Development of piglets raised in a new multi-litter housing system vs. conventional single-litter housing until 9 weeks of age

Effect of light intensity on behaviour, health and growth of growing-finishing pigs

The effect of light intensity has been explored in relation to endocrine functions and reproduction in pigs, but effects on health and behaviour are scarcely documented. The objective of this study was to evaluate the effects of different light intensities on behaviour, health and growth of growing-finishing pigs. An experiment was conducted on a commercial farm equipped with light-emitting diode-based luminaires creating four light intensity treatments: low (45 lux), medium (198 lux), high (968 lux) and spatial gradient of intensity (from 71 lux to 330 lux). Per treatment, 112 pigs were studied in two batches of eight pens. Once every two weeks behaviours such as exploration, positive and negative social interactions, play and abnormal behaviours were observed. Health issues were assessed weekly and included biting lesions, skin lesions, leg and respiratory disorders. The average daily gain over the experiment was calculated and after slaughter carcasses were inspected. Generalised linear mixed models were used for the analysis of behaviours, binary health scores, carcass abnormalities, ordinal logistic regression for multilevel health scores, and linear mixed models for average daily gain. Interactions between intensity and week were found for some behaviours (i.e., exploration, negative social interactions and abnormal behaviour) and health issues (i.e., tear stains, conjunctivitis, body lesions, bursitis and tail lesions). However, none of the treatments consistently outperformed another one. Light treatments did not affect pig growth and carcass abnormalities. These variable results support studies suggesting that pigs are adaptable to light intensities, and inconsistencies over weeks might have been caused by environmental factors that could not be controlled in a commercial farm setting. To conclude, tested light intensities had no clear effects on pig behaviour, health and growth.

Effects of socialising piglets on sow and piglet performance and behaviour of entire male piglets

Entire male pigs show more aggressive behaviour and mounting than female pigs. By sorting growing pigs into male and female pens, at least half of the pigs are protected from the aggressive behaviour and mounting of the entire males. Mixing of unknown pigs provokes them to perform such behaviours which increase the risk for injuries. The idea behind socialising piglets is to create groups of piglets from several litters that become familiar with each other and thus show less aggressive behaviour and mounting later, when housed together after weaning. The effect of socialising piglets on animal welfare was studied on 24 sows and their 235 piglets. Male piglets were not castrated. Sows were housed in individual farrowing pens without crates. A small door was opened between two adjacent pens at a piglet age of two weeks for half of the litters (12 litters), and the other half was regarded as a control (12 litters). At weaning, control piglets were kept in groups of eight litter mates whereas socialised piglets were kept in groups of either eight entire males or eight females from two litters. Sow weight, body condition and health were recorded together with nursing events and social behaviour of piglets (aggressive, mounting, contact). There was no effect of socialisation on udder lesions or sows' relative change in body reserves. Socialised and control piglets did not differ in daily weight gain before weaning, but socialised piglets tended to have higher growth rate during the week after weaning (P = 0.07). The day after opening between pens, skin lesions were more common among socialised piglets (as compared to control piglets at the same age, P = 0.02) but at weaning, skin lesions were more common among control piglets than socialised piglets (P = 0.01). Almost all lesions were mild. No aggressive behaviour of sows towards piglets was observed. No difference between control and socialised piglets in social behaviour was seen before weaning. The frequency of aggressive and mounting behaviours was low after weaning for both socialised and control piglets, but socialised piglets showed more contact behaviour (P = 0.02). Socialised entire males showed as little aggressive and mounting behaviour as females. Nursing frequency was not affected by piglet socialisation and cross-suckling was rare. Based on the performance of piglets and sows, nursing frequency, and health of piglets and sows, we conclude that socialising entire male piglets (and their sisters) improve piglet welfare without any negative effect on the sows.

Amino acid supplementation counteracts negative effects of low protein diets on tail biting in pigs more than extra environmental enrichment

Low protein (LP) diets may increase the occurrence of damaging behaviours, like tail biting, in pigs. We investigated the effect of supplementing a LP diet with indispensable amino acids (IAA) or environmental enrichment on tail biting. Undocked pigs (n = 48 groups of 12) received either a normal protein diet (NP), a LP, LP with supplemented IAA (LP+), or LP diet with extra environmental enrichment (LP-E+) during the starter, grower, and finisher phase. Performance, activity, behaviour, and body damage were recorded. LP and LP-E+ had a lower feed intake, growth, and gain-to-feed ratio, and were more active than NP and LP+ pigs. LP-E+ pigs interacted most often with enrichment materials, followed by LP, LP+, and NP pigs. LP pigs showed more tail biting than all other groups during the starter phase and the finisher phase (tendency) compared to NP and LP+ pigs. Thus, LP-E+ only reduced tail biting in the starter phase, whereas LP+ tended to do so throughout. Tail damage was more severe in LP pigs than in NP and LP+, with LP-E+ in between. In conclusion, IAA supplementation was more effective than extra environmental enrichment in countering the negative effects of a low protein diet on tail biting in pigs.

