Effect of crate opening from day 3 postpartum to weaning on nursing and suckling behaviour in domestic pigs

Temporary crating may be a more acceptable housing system for lactating sows than permanent crating and loose-housing because it combines benefits of both systems while reducing some of their limitations. It remains unclear whether nursing and sucking behaviour is influenced after crate opening. The aim of this study was to assess the short- (24 h post-crate opening) and long-term (day 25 postpartum (pp.)) effects of opening the farrowing crate from day 3 pp. to weaning on nursing and suckling behaviour. Sows were crated from 5 days prepartum either to weaning (permanently crated group; n = 14) or 3 days pp. (temporarily crated group; n = 13). Sows and their litters were observed on days 4 and 25. Duration of pre- and post-massages, nursing termination, number of piglets missing milk ejection and number of piglets fighting during pre- and post-massages were scored at 15-s intervals. Nursing success (i.e. with or without milk ejection) was also recorded. Data were analysed using PROC GLM and PROC GENMOD of SAS including housing, litter size and parity as fixed effects. Nursing behaviour did not differ between sows housed in temporary crates and those housed in permanent crates on days 4 and 25 pp., that is, same number of nutritive nursings (NNs), same proportion of non-NNs, same duration of post-massages and same proportion of termination of post-massages. There was only a housing effect on day 25; with sows having longer pre-massages in permanent crates (P < 0.05). Suckling behaviour was overall similar between treatments. There were no differences in the number of piglets attending pre- and post-massages, proportion of piglets fighting during pre-and post-massages and the proportion of piglets missing milk ejection on both days. The only housing effect was found on day 25 during which fewer piglets attended post-massages (P < 0.05) in permanent crates. Sows with larger litters terminated post-massages more often (P < 0.05), allowed shorter post-massages (P < 0.05) on day 4, and had more piglets miss milk ejection on days 4 and 25 (P < 0.05). In conclusion, the results of this study showed that housing had a very limited effect on nursing and suckling behaviour. Sow and piglet behaviours were not altered after crate opening (short-term effect) and nursing was to some extent calmer (shorter pre-massages and more piglets attended post-massages) in temporary crates on day 25. Increased litter size impaired nursing and suckling behaviour of sows and piglets independently of the housing system.     

Temporary crate opening procedure affects immediate post-opening piglet mortality and sow behaviour

Producers are interested in utilising farrowing systems with reduced confinement to improve sow welfare. However, concerns of increased mortality may limit commercial uptake. Temporary confinement systems utilise a standard crate which is opened 3 to 7 dayspostpartum, providing protection for neonatal piglets at their most vulnerable age and later increased freedom of movement for sows. However, there is anecdotal evidence that piglet mortality increases immediately after the temporary crate is opened. The current study aims were to determine if piglet mortality increases post-opening, to trial different opening techniques to reduce post-opening piglet mortality and to identify how the different opening techniques influence sow behaviour. Three opening treatments were implemented across 416 sows: two involved opening crates individually within each farrowing house when each litter reached 7 days of age, in either the morning or afternoon (AM or PM), with a control of the standard method used on the farm to open all crates in each farrowing house simultaneously once the average litter age reached 7 days (ALL). Behavioural observations were performed on five sows from each treatment during the 6 h after crate opening, and during the same 6 h period on the previous and subsequent days. Across all treatments, piglet mortality was significantly higher in the post-opening than pre-opening period (P<0.0005). Between opening treatments, there were significant differences in piglet mortality during the 2 days after crate opening (P<0.05), whilst piglet mortality also tended to differ from crate opening until weaning (P=0.052), being highest in ALL and lowest in PM. Only sows in the PM treatment showed no increase in standing behaviour but did show an increased number of potentially dangerous posture changes after crate opening (P=0.01), which may be partly attributed to the temporal difference in observation periods. Sow behaviour only differed between AM and ALL on the day before crate opening, suggesting the AM treatment disrupted behaviour pre-opening. Sows in AM and PM treatments showed more sitting behaviour than ALL, and therefore may have been more alert. In conclusion, increases in piglet mortality after crate opening can be reduced by opening crates individually, more so in the afternoon. Sow habituation to disturbance before crate opening may have reduced post-opening piglet mortality, perhaps by reducing the difference in pre- and post-opening sow behaviour patterns.     

