effects of low birth weight on ADG in piglets without decreasing the ADG of high birth weight piglets. However, to avoid hypothermia in the smallest piglets it may be beneficial to increase the room temperature above 20°C during the farrowing period of loose housed sows.

Genetic trends in maternal and neonatal behaviors and their association with perinatal survival in French Large White swine

Genetic trends in maternal abilities were studied in French Large White sows. Two lines representing old-type and modern-type pigs were obtained by inseminating modern sows with semen from boars born in 1977 or 1998. Successive generations were produced by inter-se mating. The maternal performance of sows from the second generation was compared in farrowing crates. Video analysis was performed for the 1st h after the onset of 43 and 36 farrowing events, and for the 6 first hours for 23 and 21 events, in old-type and modern-type sows, respectively. Genetic trends were estimated as twice the difference in estimates between the 2 lines. The contribution of behavior to the probability of stillbirth and piglet death in the first 2 days was estimated as the percentage of deviance reduction (DR) due to the addition of behavior traits as factors in the mortality model. Sow activity decreased strongly from the 1st to the 2nd h in both lines (P < 0.001). In the first 6 h, old-type sows sat (1st parity), stood (2nd parity) and rooted (both parities) for longer than modern-type sows, which were less active, especially in 2nd parity. In modern-type sows, stillbirth was associated positively with lying laterally in the first 6 h (4.6% DR) and negatively in the 1st h (9.1% DR). First-parity old-type sows were more attentive to piglets (P = 0.003) than modern-type sows which responded more to nose contacts at 2nd parity (P = 0.01). Maternal reactivity of modern-type sows was associated with a higher risk of piglet death (4.6% DR). Respiratory distress at birth tended to be higher in modern-type piglets than in old-type piglets (P < 0.10) and was associated with a higher risk of piglet death in both lines (2.7–3.1% DR). Mobility at birth was lower in modern-type than old-type piglets (P < 0.0001). Genetic trends show that sow and piglet behaviors at farrowing have changed. Our results indicate reduced welfare in parturient modern-type sows and their newborn piglets.

Avoiding hypothermia in neonatal pigs: effect of duration of floor heating at different room temperatures

The effect of different farrowing room temperatures (15, 20, or 25°C), combined with floor heating (FH) at the birth site, on the postnatal rectal temperature of pigs, use of creep area, and latency to first colostrum uptake was investigated with 61 litters born by loose-housed sows. Pig rectal temperature was measured at birth, as well as at 0.25, 0.5, 1, 1.5, 2, 3, 4, 12, 24, and 48 h after birth. The drop in rectal temperature from birth to 0.5 h postpartum was less (P<0.05) at room temperature of 25°C compared with 20 and 15°C. Minimum rectal temperature was less (P<0.001) at 15°C than either 20 or 25°C, and the time it took for rectal temperature to increase above 37°C was longer (P<0.05) when room temperature was 15°C than 20 and 25°C. Rectal temperatures at 24 (P<0.001) and 48 h (P<0.05) postpartum were also lower at room temperature of 15°C than 20 and 25°C. Duration of FH (12 or 48 h) did not influence (P>0.28) the rectal temperature at 24 or 48 h after birth. More pigs used the creep area 12 to 60 h after birth of the first pig at a room temperature of 15°C with 12 h FH compared with all other treatments. During the latter part of this period, more pigs stayed in the creep area also at 20°C with 12 h FH. After 60 h, more pigs (P<0.01) used the creep area at low compared with high room temperatures (15°C>20°C>25°C). Odds ratio of pigs dying before they had suckled was 6.8 times greater (P=0.03) at 15 than 25°C (95% CI of 1.3 to 35.5), whereas the odds ratio of dying during the first 7 d was 1.6 greater (P=0.05) for 48 vs. 12 h of FH (95% CI of 1.0 to 2.57), mainly due to more pigs being crushed. In conclusion, FH for 48 h was no more favorable than 12 h for pigs because the risk of hypothermia was equal in the 2 treatments, and the risk of dying increased with the longer FH duration. Increasing the room temperature to 25°C reduced hypothermia and the risk of pigs dying before colostrum intake.

Genetic aspects regarding piglet losses and the maternal behaviour of sows. Part 2. Genetic relationship between maternal behaviour in sows and piglet mortality

The aim of the study was to analyse the genetic background of different traits to characterise the maternal behaviour of sows and to evaluate the relationship to different causes of piglet losses - increasing piglet survival due to higher maternal abilities of the sow. A total of 1538 purebred litters from 943 German Landrace sows in the year 2004 were available for data analysis. Around 13 971 individually earmarked piglets were included in the analyses. Maternal abilities were characterised through the sow's reaction to the separation from her litter during the first 24 h after farrowing, and on day 21 of lactation, the reaction towards the playback of a piglet's distress call and the reaction towards an unknown noise (music). In 1220 of these litters, the sows were also scored for aggressiveness in the group when regrouped before entering the farrowing crates. To describe fertility, the number of piglets born alive, stillborn piglets, number of piglets born in total and the individual birth weight were utilised. Different causes of piglet losses were evaluated as binary traits of the dam with survival rate, different definitions for crushing by the sow, being underweight and runts. The heritability for being aggressive in the group was h2 = 0.32 and for the behaviour traits during lactation, the heritabilities ranged from h2 = 0.06 to 0.14. The genetic correlations showed that more-reactive sows had fewer piglet losses.