Impact of Intestinal Microbiota on Growth Performance of Suckling and Weaned Piglets

Small-scale studies investigating the relationship between pigs' intestinal microbiota and growth performance have generated inconsistent results. We hypothesized that on farms under favorable environmental conditions (e.g., promoting sow nest-building behavior, high colostrum production, low incidence of diseases and minimal use of antimicrobials), the piglet gut microbiota may develop toward a population that promotes growth and reduces pathogenic bacteria. Using 16S rRNA gene amplicon sequencing, we sampled and profiled the fecal microbiota from 170 individual piglets throughout suckling and postweaning periods (in total 670 samples) to track gut microbiota development and its potential association with growth. During the suckling period, the dominant genera were Lactobacillus and Bacteroides, the latter being gradually replaced by Clostridium sensu scricto 1 as piglets aged. The gut microbiota during the nursery stage, not the suckling period, predicted the average daily growth (ADG) of piglets. The relative abundances of SCFA-producing genera, in particular Faecalibacterium, Megasphaera, Mitsuokella, and Subdoligranulum, significantly correlated with high ADG of weaned piglets. In addition, the succession of the gut microbiota in high-ADG piglets occurred faster and stabilized sooner upon weaning, whereas the gut microbiota of low-ADG piglets continued to mature after weaning. Overall, our findings suggest that weaning is the major driver of gut microbiota variation in piglets with different levels of overall growth performance. This calls for further research to verify if promotion of specific gut microbiota, identified here at weaning transition, is beneficial for piglet growth. IMPORTANCE The relationship between pigs' intestinal microbiota and growth performance is of great importance for improving piglets' health and reducing antimicrobial use. We found that gut microbiota variation is significantly associated with growth during weaning and the early nursery period. Importantly, transitions toward a mature gut microbiota enriched with fiber-degrading bacteria mostly complete upon weaning in piglets with better growth. Postponing the weaning age may therefore favor the development of fiber degrading gut bacteria, conferring the necessary capacity to digest and harvest solid postweaning feed. The bacterial taxa associated with piglet growth identified herein hold potential to improve piglet growth and health.

Managing Reproduction in Hyperprolific Sow Herds

The rearing of large litters from hyperprolific sows is a characteristic of modern genotypes. However, these sows have body and reproductive characteristics that differentiate them from the genotypes of the past decades, making it necessary to adopt different management strategies. This review describes the main care and challenges associated with the hyperprolificity of sows during the period in which replacement gilts are selected, along with gestation, parturition, lactation, and the weaning-estrus interval. It describes the challenges that these sows' piglets will face during the lactation period and includes some strategies adopted to develop these surplus piglets. In addition, it identifies areas where more research is needed to understand the reproductive management of modern genotypes.

Reducing Weaning Stress in Piglets by Pre-Weaning Socialization and Gradual Separation from the Sow: A Review

The weaning of pigs in most commercial pork production systems is an abrupt event performed at a fairly young age, i.e., mostly between 2.5 and 5 weeks of age. This practice induces a stress response, and its impact on behavior, performance and the gastrointestinal tract has been well described. Historically, there has been a focus on pre- and post-weaning nutritional strategies and post-weaning housing conditions and medication to improve production and reduce mortality after weaning. However, alternative pre-weaning housing and management systems that promote the development of natural social behaviors of piglets before weaning have recently received more attention. Co-mingling of non-littermates before weaning is a strategy that aims to initiate social interactions prior to weaning. The separation of the litter from the sow in the period leading up to weaning, termed intermittent suckling, aims to enhance the gradual separation from the sow. In addition, these practices encourage the young pig to learn explorative nutrient sourcing. Altogether, they may reduce weaning-associated stress. In this review, these strategies are defined, and their effects on behavior, performance, mortality, gastrointestinal function and immunocompetence are described. Though these strategies may be adapted to a commercial setting, it also becomes clear that many factors can contribute to the success of these strategies.

Effects of Birthweight of Piglets in a Multi-Suckling System on Mortality, Growth Rate, Catch-Up Growth, Feed Intake and Behaviour

Multi-suckling systems aim to improve animal welfare, but in these systems, a large variation is seen in piglet growth rate. Birthweight (BiW) plays an important role in explaining the variation in body weight (BW) gain of piglets. This study aims to investigate the relationships between BiW and piglet traits up to day 44 postpartum (p.p.). A total of 55 sows were used. The growth rate and mortality were assessed for all piglets. Feed and milk intake, behaviours, and skin lesions were assessed in four focal piglets per litter. Focal piglets were divided into four groups based on their BiW class (high BiW (HBiW) vs. low BiW (LBiW)) and growth rate class (fast vs. slow). Results showed that increased mortality was observed in piglets with a BiW below 1.1 kg. Birthweight was positively related with the number of sucklings (β = 2.8 no./kg of BiW per 7.5 h), corresponding to milk intake (β = 102 g/kg of BiW per day), and to a lesser extent, to the intake of sow feed (β = 44 g/kg of BiW per day) in week 6. Birthweight was positively related with the number of skin lesions (β = 4.3 no./kg of BiW) in week 4. We found no indications that fast-growing LBiW piglets differed from fast-growing HBiW piglets, however, fast-growing piglets of both HBiW and LBiW tended to eat more feed (485 ± 18 vs. 420 ± 17 g/day, p = 0.068), were present less often at teats of alien sows (1.1 ± 0.2 vs. 1.8 ± 0.3, p = 0.010), and had more skin lesions (9.0 ± 0.6 vs. 7.4 ± 0.4, p = 0.047), compared to slow growing piglets. Our study, thus, provides little insight into the traits that affect catchup growth in a multi-suckling environment but increases insight into the differences between fast-growing and slow-growing piglets, regardless of their birthweight class.

