Belly Nosing Research Articles

Effects of artificial rearing on behaviour, welfare, and immune function in piglets

With the steady increase in litter sizes, artificial rearing is becoming widely used to raise surplus piglets. The study aimed to evaluate the potential impacts of artificial rearing on behaviour and immune function in piglets. A total of 240 piglets were divided into three groups: piglets reared by the sow until weaning on day 35 (CON group), piglets artificially reared from day 7 (AR7 group), and piglets artificially reared from day 21 (AR21 group). Behavioural observation was conducted for 8 hours weekly, and the elimination position was recorded on days 7, 21, and 35. Serum and hair samples were collected to measure immunoglobulins and cortisol concentration, respectively. The results revealed that piglets in the AR7 group exhibited less frequent milk-drinking, exploring, and playing, but more frequent belly nosing and oral manipulation of conspecifics. Moreover, artificial rearing affected the elimination sites of AR7 piglets on day 21, but this phenomenon was not observed on day 35. In addition, the AR7 piglets had higher levels of cortisol and CRP, as well as lower levels of IgG and IgA compared to the CON piglets. The AR21 piglets also had a higher CRP level compared to the CON piglets. In conclusion, artificial rearing, initiated either from day 21 or day 7, negatively affected behavioural expression and immune function. Artificial rearing from day 7 was found to be the most physiologically detrimental.

Burlap and buddies: the effects of social enrichment (preweaning mixing) and object enrichment (burlap) on piglet behavior and welfare in the postweaning environment.

The process of weaning piglets in commercial swine operations subjects them to numerous abrupt and stressful changes often resulting in negative welfare consequences. The objective was to study the postweaning effects of early-life (1 to 3 d of age) preweaning socialization in multi-litter groups as well as object enrichment (burlap sheet) in the pre- and postweaning environment by comparing six treatments that combined mixing of one vs. two vs. four litters mixed preweaning with and without burlap provision. An ANOVA linear model was run on all normal data, expressed per experimental unit (and behavior data were averaged over time), while non-normal data were analyzed using the Kruskal-Wallis test. Non-enriched groups of piglets were observed manipulating pen objects more often than the enriched groups (P = 0.005). Biting behaviors, including the chewing of ears and tails of pen-mates but excluding fighting, were observed the least in groups of pigs of four litters mixed preweaning, while piglets that were not mixed preweaning were observed biting the most (P = 0.03). Piglets who were not mixed preweaning also manipulated the burlap more frequently than the piglets from groups of 4 litters mixed preweaning (P = 0.02). Biting (P < 0.001) and displacements (P = 0.03) and fighting (P = 0.002) throughout the pen were observed less in the enriched groups. There were fewer lesions per pig in the enriched groups vs. non-enriched groups initially (P = 0.07) and 1wk after weaning (P = 0.10). Furthermore, pigs mixed in groups of four litters preweaning also tended to have lower lesion scores (P = 0.07) 1-wk postweaning compared to the other treatments. However, there were no differences between treatments in the proportion of piglets resting, eating/drinking, being active, or using the burlap, or for the observed frequency of displacements at the feeder, social behaviors, or belly nosing (P > 0.10). Overall, social enrichment encourages socialization with unfamiliar conspecifics at a younger age while object enrichment allows pigs to redirect their attention toward objects such as burlap. Both may improve pig behavior and welfare after weaning.

Stress responses in pigs postweaning: Effect of heavier hybrid and weaning intact litters

