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.     

Does the environmental background (intensive v. outdoor systems) influence the behaviour of piglets at weaning?

Under intensive pig husbandry, outdoor systems offer a more complex physical and social environment compared with indoor systems (farrowing sheds). As the rearing environment affects behavioural development, it can, therefore, influence behavioural responses of pigs to stressful environments in later stages of production. We tested how the rearing environment influenced behavioural responses to a novel arena test in piglets on the day that they were weaned and mixed into large groups. We recorded video footage and compared the behavioural responses of 30 outdoor-raised and 30 farrowing shed-raised piglets tested in an experimental arena and sequentially exposed to four challenges (each for 5 min) on the day of weaning. Quantitative and qualitative behavioural measures were recorded using time budgets and scoring demeanour or ‘qualitative behavioural expression’ (using Qualitative Behavioural Assessment (QBA)). When held in isolation (challenge 1), both groups were scored as more ‘scared/worried’, while outdoor-raised piglets spent more time eating and jumping against the arena walls. Both groups interacted with a plastic ball (challenge 2: exposure to a novel object) during which they were scored as more ‘playful/curious’ than other challenges. When a food bowl was introduced (challenge 3), farrowing shed-raised piglets were more interested in playing with the food bowl itself, whereas outdoor-raised piglets spent more time eating the feed. Finally, there were no significant differences in social behaviour (challenge 4: introduction of another piglet) between the two groups in terms of the latency to contact each other, amount of time recorded engaged in aggressive/non-aggressive social interactions or QBA scores. Although piglets spent 30% of their time interacting with the other piglet, and half of this time (47%) was engaged in negative interactions (pushing, biting), the levels of aggression were not different between the two groups. Overall, outdoor-raised piglets ate more and were scored as more ‘calm/passive’, whereas farrowing shed-raised piglets spent more time investigating their environment and were scored as more ‘playful/inquisitive’. In conclusion, we did not find differences in behaviour between outdoor-raised and farrowing shed-raised piglets that would highlight welfare issues. The differences found in this study may reflect conflicting affective states, with responses to confinement, neophobia and motivation for exploration evident.     

Relationships between individual behavioural traits and post-weaning growth in segregated early-weaned piglets

Piglets' individual behavioural traits have been studied in the last decade but no report has linked these traits with growth. This experiment was conducted to determine if behavioural traits of segregated early-weaned piglets could be good predictors of their post-weaning growth and, thus, help to predict their adaptation to early weaning. Following segregated early weaning at 17+/-1 days old, 252 piglets were submitted to three tests between 20 and 25 days of age: open-field, reaction to humans and rank order based on competition for a restricted-access feeder. The body weight of each piglet was measured the day before weaning and once a week for the next 4 weeks. A principal component analysis yielded five factors with an Eigenvalue higher than 0.90 that accounted for 81% of the total variation between individuals: reaction to humans (25%), active response to stress (21%), passive response to stress (14%), feeding behaviour (10%) and rank order (9%). Passive reaction to stress was associated with better weight gain during the first week post-weaning (r=0.18; P=0.01), and a positive correlation was found between social status and weight gain during the 4 weeks following weaning (-0.15相似文献   

Cortisol administration to pregnant sows affects novelty-induced locomotion, aggressive behaviour, and blunts gender differences in their offspring

Several behavioural effects of prenatal stress are reported in literature, and these seem to depend, among other factors, on the gender studied and the period of gestation in which prenatal stress is applied. In the present study, oral administration of hydrocortisone-acetate (HCA) to 41 pregnant sows was used as a model for prenatal stress, since corticosteroids are considered a key mediator in the effects of prenatal stress. HCA was orally administered to pregnant sows during three periods of gestation: 21-50 (period 1, P1, n = 10), 51-80 (period 2, P2, n = 10) and 81-110 (period 3, P3, n = 10) days after insemination (term 115 days). Control sows (n = 11) received vehicle from 21 to 110 days after insemination. Between days 9 and 48 after birth, treatment effects on male and female piglet behaviour were determined in the home pen and in four different behavioural tests. During the backtest, no gender differences were observed in vocalisations in HCA-piglets, while control males vocalised more than control females. In the home pen at 14 days of age, HCA-piglets spent less time in social interactions than control piglets. During the novel environment test, P1- and P3-piglets walked more than control piglets, but this was not observed during the novel object test, four days later. At weaning, P2- and P3-piglets performed less individual play. Prior to mixing with an unfamiliar piglet (male piglets only), HCA-piglets had lower salivary cortisol concentrations than control piglets, but no difference was observed after mixing. P1-, P2-, and P3- piglets had fewer non-aggressive encounters, and P2-piglets continued fighting longer than control piglets. The present study demonstrates that elevated maternal cortisol concentrations during gestation affect piglet behaviour, and effects do differ between male and female piglets. In addition, effects depend on the period of cortisol administration.     