Development of flank lesions in growing pigs after weaning: A case study

Flank lesions in pigs are a common yet poorly understood consequence of damaging social behavior. One group of pigs on a commercial farm with group lactation and late weaning, and with the history of flank lesions was studied. Skin lesions on the flanks, including linear and circular lesions, and tail lesions on 69 pigs were recorded six times during 5 weeks after weaning at the age of 9 weeks. Nosing behavior was scanned during six sessions with multiple scans. The associations of age, trunk whiteness, weight gain, sow parity, litter size, sex, and tail lesions with the number of circular and linear lesions were analyzed using linear mixed models. The number of linear lesions increased as pigs aged, and pigs with a higher weight gain had more linear lesions. Moreover, pigs with a whiter trunk color were scored with more lesions of both types. According to descriptive behavior data, nosing and biting behaviors were most frequent during weeks 2-4 after weaning at the age of 11-13 weeks. On average, seven circular flank lesions were found per pig during the experiment, at the age of 10-14 weeks. After the peak on day 17, their occurrence decreased. Skin lesion occurrence was related to a lighter skin color on the trunks of pigs. We recommend reporting skin color in connection with lesion scoring results. Nosing behavior and flank lesions both peaked from 2 to 4 weeks after weaning, suggesting that nosing behavior contributed to lesion development during this time.

Estimation of Resilience Parameters Following LPS Injection Based on Activity Measured With Computer Vision

Resilience could be referred to as the animal’s ability to successfully adapt to a challenge. This is typically displayed by a quick return to initial metabolic or activity levels and behaviors. Pigs have distinct diurnal activity patterns. Deviations from these patterns could potentially be utilized to quantify resilience. However, human observations of activity are labor intensive and not feasible in practice on a large scale. In this study, we show the use of a computer vision tracking algorithm to quantify resilience based on activity individual patterns following a lipopolysaccharide (LPS) challenge, which induced a sickness response. We followed 121 individual pigs housed in barren or enriched housing systems, as previous work suggests an impact of housing on resilience, for eight days. The enriched housing consisted of delayed weaning in a group farrowing system and extra space compared with the barren pens and environmental enrichment. Enriched housed pigs were more active pre-injection of LPS, especially during peak activity times, than barren housed pigs (49.4 ± 9.9 vs. 39.1 ± 5.0 meter/hour). Four pigs per pen received an LPS injection and two pigs a saline injection. LPS injected animals were more likely to show a dip in activity than controls (86% vs 17%). Duration and Area Under the Curve (AUC) of the dip were not affected by housing. However, pigs with the same AUC could have a long and shallow dip or a steep and short dip. Therefore the AUC:duration ratio was calculated, and enriched housed pigs had a higher AUC:duration ratio compared to barren housed pigs (9244.1 ± 5429.8 vs 5919.6 ± 4566.1). Enriched housed pigs might therefore have a different strategy to cope with an LPS sickness challenge. However, more research on this strategy and the use of activity to quantify resilience and its relationship to physiological parameters is therefore needed.

A multi-suckling system combined with an enriched housing environment during the growing period promotes resilience to various challenges in pigs

Little is known about the impact of social and environmental enrichment on improving livestock resilience, i.e. the ability to quickly recover from perturbations. We evaluated the effect of an alternative housing system (AHS) on resilience of pigs, as compared to conventional housing (CONV). The AHS consisted of multi-litter housing during lactation, delayed weaning, extra space allowance and environmental enrichment at all times. We assessed recovery to a 2 h-transport challenge, an LPS injection, 2 h-heat stress and a biopsy wound in 96 pigs. Additionally, indicators of long-term “wear and tear” on the body were determined. AHS pigs had better physiological recoveries with quicker returns to baseline in the transport and LPS challenges, showed lower cortisol accumulation in hairs and lower variance in weight gain over the experimental period compared to conventionally-housed (CONV) pigs. They also had higher levels of natural antibodies binding KLH than CONV pigs. Their response to heat stress revealed a different strategy compared to CONV pigs. Taken together, AHS pigs appear to be more resilient and experience less chronic stress. Enhancing welfare by provision of social and environmental enrichment that better meets the behavioural needs of pigs seems to be a promising approach to improve their resilience.