Early and abrupt weaning of pigs is a stressful event. In addition, the use of hyperprolific sows with increasing numbers of live born piglets has decreased the average pig’s birth weight, colostrum intake and weaning weight. The aim of this study was to investigate whether behavioural (tail posture, agonistic and abnormal behaviour), clinical (ear and tail lesions) and physiological (saliva cortisol) indicators of stress postweaning can be minimised by 1) using a pig hybrid that is heavier at birth and weaning, and 2) trough specific-stress-free housing where intact litters of pigs stay in the pen of birth after removing the sow at weaning. The study was a 2 × 2 factorial design, with pigs from Topigs Norsvin TN70 (TN) sows as a heavier alternative to the lighter pigs from DanBred LY sows (DB), and the specific-stress-free (SSF) weaning strategy as an alternative to the conventional weaning strategy (CON) where pigs are regrouped and moved to weaner pens. Fiftyseven litters, on average 26 days of age, were included. Behaviour recordings on the day (d) of weaning (d0), showed that the rate of fights and attacks were 23 and 42 times higher in CON compared to SSF, respectively. Furthermore, on d+1 pig in CON had a 9 (in DB) to 13 (in TN) times higher odds of having clinical ear lesions compared to SSF. Only on d+2, saliva cortisol was lower in TN-SSF than TN-CON, but not lower that DB-SSF. A higher rate of high tail posture was seen in CON d+1, which may reflect higher arousal due to mixing and moving. The rate of belly nosing was 5 times higher in the lighter hybrid (DB compared to TN), but increased from d+7 to d+14 in both hybrids. On d+7 the rate of ear directed behaviour tended to be higher in DB than TN, but the rate increased from d+7 to d+14 in TN to a similar rate as in DB. The rate of tail directed behaviour increased from d+7 to d+14 and tended to be higher in CON than SSF. In conclusion, specific-stress-free weaning reduced agonistic behaviour and ear lesions and tended to reduce tail directed behaviour postweaning. Using the heaver hybrid TN reduced belly nosing postweaning. However, since belly nosing and tail directed behaviour increased over time for both hybrids and weaning strategies additional measures are needed to reduce stress associated with early and abrupt weaning.

Assessment of the drinker type on water intake and toy type on behaviour of nursery piglets

This study was conducted to assess the effect of two types of drinkers on water intake (WI) and two types of toys on behavioural observations of piglets in the nursery phase. A total of 72 crossbred entire male piglets (Landrace × Large White, Agroceres♂ and DanBred♀), weaned at 21 days of age, with an average initial body weight (AIBW) of 6.75 ± 0.19 kg were used. Two statistical models were fitted for WI. In model I, animals were distributed in a completely randomized design (CRD) with a split-plot in time, composed of six treatments (2 types of drinkers × 3 experimental phases), eight replications (days of sampling), and 36 animals/experimental unit (EU), without using AIBW as a covariate. In model II, animals were distributed in a CRD with two treatments (fixed or pendular nipple drinkers), eight replications (days of sampling) and 36 animals/EU, with use of AIBW as a covariate. For assessment of behavioural observations, the model was adjusted in a randomized block design, consisting of four treatments [two types of toys (metal chain and plastic bottle) × two daytime periods (morning and afternoon)], nine replications and three blocks constituted in time (days), totalling four pigs/EU. The results indicated an effect on animal daily WI in the starter phase in model I (p &lt; 0.000) and II (p = 0.006). There was an effect (p ≤ 0.05) of toy type for behavioural observations, in which pigs showed a greater proportion of fighting and belly nosing when they had the bottle toy. However, animals spent more time (p ≤ 0.05) eating, drinking water, overlapping, and playing with the toy when they had access to the chain toy. There was an increase (p ≤ 0.05) in sleeping behaviour in the morning period, as well as greater (p ≤ 0.05) behavioural activity in the afternoon period. In conclusion, WI of nursery piglets was positively influenced by growth phase, and the fixed drinker stimulated greater WI in piglets in the starter phase. In addition, the metal chain, as an environmental enrichment, promoted improvements in feeding behaviour and WI, reducing fighting events, and the afternoon period had increased behavioural observations overall.

Effect of toys on behaviour and body weight of weaned pigs after mixing

This study was conducted to evaluate the effects of a toy on the behaviour and body weight of weaned pigs after mixing. Two groups (192 pigs in total, control: without toy; treatment: with toy placed on the floor) of weaned pigs housed in pens (1.8 m × 1.4 m, 4 pigs/pen) were This study was conducted to evaluate the effects of a toy on the behaviour and body weight of weaned pigs after mixing. Two were observed with the aid of video technology for nine consecutive hours in the early (days 1 and 2) and late (days 38 and 39) period after mixing. Bodyweight of pigs at the end of the study (Mann-Whitney U-test, Z = –2.46, P = 0.01) and the average daily gain (Z = –2.75, P &amp;lt; 0.01) were 10% higher in the treatment group than in the control group. The presence of the toy in the pen influenced the pig behaviours. In pens enriched with toys, there was an increase in feeding behaviour and a decrease in agonistic and belly nosing behaviours. Toy supply reduced negative social behaviours and thereby improved the bodyweight of weaned pigs. The results of this study suggest that toys used as environmental enrichment are useful for enhancing pig welfare and effective for farmers.

Improving behavior characteristics and stress indices of gestating sows housed with group housing facility.

