Stress and Parturition in the Pig

Localization of Catecholaminergic Neurofibers in Pregnant Cervix as a Possible Myometrial Pacemaker

In eutocic labor, the autonomic nervous system is dominated by the parasympathetic system, which ensures optimal blood flow to the uterus and placenta. This study is focused on the detection of the quantitative presence of catecholamine (C) neurofibers in the internal uterine orifice (IUO) and in the lower uterine segment (LUS) of the pregnant uterus, which could play a role in labor and delivery. A total of 102 women were enrolled before their submission to a scheduled cesarean section (CS); patients showed a singleton fetus in a cephalic presentation outside labor. During CS, surgeons sampled two serial consecutive full-thickness sections 5 mm in depth (including the myometrial layer) on the LUS and two randomly selected samples of 5 mm depth from the IUO of the cervix. All histological samples were studied to quantify the distribution of A nerve fibers. The authors demonstrated a significant and notably higher concentration of A fibers in the IUO (46 ± 4.8) than in the LUS (21 ± 2.6), showing that the pregnant cervix has a greater concentration of A neurofibers than the at-term LUS. Pregnant women's mechanosensitive pacemakers can operate normally when the body is in a physiological state, which permits normal uterine contractions and eutocic delivery. The increased frequency of C neurofibers in the cervix may influence the smooth muscle cell bundles' activation, which could cause an aberrant mechano-sensitive pacemaker activation-deactivation cycle. Stressful circumstances (anxiety, tension, fetal head position) cause the sympathetic nervous system to become more active, working through these nerve fibers in the gravid cervix. They might interfere with the mechano-sensitive pacemakers, slowing down the uterine contractions and cervix ripening, which could result in dystocic labor.

Factors contributing to high performance of sows in free farrowing systems

BACKGROUND

Pressure to abolish farrowing crates is increasing, and producers are faced with decisions about which alternative system to adopt. For sow welfare, well designed free farrowing systems without close confinement are considered optimal but producers have concerns about increased piglet mortality, particularly crushing by the sow. Reporting accurate performance figures from commercial farms newly operating such systems could inform the transition process. This study investigated performance on three commercial farms operating four different zero-confinement systems, three of which were newly installed. A total of 3212 litters from 2920 sows were followed from farrowing to weaning over a three-year period with key performance indicators (KPIs) recorded. Mixed Models (LMMs, GLMMs) determined the influence of different factors (e.g. farrowing system, sow parity, management aspects) and litter characteristics on performance, including levels and causes of piglet mortality.

RESULTS

Piglet mortality was significantly influenced by farm/system. Live-born mortality ranged from 10.3 to 20.6% with stillbirths ranging from 2.5 to 5.9%. A larger litter size and higher parity resulted in higher levels of mortality regardless of system. In all systems, crushing was the main cause of piglet mortality (59%), but 31% of sows did not crush any piglets, whilst 26% crushed only one piglet and the remaining sows (43%) crushed two or more piglets. System significantly influenced crushing as a percentage of all deaths, with the system with the smallest spatial footprint (m2) compared to the other systems, recording the highest levels of crushing. Time from the start of the study influenced mortality, with significant reductions in crushing mortality (by ~ 4%) over the course of the three-year study. There was a highly significant effect of length of time (days) between moving sows into the farrowing accommodation and sows farrowing on piglet mortality (P < 0.001). The less time between sows moving in and farrowing, the higher the levels of piglet mortality, with ~ 3% increase in total mortality every five days. System effects were highly significant after adjusting for parity, litter size, and days pre-farrowing.

CONCLUSION

These results from commercial farms demonstrate that even sows that have not been specifically selected for free farrowing are able, in many cases, to perform well in these zero-confinement systems, but that a period of adaptation is to be expected for overall farm performance. There are performance differences between the farms/systems which can be attributed to individual farm/system characteristics (e.g. pen design and management, staff expertise, pig genotypes, etc.). Higher parity sows and those producing very large litters provide a greater challenge to piglet mortality in these free farrowing systems (just as they do in crate systems). Management significantly influences performance, and ensuring sows have plenty of time to acclimatise between moving in to farrowing accommodation and giving birth is a critical aspect of improving piglet survival.

Large litters have a detrimental impact on litter performance and postpartum maternal behaviour in primiparous sows

BACKGROUND

Our previous study confirmed that large litter size adversely affects prepartum maternal hormones and behaviour, concurrently with heightened oxidative stress in primiparous sows. The purpose of this study was to examine the effect of large litter size on litter performance, postpartum maternal behaviour, salivary cortisol levels, and colostral immunoglobulin levels in sows, as well as investigate their correlations with the levels of oxidative stress parameters.

