The effect of two teeth resection procedures on the welfare of piglets in farrowing crates. Part 1

Teeth resection is a method of controlling the injurious effects of the aggression displayed when newborn piglets fight to establish a teat order. Recent European legislation discourages the practice. The objective of this study was to assess the effect of clipping and grinding piglets’ needle teeth, compared to leaving them intact, on the welfare of piglets in farrowing crates.

Six days pre-partum, 60 sows were assigned to one of three treatments. Litters had their teeth clipped (C), ground (G) or left intact (I) at birth. The time taken to carry out each procedure was recorded. Piglet weights and facial lesions, which were scored according to severity, were recorded on days 1, 4, 11, 18 and 27. Piglet weights were also recorded at birth. Mouth lesions were recorded on days 1, 4 and 27. Instantaneous scan samples of piglet behaviour were carried out for 30 min post-teeth resection procedure (1 min intervals), and for 6 h on days 1, 4, 8, 14, 21 and 26 (5 min intervals). One male and one female piglet per litter were chosen as focal animals and observed for 5 min each post-procedure and for 10 min each twice per day on days 1, 5, 12, 20 and 26. Mortalities were recorded throughout lactation.

Grinding took significantly longer than clipping the teeth or leaving them intact (F = 638.87, P < 0.001). I piglets had higher facial lesion scores than C and G piglets (F = 10.58, P < 0.001). A smaller proportion of piglets in I litters than C and G litters and a smaller proportion of piglets in G litters than C litters had at least one mouth lesion (F = 4.74, P < 0.001). During 30 min post-procedure, I piglets were active on the heatpad in more observations than C and G piglets (F = 3.49, P < 0.05). During 5 min post-procedure C piglets spent longer chomping than I piglets (F = 5.92, P = 0.05). On day 21, I piglets were active in more observations than G piglets (F = 2.11, P < 0.05). On day 26, G piglets were inactive in more observations than C and I piglets (F = 5.02, P < 0.05). On days 14 and 26, C piglets were sleeping in more observations than G piglets (F = 2.87, P = 0.05). There was a tendency for a larger proportion of I than C piglets to die due to overlying (F = 2.68, P = 0.08).

In conclusion, although all three options were associated with welfare problems, grinding can be recommended in preference to clipping or leaving the teeth intact.     

A note on the effects of co-mingling piglet litters on pre-weaning growth, injuries and responses to behavioural tests

The purpose of this study was to determine how co-mingling litters affected piglets’ pre-weaning growth, ear injuries, suckling behaviour and responses to behavioural tests used to measure coping abilities. Thirty sows and their respective litters were housed in standard farrowing crates until day 13 after birth. On day13, the partition between two neighbouring pens was removed for 20 litters allowing piglets to interact (forming 10 co-mingled litters). The remaining 10 control litters were kept in standard farrowing crates throughout the experiment. Three focal piglets from each litter were used for data collection. Focal piglets were weighed and ear injuries recorded on days 2, 4, 9, 12, 15 and 18 after birth. There were no differences in piglets’ weight gain before or after co-mingling. Ear injuries were more abundant in co-mingled litters on day 15 (P < 0.05) but these differences disappeared by day 18. Suckling behaviour was recorded on days 5, 8, 10, 14, 16 and 18 after birth. There were no differences in teat fidelity, suckling frequency and mother fidelity between treatments. Three behavioural tests, social challenge, isolation, and backtest, were performed before and after co-mingling. There were no treatment effects on piglets’ response to the isolation test and backtest. Co-mingled piglets showed longer latency for the first aggressive interaction (P < 0.05), spent more time in proximity to one another (P < 0.05) and performed less single bites (P < 0.05) than control piglets during the social challenge. In addition, the duration and frequency of aggressive interactions (P < 0.05) were lower in co-mingled piglets than control piglets. Co-mingling did not affect the frequency of single head thrusts or oral–nasal contact, but did tend to increase the frequency of escape attempts (P < 0.10). Our results suggest that co-mingling litters during lactation affects piglets’ social behaviour, by primarily decreasing aggressive interactions during social challenges.     