This study was conducted to investigate the effects of group-housing facility (GHF), compared to an individual confinement stall (CON), on the reproductive performance, behavior, and stress hormones of gestating sows. A total of 50 primiparous sows (Landrace × Yorkshire) were randomly allocated into either CON (n = 25) or GHF (n = 25) during the gestation period. One week before parturition, the sows were transferred into conventional farrowing crates, and cross-fostering was conducted within 1 d of delivery. Blood was collected for analyses of stress indices at 75 d of gestation and postpartum. Reproductive performance was estimated during the period of birth to weaning. Behavior patterns were identified at 90 d of gestation. Litter size was not different between the CON and GHF treatments. Weaning to estrus interval, however, tended to be lower in the GHF than in the CON (p < 0.1). Activity, treating, belly nosing, and exploring behaviors were observed only in the GHF group, whereas rubbing was shown only with the CON. Serum cortisol concentration was lower in the GHF than in the CON at 75 d of gestation (p < 0.05). Sows housed in the GHF showed lower epinephrine and norepinephrine concentrations than those housed in the CON at postpartum (p < 0.05). The GHF sows demonstrated more natural behavior characteristics associated with stress relief than the CON sows with no adverse effects on reproductive performance. Therefore, these results suggest that GHF could be applied as an alternative housing facility to improve animal welfare on swine farms.

Effect of environmental enrichment for piglets in the nursery phase.

ObjectiveThe effect of environmental enrichment on the behaviour of piglets in the nursery phase was evaluated.MethodsA total of 450 hybrid pigs (21 day old), including both females and uncastrated males, weighing approximately 6 kg, were distributed in a completely randomised design with 3 treatments and 3 replicates of 50 animals each. The treatments were: i) pen without environmental enrichment (control), ii) treatment consisting of continuous environmental enrichment (CEE) with rubber balls throughout the experimental period, and iii) treatment consisting of environmental enrichment with washed balls (EEWB) during the whole experimental period which were removed daily for washing. For the behavioural evaluation, 10 animals were randomly selected per replicate. The behavioural assessments were performed once a week, from 8 am to 6 pm, using images captured with a video camera. The data were submitted to non-parametric analyses, the means were compared using the Bonferroni test, and Person’s correlations were also calculated.ResultsA statistical difference (p = 0.001) was observed in the B5 (playful) behaviour; the animals in the EEWB treatment group had a higher frequency of this behaviour than animals in the control treatment group. The animals in the control group showed a higher frequency of B7 behaviour (lying down) (p = 0.026) than those in the EEWB and CEE treatment groups. The animals in the control group had a higher frequency of the B9 (belly nosing) behaviour than those in the EEWB group (p = 0.015). There was a tendency towards a higher frequency of behaviour B3 (walking in the pen) (p = 0.067) when the animals received the control treatment than treatments EEWB or CEE.ConclusionThe use of an enriching object improved the animal welfare and altered the correlation between the evaluated behaviours compared to the animals that did not have environmental enrichment.

Impact of increasing weaning age on pig performance and belly nosing prevalence in a commercial multisite production system.

The effects of increasing weaning age in a commercial production system on nursery and finishing performance were evaluated. A total of 1,176 pigs (PIC 337 × Camborough) were used in a 136-d growth trial with 14 and 10 replications/weaning age on the nursery and finishing phases, respectively. Treatments included weaning litters at 19, 22, 25, or 28 d of age. In the nursery, as weaning age increased, initial (5.04, 5.70, 6.52, and 7.26 kg) and final body weight (BW) (18.2, 19.8, 23.0, and 25.1 kg) increased (linear, P < 0.001). Increasing the weaning age reduced (linear, P < 0.001) the prevalence of pigs exhibiting belly nosing (27.6%, 15.0%, 6.5%, and 1.4%) during the first 3 wk. The percentage of pigs losing weight during the first week after weaning (35.1%, 28.7%, 12.4%, and 9.2%) decreased (linear, P < 0.001) as weaning age increased. Average daily gain (ADG; 295, 320, 374, 406 g/d) and average daily feed intake (493, 534, 619, 661 g/d) increased (linear, P < 0.001), while feed efficiency (G:F) (596, 599, 604, and 615) tended to increase (linear, P = 0.081) with weaning age. Removal rate (8.01%, 3.79%, 2.29%, and 1.65%) declined (linear, P = 0.001) as weaning age increased, while there was no evidence of difference (P = 0.463) in mortality rate (0.71%, 0.36%, 0.96%, 1.04%). In the finishing period, BW at 136 d post-weaning (114.9, 117.8, 124.7, and 126.5 kg) and ADG (1.02, 1.04, 1.08, and 1.07 kg/d) improved (linear, P < 0.001). There was no evidence of differences (P > 0.24) in removal (1.5%, 2.4%, 1.0%, and 0.0%) or mortality rates (0.9%, 1.0%, 1.0%, and 1.4%) with changes in weaning age. When performance was analyzed at a common day of life (164 d of age), no effects of weaning age (P > 0.25) were found for BW (125.2, 124.4, 128.0, and 126.5 kg) and lifetime ADG (growth rate from birth to market) (754, 751, 774, and 762 g/d). The BW sold per pig weaned increased (linear, P < 0.001) with weaning age. Even though the slope indicated a linear response, the magnitude of improvement was high until 25 d, before exhibiting diminishing returns from 25 to 28 d. Thus, the study suggests that increasing the weaning age can be an effective strategy to improve the overall performance in a commercial system. Although lifetime performance was not affected by the weaning age range studied, the consistent effect in the nursery and the increment in the number of pigs reaching the market facilitated by the improvement in the removal rate in the nursery phase imply that 25 d is the optimal weaning age.