RESULTS

A total of 24 primiparous sows (Landrace[Formula: see text]Large white) and their offspring were categorised into two groups based on litter size: NORMAL (n = 8) with litter size ranging from 7 to 14 (mean 11.5[Formula: see text]2.7), and LARGE (n=16) with litter size ranging from 15 to 20 (mean 15.9[Formula: see text]1.4). All sows were housed in a group housing system during gestation and transitioned to an adaptable loose housing system (2.4[Formula: see text]2.3 m) during the farrowing and lactation periods. The nursing and carefulness behaviour of the sows was monitored over a 24-h period between 72 and 96 h after parturition. Saliva samples were collected for cortisol assay on 35, 21, and 7 days before parturition (D-35, D-21, and D-7, respectively), as well as on days 1, 7, and 28 after parturition (D1, D7, and D28, respectively). On D1, higher piglet mortality rates were observed among the LARGE group compared to the NORMAL group (p<0.01). The total and successful nursing behaviours of the sows were less frequent in the LARGE group than in the NORMAL group (p<0.05, for both), and the carefulness score of the LARGE group was also lower than that of the NORMAL group (p< 0.01). On D1, cortisol levels in LARGE sows were higher than those in NORMAL sows (p< 0.05), and for other time points (D-21, D-7, D7, and D28), cortisol levels in LARGE sows tended to be higher than those in NORMAL sows (p < 0.10, for all). Successful nursing behaviour displayed negative correlations with levels of salivary cortisol and certain oxidative stress parameters measured on D1.

CONCLUSIONS

These findings suggest that the strategy for alleviating physiological and oxidative stress during the peripartum periods could benefit potential postpartum maternal behaviour and litter performance in the sows with large litters.

Effects of Nesting Material Provision and High-Dose Vitamin C Supplementation during the Peripartum Period on Prepartum Nest-Building Behavior, Farrowing Process, Oxidative Stress Status, Cortisol Levels, and Preovulatory Follicle Development in Hyperprolific Sows

Hyperprolific sows often experience increased oxidative stress during late gestation and lactation periods, which can adversely affect the farrowing process and overall lactation performance. This study examines the influence of providing a coconut coir mat (CCM; 1 × 1 m) as nesting material, supplementing high-dose vit-C (HVC; 20% vit-C, 10 g/kg feed) as an antioxidant, or both on maternal behavior, the farrowing process, oxidative status, cortisol levels, and preovulatory follicle developments in sows with large litters. In total, 35 sows (Landrace × Yorkshire; litter size 15.43 ± 0.27) were allocated to the following four treatment groups: control (n = 9, basal diet), vit-C (n = 8, basal diet + HVC), mat (n = 10, basal diet + CCM), and mat + vit-C (n = 8, basal diet + HVC + CCM). A post-hoc analysis showed that compared with sows that were not provided CCM, mat and mat + vit-C groups demonstrated increased durations of nest-building behavior during the period from 24 h to 12 h before parturition (p < 0.05 for both), reduced farrowing durations, and decreased intervals from birth to first udder contact (p < 0.01 for both). The mat group exhibited lower advanced oxidation protein product (AOPP) levels during late gestation and lactation periods than the control group (p < 0.05). Sows with HVC supplementation showed longer farrowing durations than those without HVC supplementation (p < 0.0001). The vit-C group had higher salivary cortisol levels on day 1 after farrowing than the other treatment groups (p < 0.05). Furthermore, the follicle diameters on day 3 after weaning in the vit-C group tended to be smaller than those in the control group (p = 0.077). HVC supplementation prolonged farrowing and increased the physiological stress on postpartum, and no advantageous effects on maternal behavior and developmental progression of preovulatory follicles were observed. Hence, alternative solutions beyond nutritional approaches are required to address increased oxidative stress in hyperprolific sows and secure their welfare and reproductive performance. The present results substantiated the positive impact of providing CCM as nesting material for sows with large litters on nest-building behavior and the farrowing process, which could mitigate the deleterious consequences induced by peripartum physiological and oxidative stress.