Higher light intensity and mat temperature attract piglets to creep areas in farrowing pens

Loose farrowing pens have been considered as alternatives to crates to enhance sow welfare. A major concern with pen systems is often higher piglet pre-weaning mortality, especially due to crushing by the sow. An optimal management of light and mat surface temperature may promote greater piglet use of the creep, which has been associated with reduced piglet crushing. A total of 108 sows and their piglets were studied in sow welfare and piglet protection pens on a commercial piggery, across two replicates. Sows were randomly assigned to pens arranged within two creep treatments (bright creep: 300 lx v. dark creep: 4 lx), considering mat temperature as a covariate. Twelve sows and their litters in each treatment (24 in total) had their behaviour continuously recorded for 72-h postpartum (pp), and four focal piglets per litter were weighed on the first and third days pp. In situ behaviour observations were performed daily (from 0800 to 1700 h) on all sows and their litters, every 15 min over 72-h pp to record piglet time spent in the creep, latency to enter the creep for the first time, latency for the litter to remain in the creep for at least 10 min, and piglet and sow use of pen areas immediately in front of (A2) and farthest from the creep (A3). Piglets with access to bright creeps spent on average 7.2% more time (P<0.01) in the creeps than piglets in pens with Dark creeps. In addition, for each degree increase in mat temperature, piglets spent on average 2.1% more time (P<0.01) in the creep. Piglets in pens with bright creeps spent less time in A2 (P=0.04) and the least time in A3 (P=0.01). Light or mat temperature did not affect sow use of pen areas or piglet weight gain. Piglets with bright creeps tended (P=0.06) to take longer to enter the creep for the first time after birth, but the latency for 30.0% of the litter to remain clustered for 10 min tended (P=0.08) to be shorter in bright compared to dark creeps. Overall, piglet use of the creep increased with warm mat temperatures and brightness, which should be further investigated as potential strategies to promote piglet safety and reduce crushing in pen farrowing systems.     

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.     

Short confinement of sows after farrowing,but not pen type affects live-born piglet mortality

Over the last decades, permanent crating of farrowing and lactating sows has led to serious public concerns with regard to sow welfare. As one alternative, it has been suggested to restrict crating to the period when suckling piglets are at the highest risk to die. Therefore, the aim of this study was to investigate live-born piglet mortality with regard to different confinement periods (CFP) as well as farrowing pen types. On three research farms (A, B and C), four confinement periods were compared: In CFP 0 (control), sows were not confined at all, sows in CFP 3 were crated after the end of farrowing for three days. In CFP 4, sows were confined one day before the due date of farrowing until three days after parturition and sows in CFP 6 were crated one day before expected farrowing until five days after parturition. Furthermore, five different pen types designed for temporary crating (PT; 5.5–7.3 m²) were compared. In total, production data from 638 litters were analysed. For each piglet found dead (n = 1 580), the cause of death was determined by the farm personnel and verified by necropsy (all three farms) and additional video analysis (farms A and B only). Data were analysed using logistic mixed models with CFP 0 and pen type Fluegel as reference categories (CFP 0 was control and this pen type was present on all three farms and the largest number of litters was born in this pen type). Live-born piglet mortality was lower in temporarily crated sows than in sows without confinement (CFP 0; P < 0.015). Pairwise posthoc tests did not reveal differences between CFP 3, CFP 4 and CFP 6 (odds ratios 0.75, 0.59 and 0.69), nor between pen types. Additional factors associated with increasing live-born piglet mortality were larger litter size, higher sow parity as well as the administration of hormones around farrowing. Factors influencing mortality due to crushing were similar to those for total live-born mortality with the exception of CFP 3 not differing significantly from CFP 0. It can be concluded, that confinement of the sow for three days after farrowing is an effective measure to reduce live-born piglet mortality in the pen types tested. An extension of the confinement period to five days after parturition does not result in a further reduction of live-born mortality rate.     

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.     