The effect of pen environment on pen-mate directed behaviour prior to feeding in finisher pigs with intact tails

Tail biting is one of the largest problems in intensive pig production among finishers. Currently, tail docking is performed to minimize tail biting, such as bleeding, sores, infection and amputation, however, due to legislation and consumer demand, there is a need for finding other alternatives. The aim of this study was to investigate the effect of pen environment on the prevalence of pen-mate directed behaviour prior to feeding in finishers with intact tails. Pigs were assigned to one of two pens. Compared to PEN1, PEN2 housed fewer pigs, had a higher space allowance per pig and a larger area of solid floor than PEN1, whereas the space per pig at the feeding trough was the same. Straw was provided in a straw rack in PEN1 and on the floor in PEN2. Recorded behaviour (tail directed, ear directed, aggression, feeding, belly nosing and other nosing behaviour) was observed continuously 30 min prior to the last feeding of the day by the use of video recordings in three focal pigs in a total of 30 pens. The hypothesis was that PEN2 would generate a lower prevalence of pen-mate directed behaviour compared to PEN1. However, there was a similar prevalence of tail directed, ear directed and other nosing behaviour between pens and a tendency of a higher prevalence in counts of aggression and belly nosing in PEN2, thus rejecting the hypothesis. Furthermore, there was a difference in feeding behaviour with a higher prevalence in PEN1 (P ≤ 0.01).

Can body nosing in artificially reared piglets be reduced by sucking and massaging dummies?

Selection for hyper-prolific sows has substantially increased litter size. Consequently, the number of piglets in a litter may exceed the number of functional teats. To solve this problem, surplus piglets may be removed from the sow 2 days after birth and raised artificially. However, these piglets show increased levels of oral behaviours, such as belly nosing, directed at other piglets. This behaviour resembles massaging and sucking at the sow’s udder and thus is considered to be redirected suckling behaviour. The present study investigated whether oral behaviour directed at piglets can be reduced in artificially reared piglets by providing them with sucking and massaging dummies. In a two-by-two between-group factorial design, the artificial rearing pens were equipped with one of four treatments: a sucking dummy, a massaging dummy, a combined sucking–massaging dummy, or no dummy. The behaviour of 126 piglets (in 21 groups of 6 piglets) was scored from video by continuous focal observation lasting 90 min per piglet each on days 4 and 18 after introduction to the artificial rearing system. Data were analysed using linear mixed-effects models. Body nosing (composed of belly nosing and nosing on any other body part) increased from day 4 to 18 in all treatments, but piglets provided with a combined sucking–massaging dummy showed the smallest increase. Piglets spent more time nosing the combined dummy than the sucking or the massaging dummy. However, there was no causal inverse relationship between the duration of body nosing and dummy nosing. All but one piglet showed body nosing at least once. Resting, play-fighting, or oral manipulation of piglets (other than body nosing), dummies, and pen equipment were hardly affected by the treatments. Piglets with a combined dummy tended to have a longer average resting bout duration compared with piglets in other treatments. In conclusion, only the combined sucking–massaging dummy was effective in reducing the increase in body nosing over time. However, this reduction was rather small in absolute terms and the combined dummy did not prevent body nosing. The tested dummies were thus not successful in eliminating the redirected oral behaviour in artificially reared piglets.

Hiding walls for fattening pigs: Do they affect behavior and performance?

