Indicators of piglet survival in an outdoor farrowing system

Effects of Bacillus subtilis supplementation on reproductive parameters during late gestation in multiparous sows

Background and Aim

Probiotics are used at different stages of gestation to promote reproductive performance in sows. This study investigated the effect of Bacillus subtilis QST 713 supplementation during late gestation in multiparous sows on different reproductive parameters.

Materials and Methods

On day 85 of gestation, 115 multiparous healthy Landrace Yorkshire sows were randomly assigned to two groups with equal parity numbers. The control group (58 sows) was fed with basal diets, and the probiotic group (57 sows) was fed with basal diets +1010 colony-forming unit (CFU) B. subtilis QST 713 from day 85 to parturition. Back fat thickness on days 85 and 110, number of total born, number of born alive, stillbirth and mummy rates, individual birth weight, litter birth weight, within-litter variation of piglet birth weight, and postpartum vaginal discharge duration were recorded and compared between the two groups.

Results

The number of total born, number born alive, back fat thickness of sows before farrowing, litter weight, within-litter variation of piglet birth weight, and postpartum vaginal discharge duration were similar in both groups (p > 0.05). Dietary supplementation with B. subtilis QST 713 decreased the stillbirth rate (3.96 vs. 6.39%, p = 0.046) and born dead rate (5.12 vs. 8.57%, p = 0.035) and increased the birth weight of piglets (1552.78 vs. 1506.15 g, p = 0.049).

Conclusion

Daily supplementation with 1010 CFU of B. subtilis QST 713 during late gestation in multiparous sows could increase reproductive performance by increasing birth weight and decreasing stillbirth rate.

Effects of Auditory Enrichment on Welfare and Performance of Sows During Pregnancy and Farrowing/lactation Periods

This study is an observational study that aimed to evaluate whether exposure to music in the final third of sows' gestation and during farrowing/lactation would change behavior, reduce stress, and improve reproductive rates. Forty-eight sows were used at 90 days of gestation until the weaning of their piglets. During gestation, sows were divided into two treatments: control and with music enrichment. In farrowing/lactation, sows were divided into four treatments: control - control (without music); control - music (music during farrowing/lactation); music - control (music during pregnancy); music - music (music in both phases). Sows' behavior, eye temperature, and reproductive performance were evaluated. In the gestation phase, control group sows remained standing more times and had more negative interactions with the other sows in the pen. In the farrowing/lactating phase, sows exposed to music presented more nursing behaviors. The number of weaned piglets was higher in litters in which the sows had environmental enrichment in at least one of the phases of reproductive lives. Music may be used as environmental enrichment for sows in their reproductive phases due to beneficial responses in behavior, stress relief, and reproductive rates.

Changes in piglet and litter characteristics across parities in two highly prolific sow hybrids in an outdoor organic herd

High piglet mortality constitutes a welfare challenge in organic pig production. Litter characteristics were investigated from parities 1-5 of two hyper-prolific hybrids with different selection traits in an organic commercial herd (DanBred vs. Topigs Norsvin [TN70]). TN70 sows had more functional teats than DanBred sows, and their offspring had higher birth weights. Several interactions between hybrid and parity were found. The total born increased with higher parity and was more pronounced for DanBred sows. Litter weight at weaning was higher in parities 1-4 for TN70 compared with DanBred, and within DanBred parities 4 and 5 had higher litter weight at weaning than parity 1. The survival rate was higher for TN70 in parities 1 and 2 compared with DanBred, and for both hybrids, the survival rate was higher in parities 1 and 2 compared with parities 4 and 5. The number of weaned piglets was stable across parities 1-4 but lower in parity 5 for both hybrids. Thus, despite a lower number of total born piglets in TN70, TN70 sows weaned the same number of piglets as DanBred, with a lower mortality rate and a heavier litter at weaning.

Welfare of pigs on farm

This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.