Factors affecting piglet mortality during the first 24 h after the onset of parturition in large litters: effects of farrowing housing on behaviour of postpartum sows

The present study aimed to identify the factors that affect immediate (within 24 h after farrowing onset) postnatal piglet mortality in litters with hyperprolific sows, and investigate their associations with behaviour of postpartum sows in two different farrowing housing systems. A total of 30 sows were housed in: (1) CRATE (n=15): the farrowing crate closed (0.80×2.20 m) within a pen (2.50×1.70 m), and (2) OPEN (n=15): the farrowing crate open (0.80×2.20×1.80 m) within a pen (2.50×2.40 m) with a provision of 20 ls of hay in a rack. A total of 518 live born piglets, produced from the 30 sows, were used for data analyses during the first 24 h after the onset of parturition (T24). Behavioural observations of the sows were assessed via video analyses during T24. Total and crushed piglet mortality rates were higher in OPEN compared with CRATE (P<0.01, for both). During T24, the OPEN sows tended to show higher frequency of postural changes (P=0.07) and duration of standing (P=0.10), and showed higher frequencies of bar-biting (P<0.05) and piglet trapping (P<0.01), when compared with the CRATE sows. During T24, the mortality rates caused by crushing were correlated with the piglet trapping event (r=0.93, P<0.0001), postural changes (r=0.37, P<0.01), duration of standing (r=0.32, P<0.01) and frequency of bar-biting behaviour (r=0.51, P<0.01) of the sows (n=30). In conclusion, immediate postnatal piglet mortality, mainly due to crushing, may be associated with potential increases in frequency of postural changes, duration of standing and incidence of piglet trapping in postpartum sows in the open crate system with large litters.     

Piglet use of the creep area—Effects of breeding value and farrowing environment

The objective of this study was to investigate piglet use of the creep area, comparing litters of sows with a high vs. low breeding value for piglet survival in the first 5 days postpartum, that were either housed in crates or individual pens during farrowing and lactation. Seventy-five Yorkshire × Danish Landrace sows were video recorded for 4 days after farrowing, and the analysis was conducted using instantaneous sampling every 10 min commencing 24 h after the birth of the first piglet for a period of 72 h. Breeding value for piglet survival had no effect on piglet use of the creep area or time spent in any location of the farrowing environment. Farrowing environment had significant effects on piglet location; during all days there were significantly more piglets in the creep area in the crates compared to the pens (P < 0.01), and this difference was larger at 24–48 h than at 49–72 h and at 73–96 h after birth (P < 0.05). Piglets in pens spent significantly more time resting near the sow, excluded nursing (P < 0.001), and this percentage decreased over time after farrowing (P < 0.001) in both the crates and the pens. In conclusion, piglet use of the creep area was higher in the crate compared to the pen particularly during the second day of life. This may partly be due to a much larger proportion of uncomfortable, slatted floor in the crates, and the shorter distance from the sow to the creep area in the crate.     

Early piglet mortality in loose-housed sows related to sow and piglet behaviour and to the progress of parturition

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.     

Effects of meloxicam (Metacam®) on post-farrowing sow behaviour and piglet performance

Farrowing is an intrinsically risky process for both the sow and the piglets that can cause welfare and economic problems. The effects of the non-steroidal anti-inflammatory drug meloxicam on post-farrowing behaviour of sows, and the performance of piglets were investigated. A total of 48 sows were randomly allocated at the day of farrowing (day 0) into two homogeneous groups regarding parity, and treated with either meloxicam or saline solution as placebo. For each sow, number of position changes, total time lying and standing or sitting, feed intake and rectal temperature (RT) were recorded during 3 days after farrowing. Piglets were individually weighed at farrowing and at weaning. The number of position changes did not show significant differences between treatments (P = 0.79). Sows spent significantly less time lying during day +3 after farrowing in the meloxicam group than in the placebo group (P = 0.04). Feed intake and RT showed a parity effect (P < 0.001 in both cases); however, no treatment effect was observed (P = 0.67 and P = 0.47, respectively). Pre-weaning mortality rate in piglets was not affected by treatment. In litters from multiparous sows, piglets of low birth weight (defined as percentile 15: BW <1180 g) had an average daily gain significantly higher in the meloxicam group than in the placebo group (196.6 ± 7.2 v. 166.6 ± 9.1 g/day; P = 0.03). Although the administration of meloxicam 90 min after farrowing showed a positive effect on the total time lying of the sows, additional investigations are required to better qualify relevant indicators of pain following farrowing in sows and to specify the analgesic effects of meloxicam on piglet performance.     