The prevalence of harmful and unwanted behavior in fattening pigs is influenced by different factors including housing. Housing may include the opportunity to hide from aggressive pen mates and this ability is related to pen design and shape. The aim of this study was to investigate the effect of a hiding wall in the pen on the behavior and performance of pigs during the entire fattening period (30–110kg). A total of 383 pigs were spread over standard control pens without hiding opportunities, and treatment pens. In the latter pens, a hiding wall was constructed, consisting of two solid panels positioned in a “T” shape against the side or back wall of the pen. Behaviors using an extended ethogram, the presence of lesions and weight were recorded during the entire fattening period. The presence of a hiding wall influenced neither growth, nor the prevalence of most pen mate manipulations (based on behavioral observations), but it did affect the prevalence of belly nosing and manipulating pen fittings. A lower frequency of these behaviors was observed in pens with hiding walls, which might indicate a lower stress level. Severe ear lesions were recorded more frequently in pens with a hiding wall, while severe tail lesions were recorded more often in control pens. These contradictory results might be related to the fact that the hiding wall disturbed lying behavior in the pen and caused restricted access to the backside of the pen, due to its position. Consequently, ear lesions might have been caused by pigs trying to reach the back of the pen. Other aggressive behaviors were not affected, as both the frequency of fighting and head knocking were not influenced by the prevalence of a hiding wall, and the prevalence of lesions on the front region of the body did not differ between control and treatment pens. In conclusion, the hiding wall did not contribute to a lower frequency of aggressive behavior, but was associated with less tail lesions, and a lower frequency of pen manipulation and belly nosing. The latter results might indicate a lower stress-level in pens with hiding walls.

A link between damaging behaviour in pigs, sanitary conditions, and dietary protein and amino acid supply.

The tendency to reduce crude protein (CP) levels in pig diets to increase protein efficiency may increase the occurrence of damaging behaviours such as ear and tail biting, particularly for pigs kept under suboptimal health conditions. We studied, in a 2×2×2 factorial design, 576 tail-docked growing-finishing entire male pigs in 64 pens, subjected to low (LSC) vs. high sanitary conditions (HSC), and fed a normal CP (NP) vs. a low CP diet (LP, 80% of NP) ad libitum, with a basal amino acid (AA) profile or supplemented AA profile with extra threonine, tryptophan and methionine. The HSC pigs were vaccinated in the first nine weeks of life and received antibiotics at arrival at experimental farm at ten weeks, after which they were kept in a disinfected part of the farm with a strict hygiene protocol. The LSC pigs were kept on the same farm in non-disinfected pens to which manure from another pig farm was introduced fortnightly. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored for 10×10 min per pen per week. The prevalence of ear damage during the finisher phase (47 vs. 32% of pigs, P < 0.0001) and the frequency of ear biting (1.3 vs. 1.2 times per hour, P = 0.03) were increased in LSC compared with HSC pigs. This effect on ear biting was diet dependent, however, the supplemented AA profile reduced ear biting only in LSC pigs by 18% (SC × AA profile, P < 0.01). The prevalence of tail wounds was lower for pigs in LSC (13 ± 0.02) than for pigs in HSC (0.22 ± 0.03) in the grower phase (P < 0.007). Regardless of AA profile or sanitary status, LP pigs showed more ear biting (+20%, P < 0.05), tail biting (+25%, P < 0.10), belly nosing (+152%, P < 0.01), other oral manipulation directed at pen mates (+13%, P < 0.05), and aggression (+30%, P < 0.01) than NP pigs, with no effect on ear or tail damage. In conclusion, both low sanitary conditions and a reduction of dietary protein increase the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare. Attention should be paid to the impact of dietary nutrient composition on pig behaviour and welfare, particularly when pigs are kept under suboptimal (sanitary) conditions.

Gradually reducing sow contact in lactation is beneficial for piglet welfare around weaning

This study tested whether a gradual reduction in sow contact during lactation, achieved through housing the sow in a ‘sow only’ area, would influence piglet stress responses to weaning. Gradual reduction in sow contact was achieved by separating the sow from her piglets (SP, n=30) for 5, 7, and 9h per day on days 10–15, 16–20 and 20 to weaning, respectively. Litters from 20 sows were followed as controls (CON), remaining in full contact with one another until weaning. Weaning occurred on day 28±1.3 of lactation. Piglet body weight, injury scores and evidence of creep ingestion were measured throughout lactation and after weaning. Continuous video footage was collected for 6h on the days following weaning for behavioural analyses. After weaning, SP piglets were lighter than CON piglets (6.8±0.22 versus 7.6±0.16kg); however, by day 7 post-weaning piglet weights were similar (P>0.05) for the CON (8.6±0.22kg) and SP (8.4±0.15kg) treatments, possibly reflecting a reduced growth check in SP piglets. There was a significant effect of treatment (CON versus SP) on the duration of aggressive (6.5±1.1 versus 4.2±0.8s) and belly nosing (6.3±2.0 versus 2.4±1.3s) events post-weaning. Injury scores were higher for CON piglets on almost all days examined (P<0.05). Plasma circulating cortisol concentrations following weaning were increased in CON piglets (18.7±13.3nmol/L), and decreased in SP piglets (−12.3±14.1nmol/L; F1,127=4.425, P<0.05). These findings imply sow separation during lactation provides welfare benefits for piglets around the highly stressful weaning period.