Tail docking in pigs: acute physiological and behavioural responses

Tail docking of piglets is a routine procedure on farms to control tail-biting behaviour; however, docking can cause an acute stress response. The objectives of this research were to determine the stress responses to tail docking in piglets and to compare two methods of tail docking; cautery iron (CAUT) and the more commonly used blunt trauma cutters (BT). At approximately 6 days of age, piglets were tail docked using CAUT (n = 20), BT (n = 20) or sham tail docked with their tails remaining intact (CON; n = 40). Blood samples were taken prior to tail docking and at 30, 60 and 90 min after tail docking to evaluate the effect of tail docking on white blood cell (WBC) measures and cortisol concentrations. The above experiment was repeated to observe behaviour without the periodic blood sampling, so as not to confound the effects of blood sampling on piglet behaviour. Piglet behaviour was recorded in the farrowing crate using 1 min scan-samples via live observations for 60 min prior to and 90 min after tail docking. Total WBC counts were reduced (P > 0.05) among BT and CAUT compared with CON piglets 30 min after tail docking. Cortisol concentrations were higher (P < 0.01) among BT compared with CON and CAUT piglets 60 min after tail docking. Cautery and BT-docked piglets spent more (P < 0.05) time posterior scooting compared with CON piglets between 0 and 15 min, and 31 and 45 min after tail docking. Piglets tail docked using CAUT and BT tended to spend more (P < 0.07) time sitting than CON piglets between 0 and 15 min post tail docking. Elevated blood cortisol can be reduced by the use of the CAUT rather than the BT method of tail docking. Although the tail docking-induced rise in cortisol was prevented by using CAUT, the behavioural response to BT and CAUT docking methods was similar.     

Effect of rearing system and mixing at loading on transport and lairage behaviour and meat quality: comparison of free range and conventionally raised pigs

Free range pigs, born outdoors and reared after weaning in enriched indoor accommodation, were compared with conventionally raised pigs from a farm, matched for effects on meat quality, with respect to behaviour during transport and lairage, blood chemistry at slaughter and meat quality characteristics. Pigs were either kept in farm pen groups or were mixed at loading and kept in the groups, so formed, until slaughter. Free range pigs tended to settle faster during the 2½ h transport and 2 h lairage than conventionally raised pigs and were more likely to lie as resting posture during transport. Mixing at loading had no effect on posture during transport or during lairage for free range pigs but mixed conventionally raised pigs showed a greater variability in posture during lairage compared to non-mixed conventionally raised pigs, presumably as a result of disturbance from fighting conspecifics. Conventionally raised and free range pigs showed similar levels of aggression during transport but conventionally raised pigs were more aggressive during the lairage (average for mixed groups 12 v. 2 fights, P < 0.001). Aggressive interactions, such as one-way bites, were almost exclusively confined to mixed groups and all fights with mutual biting in mixed groups occurred solely between unfamiliar animals. The frequency of unacceptable skin damage in the middle and shoulder was highest in conventionally raised pigs and in mixed groups. Cortisol concentration and creatine kinase (CK) activity in slaughter blood were not affected by the rearing system. Mixing did not affect cortisol concentrations but led to higher CK activities compared to non-mixing (957 v. 588 U/l, respectively, P < 0.05). The rate of pH fall after slaughter was not affected by the rearing system but muscle temperatures early post mortem were highest in free range pigs. Mixing did not affect pH or temperature early post mortem. Neither rearing system nor mixing at loading affected ultimate pH or internal reflectance (meat quality marbling values).     