The effects of farrowing nest size and width on sow and piglet behaviour and piglet survival

The ‘Werribee farrowing pen' (WFP) was developed as a loose housing alternative to the farrowing crate. The WFP occupies about twice the space of a crate and comprises two compartments, a ‘nest' and a ‘non-nest' area. In this experiment, we investigated the effects of reducing total pen space by modifying the dimensions of the ‘nest'. The hypothesis was that modifying ‘nest' size and width would not negatively affect piglet survival. A reduction in total floor space in the WFP may increase attractiveness for adoption of the system by pig producers. The experiment had a 2×2 factorial design with nine replicates and a total of 72 primiparous sows (Large White×Landrace) and their litters. All subjects were included to day 4 of lactation, but production data to weaning (day 23) was restricted to 36 litters. We examined the effects of ‘nest' size (large: L vs. small: S) and width (wide: W vs. narrow: N) on sow and piglet behaviours and piglet survival. The W, as compared to N treatment sows, had longer mean bouts of standing in the ‘nest' during 16–8 h pre-farrowing (3.7 vs. 2.0 min, P<0.01), suggesting that pre-farrowing (‘nesting') behaviour may have been adversely affected by narrow nest width. On the first 2 days of lactation, sow suckling grunts occurred more in the W than N treatment (14.1 and 8.0% of observations, P<0.01). However, this was due to an approximately 50% lower incidence in the SN treatment, as compared to the other treatments combined (5.9 and 12.7%). Piglets spent more (P<0.01) time at the udder in L vs. S (41 and 30%) and W vs. N nests (40 and 31%) and performed more (P<0.05) sucking behaviour (i.e., drinking milk from a teat) in L vs. S nests (2.5 and 1.2%). These differences were due to SN treatment litters sucking less than other treatments combined (0.9 vs. 2.2%). Of the 680 piglets born (n=72 litters), 3.8% were stillborn and 6.8% died between birth and day 4 of lactation. From day 5 to weaning (n=36 litters), 3.5% of piglets died, all due to Escherichia coli infection. While there were no effects of treatment on piglet survival, liveborn piglets were less likely (P<0.05) to die from E. coli in the L vs. S treatments (9/24 vs. 23/33 piglets). In conclusion, our results provide evidence that the size and width of the farrowing ‘nest' in a loose farrowing system may effect sow and piglet behaviours that may be relevant to piglet survival.     

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.     

A behavioural scale to measure ease of farrowing in sows

Farrowing is one of the most critical phases in pig production, as it has an impact on neonatal pig survival. Assessing the ease of farrowing can improve the management of sows and thus increase litter survival. The aims of this study were: 1) to develop an ease of farrowing score (EFS) in sows based on the behaviour of the sows and their piglets, and 2) to determine the relationship between the EFS and productive, physiological, and subjective parameters. Eighty hybrid (Large White × Landrace) sows from first to seventh parity housed in individual crates were used. An EFS was constructed using the total duration of farrowing, the birth interval, the total time standing or sitting, the number of position changes during the day before and the day of farrowing, the sow posture at birth, the viability and the position of the piglets at birth (head or back born). Moreover, rectal temperature at 90 min after farrowing, a four categorical subjective visual assessment (VA) of farrowing and litter size (piglets born alive, stillborn and mummified foetus) were recorded. A common factor analysis model yielded five factors with an eigenvalue higher than 0.95 that accounted for 75.05% of the total variation between individuals. The three main factors were “farrowing duration”, “sow posture”, and “sow activity” of sows and explained 23.44%, 15.67%, and 14.23% of the variance, respectively. Primiparous sows had higher values for factor 3 (sow activity) than multiparous sows (P = 0.02). Sows without stillborn or mummification foetus showed higher values of EFS than sows with at least one stillborn or mummification foetus (P = 0.06 and 0.01, respectively). Sows that received a visual assessment of 3 and 4 showed higher values of EFS than sows that received a VA of 1 and 2 (P = 0.0017). The EFS appears to be a good behavioural scale to measure ease of farrowing in sows kept in individual farrowing crates. Duration of farrowing, sow position, and presence of stillborn piglets and mummified foetuses appear to be important ease of farrowing indicators.     