Neonatal piglet traits of importance for survival in crates and indoor pens

The primary aim of the present study was to investigate whether the same piglet traits contributed to the same causes of neonatal piglet mortality in crates (CT) and pens (PN). Gilts originating from 2 distinct genetic groups that differed in breeding value for piglet survival rate at d 5 (SR5) were used. These were distributed to farrow in either PN or CT as follows: high-SR5 and CT (n = 30); low-SR5 and CT (n = 27); high-SR5 and PN (n = 22); and low-SR5 and PN (n = 24). Data on individual piglets were collected at birth, including interbirth interval; birth order; birth weight; rectal temperature at birth, 2 h after birth, and 24 h after birth; cordal plasma lactate; and latency to first suckle. Based on autopsy, causes of mortality were divided into stillborn, bitten to death, starvation, crushed, disease, and other causes. Potential risk factors of dying were estimated using a GLM with a logit link function. No significant effect (NS) of housing was observed on the odds of a piglet being stillborn (F(1,73) = 0.1, NS), being crushed (F(1,53) = 1.4, NS), or dying of starvation (F(1,53) = 0.3, NS). No significant differences were observed between the 2 genetic groups for any category of mortality. Piglet traits for pre- and postnatal survival were the same for CT and PN. The odds of being stillborn were increased in piglets born late in the birth order (F(1,1061) = 33.5, P < 0.0001), after a long interbirth interval (F(1,1061) = 19.2, P < 0.0001), and with a lighter birth weight (F(1,1061) = 9.2, P = 0.003). The lighter the birth weight of the piglets, the greater were the odds of being crushed (F(1,1050) = 18, P < 0.0001) and dying of starvation (F(1,1050) = 19, P < 0.0001). The lower the rectal temperature 2 h after birth, the greater were the odds of being crushed (F(1,1050) = 4.6, P = 0.03), starving (F(1,1050) = 16.6, P < 0.0001), or dying of diseases (F(1,1050) = 4.9, P = 0.03). Increased cordal plasma lactate increased the odds of dying from starvation (F(1,1050) = 18, P < 0.0001). In both CT and PN, the birth weight, body temperature 2 h after birth, and birth process were important traits related to crushing, starvation, and disease. Neither housing nor breeding value influenced mortality or traits of importance for the inborn viability of piglets. The results emphasize that the microclimate in the PN for newborn piglets and its heat-preserving properties are more important for survival than whether the sow is crated or penned.

The effect of nesting material on the nest-building and maternal behavior of domestic sows and piglet production

Nest building is an important part of maternal behavior in domestic pigs. The aim of the study was to assess the effect of nesting material sawdust vs. straw on sow behavior 24 h before and after birth of the first piglet (BFP) and piglet production. Sows, housed in farrowing crates, were randomly divided into 2 treatments: sawdust (n = 12) and straw (n = 13). Sawdust and straw were provided during the pre- and parturient period; after parturition, straw was given to both experimental groups. The prepartum nesting period (the time interval between the first and last nest-building records, including all other activity and resting before BFP), the nesting records (number of nesting records), nesting duration (duration of all nesting records), the start and termination of nesting, and the frequency of prepartum postural changes were collected 24 h before BFP. After BFP, number of nesting records and time to first sucking of the litter were collected. Frequency of postural changes and duration of udder access were collected 24 h after BFP during 3 time periods (during parturition, from the end of parturition to 12 h after BFP, and 12 to 24 h after BFP) and the frequency of nursing during 2 time periods (from the end of parturition to 12 h after BFP, and 12 to 24 h after BFP). Piglet BW gain and mortality were estimated 24 h after BFP. Data were analyzed using PROC MIXED and the probability of the piglet mortality using PROC GENMOD in SAS. Nesting material did not affect (P > 0.10) most of sow prepartum nesting behavior and had no effect (P > 0.10) on the prepartum frequency of postural changes. Sows from the sawdust treatment had a longer nesting period (P < 0.05), and nest building tended to start sooner (P < 0.10) than in the straw treatment. Nesting material had only a small effect on later maternal behavior. Sows from the straw treatment tended to have more nesting records after BFP (P < 0.10). The frequency of postural changes was affected by the interaction (P < 0.01) between treatments and time period: sow from the straw treatment had more postural changes during parturition compared with other time periods and sawdust treatment. No effect (P > 0.10) of the nesting material on piglet BW gain and mortality was found. The results suggest that sawdust compared with straw as nesting material provided to sows before and through parturition does not negatively affect maternal behavior during the 24 h before and after parturition or piglet production. Therefore, sawdust can be recommended as a suitable nesting material for farrowing sows when straw is not available.

The effects of floor heating on body temperature, water consumption, stress response and immune competence around parturition in loose-housed sows

The aim of the present study was to study whether floor heating from 12h after onset of nest building until 48 h after birth of the first piglet had any effect on measures related to body temperature, water consumption, stress response and immune competence in loose-housed sows (n=23). In conclusion, the present results indicate that floor heating for a limited period around parturition did not compromise physiological and immunological parameters, water intake and body temperature in loose-housed sows. The water intake peaked the day before parturition and the body temperature peaked on the day of parturition. A cortisol peak at parturition, a transient rise in the number of leucocytes and neutrophils and a transient reduction in the number of lymphocytes, erythrocytes and in the PCV value were observed. Around and after parturition some non-specific immunological variables seemed to be stimulated while others seemed to be compromised.