Effect of fermented liquid diet prepared with Lactobacillus plantarum LQ80 on the immune response in weaning pigs

Probiotics such as lactic acid bacteria directly influence the host's health and have beneficial effects such as decreasing the number of enteric pathogens, regulating intestinal immune responses and preventing diseases. Among domestic animals, probiotics have been expected to be an alternative to antibiotics added in the diet; and fermented liquid diet (FLD) containing probiotics has great potential as a diet for reducing the use of antibiotics. In this study, we evaluated the immunomodulatory effects of FLD, prepared using Lactobacillus plantarum LQ80 (LQ80), on the immune response of weaning pigs. Ten weaning piglets were divided into two groups and were fed the FLD (n = 5) or a non-fermented liquid diet (NFLD) (n = 5) for 28 days. At the end of the experiment, the total immunoglobulin M (IgM) and immunoglobulin G (IgG) levels in the sera of the FLD-fed piglets were significantly higher than those of the NFLD-fed piglets (P < 0.05). In contrast, the total immunoglobulin A (IgA) levels in the feces and saliva were not significantly affected by FLD feeding. However, the mean fecal IgA levels of FLD-fed piglets at day 28 were higher than those at 14 and 21 days (P < 0.05). Blood cells from the FLD-fed piglets showed a low level of interferon-γ secretion and mitogen-induced proliferation compared to that of the NFLD-fed piglets. Furthermore, the levels of interluekin-8 and tumor necrosis factor-α, which are proinflammatory cytokines, in the blood cells of the FLD-fed piglets were lower than those of the NFLD-fed piglets (P < 0.05). In conclusion, the FLD used in this study could alter the immune responses of weaning piglets by stimulation of the systemic or mucosal antibody response, without unnecessary inflammatory reactions. This indicates, that the FLD feed prepared with the use of LQ80 may be a candidate feed, with regard to enhancing immune responses and preventing diseases in weaning piglets.     

Cortisol concentrations in the perinatal and weaning periods of alpacas.

Cortisol concentrations were determined during the perinatal and weaning periods in alpacas. Fifty males and 50 females were chosen at random (25 at each period) for blood collection on day of parturition, 3 and 5 days after birth. For the weaning period, blood samples were collected 2 days before, on the day of weaning (0), and at days 3 and 5 after weaning. Cortisol was determined using an ELISA protocol validated for the alpaca. There was no difference (P>0.05) in cortisol concentrations in both periods, perinatal and weaning between male and female crias. Cortisol was elevated at day of parturition (125.8 ng/ml) and then decreased to 27.2 ng/ml at 3 days after birth (P<0.05). Conversely, cortisol was 32.5 ng/ml 2 days before weaning and then increased at day 3 to 64.7 ng/ml (P<0.05), but then decreased to 29.4 ng/ml at day 5 after weaning. Cortisol is elevated in new-born alpacas and then decreases at the third and fifth after birth. Concentrations of cortisol are also increased after weaning and then decreased 5 days after weaning.     

Cortisol and β-endorphin levels in peripheral circulation around weaning in primiparous sows

Peripheral plasma patterns of cortisol and β-endorphin were compared around weaning in primiparous sows. Blood samples for hormone analysis were collected repeatedly on the day before weaning, on the day of weaning and on the day after weaning. Peak cortisol and β-endorphin levels occurred shortly after weaning on the day of weaning. Cortisol concentration on the day of weaning was greater (P < 0.001) than on the day before weaning, which in turn was higher (P < 0.05) than on the day after weaning. β-Endorphin concentrations on the day before weaning and on the day of weaning were similar, but were greater (P < 0.01) on both these days than on the day after weaning. Overall, cortisol and β-endorphin patterns followed a similar trend, which was more marked on the day before weaning and on the day of weaning than on the day after weaning. Pearson's correlation coefficients for peripheral plasma cortisol and β-endorphin secretion were 0.61 (P < 0.001) on the day before weaning, 0.63 (P < 0.001) on the day of weaning and 0.15 (P < 0.13) on the day after weaning. The present study indicates that suckling and weaning are stressful stimuli during which the peripheral plasma concentrations of cortisol and β-endorphin follow a similar trend.     

