Effects of space allowance on the welfare of dry sows kept in dynamic groups and fed with an electronic sow feeder

The minimal legal space allowance for grouped pregnant sows in the EU is 2.25 m²/sow. The effect of higher space per animal on agonistic behaviour and social stress of animals living in dynamic groups is not known.Two groups of 34 pregnant Belgian Landrace sows were housed in two pens of respectively 102 m² (3 m²/sow) and 76.5 m² (2.25 m²/sow). Each sow lived there for 15 weeks. Sows were fed through an electronic sow feeder. According to the dynamic system, one third of each group (i.e. 11 or 12 nearly parturient sows) was replaced every 5 weeks by the same number of recently inseminated sows. Welfare indicators were collected during six of these 5 week-periods: performance, agonistic behaviour, skin lesion score and salivary cortisol. No differences were observed for production parameters, or for fighting activity. However, the mean number of one-way aggressions, when observed during 2 h-periods at 3 and 8 days after grouping, was significantly lower in the large pen than in the small one (respectively 16 ± 2 versus 26 ± 3, p < 0.01, and 10 ± 2 versus 20 ± 5, p < 0.05). The mean number of injuries was also lower with the 3 m² space allowance, when collected on the introduced sows one, 2 and 3 weeks after grouping. Some contradictory differences in salivary cortisol were noted 2 and 26 h after mixing, but without reaching statistical significance. An available area 33% higher than the EU legal minimum reduced agonistic behaviour and consecutive wounds and thus induced better welfare conditions for sows living in dynamic groups and fed with an electronic sow feeder. The impact on productivity and social physiological stress need further research.     

On-farm evaluation of methods to assess welfare of gestating sows

The objectives were to evaluate quantitative animal-based measures of sow welfare (lameness, oral stereotypies and reactivity to humans) under commercial farm conditions, and to estimate the influence of housing, sow parity and stage of gestation on the outcome of these measures. Across 10 farms, 311 sows were used. Farms differed in terms of housing design (pen v. stall), space allowance, floor type in stalls (partially v. fully slatted), and feeding system in pens (floor v. trough). Lameness was assessed in terms of gait score, walking speed, stride length, stepping behaviour, response to a stand-up test and latency to lie down after feeding. The presence of oral stereotypies and saliva foam were recorded. Reactivity to humans was assessed by approach (attempt to touch the sow between the ears) and handling tests (exit of the stall for stall-housed sows, or isolation of the animal for pen-housed sows). Only stride length and walking speed were associated with lameness in stall-housed sows (P<0.05 and P<0.01). In stalls, the probability that a sow was lame when it presented a short stride length (<83 cm) or a low speed (<1 m/s) was high (69% and 72%, respectively), suggesting that these variables were good indicators of lameness, but were not sufficient to detect every lame sow in a herd (sensitivity of 0.39 and 0.71, respectively). The stage of gestation and parity also influenced measures of stride length and walking speed (P<0.05). Saliva foam around the mouth was associated with the presence of sham chewing and fixture biting (P<0.05). The probability that a sow presents sham chewing behaviour when saliva foam around her mouth was observed was moderate (63%) but was not sufficient to detect all sows with stereotypies (41%). A high discrimination index was obtained for behavioural measures (aggressions, escapes) and vocalisations during the approach test (stalls: 78.0 and 64.0; pens: 71.9 and 75.0, respectively), the number of interventions needed to make the sow exit the stall during the handling test for stall-housed sows (74.9), and attempts to escape during the handling test for pen-housed sows (96.9). These results suggest that these measures have a good power to discriminate between sows with low and high reactivity to humans. Finally, the outcome of several measures of lameness, stereotypies and reactivity to humans were influenced by the housing characteristics, sow parity and stage of gestation. Therefore, these factors should be considered to avoid misinterpretations of these measures in terms of welfare.     