Indicators of improved gestation housing of sows. Part I: Effects on behaviour, skin lesions, locomotion, and tear staining

Commercial gestation housing systems for sows generally fail to cater fully for their needs in terms of comfort or the ability to perform highly motivated behaviours, which can lead to chronic stress and an impairment to welfare. We compared a typical gestation system (CONTROL) with an IMPROVED one as regards oral stereotypies, aggressive behaviour, skin lesions, locomotion, and tear staining. Sows were mixed into 12 stable groups (six groups per treatment, 20 sows per group), 29 days post-service in pens with free-access, full-length individual feeding/lying stalls. CONTROL pens had fully slatted concrete floors, with two blocks of wood and two chains suspended in the group area. IMPROVED pens were the same but with rubber mats and a length of manila rope in each feeding stall, and straw provided in three racks in the group area. Direct observations of oral stereotypical (30 instantaneous scans per sow per day) and aggressive (all-occurrence sampling, 3 h per sow per day) behaviours were conducted 72 h post-mixing, in mid and late gestation. Skin lesions were counted 24 h and three weeks post-mixing, and in late gestation. Sows' locomotion (locomotory ability) was scored using a visual analogue scale in mid and late gestation. Right and left eye tear staining was scored in late gestation. Indications of better welfare in IMPROVED sows included performance of fewer oral stereotypies in mid and late gestation, and lower tear stain scores. These sows performed more aggression in late gestation, which was associated with access to enrichment, but skin lesion counts were not affected. Thus, the changes made in the IMPROVED treatment benefitted aspects of sow welfare.

Detection of foaling using a tail-attached device with a thermistor and tri-axial accelerometer in pregnant mares

It is desirable to attend to the mare at the time of foaling in order to assist fetal delivery and prevent complications. The early detection of the onset of labor is an important issue for the equine industry. The purpose of this study was to examine the applicability of a sensor for foaling detection using the data of surface temperature (ST), roll angle (rotation about the y-axis) and y-axis (long axis of the tail) acceleration which were collected from a multimodal device attached to the ventral tail base of the mare. The data were collected every 3 minutes in 17 pregnant mares. Roll angle differences from the reference values and the mare's posture (standing or recumbent) confirmed by video were compared and associated. Cohen's kappa coefficient was 0.99 when the threshold was set as ± 0.3 radian in roll angle differences. This result clearly showed that the sensor data can accurately distinguish between standing and recumbent postures. The hourly sensor data with a lower ST (LST < 35.5°C), a recumbent posture determined by the roll angle, and tail-raising (TR, decline of 200 mg or more from the reference value in y-axis acceleration) was significantly higher during the last hour prepartum than 2-120 hours before parturition (P < 0.01). The accuracy of foaling detection within one hour was verified using the following three indicators: LST; lying down (LD, change from standing to recumbent posture); and TR. When LST, LD and TR were individually examined, even though all indicators showed that sensitivity was 100%, the precision was 13.1%, 8.1% and 2.8%, respectively. When the data were combined as LST+LD, LST+TR, LD+TR and LST+LD+TR, detection of foaling improved, with precisions of 100%, 32.1%, 56.7% and 100%, respectively. In conclusion, the tail-attached multimodal device examined in this present study is useful for detecting foaling.

Early-life maternal deprivation affects the mother-offspring relationship in domestic pigs, as well as the neuroendocrine development and coping behavior of piglets

Early-life adversity may have programming effects on the psychological and physiological development of offspring. Domestic pigs (Sus scrofa) are an excellent model species for studying these effects because of their many physiological similarities to humans. Piglets from 10 sows were subjected to daily 2-h maternal deprivation on postnatal days (PND) 2–15 alone (DA) or in a group of littermates (DG). Control piglets (C) from 10 sows stayed with their mothers. Mother-offspring interaction, milk oxytocin, and cortisol were analyzed. An open-field/novel-object (OF/NO) test was performed with piglets on PNDs 16 and 40. Plasma cortisol and immune parameters were determined on PND 5 and 16. Two piglets from each group and sow were sacrificed on PND 20 and stress-related gene expression in the limbic system and prefrontal cortex (PFC), as well as splenic lymphocyte proliferative abilities, were examined. The milk cortisol of sows increased during the first separation of mother and offspring on the second day of lactation, whereas milk oxytocin did not change. The increase in cortisol by the OF/NO test on PND 16 was greater in C piglets than in DA and DG ones. DA piglets showed less agitated behavior than DG and C piglets in the OF/NO test at PND 16, but appeared more fearful. On PND 40, DA piglets showed more arousal than DG and C piglets in the OF/NO test. Neither plasma IgA nor N/L ratios in blood nor mitogen-induced proliferation of spleen lymphocytes were affected by deprivation. We found a higher mRNA expression of CRHR1 in the hypothalamus and a higher expression of MR in the hippocampus in DA piglets than in DG ones. The expression of GR, MR, and CRHR1 genes in the PFC was reduced by maternal deprivation, however, the expression of arginine vasopressin and oxytocin receptors was not affected. Repeated maternal deprivation induces sustained effects on stress reactivity and behavior of domestic piglets. Some of these effects were buffered by the presence of littermates. In addition, we found sex-specific differences in behavior and gene expression.