半胱胺对断奶前后仔猪血清皮质醇、T3、T4和IL-2水平的影响

选取新生仔猪18窝,随机分为对照组和处理组各9窝。从12日龄开始,对照组饲喂基础乳猪料;处理组在基础乳猪料中添加半胱胺,剂量为120mg／kg饲料。两组仔猪均在35日龄断奶。分别于断奶前7d(28日龄,D28),断奶当天(D35),断奶后36h(D36．5)、72h(D38)、7d(D42)、10d(D45),随机选取对照组和处理组仔猪各6头,屠宰采集血样。采用放射免疫分析法测定仔猪血清皮质醇、三碘甲腺厚氨酸(T3)、甲状腺激素(T4)和白细胞介素-2(IL-2)水平。结果表明：(1)对照组血清皮质醇水平在断奶前保持稳定,在D36．5时升高,在D42时恢复至D35水平,随后保持稳定;处理组血清皮质醇水平在D36．5时较D35有升高趋势,在D38时恢复至D35水平,随后保持稳定。对照组血清T3水平在D36．5显著高于D28,其他日龄点间无显著差异,处理组基本保持稳定。对照组血清T4水平在D36．5时升高,在D38日时恢复至D35水平,随后保持稳定;处理组血清T4水平从D35至D45基本保持稳定。两组中血清IL-2水平在D28至D42保持稳定,D45升高。(2)在D36．5时,处理组血清皮质醇水平较对照组降低30％,处理组血清T3水平在D35和D45较对照组提高49．2％和38．6％,T4水平在D35和D45提高31％和45．8％,在其他日龄点,处理组T3、T4水平较对照组有升高趋势,但差异不显著。处理组IL-2水平在D36．5、D38、D45也分别较对照组提高22．1％、12．6％和17．8％,在其他日龄点有升高趋势。以上结果提示半胱胺能抵抗仔猪断奶应激,提高仔猪血清T3、T4水平,增强仔猪的免疫力。     

Body composition and organ development of intra-uterine growth restricted pigs at weaning

Sow litter sizes have increased, subjecting more small piglets to intra-uterine growth restriction (IUGR). Research on the development and growth of IUGR pigs is limited. The objective of this study was to compare the body composition and organ development of IUGR pigs at weaning, and to estimate their growth performance from birth to 30 kg. A total of 142 IUGR and 142 normal piglets were classified at birth based on their head morphology. At weaning, 20 IUGR and 20 normal piglets were collected, a whole-body dual-energy x-ray absorption scan was performed, and the piglets were euthanized for organ measurements. Body weight (BW) was measured weekly from birth to 30 kg, rectal temperature and whole-blood glucose levels were measured weekly from birth to weaning, and blood samples were collected at days 7, 14 and 21 for IGF-1 analysis. Results showed that IUGR pigs have a similar percentage of adipose tissue (P > 0.05) compared to normal pigs at 24 days of age. Organs were smaller (P < 0.001) in IUGR pigs than in normal pigs, whereas brain, liver, lungs and adrenal glands were relatively larger (P < 0.05) in relation to the BW of IUGR pigs. Average birth weight (BiW) of normal pigs was greater (P < 0.001) compared with IUGR pigs (1.38 v. 0.75 kg), and the average daily gain (ADG) of IUGR pigs was reduced from day 0 to 14, day 0 to 28 (weaning) and from weaning to 30 kg compared to normal pigs. From birth to weaning at day 28, IUGR piglets had a 72.9 g/day greater fractional ADG (FADG) in relation to their BiW (P < 0.05), but FADG did not differ (P > 0.05) from weaning to 30 kg. Rectal temperature of IUGR piglets was greater (P < 0.05) on day 7 compared with normal piglets, and, even though blood glucose levels were decreased (P < 0.001) in IUGR piglets at day 0, neither glucose nor IGF-1 concentrations differed (P > 0.05) between IUGR and normal piglets. In conclusion, IUGR piglets exhibited some relatively larger organs at weaning compared to normal pigs, but body composition was similar between IUGR and normal pigs. In addition, IUGR pigs had a reduced ADG from birth to 30 kg, and, although they exhibited a greater FADG during nursing, IUGR pigs still require six additional days to reach a BW of 30 kg in comparison to normal pigs.     