Bacillus subtilis QST 713 Supplementation during Late Gestation in Gilts Reduces Stillbirth and Increases Piglet Birth Weight

Recent studies have shown that probiotic supplementation during late gestation exerts some beneficial effects on reproductive performance of the sows. This study aimed to investigate effects of Bacillus subtilis QST 713 supplementation in gilts on different reproductive criteria. A total of 94 Camborough-48 gilts at day 85 of gestation were randomly allocated into 2 groups: (1) control diet; (2) control diet + 4 × 10⁸ CFU Bacillus subtilis QST 713 per day. Gilts were supplemented until farrowing. At farrowing, litter size, number of piglets born alive, stillbirths, mummies, birth weight, farrowing duration, and birth interval were recorded. Within litter variation of piglet birth weight, depicted as SDBW and CVBW, was also calculated. Results showed that Bacillus subtilis QST 713 supplementation decreased stillbirth rate (1.26 vs. 4.37%, p=0.035) and increased birth weight of the piglets (1303.94 vs. 1234.09 g, p=0.007). Also, the litter size (11.85 vs. 10.67, p=0.03), number of piglets born alive (11.71 vs. 10.23, p=0.008), and litter weight (15473.06 vs. 13174.86 g, p=0.002) in the treatment group were higher than those in the control. Farrowing duration (174.39 vs. 160.81 minutes, p=0.162), birth interval (16.32 vs. 16.59 minutes, p=0.674), SDBW (85.07 vs. 94.65 g, p=0.343), and CVBW (6.42 vs. 7.85, p=0.12) were independent of the Bacillus subtilis QST 713 supplementation. Results of the present study indicate that supplementation of Bacillus subtilis QST 713 during late gestation in gilts reduces stillbirth and increases birth weight thereby improving their reproductive performance.

Biological sex: an understudied factor driving disease susceptibility in pigs

Biological sex is a major host factor influencing risk for infectious disease-associated mortality, and chronic inflammatory and metabolic diseases. Research in human and rodent models -has revealed sex differences that exist across organ systems during health and disease that may contribute to sex biases in disease risk. Despite the robust and growing literature on the role of sex as a risk factor in human disease, comparatively little attention has been focused on investigating the role of biological sex in disease susceptibility in agriculturally important animal populations such as the pig. To date, comparisons between sexes have focused on carcass composition, growth rate, and feed efficiency in pigs. However, there is a large gap in the literature regarding the effects of biological sex on other integral aspects of health and disease. The objective of this review is to highlight the available literature reporting sex differences in pig health and biology with an emphasis on sex differences in mortality, immunity, and gastrointestinal (GI) physiology and to address biological sex as a significant biological variable in disease risk and research study design. A basic overview of the biology of sex differences including the major hormonal and genetic/chromosomal mechanisms of sexual differentiation and the developmental periods in which sex differences emerge will be covered. This review will also discuss how production-relevant management and environmental factors (e.g., wean age, castration, stress, and nutrition) interact with biological sex to shape host immune and GI development and function. Perceived gaps in knowledge and areas of future research will also be discussed.

Improving young pig welfare on-farm: The Five Domains Model

Considering welfare through the "neonatal and nursery pig perspective" is an exciting approach, and one that resonates with consumers. Overlaying this with the Five Domains Model, as we suggest in this review, points to practical on-farm improvements that provide each pig the opportunity to experience positive mental states. The Five Domains Model is broken into physical and functional states, that includes Domain 1 Nutrition, Domain 2 Physical Environment, Domain 3 Health and, Domain 4 Behavioral Interaction, and Domain 5 Mental State. The Five Domains Model can build on the breadth and depth of swine welfare science to highlight opportunities to improve welfare on-farm. In Domain 1 management of increasingly large litters is considered, with examples of sow vs. artificial rearing, colostrum quality and quantity, and creep feed management strategies. Efforts can result in positive mental states such as feeling full and content and the ability to experience pleasure of drinking and food tastes/smells. Domain 2 considers space complexity and access to key resources, along with thermal and physical amenities, to promote feelings of physical comfort. Domain 3 considers pig health in three broad, yet inter-linking categories, (a) congenital and hereditary health, (b) environmental pathogen load and, (c) colostrum quality and quantity, and its effect on the microbiome. Improvements can result in a pig that displays vitality and feels healthy. Domain 4 provides the pig opportunities to express its rich behavioral repertoire, specifically positive social interactions, play, and exploration. These efforts can result in pigs feeling calm, safe, comfortable, having companionship, engaged, interested and rewarded. In conclusion, using the Five Domains Model can highlight numerous opportunities to improve current and future housing and management through the "neonatal and nursery pig perspective" with a focus on inducing positive mental states that can result in improved quality of life and welfare state.