Piglets’ behaviour and performance in relation to sow characteristics

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

Seasonal and management effects on fertility of the sow: a descriptive study

This study was undertaken to determine management and seasonal effects on fertility in 1298 Finnish sow units over a 4-year period in 1992-1996. A multivariate analysis of the herd record data was undertaken to study the effect of various management factors on rebreeding rate. Factors found to have an effect were further subjected to time series plotting for seasonal effects. In addition, seasonal effects on the farrowing rate, age of gilts at first mating and littersize as well as the 3-week litterweight were studied. Year and month caused the most significant variation in the rebreeding rate. Moreover, geographical area, herd and way of breeding (mating vs. artificial insemination) were found to be significant determinants of rebreeding rate. Dry sows loosely housed were more likely to be rebred than sows housed in individual stalls. Sows receiving roughage feed (hay, straw) or bedding (straw) were less likely to require rebreeding. A significant seasonal fluctuation in farrowing rate was found with a nadir of 72.6% in August and a high of 80.9% in January. The average farrowing rate for the 4-year period was 77.7%. The age of gilts at first mating showed seasonal variation of 11 days (229.9 +/- 0.5 days in March and 241.4 +/- 0.5 days in November). In conclusion, this study indicates that group housing of dry sows increases the risk of rebreeding. In group housed sows, rebreeding more often occurs after an irregular oestrus-to-oestrus interval in summer-autumn whereas a not-in-pig seems to be a more common finding at late gestation in individually housed sows.     

Effects of individual versus group housing system during the weaning-to-estrus interval on reproductive performance of sows

Selection of appropriate housing conditions for sows is critical for their physical health and long-term reproductive success. The present objective was to evaluate the influences of housing system postweaning (i.e., individual stalls (IS) or group pens (GP)), season and parity on piglet productivity of sows in a commercial setting. This study utilized 3 053 Polish Large White × Polish Landrace sows that were weaned at a rate of 20–30 animals per week at the median age of 4 weeks; 1 474 sows were moved into GP of seven to eight animals each, while 1 579 were placed in IS after weaning. Starting 2 days postweaning all animals were checked for estrus with a teaser boar and then artificially inseminated using 3 × 10⁹ spermatozoa per dose of an inseminate at the onset of heat and 24 h later. The proportion of sows showing the signs of standing heat at or before 6 days postweaning was greater (P < 0.05) for sows moved to GP compared with IS; this difference manifested mainly in second parity sows weaned in the summer and fall. Conception and farrowing rates were significantly higher (P < 0.01) and the weaning-to-estrus interval shorter in GP compared with IS sows in every season but autumn. Mean litter size was lower (P < 0.05) in IS groups in summer, autumn, and winter, and the number of live-born piglets/sow was lower (P < 0.05) for IS sows in the summer and fall. Beneficial effects of group housing on piglet productivity manifested up until the seventh consecutive farrowing and then began to wane. In summary, there was a significantly greater proportion of sows going estrus “on time” (i.e., < 7 days) in group housing compared to single stalls but this effect was confined to the second parity sows during the summer and fall months; these results suggest the existence of a seasonal and age-related aspect to sow fertility worthy of further investigation. While both housing systems have their pros and cons, our present results indicate that, in commercial settings, group housing postweaning improved nearly all reproductive parameters of sows.     

Diurnal rhythm of bar-biting in relation to other behaviour in pregnant sows

Instantaneous observations of behaviour were made with video once every sixth minute around the clock (in 20-s recordings at each interval) during the first 3 days following the introduction of pregnant sows into one of the following three environments: (1) loose housing in groups of five with a common lying area, a dunging area and individual feeding stalls (20 sows); (2) semiconfinement in groups of four in individual feeding stalls with access to a common dunging area (16 sows); (3) confinement in individual stalls (16 sows). In addition, direct observations of straw-directed behaviour after feeding were made. Bar-biting was most frequent in confinement and least in loose housing (22.5% of observations when the sows were active in confinement, 7.5% in semi-confinement and 3% in loose housing). Bar-biting was mainly performed during ∼2 h following feeding. At the time when confined and semi-confined sows performed most bar-biting, the loose-housed sows moved a lot and performed complex straw-directed activities, including several of the normal nest-building behaviours. It was concluded that the differences in frequencies of stereotypies cannot be explained only by frustration at feeding, but depend on the housing system of the sows. Many of the movements in the stereotyped sequences of the confined sows resembled elements in the nesting sequences of loose-housed sows, supporting the hypothesis that a thwarted movement pattern can develop into a stereotypy, which then may bear resemblance to the normal movements.     