Effects of a Multi-Suckling System Combined With Enriched Housing Post-Weaning on Response and Cognitive Resilience to Isolation

Improving welfare is still a critical issue in pig husbandry. Upgrades of the housing environment seem to be a promising solution to optimise resilience as a whole, and therefore improve animal welfare. The objective of this study was to evaluate the effect of an alternative housing system to enhance cognitive resilience and also to promote the pigs' welfare. A total of 96 piglets from two contrasted housing systems [alternative housing system (AHS) vs. conventional system (CONV)] was used. The major upgrades of the alternative system were multi-litter housing during lactation, delayed weaning, extra space allowance, and environmental enrichment from birth onwards. To estimate welfare, weight, and feed intake (as a general indicator of performances), the tear staining area (as a chronic stress indicator), behavioural postures, heart rate traits, and saliva cortisol concentration were measured over a 21 h-isolation. To assess cognitive resilience, the pigs were subjected to a maze with a social reward both before and after the isolation challenge and indicators of cognitive abilities were followed. The AHS pigs showed lower cortisol levels and tear staining area before the challenge, demonstrating overall better welfare due to the alternative housing conditions. During the challenge, AHS pigs had a lower heart rate, higher heart rate variability, and higher vagal activity than the CONV pigs, which might indicate a reduced sensitivity to the stressor. AHS pigs appeared to have a better long-term memory tested in a maze. Providing social and environmental enrichments, that fit the satisfaction of the essential needs of the pigs better, appears to be beneficial for pig welfare as a whole. Its effects on cognitive resilience still need to be proven.

Impact of Enrichment and Repeated Mixing on Resilience in Pigs

Resilience, the capacity of animals to be minimally affected by a disturbance or to rapidly bounce back to the state before the challenge, may be improved by enrichment, but negatively impacted by a high allostatic load from stressful management procedures in pigs. We investigated the combined effects of diverging environmental conditions from weaning and repeated mixing to create high allostatic load on resilience of pigs. Pigs were either exposed to barren housing conditions (B) from weaning onwards or provided with sawdust, extra toys, regular access to a “play arena” and daily positive human contact (E). Half of the pigs were exposed to repeated mixing (RM) and the other half to one mixing only at weaning (minimal mixing, MM). To assess their resilience, the response to and recovery from a lipopolysaccharide (LPS) sickness challenge and a Frustration challenge were studied. In addition, potential long-term resilience indicators, i.e. natural antibodies, hair cortisol and growth were measured. Some indications of more favorable responses to the challenges in E pigs were found, such as lower serum reactive oxygen metabolite (dROM) concentrations and a smaller area under the curve of dROM after LPS injection. In the Frustration challenge, E pigs showed less standing alert, escape behaviors and other negative behaviors, a tendency for a smaller area under the curve of salivary cortisol and a lower plasma cortisol level at 1 h after the challenge. Aggression did not decrease over mixings in RM pigs and was higher in B pigs than in E pigs. Repeated mixing did not seem to reduce resilience. Contrary to expectations, RM pigs showed a higher relative growth than MM pigs during the experiment, especially in the week of the challenges. Barren RM pigs showed a lower plasma cortisol concentration than barren MM pigs after the LPS challenge, which may suggest that those RM pigs responded less detrimentally than MM pigs. Enriched RM pigs showed a higher level of IgM antibodies binding keyhole limpet hemocyanin (KLH) than enriched MM and barren RM pigs, and RM pigs showed a sharper decline in IgG antibodies binding Bovine Serum Albumin (PC-BSA) over time than MM pigs. Hair cortisol concentrations were not affected by enrichment or mixing. To conclude, enrichment did not enhance the speed of recovery from challenges in pigs, although there were indications of reduced stress. Repeated as opposed to single mixing did not seem to aggravate the negative effects of barren housing on resilience and for some parameters even seemed to reduce the negative effects of barren housing.

Factors associated with antimicrobial use in pig and veal calf farms in the Netherlands: A multi-method longitudinal data analysis

Minimizing antimicrobial use (AMU) in livestock is needed to control antimicrobial resistance (AMR). In the Netherlands, the livestock sector reduced AMU by almost 70 % since 2009, but this reduction stagnated in recent years. With only therapeutic AMU allowed, it is clear that besides socio-economic and behavioral factors, also the farm technical characteristics influence the conditions under which farmers need AMU. These characteristics pertain to farm management, including biosecurity, vaccination schemes, nutrition, micro-climate and husbandry practices. Identifying farm-related risk factors for AMU is needed to control AMR in a sustainable and pragmatic way. This need, often concerns the overall contribution of seemingly related (rather than individualized) factors. Here, risk factors for AMU in pig and calf farms were determined using two approaches: a typical risk factor analysis based on generalized estimating equations (GEEs) or hierarchical mixed-effects models and a multiblock partial least-squares regression analysis. These methods were applied to longitudinal data from two previous studies, i.e. a panel study and an intervention study involving 36 multiplier pig farms and 51 veal calf farms in the Netherlands, respectively. The multiblock analysis allowed us to quantify the importance of each factor and their respective block (i.e. farm management domain). For pigs, factors related to internal biosecurity had the highest impact on AMU, while for calves, these were mainly related to micro-climate. Structural characteristics, such as farm size and production type, followed in importance for both sectors. While both methods provided similar outcomes, the multiblock approach provided further insights by grouping and comparing factors believed to be inter-related.