Effect of artificial suckling devices on behaviour, adaptation pattern and growth performance of early weaned piglets

Eighteen Large White Yorkshire piglets weaned at 10 ±2 days were divided randomly into three groups (n=6) and each group was allotted to circular (T1), horizontal (T2) device and control (T3). Piglets in T3 were reared with sow through natural suckling. Piglets were acclimatised for 5 days; during this period milk was given at the rate 25 ml per piglets four times daily. Further, during first, second, third and forth fortnights feeding continued at the rate of 100, 150 and 200 ml for four, three and two times daily in T1 and T2 devices respectively. Piglets were observed for behaviour, adaptation pattern and average milk consumption time daily, while body weight gained was recorded fortnightly. 100% of piglets in T3 showed non-nutritive suckling, belly nosing, massaging and teat order behaviours, but no such observations were recorded in T1 and T2. Adaptation pattern of piglets in T1 was 66.7 % and 100% in T2 and T3. Effects of suckling devices on average milk consumption time were 10.09 % and 13.79 % lower (Pe″0.05) in T1 and T2 device respectively compared to T3. Mean body weight gain in T1 and T2 devices were 5.12% and 16.89 % higher than T3. Horizontal suckling device (T2) performed better than T1 and T3 (control). Hence it can be recommended for early weaning in piglets.

Comparison of the behaviour of piglets raised in an artificial rearing system or reared by the sow

Over the last 15 years, rising sow fertility has led to a considerable increase in litter size. As a consequence, the number of live born piglets may outnumber the number of functional teats, and surplus piglets are removed from the sow at the age of 3–6 days and fed with artificial milk. The objective of this study was to compare the behaviour of piglets raised in a commercially available artificial rearing system (group size: seven piglets) with that of piglets reared by the sow in a loose farrowing pen (seven focal piglets observed per litter). The behaviour of 98 piglets raised artificially (7 batches) and 82 piglets reared by the sow (6 batches) was videotaped on days 4, 11 (artificially raised piglets only) and 18 after introduction of the piglets to the artificial rearing system. Belly nosing, manipulation of a pen mate, play-fighting, aggressive behaviour and resting were assessed by continuous focal observation twice a day in the periods from 05:00 to 10:15 and from 13:00 to 18:15. Data were analysed by using linear mixed-effects models.Belly nosing was hardly ever observed in piglets reared by the sow, whereas the duration as well as the frequency of this behaviour increased between days 4 and 18 in piglets raised artificially. Moreover, artificially raised piglets spent more time manipulating a pen mate, showed less play-fighting, exhibited more aggressive behaviour and had shorter resting bouts compared with piglets reared by the sow. Finally, total duration of resting decreased from day 4 to day 18 in artificially raised piglets and increased in piglets reared by the sow.It is concluded that piglets removed from the sow at an early age and raised artificially redirect massaging behaviour to their pen mates, resulting in high levels of belly nosing and indicating impaired animal welfare. Moreover, the small space allowance in the tested artificial rearing system may additionally account for behavioural differences observed between artificially raised piglets and piglets reared by the sow in a loose farrowing pen.

Facilitating ‘learning from mom how to eat like a pig’ to improve welfare of piglets around weaning