An interaction between feeding rate and season affects fertility of sows

Trials were conducted in two piggeries in the summer-autumn and winter-spring periods to determine the effects of rate of feeding and type of housing (group or individual stalls) on farrowing rate. Sows were fed a low (1.6–2.0 kg per sow per day), moderate (2.5 kg per sow per day) or high (> 3.6 kg per sow per day) rate for the first 4 weeks postmating and from then until farrowing fed at a moderate (2.5 or 3.2 kg per sow per day) rate. The low level of feeding in the summer-autumn was associated with increased numbers of delayed returns to oestrus and low farrowing rate (< 75%) typical of the infertility that occurs at this time of the year. This same rate of feeding in winter-spring was associated with few delayed returns to oestrus and a high farrowing rate (> 85%). Feeding sows at the high rate during the summer-autumn significantly improved the farrowing rate reducing the adverse effect of season. Litter size was not affected by feeding rate during early pregnancy. The seasonal effect on farrowing rate was not evident in individually stalled sows fed a moderate level during pregnancy. This study demonstrated effects on farrowing rate of interactions between rate of feeding and season and type of accommodation and season. Current practice restricting feed intake postmating, aimed at reducing embryonic mortality and increasing litter numbers, appeared to contribute substantially to the decrease in farrowing rate commonly observed in summer-autumn. The optimal level of feeding to minimise the effect of season on fertility has yet to be defined. Accommodation of sows in individual stalls, rather than in groups, removed the seasonal effect on fertility.     

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.     

大豆黄酮对母猪免疫功能和血清及初乳中GH、PRL、SS水平的影响

研究口服大豆黄酮对妊娠母猪及其仔猪的免疫功能和血清、初轧中生长激素（ＧＨ）、催乳素（ＰＲＬ）、生长抑素（ＳＳ）水平的影响，结果表明：１）大豆黄酮能明显提高母猪血清和初乳中特异性抗体（猪瘟抗体或溶血素）的水平，表明母猪整体和乳腺器官的体液免疫功能明显增强。２）通过对初乳的吸收，其新生仔猪血清中母源抗体水平明显高于对照组。３）母猪血清和初乳中ＧＨ、ＰＲＬ含量明显高于对照组，而血清ＳＳ含量显著低于对照组。本实验结果提示：垂体ＰＲＬ、ＧＨ和体内ＳＳ可能参与了大豆黄酮对猪免疫功能的调节过程。     

A Field Study on Group Housing of Lactating Sows with Special Reference to Sow Health at Weaning

Four farms that group-housed sows from 2 weeks of lactation until weaning (G-farms) and 3 farms that kept the sows individually penned throughout the 5 to 6-week-long lactation period (C-farms), were compared in terms of sow health. All sows were crossbred Swedish Yorkshire × Swedish Landrace. The daily food ration was similar on all farms except during the group-housing period, when G-farm sows were fed ad libitum. Sows were grouped in the breeding section and kept grouped on deep litter in the dry sow section on all farms. Individual health examinations were performed at the time of weaning (±4 days) on 179 G-farm sows and on 167 C-farm sows. Teat- and udder skin wounds occurred less frequently (p<0.001) in G-farm sows than in C-farm sows. In addition, preweaning atrophy of all mammary glands occurred in 6.6% of the G-farm-sows but not in a single C-farm sow (p<0.001). This indicates that sow-piglet interactions decrease when sows are group housed. However, these differences did not occur in primiparous sows, suggesting that the relation between the primiparous sow and her litter is not affected. Mastitis frequency was the same in the 2 systems. Moreover, the frequency of locomotor disorders was the same in the 2 groups, and hoof overgrowth was common in both systems. These similarities could be due to the fact that all farms group housed dry sows on deep litter. A strong relation (p<0.001) between hoof overgrowth and locomotor disorders was evident. Low access to food due to low rank among primiparous group-housed sows was indicated by a lower (p<0.05) backfat thickness compared with multiparous sows, and a higher (p<0.001) frequency of skin wounds compared with individually housed primiparous sows.     