An estimation of the financial consequences of reducing pig aggression

Animal welfare scientists have accumulated knowledge and developed interventions to improve livestock welfare, but these are poorly adopted in commercial practice. Animal welfare interventions are rarely tested for economic viability and this limits their uptake. This study employs Stochastic Partial Budgeting (SPB) to determine the viability of animal welfare improvements. Aggression between pigs is used as an example because there is a large literature base from which to draw interventions, and the problem has persisted for decades without resolution. Costs and benefits of three interventions to control aggression (pre-weaning socialisation, synthetic maternal pheromones and large social groups) were estimated by reviewing the academic and industry literature and by conducting a survey of sixteen pig farmers. The net effects were compared to farmers’ willingness to pay (WTP) for interventions to reduce aggression as identified by recent research. Results are consistent with prior research which indicates that improving animal welfare generally comes at a cost to producers. Nevertheless, pre-weaning socialisation resulted in a neutral or positive net effect 38% of the time and should be central to campaigns promoting the control of aggression in the industry. Exposing pigs to synthetic maternal pheromones did not improve profitability but the net costs were small and within the realms of WTP for a sub-group of farmers with animal welfare goals. The net costs of converting existing buildings in order to house pigs in large social groups were beyond the realms of farmers’ WTP. The approach adopted in this study, of combining SPB with WTP from the sector, should be extended to other animal welfare issues.

Management and Feeding Strategies in Early Life to Increase Piglet Performance and Welfare around Weaning: A Review

The performance of piglets in nurseries may vary depending on body weight, age at weaning, management, and pathogenic load in the pig facilities. The early events in a pig's life are very important and may have long lasting consequences, since growth lag involves a significant cost to the system due to reduced market weights and increased barn occupancy. The present review evidences that there are several strategies that can be used to improve the performance and welfare of pigs at weaning. A complex set of early management and dietary strategies have been explored in sows and suckling piglets for achieving optimum and efficient growth of piglets after weaning. The management strategies studied to improve development and animal welfare include: (1) improving sow housing during gestation, (2) reducing pain during farrowing, (3) facilitating an early and sufficient colostrum intake, (4) promoting an early social interaction between litters, and (5) providing complementary feed during lactation. Dietary strategies for sows and suckling piglets aim to: (1) enhance fetal growth (arginine, folate, betaine, vitamin B12, carnitine, chromium, and zinc), (2) increase colostrum and milk production (DL-methionine, DL-2-hydroxy-4-methylthiobutanoic acid, arginine, L-carnitine, tryptophan, valine, vitamin E, and phytogenic actives), (3) modulate sows' oxidative and inflammation status (polyunsaturated fatty acids, vitamin E, selenium, phytogenic actives, and spray dried plasma), (4) allow early microbial colonization (probiotics), or (5) supply conditionally essential nutrients (nucleotides, glutamate, glutamine, threonine, and tryptophan).

Health and welfare in organic livestock production systems—a systematic mapping of current knowledge

This review aimed to systematically map and summarize the status of animal health and welfare in organic production. The prevalence of diseases and behavioural effects in organic dairy cow, beef cattle, sheep, pig, laying hen and broiler chicken were discussed in the context of the organic values and current knowledge on animal health and welfare. In total 166 peer-reviewed scientific publications between 2008 and 2020 were included. No strong evidence for neither inferior nor distinctly higher animal welfare in organic compared with conventional production could be supported. The welfare status of organic livestock is in general good in relation to the OIE definition of animal health and welfare. However, organic systems are still facing several challenges related to animal health and the arising of goal conflicts due to management and practical implications. Greater possibilities to perform species-specific behaviours in organic production systems, however, indicate that the organic standards offer a good framework for high animal welfare management. For organic dairy farmers, the main health problems are similar to those of non-organic farms; especially mastitis and lameness need improvement. Parasites, together with mastitis and lamb mortality, are important welfare issues in organic sheep production. Piglet mortality, leg problems, parasite load and increasing respiratory problems are of major relevance in organic pig production. For organic laying hens, major health challenges relate to feather pecking and cannibalism, parasites and possibilities to express species-specific behaviours. For organic broilers, dermatitis of footpads, hocks and breast are reported as main health issues.