Pre-farrow enrichment with burlap sheet: potential benefit for sow performance

Burlap has been proposed as an enrichment option for the conventional farrowing crate environment. Our objectives were to determine if burlap sheets hung in farrowing crates were used by sows and piglets and had any effect on farrowing and litter performance. Before sow entry, a sterilized burlap sheet (165 cm × 60 cm) was attached to every second farrowing crate so that it hung to the floor with easy animal access. Its length was measured immediately after farrowing and weaning. Routine sow and litter information from farrowing to weaning (day 18) were recorded. Complete data were analyzed for mixed-parity sows and litters with burlap (BURL; n = 277) and without burlap (CTRL; n = 277). Sows and their litters manipulated the burlap sheet to varying degrees. The BURL sows had a lower percentage of stillbirths (6.5% vs. 8.3%, BURL vs. CTRL, SE 0.4; P = 0.004), although there was only a trend towards more born alive (13.00 vs. 12.54, SE 0.25; P = 0.113). More piglets were fostered off BURL sows (8.4 vs. 7.1, SE 0.5; P = 0.049). No significant differences were apparent for other sow and litter measurements. Burlap sheets as a farrowing crate enrichment have potential to improve sow and litter performance.

The effect of hessian and straw as nesting materials on sow behaviour and piglet survival and growth to weaning

Sows are strongly driven to build a nest prior to farrowing, and the performance of this behaviour is linked to the environment in which the animal is housed. The aim of this study was to investigate the impact of two nest-building materials, hessian and straw, on peri-parturient sow behaviour, plasma cortisol concentration and piglet survival and performance in farrowing crates. In the first experiment, sows (parity 1.7 ± 0.1) were allocated to four treatments: (n = 15), straw provided in the lead up to farrowing in an open farrowing pen, with the pen closed after farrowing (STRAW OPEN); (n = 14), straw provided in the lead up to farrowing in a closed farrowing pen (STRAW CLOSED); (n = 15), a closed farrowing pen with hessian sacks provided in the lead up to farrowing (HESSIAN) and; (n = 13), a closed farrowing pen with no nesting materials provided (CONTROL). A second experiment was performed on a separate farm to assess the effect of the same four treatments were applied to sows (parity 2.9 ± 0.1): SRAW OPEN (n = 68), STRAW CLOSED (n = 64), HESSIAN (n = 66) and CONTROL (n = 66), at a commercial level. The first experiment revealed that providing conventionally housed sows with straw or hessian in the lead up to parturition stimulated sows to perform nest-building behaviours similar to sows housed in an open pen with access to straw (nosing events; 16 ± 11 (CONTROL); 169 ± 36 (HESSIAN); 118 ± 29 (STRAW CLOSED); 199 ± 53 (STRAW OPEN); P < 0.05). Additionally, crated sows provided with straw had reduced cortisol levels immediately after farrowing compared to all other treatments (21.9 ± 6.1 ng/ml vs CONTROL; 49.3 ± 8.6 ng/ml; P < 0.01). Piglets born to STRAW CLOSED sows displayed the highest colostrum intake levels (404.8 ± 22.7 g vs CONTROL 361.9 ± 21.9 g; P < 0.01). The second experiment demonstrated a reduced incidence of piglet mortality both prior to fostering (0.7 ± 0.2; P = 0.001) and after fostering (0.7 ± 0.2; P = 0.001) in litters born to sows which were housed in conventional farrowing crates and provided with straw compared to CONTROL (prior to fostering 1.3 ± 0.2, and postfostering 1.1 ± 0.2). In conclusion, straw and hessian sacks are a suitable substrate for stimulating sows to exhibit nest-building behaviour under crated conditions. However, only the provision of straw in the crate environment improved piglet survival and positively affected sow welfare.

Coping with large litters: management effects on welfare and nursing capacity of the sow

A number of management issues can be used as drivers for change in order to improve animal welfare and nursing capacity of the hyperprolific sow. Group housing of sows during gestation is a recommended practice from the perspective of animal welfare. Related health issues include reproductive health and the locomotor system. It appears that management of pregnant sows in groups is challenging for a producer and considerable skill is required. We explored the benefits and challenges of group housing, including feeding issues. Increasing litter size requires additional attention to the mammary gland and its ability to provide sufficient nursing for the growing litter. We discuss the fundamentals of mammary development and the specific challenges related to the hyperprolific sow. We also address challenges with the farrowing environment. It appears that the old-fashioned farrowing crate is not only outdated in terms of welfare from the public’s perspective, but also fails to provide the environment that the sow needs to support her physiology of farrowing, nursing, and maternal behaviour. Studies from our group and others indicate that providing the sow with a loose housing system adequate in space and nesting material, along with reasonable chance for isolation, can be considered as fundamental for successful farrowing of the hyperprolific sow. It has also been shown that management strategies, such as split suckling and cross fostering, are necessary to ensure proper colostrum intake for all piglets born alive in a large litter. We thus conclude that welfare and nursing capacity of the sow can be improved by management. However, current megatrends such as the climate change may change sow management and force the industry to rethink goals of breeding and, for instance, breeding for better resilience may need to be included as goals for the future.