Modifications in the aggressive and ingestive behavior of the neonatal piglet as a result of prenatal elevation of cortisol in the dam

Ninety-eight piglets from 10 sows were used to study their neonatal agonistic and ingestive behavior after stimulation of the preparturient sow with adrenocorticotrophic hormone (ACTH). The sows were randomly assigned to either an ACTH or a control group on the 104th day of gestation. Sows in the ACTH group were catheterized and infused with 1IU porcine ACTH kg⁻¹ day⁻¹ in 1 l of saline. Control sows were similarly catheterized and infused with the same volume of saline, both treatments being maintained until parturition. A blood sample was collected daily from all sows. At birth piglets were weighed, bled and freed in the rear of the farrowing crate. They were then observed for the first 6 h of life to record their birth to suckle (BTS) interval. At the same time all instigator and victim interactions were recorded. Three subsequent blood samples were then collected from the piglets at 2, 4 and 6 h of life, and analyzed for glucose and cortisol. In both groups the concentration of plasma cortisol proved to be decreased (P<0.05) after birth while glucose increased within 2 h. The total number of instigations observed was higher (P<0.05) in pigs born to control sows than in those born to ACTH-treated sows. When values were expressed as instigations per pig or number of instigations relative to the total number of possible interactions within the litter, piglets of the ACTH group also exhibited less (P<0.05) aggressive instigations than those born to the control sows. Victimizations were not influenced either by treatment or sex. ACTH pigs had slightly shorter BTS intervals (P<0.05) than those in the control group. Females were lighter (P<0.05) than males at birth but they took less time to suckle than males. Accordingly it is concluded that the prenatal treatment of the sows with ACTH reduces the rate of agonistic interactions and tends to reduce the time required for first-time successful suckling.     

Public Attitudes to Housing Systems for Pregnant Pigs

Understanding concerns about the welfare of farm animals is important for the development of socially sustainable production practices. This study used an online survey to test how views on group versus stall housing for pregnant sows varied when Canadian and US participants were provided information about these systems, including access to scientific papers, YouTube videos, Google images, and a frequently-asked-questions page (S1 Appendix). Initial responses and changes in responses after accessing the information were analyzed from Likert scores of 242 participants and from their written comments. Participants were less willing to accept the use of gestation stalls after viewing information on sow housing. For example, initially 30.4% of respondents indicated that they supported the use of gestation stalls; this declined to 17.8% after participants were provided additional information. Qualitative analysis of comments showed that supporters of gestation stalls expressed concern about the spread of disease and aggression between animals in less confined systems, whereas supporters of group housing placed more emphasis on the sow’s ability to interact socially and perform natural behaviors. These results point to public opposition to the use of gestation stalls, and indicate that the more that the public learns about gestation stalls the less willing they will be to accept their use.     

The effect of different housing conditions on behavioural and adrenocortical reactions in veal calves

Veal calves were housed either tethered indoors on slatted floorings or loose in groups of eight in a semi-open barn with straw bedding. Six weeks after arrival at the station the calves were submitted to a 10-min open-field session in either the same environment as the one in which they were housed or in the alternative environment. During this session, activity, latency time to first movement and duration of immobility were scored and blood samples were taken for cortisol determination before and after the session. In both instances, the tethered calves exhibited higher activity scores and shorter periods of immobility. Plasma cortisol levels were significantly affected by testing conditions but not by housing conditions, i.e. plasma cortisol levels increased more when the animals were tested in a different environment from the one in which they were housed. Adrenal cortex response to repeated blood sampling and to ACTH injections was found to be significantly higher in tethered calves. These results show that housing conditions strongly influenced the behaviour and endocrine activity of the calves. The dynamics of these changes need further study.     

Late gestation diet supplementation of resin acid-enriched composition increases sow colostrum immunoglobulin G content,piglet colostrum intake and improve sow gut microbiota

Resin acid-enriched composition (RAC) mainly containing tall oil fatty acid with an active component of resin acid (RA) can improve the microbial population in the digestive system, change the microbial fermentation, and improve the feed conversion ratio. We investigated the effects of dietary supplementation of RAC on sow colostrum yield (CY), colostrum composition and gut microbiota. Tall oil fatty acid and RA are commonly termed RAC and CLA, pinolenic, abietic, dehydrobiotic acids are characteristic components of RAC. The experiment was conducted in three trials in three respective herds. Sows were fed with a control diet and the same diet supplemented with 5 g RAC/day per sow during the last week of gestation. The 16S ribosomal RNA gene sequencing technique was used to assess sows’ faecal microbiota populations at farrowing. Colostrum nutritional composition, acute phase proteins (APPs) and immunoglobulin (Ig) content were also assessed. Individual piglets were weighed at birth and 24 h after the birth of first piglets in order to calculate CY and later at 3 to 4 weeks to calculate average daily gain. The RAC-fed sows had significantly higher IgG levels (P<0.05) in all three herds but treatment did not influence colostrum IgA and IgM concentration. There were no significant differences in colostrum protein, lactose and fat content in sows of the two diet groups (P>0.05), but those fed RAC had higher levels of colostrum serum amyloid A. Colostrum yield was significantly higher in RAC-fed sows in herds 2 and 3 with heavier piglets between 3 and 4 weeks of age (P<0.05), but not in herd 1 (P>0.05). Resin acid-enriched composition supplementation significantly increased some beneficial and fermentative bacteria (Romboutsia and Clostridium sensu stricto) than the control diet (P<0.01) while some opportunistic pathogens (Barnesiella, Sporobacter, Intestinimonas and Campylobacter), including Proteobacteria, were suppressed. Therefore, RAC added to the sow diet at late pregnancy increases colostrum IgG, colostrum availability for neonate piglets, and seems to promote better maternal intestinal microbial sources.     