The welfare and productivity of sows and piglets in group lactation from 7, 10, or 14 d postpartum

Transferring sows and their litters to group lactation (GL) after an initial period of farrowing crate (FC) housing could enhance the viability of GL for commercial production. Group lactation from 7 d postpartum would reduce the time sows spend in confinement, but the effects of early mixing on animal welfare and productivity require examination. Two experiments were conducted on sows and piglets kept in GL from 7, 10, or 14 d postpartum, compared with FC. Experiment 1 utilized 180 sows and 1,887 piglets over five time replicates (n = 60 sow and litter units per treatment) comparing GL from 7 or 14 d postpartum to FC. In experiment 2, 108 sows and 1,179 piglets were studied over three time replicates (n = 36 sow and litter units per treatment) comparing GL from 10 or 14 d postpartum to FC. All sows farrowed in FC. Group lactation sows were transferred to pens (one pen of five sows at 8.4 m2/sow and one pen of seven sows at 8.1 m2/sow, per GL treatment and replicate) with their litters at 7 (GL7), 10 (GL10), or 14 (GL14) d postpartum. Farrowing crate sows and their litters remained in their FC. Data were collected on sow feed intake and reproduction, piglet mortality (from day 6 postpartum), and sow and piglet weight changes, plasma cortisol concentrations, and injuries. Piglet mortality was greater in the GL7 (17 ± 1.8%) and GL10 treatments (12 ± 0.9%) compared with GL14 (8.3 ± 1.8% P ≤ 0.001 and 8.1 ± 0.9% P ≤ 0.001 in experiments 1 and 2), and greater in GL overall compared with FC (2.7 ± 1.5% and 1.8 ± 0.9% in FC in experiments 1 and 2; P ≤ 0.001). Piglets from GL7 were also lighter at weaning than GL14 piglets (P < 0.001), whereas GL10 and GL14 did not differ (P > 0.05). Overall, piglets in GL were lighter at weaning than piglets in FC (P ≤ 0.01). Sows from GL7 were heavier at weaning (P = 0.001), and GL10 sows tended to be heavier at weaning (P = 0.08), than GL14 and FC sows. Post-mixing, sow cortisol (P ≤ 0.01) and sow and piglet injuries (P ≤ 0.02) were greater in GL than FC. Treatment had no effect on sow feed intake or reproductive performance (P > 0.05). Under the conditions of this research, the known benefits of two-stage GL housing were achieved at a cost particularly to piglets in terms of increased piglet mortality and injuries after mixing, and reduced piglet growth. The risk of piglet mortality decreased with older age at mixing.

Pigs Like It Varied; Feeding Behavior and Pre- and Post-weaning Performance of Piglets Exposed to Dietary Diversity and Feed Hidden in Substrate During Lactation

Timely intake of solid feed is essential to ease the nutritional change from sow's milk to solid feed at weaning and thereby to reduce weaning-related problems. A significant percentage of piglets, however, do not or hardly consume solid feed before weaning. We studied effects of dietary variety and presenting the feed in substrate during lactation on the feeding behavior and performance of piglets up to 2 weeks post-weaning. Feed was provided ad libitum from d4 in two feeders, with four bowls each. In a 2 × 2 arrangement, 40 litters received either creep feed as a monotonous diet (MO) or four feed items simultaneously, i.e., creep feed, celery, cereal honey loops and peanuts, as a diverse diet (DD) and the feed was either provided without (CON) or with substrate (SUB), i.e., sand, in one of the two feeders up to weaning. Dietary diversity highly stimulated feed exploration and eating (≥2.5 times), feed intake and the percentage of (good) eaters from early in lactation, and enhanced piglet growth toward weaning (by 29 g/d), although MO-piglets spent more time eating creep feed from d18. Within MO, SUB-litters consisted of more good eaters than CON-litters. At weaning (d28) four piglets from the same treatment were grouped (n = 40 pens). DD-CON had the highest post-weaning feed intake and gain between d5–15 and the lowest proportion of pigs with higher tail damage scores. However, effects regarding behavior remained inconclusive, as DD-piglets had a lower and higher number of body lesions at 4 h and d15 post-weaning, respectively, spent less time exploring the feed(er) and drinker and environment, and more time nosing pen mates than MO-piglets. SUB-piglets showed a reduction in total post-weaning feed intake, gain (particularly between d0–2) and inactivity, increased levels of manipulation and aggression at week 1 and a higher number of body lesions at 4 h and d15 post-weaning. In conclusion, dietary diversity seems a promising feeding strategy in getting piglets to eat during lactation. Provision of substrate in the feeder subtly stimulated foraging behavior, but negatively impacted post-weaning adaptation, probably because treatments were not reinforced after weaning and piglets thus experienced loss of enrichment.

Feed intake of the sow and playful creep feeding of piglets influence piglet behaviour and performance before and after weaning

Creep feed intake is variable and may be partly homeostatically and exploratory driven. We studied effects of maternal feed restriction and a ‘play-feeder’ on piglet behaviour and performance. 37 Litters received creep feed in a conventional (CON) or play-feeder (PL) and their sows were full-fed (FF) or restrictedly-fed (RES). Eaters were determined via rectal swabs. At weaning (d24) four piglets from the same treatment were grouped (n = 36 pens). RES hindered piglet growth by 41 g/d and enhanced time eating, creep feed intake and percentage of eaters at weaning versus FF. RES-PL had the largest proportion of moderate and good eaters. PL stimulated feeder exploration and attracted more piglets to the feeder than CON. Post-weaning, RES increased exploratory behaviours, feed intake between d0–5, and growth between d0–2, and reduced body lesions between d0–2 (within CON), drinking and ear biting. PL increased ingestive behaviours, feed intake and growth between d0–15, and BW at d15 post-weaning by 5%. PL also lowered the prevalence of watery diarrhoea, number of body lesions and piglets with ear (within FF) and tail (within RES) damage at d15 post-weaning. Treatments did not affect FCR. To conclude, RES and particularly PL (broader and for longer) result in less weaning-associated-problems.