Consistency is key: interactions of current and previous farrowing system on litter size and piglet mortality

Global interest in alternative indoor farrowing systems is increasing, leading to a growing number of farms utilising such systems alongside standard crates. There is evidence that interchanging sows between different farrowing systems affects maternal behaviour, whilst the subsequent effect of this on piglet mortality is unknown. The current study hypothesised that second parity piglet mortality would be higher if a sow farrowed in a different farrowing system to that of her first parity. Retrospective farm performance records were used from 753 sows during their first and second parities. Sows farrowed in either standard crates (crates), temporary crates (360s) or straw-bedded pens (pens), with mortality recorded as occurring either pre- or post-processing. Inter- and intra-parity sow consistency in performance were also investigated. Overall, total piglet mortality reduced from the first to the second parity, being significantly higher in the crates and higher in the 360s during the first or second parity, respectively. In the second parity, an interaction of the current and previous farrowing systems resulted in the lowest incidence of crushing for sows housed in the same system as their first parity for the crates and pens, but not the 360s. Post-processing mortality was significantly higher in the crates if a sow previously farrowed in the 360s and vice versa. Sows which previously farrowed in a pen had a significantly larger litter size and lower pre-processing mortality from crushing in their second parity than sows previously housed in the crates or the 360s. No inter-parity consistency of sow performance was found, whilst intra-parity consistency was found in the first but not second parity. In conclusion, returning sows to the same farrowing system appears to reduce piglet mortality, whilst farrowing in a pen during the first parity significantly increased second parity litter size without increasing piglet mortality.     

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.     

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.     

Effects of floor-feeding and the presence of a foraging substrate on the behaviour and stress physiological response of individually housed gilts

Both restricted feeding and barren housing have a negative influence on sow welfare. The aim of this study was to test whether sows that have to search for their feed in a substrate on the floor show less stereotyped (and other abnormal) behaviour and have a lower physiological stress response. In three batches, 96 gilts were housed individually in two rooms in 3.1 m² pens with 1.9 m² solid floor. In a 2×2 factorial design either wood shavings (S) or no substrate (NS) were provided on the floor, and 900 g of feed was provided twice daily (06:30 and 15:00 h) either in a trough (T) or on the floor (F). In weeks 8–12, behaviour was scan-sampled once in the periods 07:00–09:00 h (P1), 10:00–12:00 h (P2), and 13:00–15:00 h (P3). Data from the 5 weeks were pooled per animal. Video recordings (24 h) in week 12 or 13 were scan-sampled for ‘standing’. Saliva samples were taken in week 11 at 2 h intervals during 24 h and measured for cortisol. Spontaneously voided morning-urine was sampled in weeks 2, 7 and 12 or 13 for determination of ratios of adrenaline (A) and noradrenaline (NA) with creatinine (CR). Most effects that were found were due to substrate presence. Main findings were that compared with S-animals, NS-animals stood more during the dark period (4.8% versus 3.0%; P<0.05) and showed more (visible) oral behaviour in P1 (56.8% versus 47.6%; P<0.05), P2 (35.8% versus 30.8%; tendency) and P3 (44.1% versus 33.8%; P<0.05). This included more sham chewing in P1 (tendency), P2 and P3, more pen manipulation in P3, and more other oral behaviour (e.g. teeth grinding) in P1 (tendency) and P2. They had higher cortisol levels before feeding (peaks) and in the early evening (24 h average: 1.49 ng/ml versus 1.02 ng/ml; P<0.05) and higher NA/CR ratios in weeks 7 (tendency) and 12 (5.5 ng/mg versus 3.7 ng/mg; P<0.05). No treatment effects were found on A/CR ratios. Substantial interactive effects of feeding method and substrate were only found in floor manipulation. In all three periods NS-T-animals manipulated the floor less than other animals, probably because they had no attraction to the floor and were not rewarded for searching. Results imply that the presence of a substrate on the floor improves welfare, whereas provision of feed in the substrate in order to stimulate foraging behaviour is of less importance.     