Piglets in commercial husbandry are weaned abruptly and at a rather young age. Many weanling piglets are poorly adapted to ingest solid food, often resulting in a period of underfeeding. The underfeeding generally leads to a poor growth, diarrhoea occurrence and the development of damaging behaviours such as belly nosing, indicating reduced welfare, in the immediate postweaning period. Weaning problems are multifactorial, but an early intake of solid food and reduced stress around weaning are major determinants of a quick adaptation of piglets to the new postweaning situation. In this paper we focus on improving welfare of piglets around weaning by allowing piglets to interact more with the sow during lactation, as would occur under more natural conditions. Besides providing piglets with more opportunity to learn from the sow about what, how and where to eat, we also discuss information transfer already before birth, perinatal flavour learning, and the merits of learning in an enriched environment.Being able to interact more with the sow is important to reduce the reluctance of piglets to eat novel foods, to increase preweaning solid food intake, and to reduce the development of damaging behaviours and increase play behaviour after weaning. Perinatal flavour learning reduced stress around weaning and increased postweaning performance and welfare. Preweaning enrichment of the environment, by providing substrates and a larger pen, can increase preweaning growth and development of feeding-related behaviours before weaning as well as food intake after weaning. Postweaning enrichment increased growth and play behaviour, and reduced the occurrence of diarrhoea and damaging behaviours. When enrichment is provided before weaning it is important to also provide enrichment after weaning. Learning from the sow and environmental enrichment are important for piglets to more easily adapt to being weaned. We conclude with recommendations for application of these results in current and future pig husbandry systems to improve welfare of newly weaned piglets.

Behavioural and Brain Gene Expression Profiling in Pigs during Tail Biting Outbreaks – Evidence of a Tail Biting Resistant Phenotype

Abnormal tail biting behaviour is a major welfare problem for pigs receiving the behaviour, as well as an indication of decreased welfare in the pigs performing it. However, not all pigs in a pen perform or receive tail biting behaviour and it has recently been shown that these ‘neutral’ pigs not only differ in their behaviour, but also in their gene expression compared to performers and receivers of tail biting in the same pen. To investigate whether this difference was linked to the cause or a consequence of them not being involved in the outbreak of tail biting, behaviour and brain gene expression was compared with ‘control’ pigs housed in pens with no tail biting. It was shown that the pigs housed in control pens performed a wider variety of pig-directed abnormal behaviour (belly nosing 0.95±1.59, tail in mouth 0.31±0.60 and ‘other‘ abnormal 1.53±4.26; mean±S.D) compared to the neutral pigs (belly nosing 0.30±0.62, tail in mouth 0.13±0.50 and “other“ abnormal 0.42±1.06). With Affymetrix gene expression arrays, 107 transcripts were identified as differently expressed (p<0.05) between these two categories of pigs. Several of these transcripts had already been shown to be differently expressed in the neutral pigs when they were compared to performers and receivers of tail biting in the same pen in an earlier study. Hence, the different expression of these genes cannot be a consequence of the neutral pigs not being involved in tail biting behaviour, but rather linked to the cause contributing to why they were not involved in tail biting interactions. These neutral pigs seem to have a genetic and behavioural profile that somehow contributes to them being resistant to performing or receiving pig-directed abnormal behaviour, such as tail biting, even when housed in an environment that elicits that behaviour in other pigs.

Relationship between growth rate and oral manipulation, social nosing, and aggression in finishing pigs

Pigs may affect each other's health, welfare and productivity through their behaviour. The effect of a pig on the growth rate of its pen mates is partly heritable and is referred to as its social genetic effect. Social genetic effects, also known as indirect genetic effects, have been found in a number of livestock breeds, in natural and laboratory populations, and in plant breeding and forestry, and have become an important research topic in recent years. In pigs, social genetic effects are hypothesized to be related to behaviour. The mechanism behind social genetic effects for growth, as well as the relationship between behaviours and growth itself, is largely unknown. To gain insight in the mechanism behind social genetic effects, we investigated the relationship between behaviours and growth rate in pigs. On a commercial pig farm, 398 finishing pigs in 50 pens (eight pigs/pen) were observed at 12 weeks of age using 2-min instantaneous scan sampling for 6h during daytime. For 324 observed pigs, growth rate during the finishing period was known. The relationship between behaviours and growth rate during the finishing period was analysed with behaviour as explanatory variable in a mixed model. Results show that time spent giving behaviours, like oral manipulation, social nosing, aggression and belly nosing, was not related to own growth rate. Receiving behaviours, however, did relate to growth. Pigs that received more oral manipulation, observed as tail biting, ear biting and paw biting, grew less well (P<0.05). Growth rate was 43(±17)g/d lower in pigs that received oral manipulation during more than 2% of the observations as compared to pigs that did not receive oral manipulation. Pigs that received social nosing, a gentle touch or sniff at any part of the body, had a higher growth rate (P<0.05): growth rate differed 29(±17)g/d between pigs that received social nosing during more than 2% of observations as compared to not receiving social nosing at all. Receiving aggression and belly nosing, a forceful rubbing of the belly, did not influence growth rate. In conclusion, receiving oral manipulation and social nosing related to growth rate. This suggests that pigs selected for positive social genetic effects for growth may potentially show behavioural changes. Effects of selection for social genetic effects on behaviour and growth will be studied in future research.