Providing Effective Environmental Enrichment to Pigs: How Far Have We Come?

Science has defined the characteristics of effective environmental enrichment for pigs. We provide an overview of progress towards the provision of pig enrichment in the three largest global pork producing regions. In the USA, enrichment has not yet featured on the policy agenda, nor appeared on farms, except when required by certain farm assurance schemes. China has very limited legal animal welfare provisions and public awareness of animal welfare is very low. Food safety concerns severely restrict the use of substrates (as enrichment) on farms. Providing enrichment to pigs is a legal requirement in the EU. In practice, enrichment is not present, or simple (point-source) objects are provided which have no enduring value. Other common issues are the provision of non-effective or hazardous objects, inadequate presentation, location, quantity and size or inadequate maintenance of enrichment. Improvements can be made by applying principles from the field of experimental analysis of behaviour to evaluate the effectiveness of enrichment; providing welfare knowledge transfer, including training and advisory services; highlighting the economic benefits of effective enrichment and focusing on return on investment; increasing pressure from the financial sector; using novel drivers of change, such as public business benchmarking. The poor implementation of scientific knowledge on farms suggests that the pig industry has not fully embraced the benefits of effective enrichment and is still a long way off achieving an enriched pig population.

Gastrointestinal tract (gut) health in the young pig

An optimally functioning gastrointestinal tract (GIT) clearly is of importance to the overall metabolism, physiology, disease status and performance of pigs of all stages of growth and development. Recently, the 'health' of the GIT ('gut health') has attracted much attention despite the lack of a clear definition to the term or its aetiology, although in broad terms, 'gut health' encompasses a number of physiological and functional features including nutrient digestion and absorption, host metabolism and energy generation, a stable and appropriate microbiota/microbiome, defence mechanisms including barrier function and mucosal immune mechanisms, and the interactions between these components. 'Gut health' in the newly-weaned (young) pig is of obvious interest due to changes in GIT structure and function associated with the post-weaning transition, and more recently to the upsurge in interest in different feed additives as dietary alternatives/replacements caused by bans/reductions in certain antimicrobial compounds being available in some parts of the world. In the presence of enteric disease(s) after weaning, a deterioration in 'gut health' may be synonymous to the overall health of the pig, and although some direct relationships can be drawn between pig performance and efficiency and a 'healthy' GIT, sometimes this connection is subtler and less obvious, especially in the absence of overt enteric disease(s). The factors and conditions involved in 'gut health' are multifactorial, complex, often poorly described and sometimes incorrectly interpreted, although it is evident that perturbations of the GIT can cause an imbalance and disturb the generalized homeostasis. In addition to any enteric diseases or conditions that might arise as a result of these disturbances, other influences will also impact such as the responses occurring in the GIT in the period immediately after weaning, any changes that might occur after a change in diet, and (or) disruptions to meal patterns and hence the flow of nutrients. Ultimately, 'gut health' represents the outcome of the GIT in response to its capacity and ability to respond and adapt to the insults and challenges it encounters.

Effects of pre-weaning housing in a multi-suckling system on performance and carbohydrate absorption of relatively light and heavy piglets around weaning

The low feed intake and stress associated with abrupt weaning in conventional pig farming often result in poor post-weaning performance, which is related to impaired intestinal function. We investigated effects of housing conditions before weaning on performance around weaning of relatively light and heavy piglets. Before weaning, piglets were housed either with five sows and their litters in a multi-suckling (MS) system or in pens with individually housed sows in farrowing crates (FC). After weaning at 4 weeks of age (day 0), 16 groups of four piglets (two light and two heavy litter-mates) were housed under equal conditions in enriched pens. Mannitol (day -5 and day 5) and galactose (day 5) were orally administered as markers for gastrointestinal carbohydrate absorption, and after 20 min a blood sample was taken (sugar absorption test). In addition, BW, feed intake and faecal consistency as an indicator for diarrhoea, were assessed frequently during 2 weeks post-weaning. Pre-weaning housing, weight class and their interaction did not affect post-weaning faecal consistency scores. Weight gain over 2 weeks did not differ between pre-weaning housing treatments, but MS piglets gained more (0.67±0.12 kg) than FC piglets (0.39±0.16 kg) between days 2 and 5 post-weaning, P=0.02), particularly in the 'heavy' weight class (interaction, P=0.04), whereas feed intake was similar for both treatments. This indicates a better utilisation of the ingested feed of the MS piglets compared with the FC piglets in the early post-weaning period. Pre-weaning mannitol concentrations were unaffected by pre-weaning housing, weight class and their interaction. On day 5 post-weaning, however, MS piglets had a lower plasma concentration of mannitol (320 v. 592 nmol/ml, SEM=132, P=0.04) and galactose (91 v. 157 nmol/ml, SEM=20, P=0.04) than FC piglets, regardless of weight class. In conclusion, MS and FC piglets differed in aspects of post-weaning gastrointestinal carbohydrate absorption and in weight gain between days 2 and 5 after weaning, but pre-weaning housing did not affect feed intake, weight gain and measures of faecal consistency over the first 2 weeks after weaning.