Group lactation from 7 or 14 days of age reduces piglet aggression at weaning compared to farrowing crate housing

Early life experiences can affect social behaviour in later life, but opportunities for socio-behavioural development are often overlooked in current husbandry practices. This experiment investigated the effects of rearing piglets in two-stage group lactation (GL) system from 7 or 14 days of age on piglet aggression at weaning. Three lactation housing treatments were applied to a total of 198 piglets from 30 litters of multiparous sows. All dams farrowed in standard farrowing crates (FCs). Group lactation litters were transferred with their dam at 7 (GL₇) or 14 days (GL₁₄) postpartum to GL pens (one pen of five sows at 8.4 m²/sow and one pen of seven sows at 8.1 m²/sow, per GL treatment). Farrowing crate litters remained with their dam in a single litter until weaning. At weaning, 10 to 14 piglets from two unfamiliar litters from the same housing treatment were mixed into pens (n=5 pens/treatment) and their behaviour was continuously recorded for 3.5 h. For each pen, the frequency of aggressive bouts (reciprocal and non-reciprocal aggression lasting <5 s), the frequency and duration of fights (reciprocal aggression lasting ⩾5 s) and bullying events (non-reciprocal aggression lasting ⩾5 s) were recorded, along with whether interactions involved familiar or unfamiliar piglets. Aggressive bouts delivered by FC piglets were approximately 1.5 and 3.0 times more frequent than that delivered by GL₇ and GL₁₄ piglets, respectively (40.5, 16.7 and 9.9 bouts/pig, respectively; P<0.05). Fighting was more frequent (1.6, 0.3 and 0.4 fights/pig, respectively; P<0.001) and fights were longer (83, 15 and 32 s fight/pig, respectively; P<0.001) between FC piglets than between GL₇ or GL₁₄ piglets. Bullying did not differ between housing treatments (P>0.05). GL₇ and GL₁₄ piglets engaged in a similar number of fights with unfamiliar as familiar piglets, but FC piglets had almost three times as many fights with unfamiliar than with familiar piglets (P<0.05). This experiment confirms the benefits of GL housing for pig social development. Further investigation is required to determine whether mixing before 14 days postpartum has implications for other indicators of animal welfare and productivity in a two-stage GL housing system.     

An association analysis of sow parity,live-weight and back-fat depth as indicators of sow productivity

Understanding how critical sow live-weight and back-fat depth during gestation are in ensuring optimum sow productivity is important. The objective of this study was to quantify the association between sow parity, live-weight and back-fat depth during gestation with subsequent sow reproductive performance. Records of 1058 sows and 13 827 piglets from 10 trials on two research farms between the years 2005 and 2015 were analysed. Sows ranged from parity 1 to 6 with the number of sows per parity distributed as follows: 232, 277, 180, 131, 132 and 106, respectively. Variables that were analysed included total born (TB), born alive (BA), piglet birth weight (BtWT), pre-weaning mortality (PWM), piglet wean weight (WnWT), number of piglets weaned (Wn), wean to service interval (WSI), piglets born alive in subsequent farrowing and sow lactation feed intake. Calculated variables included the within-litter CV in birth weight (LtV), pre-weaning growth rate per litter (PWG), total litter gain (TLG), lactation efficiency and litter size reared after cross-fostering. Data were analysed using linear mixed models accounting for covariance among records. Third and fourth parity sows had more (P<0.05) TB, BA and heavier BtWT compared with gilts and parity 6 sow contemporaries. Parities 2 and 3 sows weaned more (P<0.05) piglets than older sows. These piglets had heavier (P<0.05) birth weights than those from gilt litters. LtV and PWM were greater (P<0.01) in litters born to parity 5 sows than those born to younger sows. Sow live-weight and back-fat depth at service, days 25 and 50 of gestation were not associated with TB, BA, BtWT, LtV, PWG, WnWT or lactation efficiency (P>0.05). Heavier sow live-weight throughout gestation was associated with an increase in PWM (P<0.01) and reduced Wn and lactation feed intake (P<0.05). Deeper back-fat in late gestation was associated with fewer (P<0.05) BA but heavier (P<0.05) BtWT, whereas deeper back-fat depth throughout gestation was associated with reduced (P<0.01) lactation feed intake. Sow back-fat depth was not associated with LtV, PWG, TLG, WSI or piglets born alive in subsequent farrowing (P>0.05). In conclusion, this study showed that sow parity, live-weight and back-fat depth can be used as indicators of reproductive performance. In addition, this study also provides validation for future development of a benchmarking tool to monitor and improve the productivity of modern sow herd.     