Effects of Reduced Nocturnal Temperature on Performance and Behavior of Nursery Pigs

Previous studies suggested that pigs prefer lower environmental temperatures during nighttime compared to daytime. So reducing nocturnal temperature in nursery barns may not jeopardize performance or welfare of pigs, but can save energy for heating the barn. A study was conducted to investigate growth performance and behavioral response of nursery pigs to reduced nocturnal temperature. This study was conducted in four replicates, each utilizing 270 newly weaned pigs and lasting for 5 wk. Temperature setpoint in the control room (CON) was started at 30°C and decreased by 2°C per week. In the treatment room (RNT), temperature setpoint was maintained same as in CON between 7:00 h and 19:00 h, and reduced by 8°C between 19:00 h and 7:00 h starting from d 5. Growth performance (15 pens/room, 9 pigs/pen, BW=(6.30.61) kg) was monitored for 5 wk, and behaviors in 6 pens in each room were video-recorded for 24 h 3 d after being exposed to the experimental temperature. Instantaneous scan sampling was performed to determine time budgets for standing, sitting, eating, drinking, belly nosing, three postures of lying, and huddling. Two focal pigs were continuously viewed to record duration and occurrence of eating and drinking. Reduced nocturnal temperature did not affect the growth performance of the pigs, time spent standing, sitting, total lying and eating or duration and frequencies of eating and drinking (all P>0.10). However, RNT increased time spent lying sternal (83 vs. 72%, P<0.001) and number of pigs that were huddling (70 vs. 50% of lying pigs, P<0.001), and decreased time spent lying laterally (0.8 vs. 4.6%, P<0.001), lying half laterally (5.3 vs. 11.0%, P<0.001), and belly nosing (0.9 vs. 1.7%, P=0.01) during nighttime. These results indicate that nursery pigs adopted the posture of lying sternal and huddled together to reduce heat loss from their body surface to maintain thermal balance and growth performance in RNT. Such mild reduction in nocturnal temperature in the nursery barn can save energy for heating the barn without negative effects on performance and behavior of nursery pigs.

Behavioral changes in neonatal swine after an 8-hour rest during prolonged transportation12

Long distance transportation of weaned piglets (Sus scrofa) is increasingly common in the united states and may result in delayed eating, drinking, or normal social behaviors. A potential solution is a mid-journey rest (lairage). The objective of this study was to determine if a lairage altered behavior after a 16-h transport. Pigs that weighed approximately 18 kg each (n = 894) were housed in 16 pens with 8 pens per treatment. Lairaged pigs were transported for 8 h and given an 8-h rest with food and water, whereas control pigs were transported continuously for 16 h. The heaviest, the lightest, and 2 average-BW pigs relative to the average weight of the pen were observed by video recording for 24 h immediately before and after transport, and during d 6 and 13 after transport. Postures (lying, sitting, and standing) were recorded using 10-min-interval scan sampling, and behavioral categories included inactivity, activities (eating, drinking, alert, manipulating pen, rooting, and walking) and social interactions (aggression, belly nosing, playing, tail biting, and positive social behaviors). In both treatments, sitting occurred most before transport (P < 0.01) than at other times, but did not differ between treatments. Standing increased (time effect; P < 0.01) for both treatments immediately after transport through d 6, but returned to pre-transport values by d 13. In contrast, lying decreased (time effect; P < 0.01) after transport, but returned to above pre-transport values by d 13. Time effects were evident for activity (P < 0.01), pen manipulation (P = 0.05), rooting (P < 0.01), initiation of belly-nosing (P = 0.01), and receiving belly-nosing (P = 0.03); however, initiation of aggression did not differ for day (P = 0.19) or treatment (P = 0.56). Lairaged pigs initiated more (P = 0.05) play than continuously transported pigs, but no differences (P = 0.84) were seen in receipt of play behavior. Pigs that were to be transported for 16 h continuously walked less pre-transport, walked more post-transport (treatment × time interaction; P = 0.02), and drank less pre-transport, but drank more on all days post-transport compared with the lairage group (treatment × time interaction; P = 0.001). This study indicated that extended transport without lairage alters some swine behaviors relevant to production (water consumption) and demonstrated that a long-duration transport, regardless of the mid-journey lairage treatment, affects a number of behaviors up to 13 d after transportation.