The Role of Oxytocin and the Effect of Stress During Childbirth: Neurobiological Basics and Implications for Mother and Child

The neuropeptide oxytocin acts as a hormone and a neuromodulator, influencing a multitude of human social behaviors, including reproduction. During childbirth and the postpartum period, it plays a key role in regulating and controlling processes that ensure a safe birth and the health of mother and child. Especially the onset of labor, the progress of labor and initial breastfeeding are mediated by oxytocin. In the maternal brain it controls the initiation of the mother-infant bond and the mother's emotional responses towards her child. In this review we summarize the current state of knowledge about the role of oxytocin during the different aspects and mechanisms of human childbirth, combining research from human and animal studies. Physiological and psychological stress during childbirth and lactation can have negative effects on the progress of labor, breastfeeding and bonding. We discuss how maternity caregivers can support the positive effects of oxytocin and minimize the effects of stress. Furthermore, we highlight aspects of the basic neurobiological principles and connections where further research is needed to improve our understanding of the regulation and the effects of oxytocin to support maternal and infant health.

Effects of prepartum stocking density and a blind on physiological biomarkers, health, and hygiene of transition Holstein dairy cows

Many dairy cows succumb to disease after calving. Disease risk may be affected by the cows' social environment and ability to perform maternal behaviors. In nature, cattle isolate from others and find seclusion to give birth; these behaviors may be limited in indoor group pens and could potentially affect the cows' ability to cope. The aim was to determine whether stocking density and a physical blind in prepartum bedded-pack group pens affected physiological biomarkers, disease risk, and hygiene of peripartum dairy cows. A randomized complete block designed with a 2 × 2 factorial arrangement of treatments was used. Approximately 3 wk before calving, 374 cows (primiparous = 127; multiparous = 247) were assigned randomly to 1 of 4 treatment pens with the following 2 factors: (1) high versus low stocking density (7.7 to 12.9 m² vs. 15.4 to 25.8 m² lying space per cow), and (2) presence or absence of a blind. The blind was created using plastic road barriers and plywood, a steel gate, and shade cloth. After calving, cows were moved into a freestall pen and milked 3 times per day. Blood was sampled on the day of enrollment (baseline; -24 d) and approximately -14, -7, 3, 7, 10, and 14 d relative to calving, to measure inflammatory (haptoglobin) and metabolic (nonesterified fatty acids and β-hydroxybutyrate) biomarkers. β-Hydroxybutyrate (≥1.2 mmol/L) was used to diagnose subclinical ketosis. Vaginal discharge was scored 3, 7, 10, and 14 d after calving, to diagnose metritis (none, mild, or severe). Hygiene was scored on -24, -14, and -7 d before calving. Before calving, haptoglobin was lower in pens with a blind. After calving, cows in pens with low stocking density before calving tended to be at greater odds of being diagnosed with metritis. Cows were more likely to have poorer hygiene scores in high stocking density pens. No treatment effects were detected for pre- and postpartum nonesterified fatty acids, β-hydroxybutyrate, postpartum haptoglobin, or subclinical ketosis. Results suggest that the provision of a blind and lower stocking density may be beneficial for reducing inflammation before calving. However, low prepartum stocking density might increase the odds of metritis after calving. Although the reason for this paradox is unclear, the effects of prepartum stocking density may require further exploration.

Comparison of the Productivity of Primiparous Sows Housed in Individual Stalls and Group Housing Systems

Simple Summary

Recently, South Korea amended the respective laws and will be enforcing that sows must be kept in group housing after 6 weeks from insemination by the year 2030. Accordingly, the comparison of productivity of sows in individual stalls and group housing systems was investigated in order to provide information on group housing systems for sows to pig farms. Primiparous sows were divided into four groups and housed in equal number in pen stalls, in short stalls with non-gated feeding stalls, in free access stalls, or with access to electronic sow feeders after 8 weeks from artificial insemination. Sows were transferred to farrowing crates at 110 days of gestation. No differences were found in sow productive performance, reproductive performance, and colostrum composition among housing types. Therefore, it was concluded that group housing systems could be used to replace individual stalls in commercial sow units.