The influence of early contact with humans on subsequent behavioural response of pigs to humans

This study examined the influence of three handling treatments, imposed from birth to 8 weeks, on the approach behaviour of 24 pigs to humans at 10–24 weeks of age. Piglets in two treatments, weaning/handling and handling, regularly received human contact, while piglets in the third treatment, no handling, only received human contact during routine husbandry. Piglets in the weaning/handling treatment were artificially reared, while those in the other two treatments remained on the sow until weaning at 4 weeks of age. Pigs in the weaning/handling and handling treatments showed increased approach to a stationary human in six tests from 10 to 24 weeks of age. For example, piglets in the weaning/handling and handling treatments spent more (P<0.01) time within 0.5 m of the human and were quicker (P<0.05) to physically interact with the human than pigs in the no handling treatment. Observations on the sexual behaviour of the boars from 25 to 35 weeks of age indicated that handling had no adverse effects on sexual behaviour.It is concluded that early handling of pigs will influence their behavioural response to humans later in life. Therefore, early handling may be a practical method for man to manipulate the pig's subsequent relationship with humans. The possibility of the existence of a “sensitive period” for “socialization” in pigs is discussed in the light of the present results.     

Influence of social mixing and group size on skin lesions and mounting in organic entire male pigs

Alternatives to surgical castration are needed, due to stress and pain caused by castration of male pigs. One alternative is production of entire male pigs. However, changed behaviour of entire males compared with castrated males might adversely affect the welfare of entire males and changes in management procedures and production system might be needed. Elements from the organic pig production system might be beneficial in this aspect. The aim of this article is to investigate the effect of grouping strategy including social mixing and group size on levels of mounting behaviour and skin lesions, hypothesising that procedures that disrupt the social stability (e.g. regrouping) will have a larger negative effect in small groups compared with large groups. Approximately 1600 organic entire male pigs of the breed (Landrace×Yorkshire)×Duroc were reared in parallel in five organic herds, distributed across four batches in a 2×2 factorial design in order to test the influence of social mixing (presence or absence of social mixing at relocation) and group size (15 and 30 animals). Animals were able to socialise with piglets from other litters during the lactation period, and were all mixed across litters at weaning. A second mixing occurred at insertion to fattening pens for pigs being regrouped. Counting of skin lesions (1348 or 1124 pigs) and registration of mounting behaviour (1434 or 1258 pigs) were done on two occasions during the experimental period. No interactive effects were found between social mixing and group size on either skin lesions or mounting frequency. Herd differences were found for both mounting frequency and number of skin lesions. No association between skin lesions and mounting were revealed. Social mixing and group size were shown as interacting effects with herds on mounting frequency (P<0.0001), but with no consistent pattern across all herds. In addition, no effect of social mixing was found on mean number of skin lesions, but more lesions were observed in large groups (P<0.036). This could indicate that keeping entire male pigs in groups of 30 animals as compared with smaller groups of 15 may marginally decrease the welfare of these animals.     

Short-term behavioural effects of weaning age in outdoor-reared piglets

Age at weaning affects the behaviour of piglets weaned in conventional confined environments. The adaptation of piglets to this event, which exposes piglets to important stressors, has not been examined in detail in outdoor systems. The aim of this study was to compare the behaviour of piglets weaned at 3 or 4 weeks of age in an outdoor production system. Six replicates of four piglets born and raised outdoors, originated from different litters but previously acquainted, were weaned at the age of approximately 20 (D20) or 30 (D30) days in 36 m2 outdoor pens and offered high-quality diets. Their behaviour was recorded by direct visual observation during four consecutive days after weaning (days 1 to 4). Data were analysed by repeated measures ANOVA. An effect of weaning age was observed on feeding and rooting ( P < 0.01), and a day-by-weaning age interaction for escape attempts, vocalizing, walking and fighting ( P < 0.01), and playing ( P < 0.03). Compared to D30 piglets, D20 piglets showed a higher frequency of escape attempts on day 1, vocalized more during days 1 and 2, and walked more during days 1 to 3 ( P < 0.05). Feeding behaviour, on the other hand, was higher in D30 piglets on days 1 to 3 ( P < 0.05). On days 3 and 4, D30 piglets spent more time interacting with peers (playing and fighting; P < 0.05) and on day 4 were more active than D20 piglets ( P < 0.05). As previously reported in confined environments, age at weaning affected the behaviour of piglets raised on the outdoors system. Weaning appeared to be more stressful for the piglets at 3 than at 4 weeks of age. The impact of weaning age on welfare cannot be ignored, especially when outdoor breeding of pigs is proposed to address welfare concerns of the public.     