Incidence of dystocia at piglet level in cloprostenol-induced farrowings and associated risk factors

Few studies have investigated risk factors for dystocia in swine, although this birthing abnormality can compromise welfare of both sows and piglets by increasing stillbirth rate and decreasing sow productivity. This study aimed to determine risk factors associated with dystocia at piglet level in cloprostenol-induced farrowings. A dystocia event was recorded when a birth interval exceeded 45 min or when manual extraction was applied. Data were collected from 898 piglets born from 77 Landrace × Yorkshire crossbred sows, which were induced for farrowing on day 114 of gestation. Generalized linear mixed models (GLMMs) were used to evaluate the association between dystocia and parity, gestation length, litter size, relative birth order (RBO (%) = 100 ⋅ birth order/litter size), birth weight, crown rump length, body mass index, ponderal index, piglet's sex, use of oxytocin, and stillbirth. Sows nested in farrowing batches were fitted as random factors in GLMMs. Incidence of dystocia at piglet and farrowing levels was 11.0 % and 75.3 %, respectively. The final multivariate model explained 20.1 % variation of dystocia. RBO had a quadratic effect on dystocia in which incidence of dystocia decreased from RBO ≤ 40 % to RBO = 60 %–70 %, and then increased to the end of parturition. Piglets with birth weight > 1700 g and stillborn piglets had higher odds of dystocia in comparison with piglets with a birth weight of 900–1700 g (OR = 2.63; 95 % CI = 1.66–4.18) and live-born piglets (OR = 2.62; 95 % CI = 1.12–6.15), respectively. This study indicates that dystocia is very common in cloprostenol-induced farrowings and suggests that the last one-third of parturitions is the most important stage to be supervised, and selection for homogenous litters and moderate high birth weight may reduce the rate of dystocia.

How Housing Conditions Determine the Welfare of Pigs

Humans who care for pigs prefer an environment that not only allows the pigs to express their natural behaviors but also limits the development of aggression and stereotypes. Most of the behavioral and health problems encountered by pigs in barren, conventional conditions are solved by alternative housing systems. However, it is not known whether these systems are advantageous in terms of the performance of pigs. In this work, we review the effects of housing systems on pigs' behaviors and performance, which are among the major indicators of the welfare of these animals. Research results point out that outdoor systems are more ideal for sows and fatteners than buildings. Nonetheless, outdoor housing is associated with two major effects in both groups: increased activity due to environmental exploration and higher space allowance, and increased incidence of injuries compared to indoor systems. Sows are more active when housed in groups, but they experience an increased frequency of injuries. According to the literature, group-housed sows give birth to healthy piglets with good daily weight gains. The difference in the fattening and slaughter performance of pigs raised indoors vs. outdoors remains unclear, and the results reported so far are inconsistent. Outdoor systems seem to be associated with a higher incidence of osteochondrosis and lesions of elbow and hock joints, whereas indoor systems cause a greater degree of body soiling in pigs. Based on the reviewed literature, it may be concluded that outdoor housing helps to solve behavioral issues in pigs but leads to other problems in pig production.