A note on the effect of gestation housing environment on approach test measures in gilts

Systems’ welfare evaluation, including behavioural testing, is becoming increasingly popular in farm animal assurance schemes. The aims of this study were to investigate whether fairly short-term exposure to gestation housing systems, which varied in physical, environmental and human-input factors, influenced behavioural and physiological measures during a human approach test—often used to identify problems in human–animal interactions. Twenty-four Large White×Landrace gilts were initially subjected to identical human contact and daily husbandry. Forty-two days after service, the gilts were randomly assigned to either an indoor housing system (n=16) or an outdoor housing system (n=8), which differed physically and in the amount of human contact and daily husbandry. The indoor system used an electronic sow feeder (ESF), was more space-limited and thermally-controlled and had human contact centered on cleaning out. The outdoor system was more extensive, had much greater space accessible, was not thermally-controlled and had human contact that centered around feeding. The human approach test was carried out on all gilts 30–44 days after entry to the gestation system. At testing, each individual was fitted with heart rate monitor and then moved into a test arena. After 2 min an unfamiliar human entered the pen and stood motionless for 3 min against one wall and then approached the gilt and touched her snout. Throughout the experimental period, behaviour and sound within the test arena were recorded continuously. During the 2 min familiarisation period, outdoor gilts had lower heart rates (108.2 bpm versus 123.7 bpm, P<0.05) and tended to perform fewer short vocalisations (0.5 calls per min versus 3.4 calls per min, P<0.1). Outdoor-housed gilts also carried out less locomotor behaviour (2.2 sections crossed versus 4.0 sections crossed, P<0.05) and tended to perform fewer short (1.4 calls per min versus 5.0 calls per min, P<0.1) and long vocalisations (0.2 calls per min versus 1.8 calls per min, P<0.1) over the 3 min test period. Outdoor gilts tended to be slower to approach within 0.5 m of the human (69.9 s versus 19.3 s, P<0.1) but they then took less extra time to make physical contact (3.3 s versus 52.7 s, P<0.1). Mean heart rate was significantly lower in outdoor sows over the whole 3 min period (99.5 bpm versus 115.5 bpm, P<0.05). The results demonstrate that short-term exposure to different housing systems did influence behavioural and physiological measures during a standard human approach test and thus, systems differences should be taken into account before making judgements about the human–animal relationship on any commercial farm, based on results of behavioural tests of this type.     

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.     

Effects of constant and cycling hot environments on mitogen-stimulated proliferation of peripheral blood lymphocytes from sows and litters

1. 1. Lymphocytes from sows maintained in a constant hot environment (32°C) showed reduced proliferative responses to mitogens PHA (P < 0.02) and PWM (P < 0.01) in comparison to sown maintained in a constant cool environment (21°C). In the piglets the hot constant temperature slightly reduced (P < 0.05) proliferative responses of lymphocytes to PHA.

2. 2. No significant effects of a cycling hot environment (27–32°C) were found for any proliferative responses of lymphocytes from sows and litters.

3. 3. In the constant hot environment, serum cortisol concentrations were significantly reduced in the sows (P < 0.0001) while no differences in serum cortisol concentrations were found in the litters.