The effect of modified eros centre, outdoor raising or conventional group housing on breeding gilts and its effects on reproductive performance over four parities

The present study was conducted in a large Croatian "built up unit". The objective of the study was to determine if an indoor modified eros centre (MEC) compared to indoor or outdoor group housing of gilts, influenced the onset of puberty of gilts and the reproductive performance of the evaluated females (n = 783) over four parities. The gilts were from the same nucleus herd. Gilts of same age (140-150 days of age), body condition (body condition score of 3-4) and similar genetics (four-way cross females), during the same season (January to April 1999), were randomly divided at arrival into three groups and treated as follows:MEC gilts (n = 279): These were placed into indoor MEC pens in groups of 8-10. The gilts had continuous fenceline contact to boars (one boar to two groups of gilts, boars were changed daily) and to shortly weaned oestrous sows. Gilts were regrouped and dislocated at 10-day intervals. Outdoor gilts (n = 263): These were kept in groups of 8-10 on a large pasture (80-100 m2 per group). The animals had fenceline contact to mature boar for 5-10 min daily. Control indoor gilts (n = 241): These were housed indoors in large pens in groups of 8-10. The animals had fenceline contact to mature boars for 5-10 min daily. Each outdoor group had an insulated hut with straw bedding. All gilts were fed ad libitum with the same commercial diet. Housing gilts in MEC resulted in earlier (P < 0.001) onset of estrus (MEC: 174.8 +/- 2.4 days, indoor group housing: 207.6 +/- 4.1 days, outdoor group housing: 187.4 +/- 2.1 days) and lower (P < 0.001) farrowing rate to first service (MEC: 70.97%, indoor group housing: 89.73%, outdoor group housing: 89.62%). Farrowing rate of regularly returning MEC gilts to second service was 95.00%. First total-born litter size, first liveborn litter size, first wean-to-estrus interval (WEI), percent of sows bred after first weaning, second total-born litter size, second liveborn litter size, average third and fourth total-born and liveborn litter size, number of sows having four litters, number of litters per sow, total number of pigs per sow, total number of liveborn pigs per sow showed no significant differences between the groups. More (P < 0.05) sows were culled in outdoor group. Compared to MEC and outdoor housing, indoor housed sows suffered higher (P < 0.05) percentage of anoestrus.     

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.     

Alternative farrowing systems: design criteria for farrowing systems based on the biological needs of sows and piglets

The construction of a suitable farrowing environment is a continuing dilemma: the piglet's needs must be matched with those of the sow and the farmer during the main phases that constitute farrowing: nest building, parturition and lactation. Difficulties exist in resolving the various conflicts of interest between and within these three parties (e.g. sow v. farmer: space needed for nest building v. space needed to maximise the amount of farrowing accommodation, or sow v. sow: ensuring the survival of the current litter v. maintaining condition for future litters). Thus, the challenge is to resolve these conflicts and design a system that maximises sow and piglet welfare while maintaining an economically efficient and sustainable enterprise. In order to successfully design a farrowing and lactation environment, it is necessary to consider the biological needs of both the sow and her litter. The natural behaviour of the sow has been well documented and very little variation exists between reports of peri-parturient behaviour observed in extensively kept domestic sows and their wild counterparts. The failure for domestication to significantly alter these behavioural patterns provides evidence that they are biologically significant and that the commercial farrowing environment should attempt to accommodate this behavioural repertoire. In addition, the behavioural needs of the piglets, as well as the physiological needs of both sows and their offspring should be considered. This article aims to review the considerable body of literature detailing the behavioural repertoire of sows and their offspring during the different phases of farrowing, and the accompanying physiological processes. The focus is on identifying biological needs of the animals involved in order to synthesise the appropriate design criteria for farrowing and lactation systems, which should optimise both welfare and animal production.     