The influence of hypothermia prevention by application of skin moisture absorbent on the value of body temperature, body weight and blood parameters in piglets

ABSTRACT Reducing the mortality rate is of a great economic importance for pig farming. Therefore, it is necessary to define the conditions in the farrowing unit based on the performance of the piglets, and specific hematological and biochemical parameters. Therefore, the aim of this paper is to examine the importance of using skin moisture absorbent and its influence in preventing hypothermia, which causes great economic losses in pig production. The experiment was set up on a commercial farm in Serbia and included 92 pigs divided into the experimental and control group. Body temperature values, body weight and blood parameters were monitored. The obtained values indicate that there is a significantly positive correlation of body temperature change and body weight values, and body temperature showed a significantly higher increase in the experimental group compared to the control group. The results obtained from hematological and biochemical parameters provide a clearer picture of the metabolic processes in piglets in the farrowing unit and can be used to further improve pig production and as a complement to genetic enhancement.

Risk factors associated with dystocia in swine

Background and Aim:

Dystocia in swine can increase the stillbirth rate; however, its importance in pig-breeding systems has been underestimated. Until now, few studies have investigated dystocia and associated risk factors. Therefore, in this study, we aimed to evaluate the effects of various risk factors on dystocia in swine.

Materials and Methods:

Out of 5,557 piglets, we included 4,997 piglets in risk analysis study. The dependent variable was dystocia, which was recorded when a birth interval exceeded 45 min or when obstetric assistance was applied. The independent variables were parity, gestation length, litter size, birth order, gender, presence of a dead piglet, birthweight, crown rump length, body mass index, ponderal index, and oxytocin use. We used generalized linear mixed models to examine the associations between potential risk factors and dystocia at the piglet level.

Results:

A total of 6% of the piglets were born with a dystocia event, and 47.2% of the farrowing experienced at least one event. Dead piglets and piglets with a crown rump length of >31 cm were associated with an increased dystocia rate. This rate decreased from birth order 2 to 7, stabilized to 11, and then increased till the end of the fetal expulsion process.

Conclusion:

Dystocia is common in swine. Therefore, this condition should be carefully addressed by veterinarians and farrowing house personnel so that its adverse effect on welfare and productivity of sows and survivability of piglets can be reduced. Further studies investigating dystocia status and risk factors in different swine farrowing systems should be undertaken to provide more knowledge about this neglected condition.

Non-infectious risk factors for intrapartum stillbirth in a swine farm in the North of Vietnam

Background and Aims

Stillbirth causes considerable loss to the pig farming industry. Methods aimed at reducing stillbirth should base on the understanding of risk factors for intrapartum stillbirth because it accounts for 75% of all stillbirths. Unfortunately, few studies have differentiated between intrapartum and prepartum stillbirths leading to inadequate information about risk factors for sole intrapartum stillbirth. This study investigated risk factors for piglet's intrapartum stillbirth.

Materials and Methods

Data of 1527 piglets born from 103 sows in one herd were recorded. Generalized linear mixed models were used to determine the relationship between investigated risk factors and intrapartum stillbirth at the piglet level. The potential risk factors were parity, gestation length (GL), litter size (LS), birth order (BO), birth interval (BI), cumulative farrowing duration (CFD), gender, crown-rump length, birth weight (BW), body mass index, ponderal index (PI), and BW deviation.

Results

About 60% (60.2%, 62/103) litters had stillborn piglet(s), and the intrapartum stillbirth rate was 5.8% (89/1527). BW deviation (≤0.1 and >0.6 kg), LS >13, GL (<114 and >117 days), PI ≤54, and BO >10 were the most significant factors associated with increased intrapartum stillbirth. No effect of parity, sex, BI, and CFD on intrapartum stillbirth was detected.

Conclusion

These data stressed the importance of piglets' size and shape in the prediction of intrapartum stillbirth. Furthermore, large LS, high BO, short, and long GL were associated with increased intrapartum stillbirth. The results of this study suggest that procedures aimed at increasing litter homogeneity, optimizing piglets' size and shape, avoiding short and long gestation, and increasing supervision rate, especially at the second half, of the farrowing may reduce piglet's intrapartum stillbirth.