     

Shortening sow restraint period during lactation improves production and decreases hair cortisol concentrations in sows and their piglets

Food animal welfare is an issue of great concern, as society has a responsibility for animals under human care. Pork is the most consumed meat worldwide, with more than a billion pigs being slaughtered globally every year. Still, in most countries, sows are restrained in farrowing crates throughout lactation. In these crates, sows are confined with bars to an area that is just slightly larger than their body. Thus, moving and turning around, grooming, or expressing other natural behaviors are typically impossible. In this study, we utilized a simple and practical modification of conventional farrowing crates to designed farrowing pens, by removable confinement bars, which provide the flexibility to change the housing system from one to another. Our objective was to examine the parameters of production and hair cortisol concentrations after different restraint periods during lactation. Analyses included data from 77 sows and their 997 piglets. Sows were housed in farrowing crates, but the confinement bars were removed after different periods, from 3 days post-farrowing to full restraint. For certain analyses, sows were grouped into Short or Long Restraint groups (3–10 days vs 13–24 days, respectively). Multiple linear regression revealed that for any additional day in restraint of the sows, piglets' weaning rate decreases by 0.4% (P < 0.05). Moreover, the total number of weaned piglets per litter was higher in the Short Restraint group as compared to the Long Restraint group (10.4 ± 0.3 vs 9.7 ± 0.3, respectively; P < 0.05). Accordingly, total litter weight on the weaning day tended to be higher in the Short Restraint group (68.8 ± 2.2 vs 64.9 ± 1.8 kg; P = 0.1210). The requirement for medical treatments during lactation (e.g., antibiotics, NSAID) tended to be less frequent in the Short Restraint group (Sows: 21.9% vs 40%; P = 0.1219. Piglets: 2.4% vs 17.1%; P = 0.0609). Hair cortisol as a marker for chronic stress during lactation decreased when the restraint period was shortened in both sows and piglets. Our analysis revealed that sows' hair cortisol is a significant mediator between the restraint of the sow and its piglets' hair cortisol (Sobel test; P < 0.05). For every day of sows' restraint, sows' hair cortisol increased by 0.5 pg/mg, and for any additional unit of sows' hair cortisol, piglets' hair cortisol increased by 0.36 pg/mg. In conclusion, sustainable swine farming management can be beneficial for both animals and farmers; limiting sow restraint during lactation is expected to reduce stress, enhance welfare and production, and potentially improve the economics of swine operations.     

The short-term effects of increasing meal frequency on stereotypic behaviour of stabled horses

In this study, we investigated the effect of increasing the number of meals of concentrate (whilst maintaining the same daily intake) on the behaviour of stabled horses with particular reference to stereotypic activities. The study was carried out on a working equestrian yard with stables for up to 50 horses. A pilot study was used to record incidence of stereotypic behaviour and to select subjects for the main study. In this, the behaviour of 30 warm-blooded horses was recorded during their morning (08:30 h) and afternoon (16:30 h) concentrate feeds. Whilst there was a low incidence of stereotypic behaviour (5.6% of scans) in the population, they were more commonly observed in the afternoon (7.1%) than the morning observations (4.2%; P < 0.05). The higher incidence in the afternoon observation appeared to be related to the lower availability of high fibre forage during the afternoon meal. In the main study nine horses were fed their normal ration of concentrate divided between two, four or six equally sized meals. Their behaviour was compared with seven control horses, which received two meals per day throughout the trial. As the number of meals increased, the treatment horses showed a decrease in oral stereotypies (P < 0.01), but an increase in weaving (P < 0.05) and nodding (P < 0.01) prior to feeding. The control group increased weaving, nodding and oral stereotypies (all P < 0.05) as their yard-mates received more meals. Consequently there was an overall increase in incidence of stereotypy in both treatment and control horses with the increase in meal frequency. The study, therefore, suggests that dividing the stabled horses’ concentrate ration into a number of smaller meals may be an effective means of reducing oral stereotypies, but that pre-feeding stereotypies may persist and that the practise may increase the frequency of stereotypic behaviour on unfed horses in visual contact.     

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.     

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.     