Abstract

This study was conducted to provide commercial pig farms with information about group housing systems for sows in accordance with the amendment of the prohibition law for individual stalls for sows in South Korea. Therefore, this experiment was performed to compare the effects of individual stalls (IS) and group housing systems (GS) on the productivity of sows to investigate the feasibility of replacing individual stalls with group housing systems in commercial sow units. Forty primiparous sows (Landrace × Yorkshire; 210.67 ± 2.22 kg average initial body weight) were randomly assigned to four treatments with restricted feeding after 8 weeks from artificial insemination. The four treatments were (i) individual stalls (IS; housed in pen stalls), (ii) short stalls (SS; sows housed in pens with non-gated feeding stalls), (iii) free access stalls (FAS; a non-competitive housing system), and (iv) electronic sow feeders (ESF; used with radio frequency identification technology to allow individual sow management without individual confinement). All sows were transferred to farrowing crates at 110 days of gestation. There were no differences in sow productive performance, reproductive performance, and colostrum composition between IS and GS and among GS. The considered GS did not negatively affect any productivity parameters of primiparous sows compared with IS; the GS could replace IS in commercial sow units.

Short Communication: effect of positive handling of sows on litter performance and pre-weaning piglet mortality

Fear and environmental stressors may negatively affect the welfare of farm animals such as pigs. The present study investigated the effects of music and positive handling on reproductive performance of sows (n = 1014; parity 1 to 8) from a commercial pig farm practicing a batch farrowing system. Every 2 weeks, 56 sows were moved from the gestation unit to conventional-crated farrowing houses 1 week prior to expected farrowing. Treated (T; n = 299) and control (C; n = 715) sows were included in the study. In the farrowing houses, auditory enrichment (music from a radio) was provided to sows of T groups daily from 0600 to 1800 h until the end of lactation. Until the day of farrowing, T sows were additionally subjected, for 15 s per day per sow, to continuous back scratching by one member of farm staff. Litter performance and piglet mortality were recorded and analysed between T and C sows using linear mixed regression models. The number of liveborn piglets (C 13.85 v. T 13.26) and liveborn corrected for fostering (C 13.85 v. T 13.43) was significantly higher (P < 0.05) in C groups compared to the T groups. The number of stillborn piglets was 0.60 and 0.72 in T and C groups, respectively (P > 0.05). With regard to piglet mortality, a linear mixed regression model showed a significant overall effect of treatment in reducing piglet mortality (P < 0.01). Yet, the effect of treatment varied according to litter size (number of liveborn piglets) with a diminishing treatment effect in sows with a high litter size (P < 0.01). Pre-weaning survival was improved in the current study by the combined effect of daily back scratching of sows prior to farrowing and providing music to sows and piglets during lactation. Further research is needed to assess the separate effects of both interventions.

Enrichment with Lucerne Hay Improves Sow Maternal Behaviour and Improves Piglet Survival

This study investigated the effects of providing lucerne hay on the behaviour and the performance of sows housed in farrowing crates during farrowing and lactation. Seventy-two mixed parity sows received either 1 kg lucerne hay daily from entry into the farrowing crate (-2 d from expected farrowing date) until weaning at 17 d (lucerne group, n = 36), or received no additional enrichment (control group, n = 36). In the 18 h prior to farrowing, the sows in the lucerne treatment spent more time performing nest-building behaviour (14.8% lucerne vs 11.1% control, p = 0.0009) and less time sham-chewing (1.0% lucerne vs 1.9% control, p = 0.01) than control sows, and gave birth to fewer stillborn piglets/litter (0.1 lucerne vs 0.4 control, p = 0.027). After farrowing (Day 3), the control sows spent less time lying than the lucerne sows (26% control vs 43% lucerne, p < 0.05). The control sows also spent less time interacting with their piglets during early lactation compared to late lactation (25.5% Day 5 vs 47.3% Day 12, p < 0.05), suggesting reduced maternal behaviour in this group. The lucerne sows continued to interact with the lucerne throughout lactation, indicating that they still found the enrichment rewarding after the nesting period had ceased. Based on these results, lucerne enrichment was considered to improve sow welfare during farrowing and lactation and reduce the number of stillborn piglets.