Piglets’ behaviour and performance in relation to sow characteristics

The importance of maternal care in commercial pig production is largely ignored. The sow has little possibility to interact with her piglets, and piglets are often subjected to early weaning or artificial rearing. This study aimed to investigate aspects of physiological and behavioural maternal provisioning that contribute to offspring outcomes. We hypothesised that better maternal care and nutritional provisioning would relate positively to piglet immunity, growth and behaviour. Nineteen sows and their litters were studied in free-farrowing pens. Oxytocin and tumour necrosis factor-α in colostrum/milk and salivary cortisol were sampled from sows throughout lactation. Sows were assessed for dominance rank, response to handling, maternal defensiveness, suckling initiation and termination, posture and sow-piglet contact. Piglets were weighed, measured for body mass index (BMI) and sampled for blood (Immunoglobulin G; at birth). After weaning, they experienced a human approach test (HAT) and novel object test. Correlations were explored between individual sow characteristics, individual piglet outcomes, and between sow characteristics and piglet outcomes averaged by litter. Significant correlations between sow and piglet factors were analysed at the litter level in mixed models with piglet outcomes as response variables and sow characteristics as predictor variables, while accounting for sow parity, litter size and batch. Litters grew faster when their sow had lower cortisol values (P = 0.03), while sows with lower cortisol levels had more successful suckling bouts and engaged in greater amounts of sow-piglet contact. Litters had a lower BMI at weaning when the sow had a higher milk fat percentage at d3. Litters of the most dominant sows took longer to approach the human in the HAT, while litters of sows with higher cortisol at d0 took longer to approach the novel object when assessed on correlations (r = 0.82, P < 0.001) but not when the model accounted for parity and litter size (P = 0.35). Only some of the measured nutritive and non-nutritive sow factors influenced litter performance and behaviour, with parity and litter size also playing a role. Given the continued increase in litter size, but also the interest in loose-housed lactation pens for sows, further research on sows’ maternal investment and how it can be optimised is warranted.     

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.     

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.     

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.     

Supplying sows energy on the expected day of farrowing improves farrowing kinetics and newborn piglet performance in the first 24 h after birth

The farrowing process is one of the most energy-demanding activities for the modern hyperprolific sow. This study evaluated the effects of supply of energy on the expected date of farrowing on the farrowing kinetics and piglets’ performance during the first 24 h after birth. A total of 80 sows were used. The sows and their respective litters were considered as the experimental unit. On the expected day of farrowing, the sows were allocated to one of the following groups: sows that did not have access to feed from farrowing induction until the end of the farrowing process (CON, n = 40); sows fed 500 g of energetic supplement, which consisted of 250 g of the basal lactation diet plus 250 g of cane sugar, 18 h after farrowing induction (SUP, n = 40). The farrowing duration, farrowing assistance, birth interval, number of total born, stillborn and mummified piglets were recorded for each sow. Piglets were weighed individually at birth and 24 h later. The interval from birth to first suckle was evaluated individually for each piglet in 16 randomly selected litters (eight litters per treatment group). Blood glucose concentrations of six sows were measured shortly after expulsion of the first piglet. Farrowing duration, farrowing assistance and stillborn rate tended to be greater (P = 0.06, P = 0.09 and P = 0.07, respectively) in sows from the CON group compared to sows from the SUP group. However, there was no difference (P > 0.05) between the groups for birth interval. Colostrum intake was greater (P < 0.05) for piglets from the SUP group compared to piglets from the CON group. Additionally, BW gain of the piglets suckling the SUP group was greater (P < 0.05) than those suckling the CON group at 24 h after birth. The blood glucose concentrations during the expulsive stage of farrowing were greater (P < 0.05) in the SUP group than for sows from the CON group. In conclusion, supplying modern hyperprolific sows energy on the expected day of farrowing is a valuable nutritional intervention to improve the farrowing kinetics and piglets’ performance in early life.     