The influence of a magnesium-rich marine extract on behaviour,salivary cortisol levels and skin lesions in growing pigs

Growing pigs can display undesirable behaviours, reflecting or causing poor welfare. Addition of magnesium (Mg) to the diet could reduce these, as Mg supplementation has been associated with improved coping ability in response to stress. This study examined the effect of supplementation with a Mg-rich marine extract-based product (Supplement) on the behaviour, skin and tail lesion scores and salivary cortisol concentrations of growing pigs. At weaning (28 days), 448 piglets were assigned to either Control or Supplement (0.05%) diets in single-sex groups of 14. Four weeks later (c. 17 kg), pigs were blocked according to weight and back test scores. Seven piglets from each pen were mixed with seven from another pen of the same sex and dietary treatment to yield the following groups: control male, Supplement male, control female and Supplement female (n = 4 of each). This marked the start of the 9-week experimental period. Instances of the following behaviours were recorded in each pen for 8 × 2 min periods 1 day/week: aggression (fight, head-knock and bite); harmful (tail-in-mouth, ear-chewing and belly-nosing); and sexual/mounting behaviour. Four focal pigs were selected from each pen, and their behaviour was continuously recorded for 2 × 5 min periods on the same day. Saliva was collected once per week at 1000 h by allowing pigs to chew on a cotton bud for c. 1 min. Salivary cortisol was analysed in duplicate by an enzyme immunoassay. Skin and tail lesions were scored according to severity 1 day/week. There were fewer aggressive incidents in Supplement pens (P < 0.01), and mounting behaviour (performed only by males) was almost three times lower in Supplement than in control pens (P < 0.01). However, there was no effect of Supplement on the incidence of each of the harmful behaviours. Behaviour of the focal pigs showed no treatment effect on the duration or incidence of aggressive behaviour. However, Supplement pigs spent less time performing harmful behaviours compared with control pigs (P < 0.001). Supplement had no effect on the occurrence or severity of tail-biting outbreaks or on tail lesion scores. However, Supplement females had lower skin lesion scores, in particular in the ears and shoulders (P < 0.01). Finally, Supplement pigs had lower salivary cortisol concentrations (P < 0.01). Mounting is a major welfare concern in uncastrated pigs, and therefore this represents an important welfare benefit of Supplement. Reduced salivary cortisol, in conjunction with reduced skin lesion scores in supplemented females, suggests that addition of a Mg-rich marine extract improved pig welfare in this system.     

Behavioral,immunological, and hormonal responses associated with social change in rhesus monkeys (Macaca mulatta)

Twelve animals to be socially reorganized in a group of 49 animals were compared with ten animals in a socially stable group (n = 51) for reproductive hormones, cortisol concentrations, immune function, and behavioral patterns for a 6 week baseline and 16 week postreorganization period. Cortisol values, mitogen-induced lymphocyte blastogenesis, and rates of behavior reflected social events. Increased cortisols, increased noncontact aggression, and decreased mitogen response were associated with animal introductions. Increased cortisol concentration and decreased mitogen response correlated significantly only in animals removed from the group for trauma, and females successful at group membership exhibited lower cortisol concentrations. High-ranking animals in small stable groups exhibited significantly higher lymphocyte proliferation than middle- or low-ranking animals. While relative ranks established in small groups were maintained following reorganization, baseline cortisol values, immune measures, or male testosterone values did not predict success at group membership. © 1996 Wiley-Liss, Inc.     

The Weaning Process of Free-ranging Domestic Pigs: Within- and Between-litter Variations

To determine variations within and between litters in the weaning process and behavioural development, the behaviour of four focal piglets from each of nine litters was recorded at the ages of 4, 6, 8 and 10 wk in a 12.5-ha semi-natural environment. The piglets were weighed at birth, at 7–11 d and at 7 wk. Activities and nearest-neighbour distances were recorded instantaneously and social interactions continuously during 4 times 11 min/piglet at all ages. Within-litter comparisons were obtained by transforming raw data to standard scores within litters. There were significant age effects on all behavioural variables except aggression, which, however, was very rare. There were also significant effects of sow and boar on several behavioural variables, as well as interactions between sow/boar and age, indicating a possible genetic influence on the behavioural development. Within-litter variations did not relate to sex or weight. Within litters, some individuals tended to be more associated with their families and to rely more on milk for nutrients whereas others tended to affiliate with other families and spend more time feeding on solids. The latter group could be conceived of as piglets starting the weaning process earlier.     