Stress effects on the regulation of parturition in different domestic animal species

This review summarizes current knowledge on stress-like responses in parturient animals and their role for the onset and fine-tuning of parturition. The antepartum maternal cortisol increase is part of the endocrine changes that initiate parturition but a further increase in cortisol release during labor indicates a stress response. During the last minutes of delivery, sinus arrhythmias occur in 80% of foaling mares and 60% of calving cows. Expulsion of the neonate is thus characterized by parasympathetic dominance. In late-pregnant cows transported by road, cortisol concentrations increased but relations between transport stress and abortion remain unclear. In mares, transport not only elicited a stress response but also advanced the time of foaling. Transferring parturient rats, mice and pigs after birth of the first pup or piglet, respectively, to a stressful environment prolonged the time until delivery of the next littermate. In rats and pigs, this was caused by an increased opioidergic tone that restrained oxytocin release. In mice, a stress-induced delay of subsequent deliveries was caused by increased sympathoadrenal activity. When foaling mares were transferred to an uncomfortable stable at fetal membrane rupture, time until complete birth of the foal was doubled. As in mice, increased sympathetic activity was the mechanism delaying the progress of foaling. An increased sympathetic activity is also present in parturient cows disturbed during an early stage of calving. In equine and bovine neonates, the immediate postnatal period is characterised by high sympathetic activity and an increase in cortisol concentration, indicating a pronounced stress-like response.

External stress increases sympathoadrenal activity and prolongs the expulsive phase of foaling in pony mares

Mares usually give birth when they perceive their environment as safe and therefore disturbance at foaling may inhibit labor. In this study, foaling mares were transferred to an unfamiliar environment at rupture of the allantochorion (stress, n = 6) or were left undisturbed (control, n = 5). The progress of foaling, heart rate, heart rate variability (HRV) and plasma catecholamine, oxytocin and cortisol concentration were determined. In stressed mares, time from rupture of the allantochorion to appearance of the fetal feet (5.3 ± 1.1 vs. 1.6 ± 0.4 min) and total length of fetal expulsion were longer than in controls (both p < 0.05). Heart rate decreased during the expulsive phase of foaling in control mares (p < 0.01) but increased transiently in stressed mares. Heart rate calculated as percentage of the baseline was higher in stressed than in control mares (p = 0.05). HRV variables SDRR (standard deviation of the beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat differences) increased during foal expulsion (SDRR p < 0.01 and RMSSD p < 0.05). The increase in HRV was delayed in stressed compared to control mares (SDRR and RMSSD time x group p < 0.05). Plasma epinephrine and norepinephrine concentrations calculated as area under the curve for the expulsive phase of foaling were higher in stressed than control mares (p < 0.05). Concentrations of oxytocin and cortisol were elevated during foal expulsion (both p < 0.001) but not different between groups. In conclusion, disturbance of mares during expulsion of the foal prolonged foaling. This effect is most likely mediated via increased sympathetic activity and not inhibition of oxytocin release.

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&lt;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 (χ 2 4=10.8, P0.05) and all nurse sows had a higher salivary cortisol concentration at fostering, compared with the other days (F 10,426=3.47; P&lt;0.05). Acute effects of fostering differed between nurse sow treatments (F 2,113=3.45, P0.05). 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.

The effect of farrowing duration and parity on preovulatory follicular size and oxytocin release of sows at subsequent oestrus

This study examined the extent to which prolonged farrowing and parity are associated with plasma oxytocin concentrations and follicular development of oestrous sows during subsequent insemination. A total of 30 sows were allocated to two groups based on farrowing duration: (i) SHORT (n = 14): 159 ± 29 min, (ii) LONG (n = 16): 533 ± 190 min. The sows were also divided into two parity classes: (i) YOUNG (n = 14): parity 2.5 ± 0.8, (ii) OLD (n = 16): parity 6.4 ± 2.3. After weaning, the ovaries were examined daily with transrectal ultrasound. On the second day of oestrus, blood samples were collected for oxytocin (OT) assay at -15, -10, -5, 0, +1, +2, +3, +4, +6, +8, +10, +15, +20, +25, +30, +40, +50 and +60 min with a boar contact between 0 and +10 min. Boar presence stimulated an increase in OT concentrations (p < .05). During boar presence, OT in the LONG group was higher than in the SHORT group (p < .01). The sows in the OLD group had a longer farrowing duration than in the YOUNG group (p < .05). OT levels and diameters of follicles were more relevant for parity than was the duration of farrowing. We therefore conclude that the OT levels and follicular development of oestrous sows are associated due to parity but difficult to be predicted from the duration of previous farrowing.

Prepartum Maternal Behavior of Domesticated Cattle: A Comparison with Managed, Feral, and Wild Ungulates