Post-weaning social and cognitive performance of piglets raised pre-weaning either in a complex multi-suckling group housing system or in a conventional system with a crated sow

We studied the social and cognitive performance of piglets raised pre-weaning either in a conventional system with a sow in a farrowing crate (FC) or in a multi-suckling (MS) system in which 5 sows and their piglets could interact in a more physically enriched and spacious environment. After weaning at 4 weeks of age, 8 groups of 4 litter-mates per pre-weaning housing treatment were studied under equal and enriched post-weaning housing conditions. From each pen, one pair consisting of a dominant and a submissive pig was selected, based on a feed competition test (FCT) 2 weeks post-weaning. This pair was used in an informed forager test (IFT) which measured aspects of spatial learning and foraging strategies in a competitive context. During individual training, submissive (informed) pigs learned to remember a bait location in a testing arena with 8 buckets (the same bucket was baited in a search visit and a subsequent relocation visit), whereas dominant (non-informed) pigs always found the bait in a random bucket (search visits only). After learning their task, the informed pigs' individual search visit was followed by a pairwise relocation visit in which they were accompanied by the non-informed pig. Effects of pre-weaning housing treatment were not distinctly present regarding the occurrence of aggression in the FCT and the learning performance during individual training in the IFT. During paired visits, informed and non-informed pigs changed their behaviour in response to being tested pairwise instead of individually, but MS and FC pigs showed few distinct behavioural differences.

Intermittent suckling with or without co-mingling of non-littermate piglets before weaning improves piglet performance in the immediate post-weaning period when compared with conventional weaning

Background

In this experiment, intermittent suckling (IS) with or without the co-mingling (CoM) of piglets was studied as a method to stimulate solid feed intake and reduce post-weaning stress.

Methods

Three weaning regimes using 30 multiparous sows were compared: (1) conventional weaning (CW) (n = 10 litters), where piglets had continuous access to the sow until weaning (d 0, farrowing = d −25 relative to weaning); (2) intermittent suckling (IS) (n = 10 litters), where piglets were separated from the sow for 8 h/d starting at d −7 (relative to weaning); and (3) intermittent suckling with co-mingling (ISCo) (n = 10 litters) where IS started at d −7 and two litters were housed together during separation and then returned to their original sow. Ad libitum creep feed was available from d −17. At weaning pigs were housed in pens of 11 pigs, 27 pens in total. The ISCo treatment was divided in half to examine effects of different mixing strategies after weaning. Half of the ISCo litters were kept in familiar groups (ISCoF, familiar, n = 4) and the other half were mixed within treatment resulting in groups of unfamiliar pigs (ISCoNF, not familiar, n = 5), the same as IS (n = 9) and CW (n = 9) treatments.

Results

The ISCo piglets ate more creep feed in the week before weaning (P < 0.01), but also showed more aggressive and manipulative behaviour on first day of CoM compared with CW piglets (P < 0.05). IS with or without CoM increased exploratory and play behaviour on the first day of treatment intervention (P < 0.001) and increased sleeping behaviour on the last day of treatment intervention compared with CW (P < 0.001). Mixing strategy at weaning had an effect on performance data with the highest growth and feed intake seen in ISCoF pigs 2 to 8 d after weaning (P <0.001). IS and ISCoNF pigs also grew faster and ate more than CW pigs 2 to 8 d after weaning (P < 0.001). Post-weaning injury scores suggested reduced aggression in ISCo as evidenced by reduced redness (skin irritation) (P < 0.05), and a tendency for ISCo to have less scratches than CW (P < 0.1). The IS pigs slept the most and displayed less manipulative behaviours on the day of weaning and plasma haptoglobin levels remained low in IS pigs after weaning (P ≤ 0.01).

Conclusions

Both intermittent suckling techniques improved production indices in the immediate post-weaning period. However, the addition of co-mingling before weaning in combination with grouping familiar pigs together after weaning improved performance in an additive manner.

Omnivores Going Astray: A Review and New Synthesis of Abnormal Behavior in Pigs and Laying Hens

Pigs and poultry are by far the most omnivorous of the domesticated farm animals and it is in their nature to be highly explorative. In the barren production environments, this motivation to explore can be expressed as abnormal oral manipulation directed toward pen mates. Tail biting (TB) in pigs and feather pecking (FP) in laying hens are examples of unwanted behaviors that are detrimental to the welfare of the animals. The aim of this review is to draw these two seemingly similar abnormalities together in a common framework, in order to seek underlying mechanisms and principles. Both TB and FP are affected by the physical and social environment, but not all individuals in a group express these behaviors and individual genetic and neurobiological characteristics play an important role. By synthesizing what is known about environmental and individual influences, we suggest a novel possible mechanism, common for pigs and poultry, involving the brain-gut-microbiota axis.