Influence of individual predisposition, maternal experience and lactation environment on the responses of pigs to weaning at two different ages

This study assessed the effect of predisposition to perform harmful social behaviour, maternal rearing environment, and lactation environment on the responses of pigs to weaning at 3 or 5 weeks of age. Predisposed and non-predisposed gilts were selected as dams for this study at 7 weeks of age. Selection was based on behaviour in a “tail chew” test and performance of harmful social behaviour towards penmates. The gilts were mated at puberty with boars of a similar predisposition, and farrowed at approximately 44 weeks of age. Half of the gilts of each predisposition were reared from the time of selection until farrowing in barren environments, and half in enriched environments. During lactation, gilts and litters were either housed in a similar environment to that which gilts had experienced during rearing, or in a different environment (i.e. in terms of being barren or enriched). Litters from each treatment group were weaned at either 3 weeks of age (early weaning), or 5 weeks of age. After weaning, piglets were regrouped and housed in slatted pens without access to substrates. Non-predisposition to perform harmful social behaviour was associated with reduced growth during the post-weaning period (P < 0.01), and increased belly nosing behaviour in response to early weaning (P < 0.05). These effects were not mitigated by maternal experience or lactation environment factors, and it is concluded that this type of selection may not be commercially viable. Rearing dams in barren rather than enriched environments led to reduced welfare in offspring. This was reflected in increased adrenocortical reactivity during the lactation period (P < 0.01), and increased belly nosing behaviour in response to early weaning (P < 0.05). The effect of barren maternal rearing environments on belly nosing behaviour by offspring was eliminated when pigs were housed in enriched lactation environments (P < 0.01). Enrichment during the lactation period also led to improved growth rates in the post-weaning period (P < 0.01). It is suggested that this effect was due to an enhanced ability to cope with the weaning process. Overall, the results show that both genetic and early environmental factors are important determinants of the responses of pigs to weaning. Adverse effects of barren maternal rearing environments may be overcome by housing pigs in enriched lactation environments.     

Surgical castration of pigs affects the behavioural response to a low-dose lipopolysaccharide (LPS) challenge after weaning

The objective of the present study was to evaluate the effect of an acute stressor in the early postnatal life of pigs, surgical castration, on post-weaning behaviour, and on the behavioural, endocrine and immune responses elicited by a low-dose lipopolysaccharide (LPS) challenge after weaning. At 5-days-of-age, 64 male piglets were randomly assigned to undergo surgical castration or were left untreated (treatment). Pigs were weaned at 28 days-of-age. Behaviour post-weaning and mixing was assessed during a 1-h period, during which agonistic interactions were recorded. One day post-weaning, pigs were injected intraperitoneally with a single dose of 0 or 5 μg/kg of BW of LPS from Escherichia coli (challenge). Sickness behaviour was studied by scan sampling every 5 min for 45 min at 0, 1, 2, 3, 4, 6 and 8 h after the challenge. Blood samples were taken at 0, 2, 12 or 24 h after injection and were analysed for plasma concentrations of tumor necrosis factor-alpha (TNF-), interleukin-1beta (IL-1β), C-reactive protein (CRP), serum amyloid A (SAA) and cortisol. Results showed that non-castrated pigs were more aggressive than castrated pigs immediately after weaning (P < 0.05). Administration of LPS provoked behaviours characteristic of sickness including a reduction in general activity, as well as decreased eating and exploratory behaviours (P < 0.05). These altered behaviours occurred predominantly 3-h post injection (P < 0.05). Significant treatment by challenge interactions showed that castration reduced the occurrence of sickness behaviours induced by LPS, such as depressed general activity (P < 0.01), anorexia (P < 0.01) and reduced exploratory behaviours (P < 0.05). LPS administration increased TNF- levels (P < 0.05), with peak concentrations 2 h after injection (P < 0.01). CRP levels of LPS-treated pigs were higher than saline-treated animals at 12 h (P < 0.05). LPS administration tended to increase plasma SAA levels (P < 0.1), but did not increase cortisol levels (P > 0.1). However, castration did not affect the response of pro-inflammatory cytokines, acute phase proteins and cortisol to the challenge. These results show that surgical castration reduces aggressiveness at weaning and affects specific sickness behaviours but not the endocrine and immune responses elicited by low-dose endotoxin challenge in weaned pigs.     