Can novel methods be useful for pain assessment of castrated piglets?

Given that surgical castration is a painful practice performed on millions of pigs every year, a need to identify novel reliable pain assessment tools exists in order to test anaesthetic and analgesic protocols that may reduce related pain. Two treatments were considered: handling (H) and surgical castration (C). Physiological (cortisol, lactate, glycaemia, rectal and eye temperature) and behavioural variables (latency to move after treatment and alterations in posture and walking) were analysed. Cortisol showed the greatest level in C piglets within 20 min after the surgical procedure and a positive correlation with glucose concentration. Eye temperature was higher in C piglets, and the same difference was detected for rectal temperature 3 h after castration. Behavioural parameters revealed that C piglets had longer latency to move and a higher percentage of them showed alterations in posture and walking. Results of this study showed that, in castrated piglets behavioural and physiological alterations occur mainly in the first 3 h from treatment. Latency to move, alterations in posture and walking, and eye temperature appear to give additional and useful information in piglet pain assessment. However, differently from the behavioural parameters considered, eye temperature involves several manipulations of the animals and a long process to acquire the data.     

Effect of a bovine colostrum whey supplementation on growth performance, faecal Escherichia coli population and systemic immune response of piglets at weaning

This study examined the effect of a bovine colostrum whey supplementation on growth performance, feed intake, faecal Escherichia coli population and systemic immune response of piglets at weaning. A total of 96 piglets weaned at 26 ± 2 days of age were assigned for 4 weeks to one of the two treatments: (1) the control (commercial diet with bovine milk whey powder) and (2) the colostrum (commercial diet with freeze-dried bovine colostrum whey) treatments. The two supplements were incorporated in the diet at a level of 20 g/kg during the first 2 weeks after weaning and lowered to a level of 10 g/kg for the next 2 weeks. BW and feed intake were measured weekly. Faecal E. coli counts were determined weekly on specific culture media. Blood samples were collected weekly and submitted to a cell counter analyser for their main components (red and white blood cells, platelets) and flow cytometry was used to determine the lymphocyte population (B, T, Th and Tc). Finally, total seric immunoglobulin (IgM, IgG and IgA) concentrations were determined by the ELISA method. During the first week of the trial, the piglets from the colostrum treatment had improved average daily gain (170 g/day v. 81 g/day, P < 0.001), average daily feed intake (346 g/day v. 256 g/day, P = 0.03) and feed efficiency (BW gain/feed intake) (0.48 v. 0.31, P = 0.04). The pigs fed the colostrum treatment had also a 25% increase in circulating IgA (P = 0.03) compared with the control treatment the first week. It is concluded that a distribution of bovine colostrum whey (20 g/kg diet) during the first week post-weaning induces a systemic IgA response and has a beneficial action on growth performances and feed efficiency.     

Behavioural, growth and immune consequences of early weaning in one-week-old large-white piglets.

Genetic improvement in sows' prolificity is limited by their milk capacities, which do not allow all piglets to survive or grow normally. This experiment compared the behaviour, growth and immune responses of piglets that were weaned early at 6 days of age (EW) vs. control Large White piglets' (C) suckled by their mothers. Behaviour of 9 litters of 5 to 8 piglets in each group were observed from d5 to d20. All piglets were weighed from birth to d74. Three piglets from each group were slaughtered on d36 for immunological analysis. Until they began to eat dry food, EW piglets walked and vocalised more than C piglets. After that time, when resting, they were less often lying down and more frequently in contact with littermates under the heater. Aggressive behaviour and belly-nosing were more frequent. They displayed a more marked growth check after weaning than did C piglets until 28 days of age. In EW piglets, at 36 days of age, there was a higher density of T- and B-lymphocytes in the gut epithelium and lamina propria, fespectively, in relation to the size of lymphoid follicles of Peyer's patches. The results indicate great behavioural adaptation capacities of very early-weaned piglets, together with earlier maturation of their gut immune system.