Suitability of Different Thermometers for Measuring Body Core and Skin Temperatures in Suckling Piglets

Simple Summary

After birth, piglets’ temperatures usually drop some degrees because of low ambient temperatures in the stable. Piglets have no ability to increase their body temperatures during their first days of life, which can cause health issues if piglets are not appropriately cared for. Monitoring temperatures can, therefore, contribute to reducing impaired wellbeing and unnecessary losses. The most common method for assessing core temperatures is measuring rectally with a digital thermometer. This, however, takes time and requires securing of the animal, which is stressful. Therefore, the aim of this study was to determine whether other thermometers or thermometric devices, such as an infrared camera, can deliver results similar to the digital thermometer. For the measurements in newborn piglets, infrared ear thermometers, infrared forehead thermometers, and infrared laser thermometers were used, as it was assumed that these would deliver results fast and cause little distress in piglets. The results were compared to rectally measured temperatures and it was found that the temperatures measured in-ear correspond to a great extent to rectal temperatures and show little variation between measurements, while the other used devices can only give a rough estimate of the actual core temperatures.

Abstract

Monitoring the temperature of piglets after birth is critical to ensure their well-being. Rectal temperature measurement is time-consuming, requires fixation of the animal and is stressful for piglets. This study aims to evaluate the effectiveness of infrared thermometry and thermography as compared to rectal temperatures. We investigated digital thermometers for rectal measurements, infrared ear thermometers, infrared forehead thermometers, infrared laser thermometers and an infrared camera during field trials with piglets aged 1–13 days. Temperatures differed between the left and right ear and ear base (p < 0.01), but not between temples. Three forehead and laser devices yielded different temperatures (p < 0.01). Temperatures assessed with a laser thermometer decreased with distance from the target (p < 0.01). The highest correlation observed was between the rectal and tympanic temperatures (r = 0.89; p < 0.01). For temperatures assessed with the camera, inner thigh and abdomen correlated most closely to core temperature (0.60 ≤ r ≤ 0.62; p < 0.01). Results indicate that infrared ear thermometry commonly used in humans is also suited for assessing temperature in piglets. The inner thigh and abdomen seem promising locations for estimating core temperature with an infrared camera, but this approach needs to be adapted to reduce time exposure and stress for the piglets to be used under practical conditions.

Thermoregulation at birth differs between piglets from two genetic lines divergent for residual feed intake

Thermoregulation is essential to piglets' neonatal survival. This study used infrared thermography (IRT) to assess thermoregulation abilities of piglets from two lines divergent for residual feed intake (RFI). At birth, morphology (weight, length, width and circumference), vigour (respiration, mobility and vocalisation), and rectal temperature were recorded from piglets of the 11th generation of the low RFI (LRFI, more efficient; n = 34) and the high RFI (HRFI, less efficient; n = 28) lines. Infrared thermography images were taken at 8, 15, 30 and 60 min post partum. Temperatures of the ear base and tip, and of the back (i.e. shoulders to rumps) were extracted (Thermacam Researcher Pro 2.0) and analysed with linear mixed models (SAS 9.4). Piglets had different average hourly weight gain (HRFI = 7.1 ± 1.3 g/h, LRFI = 3.6 ± 1.3 g/h; P < 0,001) but did not differ in morphology or vigour. All temperatures increased overtime. At birth, piglets' rectal temperature was correlated with the initial temperature of the ear base and the maximum back temperature (0.37 and 0.33, respectively; P < 0.05). High residual feed intake piglets had lower ear tip temperatures than LRFI piglets at 15 (24.7 ± 0.37 °C vs. 26.3 ± 0.36 °C, respectively; F1, 63.5 = 9.11, P < 0.005) and 30 min post partum (26.2 ± 0.47 °C vs. 27.6 ± 0.44 °C, respectively; F1, 66.9 = 4.52, P < 0.05). Moreover, thermal pattern of the ear tip differed between the two genetic lines. In conclusion, IRT allowed non-invasive assessment of piglets' thermoregulation abilities and indicated an influence of genetic selection for RFI on neonatal thermoregulation abilities.