Nurse sow strategies in the domestic pig: I. Consequences for selected measures of sow welfare

Management strategies are needed to optimise the number of piglets weaned from hyper-prolific sows. Nurse sow strategies involve transferring supernumerary new-born piglets onto a sow whose own piglets are either weaned or fostered onto another sow. Such ‘nurse sows’ have extended lactations spent in farrowing crates, which could have negative implications for their welfare. This study used 47 sows, 20 of which farrowed large litters and had their biggest piglets fostered onto nurse sows which were either 1 week (2STEP7, n=9) or 3 weeks into lactation (1STEP21, n=10). Sows from which piglets were removed (R) were either left with the remainder of the litter intact (I) (remain intact (RI) sows, n=10), or had their litters equalised (E) for birth weight using piglets of the same age from non-experimental sows (remain equalised (RE) sows, n=9). Piglets from 2STEP7 were fostered onto another nurse sow which was 3 weeks into lactation (2STEP21, n=9). Back-fat thickness was measured at entry to the farrowing house, at fostering (nurse sows only) and weaning. Sows were scored for ease of locomotion and skin and claw lesions at entry to the farrowing house and weaning. Salivary cortisol samples were collected and tear staining was scored at 0900 h weekly from entry until weaning. Saliva samples were also taken at fostering. Data were analysed using GLMs with appropriate random and repeated factors, or non-parametric tests were applied where appropriate. Back-fat thickness decreased between entry and weaning for all sows (F_1,42=26.59, P<0.001) and tended to differ between treatments (F_4,16=2.91; P=0.06). At weaning RI sows had lower limb lesion scores than 2STEP7 and RE sows (χ²₄=10.8, P<0.05). No treatment effects were detected on salivary cortisol concentrations (P>0.05) and all nurse sows had a higher salivary cortisol concentration at fostering, compared with the other days (F_10,426=3.47; P<0.05). Acute effects of fostering differed between nurse sow treatments (F_2,113=3.45, P<0.05); 2STEP7 sows had a higher salivary cortisol concentration than 1STEP21 and 2STEP21 sows on the day of fostering. 2STEP7 sows had a higher salivary cortisol concentration at fostering, compared with 1STEP21 and 2STEP21 sows. Tear staining scores were not influenced by treatment (P>0.05). In conclusion, no difference was detected between nurse sows and non-nurse sows in body condition or severity of lesions. Although some nurse sows experienced stress at fostering, no long-term effect of the nurse sow strategies was detected on stress levels compared with sows that raised their own litter.     

Reproductive performance of gilts and sows in temperate versus subarctic and arctic zones of Norway

The reproductive performance of gilts and sows from two regions in Norway was investigated in a retrospective analysis of data from the litter recording system. In the Northern region (North; between 65°N and 71°N), there are extreme shifts in natural photoperiod between winter and summer. In the Southern region (South; between 59°N and 60°30′N), photoperiodic changes are less dramatic.

Gilts were 8 days older at first mating or insemination in the North than in the South (P<0.01). A significantly lower proportion of sows in the North were mated or inseminated within 5 days post-weaning than in the South, a difference present both among primiparous and multiparous sows (P<0.01). Overall farrowing rate in the North was lower than in the South, but litter size (total number born) among those pigs that farrowed was larger. After correction for year, month, breed and age at first service, there were still lower odds of farrowing for gilts in North than in South. Neither for primiparous nor multiparous sows were regional differences in farrowing probability significant when year, month, breed and weaning to service interval were included in the model. Gilts and primiparous sows had a lower probability of farrowing following insemination during summer or autumn months, but service month was not significantly related to the farrowing probability of multiparous sows.

For gilts, litter size was positively related to age at first service. For sows, litter size was lowest at weaning to service intervals between 6 and 10 days. Total numbers of piglets born per litter were estimated to be 0.36, 0.38 and 0.55 larger in the North than in the South (differences in least square means; gilts, primiparous sows and multiparous sows, respectively) (P<0.01). Litter size was lower after service during natural long photoperiod than during the rest of the year.