Changes in back fat thickness during late gestation predict colostrum yield in sows

Directing protein and energy sources towards lactation is crucial to optimise milk production in sows but how this influences colostrum yield (CY) remains unknown. The aim of this study was to identify associations between CY and the sow’s use of nutrient resources. We included 37 sows in the study that were all housed, fed and managed similarly. Parity, back fat change (ΔBF), CY and performance parameters were measured. We obtained sow serum samples 3 to 4 days before farrowing and at D1 of lactation following overnight fasting. These were analysed for non-esterified fatty acids (NEFA), urea, creatinine, (iso)butyrylcarnitine (C4) and immunoglobulins G (IgG) and A (IgA). The colostrum samples collected 3, 6 and 24 h after the birth of the first piglet were analysed for their nutrient and immunoglobulins content. The technical parameters associated with CY were parity group (a; parities 1 to 3=value 0 v. parities 4 to 7=value 1) and ΔBF D85-D109 of gestation (mm) (b): CY (g)=4290–842a–113b. (R²=0.41, P<0.001). The gestation length (P<0.001) and the ΔBF between D109 and D1 of lactation (P=0.050) were identified as possible underlying factors of the parity group. The metabolic parameters associated with CY were C4 at 3 to 4 days before farrowing (a), and 10logC4 (b) and 10logNEFA (c) at D1 of lactation: CY (g)=3582–1604a+1007b−922c (R²=0.39, P=0.001). The colostrum composition was independent of CY. The negative association between CY and ΔBF D85-D109 of gestation could not be further explained based on our data. Sows that were catabolic 1 week prior to farrowing seemed unable to produce colostrum to their full potential. This was especially the case for sows with parities 4 to 7, although they had a similar feed intake, litter birth weight and colostrum composition compared with parities 1 to 3 sows. In conclusion, this study showed that parity and the use of body fat and protein reserves during late gestation were associated with CY, indicating that proper management of the sow’s body condition during late gestation could optimise the intrinsic capacity of the sow’s CY.     

Studies on Immunoglobulins and Trypsin Inhibitor in Colostrum and Milk from Sows and in Serum of Their Piglets

The concentrations of IgG, IgM, IgA and the specific sow colostrum trypsin inhibitor (SCTI) were measured by radial immunodiffusion in colostrum and milk samples from sows and in serum samples from their offspring during the suckling period. A clear time dependence was found for all the measured variates in both whey and serum. Statistically significant positive correlations were found between, on the one hand, concentrations of IgG and IgA, but not IgM, in sera from 39 suckling piglets 1 and 3 days old, and, on the other hand, concentrations of the same immunoglobulins and of the trypsin inhibitor in maternal colostrum (n = 7). Multiple regression analyses showed that at day 1 and day 3 the levels of both IgG and IgA in serum samples from the suckling piglets were positively influenced by both the SCTI and the IgG or IgA contents in maternal colostrum.     

The effects of genotype on physiological and behavioural responses related to the welfare of pregnant pigs

Plasma free-corticosteroid concentrations, aggressive behaviour and levels of motivation to socially interact and explore a novel arena were observed in an experiment to examine whether differences previously observed between pigs in neck-tethers and groups are shown by pigs of different genotypes. Thirty-two pregnant gilts of 2 genotypes were housed in either tether stalls or groups. The 2 genotypes were mainly Large White×Landrace stock, but one had been intensively selected on the basis of growth performance.

Genotypic differences had previously been observed in protein and energy metabolism, and the present experiment also showed differences in their behaviour (increased activity and a decreased motivation to socially interact in the intensively selected genotype) and free-corticosteroid concentrations (40% lower in the intensively selected genotype). In spite of these differences, the behavioural and physiological responses to housing treatments were similar. In tether stalls, pigs of both genotypes had a higher frequency of retaliation and a lower frequency of withdrawal in response to aggressive interactions than group-housed pigs. There were 50 and 56% increases in free-corticosteroid concentrations in response to tether housing in the 2 genotypes, providing evidence of a chronic stress response of a magnitude sufficient to suggest a risk to welfare in the design of tether stall used in this experiment.