The event of giving birth is an essential part of animal production. In dairy cattle production, there are substantial economical and welfare-related challenges arising around the time of parturition, and hence increased focus on efficient management of the calving cow. Drawing on the research literature on prepartum maternal behavior, this review compares cattle to other members of the ungulate clade with the aim of understanding the biological basis of bovine prepartum behavior with main emphasis on dairy cows. Ultimately, this knowledge may be used in future development of housing systems and recommendations for the management of calving cows. Maternal prepartum behavior varies among species, but the final goal of ungulate mothers is the same: ensuring a calm parturition and optimal environment for the onset of postpartum maternal behavior by locating an appropriate birth site, with low risk of predators, disturbances and mistaken identity of offspring. Features of chosen birth sites vary among species and depend largely on the environment, as ungulate females display a considerable ability to adapt to their surroundings. However, within commercial housing conditions in dairy production, the animals’ ability to adapt behaviorally appears to be challenged. Confinement alongside high stocking densities leave little room to express birth-site selection behavior, posing a high risk of agonistic social behavior, disturbances, and mismothering, as well as exposure to olfactory cues influencing both prepartum and postpartum maternal behavior. Dairy cows are thus exposed to several factors in a commercial calving environment, which may thwart their maternal motivations and influence their behavior. In addition, prepartum cattle may be more affected by olfactory cues than other ungulate species (e.g., sheep) because they are attracted to birth fluids already before calving. Hence, providing dairy cows with an environment where they can perform the maternal behavior they are motivated for, may aid a calm and secure calving and provide optimal surroundings for postpartum maternal behavior. Future research should focus on designing motivation-based housing systems allowing freedom to express prepartum maternal behavior and investigate in more detail the effects of the environment on the welfare of calving cows and their offspring.

Benefits of Prepartum Nest-building Behaviour on Parturition and Lactation in Sows - A Review

It is well known that prepartum sows have an innate motivation to build a nest before parturition. Under commercial conditions, however, the farrowing crate, which is widely used in modern pig husbandry, inhibits this innate behaviour through the lack of space, materials, or both. Thus, restriction of nest-building behaviour could generate increased stress, resulting in a decrease in maternal endogenous hormones. Hence, it could lead to detrimental effects on farrowing and lactating performance. Here we review interactions between prepartum nest-building behaviour, stress and maternal endogenous hormone levels, and discuss their effects on parturition, lactation, and welfare of sows and offspring.

A behavioural scale to measure ease of farrowing in sows

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

Maternal behavior in pigs

When sows kept under commercial conditions were put into crates in the early 1960s, the neuro-endocrine regulation of the maternal behavior in these domestic animals was disputed. Thus, the study of sow maternal behavior intensified and today a significant body of knowledge has accumulated to support the hormonal regulation of sow maternal behavior. The onset of nest building is associated with a periparturient decline in progesterone, an increase in prolactin and a major rise in plasma concentrations of PGF2alpha the day before parturition. Some nest building behaviors, such as pawing and gathering straw, have been found to correlate with changes in the levels of progesterone, prolactin and somatostatin. The duration of the birth process correlates negatively with peripheral oxytocin levels. During lactation, the stimuli from the piglets affect the release of several hormones which not only regulate the let down of milk but also sow metabolism and mammary milk production. The sow's nursing behavior ensures an even distribution of milk to her piglets. The piglets suckling behavior, in turn, is mainly a way to communicate their individual nutritional needs.

The timing of parturition in the pig is altered by intravenous naloxone

This experiment tested the hypothesis that opioid antagonists could influence the timing of the onset and progress of parturition in the pig. Primiparous pigs (gilts) received a jugular catheter on Days 104 to 106 of pregnancy. At 1400 h on Day 112 the gilts received 10 mg PGF2alpha, i.m. to induce parturition. At 1000 h on Day 113 (i.e., 20 h later) gilts received either saline (n=6), 1 mg/kg, i.v. naltrexone (n=4) or 1 mg/kg, i.v. naloxone (n=5). Blood samples were taken daily from Days 108 to 116. On Day 113, blood samples were taken hourly from 0500 to 0900 h and then every 30 min until 2400 h, or until the birth of the last piglet (BLP) (whichever was sooner) and assayed for progesterone, oxytocin (OT), cortisol and PRL. Additional blood samples for OT and cortisol assay were taken every minute from 0930 to 1100 h on Day 113 and for 30 min during parturition. Naloxone, but not naltrexone, delayed the onset of parturition relative to saline controls (by 14 h 21 min; P<0.05). Duration of parturition and rate of births were not significantly affected by treatment. Mean plasma OT increased in the 4 h following naloxone but not saline treatment, during which time OT plasma pulse amplitude was reduced in naloxone and naltrexone-treated animals relative to saline treated controls. The PRL secretion rose following treatment in saline treated animals, consistent with approaching parturition, but failed to rise in opioid antagonist treated animals. Progesterone concentrations remained elevated in naloxone-treated animals for longer than in the other groups. These data suggest that a rapid change in overall effect of parenteral administration of naloxone to parturient pigs occurs from delaying its onset when administered as in these experiments, to facilitating its progress when given during parturition (earlier experiments). The delay of onset of parturition may be mediated by interference with hypothalamic control of OT or PRL release.