Coping with large litters: the management of neonatal piglets and sow reproduction

As a result of intensive breeding, litter size has considerably increased in pig production over the last three decades. This has resulted in an increase in farrowing complications. Prolonged farrowing will shorten the window for suckling colostrum and reduce the chances for high-quality colostrum intake. Studies also agree that increasing litter sizes concomitantly resulted in decreased piglet birth weight and increased within-litter birth weight variations. Birth weight, however, is one of the critical factors affecting the prognosis of colostrum intake, and piglet growth, welfare, and survival. Litters of uneven birth weight distribution will suffer and lead to increased piglet mortality before weaning. The proper management is key to handle the situation. Feeding strategies before farrowing, management routines during parturition (e.g., drying and moving piglets to the udder and cross-fostering) and feeding an energy source to piglets after birth may be beneficial management tools with large litters. Insulin-like growth factor 1 (IGF-1)-driven recovery from energy losses during lactation appears critical for supporting follicle development, the viability of oocytes and embryos, and, eventually, litter uniformity. This paper explores certain management routines for neonatal piglets that can lead to the optimization of their colostrum intake and thereby their survival in large litters. In addition, this paper reviews the evidence concerning nutritional factors, particularly lactation feeding that may reduce the loss of sow body reserves, affecting the growth of the next oocyte generation. In conclusion, decreasing birth weight and compromised immunity are subjects warranting investigation in the search for novel management tools. Furthermore, to increase litter uniformity, more focus should be placed on nutritional factors that affect IGF-1-driven follicle development before ovulation.

Use of infrared thermography to noninvasively assess neonatal piglet temperature

Hypothermia is risk factor for piglet neonatal mortality, especially for low birth weight piglets. Piglets with intrauterine growth retardation (IUGR) also have a higher mortality risk at birth. This study aimed to validate infrared thermography (IRT) as an alternative to rectal temperature (RT) to measure piglet temperature in the hour postpartum, and to identify piglets with thermoregulation difficulties. At birth (6.3 ± 0.35 min postpartum), 67 piglets were dried, weighed, scored for growth retardation (IUGR; 0–3), and isolated in a plastic box where IRT images were taken, followed by RT. Piglets were then returned to the farrowing pen, and the process repeated at 15, 30, and 60 min postpartum. Piglets were ranked according to their weight (quartiles: 0.57–1.27 kg, 1.27–1.5 kg, 1.5–1.74 kg, 1.74–2.44 kg). Temperatures (ear base and tip; minimum, maximum and average of back) were extracted from IRT images (Thermacam Researcher Pro 2.0). Pearson correlations between temperature measures were calculated, and the effect of time, IUGR score, and weight were included in linear mixed models (SAS 9.4). RT was correlated with all IRT data across time points (P < 0.05); correlations were strongest with the ear base, and weakest with the ear tip and minimum back temperature. Both IUGR score and weight rank affected ear base (P < 0.05) and RTs (P < 0.05). The lightest piglets, and piglets with severe IUGR had the lowest temperature, relative to their counterparts. Indeed, differences between all weights categories were significant for RT. Piglets with the lowest weight (0.27–1.27 kg) had lower ear base temperatures than piglets in the third quartile (1.5–1.74 kg; 35.2 ± 0.36 °C vs. 36.5 ± 0.35 °C, t_64.9 = −4.51, P < 0.001) and the heaviest piglets (1.74–2.44 kg; 35.2 ± 0.36 °C vs. 36.4 ± 0.36 °C, t_70.4 = −3.97, P < 0.005). Overall, piglets with severe IUGR (score 3) had a lower RT than normal piglets (score 0; 35.8 ± 0.46 °C vs. 37.2 ± 0.42 °C, t_43.1 = 3.16, P < 0.05) and piglets with mild IUGR (score 1; 35.8 ± 0.46 °C vs. 37.1 ± 0.40 °C, t_45.3 = 2.92, P < 0.05); and they also had lower temperature at the base of the ear than normal piglets (35.1 ± 0.42 °C vs. 36.3 ± 0.36 °C, t_63.1 = 3.01, P < 0.05). These results confirmed that IRT is an interesting noninvasive tool for assessing neonatal piglets’ thermoregulatory abilities and could be used in research investigating successful interventions for piglets at risk of hypothermia.