Nurse sow strategies in the domestic pig: II. Consequences for piglet growth,suckling behaviour and sow nursing behaviour

Nurse sow strategies are used to manage large litters on commercial pig farms. However, new-born piglets transferred to nurse sows in late lactation might be compromised in terms of growth and survival. We investigated the effects of two nurse sow strategies on piglet growth, suckling behaviour and sow nursing behaviour. At 1-day post-farrowing, the four heaviest piglets from large litters were transferred to a nurse sow either 21 (1STEP21, n=9 litters) or 7 (2STEP7, n=10 litters) days into lactation. The remainder of the litter remained with their mother and was either kept intact (remain intact (RI), n=10 litters) or had some piglets cross-fostered to equalise birth weights (remain equalised (RE), n=9 litters). The 7-day-old piglets from 2STEP7 were transferred onto a sow 21 days into lactation (2STEP21, n=10 litters). The growth of new-born piglets on 1STEP21 and 2STEP7 nurse sows was initially lower than in RI litters (F_3,33.8=4.61; P<0.01), but weaning weights did not significantly differ (F_4,32.7=0.78; P>0.5). After the 1^st week of lactation, the weights and growth rates did not differ between treatments. Fighting behaviour during nursing bouts decreased over time. The frequency of fights was higher in 1STEP21 and 2STEP21 litters compared with RI litters (t₁₂₂=3.06 and t₁₂₃=3.00, respectively, P<0.05). The 2STEP21 litters had shorter nursing bouts than RI and 1STEP21 litters (t₁₀₇=−2.81 and t_81.7=2.8, respectively, P<0.05), which were more frequently terminated by 2STEP21 than RI sows (t₅₉₅=2.93; P<0.05). Transferring heaviest piglets from RI and RE litters to nurse sows reduced the percentage of teat changes during nursing bouts (RI: F_1,275=16.61; RE: F_1,308=43.59; P<0.001). In conclusion, nurse sow strategies do not appear to compromise piglet growth. However, new-born piglets transferred onto sows in late lactation experienced more competition at the udder, suggesting that the sows’ stage of lactation is of importance to how achievable nurse sow strategies are. Thus, the two-step nurse sow strategy is likely the best option (in relation to growth and suckling behaviour), as it minimises the difference between piglet age and sow stage of lactation.     

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.     

Supplementing sow diets with palm oil during late gestation and lactation: effects on milk production,sow hormonal profiles and growth and development of her offspring

The supplementing of sow diets with lipids during pregnancy and lactation has been shown to reduce sow condition loss and improve piglet performance. The aim of this study was to determine the effects of supplemental palm oil (PO) on sow performance, plasma metabolites and hormones, milk profiles and pre-weaning piglet development. A commercial sow ration (C) or an experimental diet supplemented with 10% extra energy in the form of PO, were provided from day 90 of gestation until weaning (24 to 28 days postpartum) in two groups of eight multiparous sows. Gestation length of PO sows increased by 1 day (P<0.05). Maternal BW changes were similar throughout the trial, but loss of backfat during lactation was reduced in PO animals (C: −3.6±0.8 mm; PO: −0.1±0.8 mm; P<0.01). Milk fat was increased by PO supplementation (C day 3: 8.0±0.3% fat; PO day 3: 9.1±0.3% fat; C day 7: 7.8±0.5% fat; PO day 7: 9.9±0.5% fat; P<0.05) and hence milk energy yield of PO sows was also elevated (P<0.05). The proportion of saturated fatty acids was greater in colostrum from PO sows (C: 29.19±0.31 g/100 g of fat; PO: 30.77±0.36 g/100 g of fat; P<0.01). Blood samples taken on 105 days of gestation, within 24 h of farrowing, day 7 of lactation and at weaning (28±3 days post-farrowing) showed there were no differences in plasma concentrations of triacylglycerol, non-esterified fatty acids, insulin or IGF-1 throughout the trial. However, circulating plasma concentrations of both glucose and leptin were elevated during lactation in PO sows (P<0.05 and P<0.005, respectively) and thyroxine was greater at weaning in PO sows (P<0.05). Piglet weight and body composition were similar at birth, as were piglet growth rates throughout the pre-weaning period. A period of 7 days after birth, C piglets contained more body fat, as indicated by their lower fat-free mass per kg (C: 66.4±0.8 arbitrary units/kg; PO: 69.7±0.8 arbitrary unit/kg; P<0.01), but by day 14 of life this situation was reversed (C: 65.8±0.6 arbitrary units/kg; PO: 63.6±0.6 arbitrary units/kg; P<0.05). Following weaning, PO sows exhibited an increased ratio of male to female offspring at their subsequent farrowing (C: 1.0±0.3; PO: 2.2±0.2; P<0.05). We conclude that supplementation of sow diets with PO during late gestation and lactation appears to increase sow milk fat content and hence energy supply to piglets. Furthermore, elevated glucose concentrations in the sow during lactation may be suggestive of impaired glucose homoeostasis.