Risk factors associated with stillbirth of piglets born from oxytocin-assisted parturitions

Aim:

The present study aimed to investigate the effects of different risk factors on stillbirth of piglets born from oxytocin-assisted parturitions.

Materials and Methods:

Data were collected from a total of 1121 piglets born from 74 Landrace x Yorkshire crossbred sows from a herd. Logistic regression models were used to determine the associations between stillbirth and different risk factors including parity (1, 2, 3-5, and 6-10), gestation length (GL) (112-113, 114-116, and 117-119 days), litter size, birth order (BO), sex, birth interval (BI), cumulative farrowing duration, birth weight (BW), crown rump length, BW deviation, body mass index, ponderal index (PI), and the use of oxytocin during expulsive stage of farrowing.

Results:

The incidence of stillbirth at litter level and stillbirth rate was 59.5% (44/74) and 8.1% (89/1094), respectively. The final multivariate logistic regression selected BO, BI, PI, GL, and parity as the five most significant risk factors for stillbirth. Increased BO and BI, GL <114 and >116 days, parity 6-10, and low PI increased the stillbirth rate in piglets.

Conclusion:

Several factors previously determined as risks for stillbirth in exogenous oxytocin-free parturitions also existed in exogenous oxytocin-assisted parturitions. One dose of oxytocin at fairly high BO did not increase stillbirth, whereas two doses of oxytocin were potentially associated with increased values.

Characteristics of Piglets Born by Two Highly Prolific Sow Hybrids

High piglet mortality constitutes a welfare challenge in Danish organic pig production with almost one in three piglets dying before weaning. Piglet characteristics such as birth weight, rectal temperature and intrauterine growth restriction (IUGR) affect piglet survival. Due to differences in breeding goals, these characteristics may be expected to differ between sow hybrids. Thus, the aims of the present study were (1) to investigate piglet characteristics in two highly prolific sow hybrids and (2) to study to which extent the aforementioned characteristics affect piglet mortality. Forty-nine sows (22 DanBred and 27 Topigs Norsvin) were followed in their first two parities. Sows were housed outdoors and gave birth in huts. On day 1 postpartum ( pp ) piglets were individually marked, weighed, their rectal temperature was recorded and they were scored for IUGR. Weight and rectal temperature were recorded again 3 days pp. Principal component analyses were conducted to explore relationships among variables. Early piglet death grouped with IUGR, lower rectal temperature and weight on day 1 pp. Late mortality grouped with increasing litter size and DanBred hybrid. Whilst, Topigs Norsvin hybrid grouped with increasing rectal temperature day 3 pp, longer crown to rump length, higher weight and more teats on the sow. Results of the statistical analyses showed that Topigs Norsvin piglets were heavier 1 and 3 days pp (p < 0.001) compared to DanBred piglets. Furthermore, Topigs Norsvin piglets had a higher rectal temperature than DanBred on day 1 pp (p = 0.023). The risk of IUGR depended on an interaction between sow hybrid and parity (p = 0.023). DanBred sows gave birth to more piglets (18.2 ± 0.6) than Topigs Norsvin sows (15.7 ± 0.5, p = 0.003), however, DanBred sows had fewer teats than Topigs Norsvin sows. Weight on day 1 pp affected both the odds of stillbirth (p < 0.001) and live born death (p < 0.001). Lower rectal temperature day 1 pp (p < 0.001) increased the odds of live born death. In conclusion, the investigated hybrids differed in several piglet characteristics related to piglet mortality. Use of sows giving birth to heavier and fewer piglets in the litter may thus be a useful tool to reduce piglet mortality in pig production with outdoor farrowing.

Practical oxygen therapy for newborn piglets

Aims: To evaluate the effect of a novel method of practical oxygen therapy on physiological parameters related to survival, weaning weight and preweaning mortality of neonatal piglets under commercial farm conditions. Methods: Piglets from hyperprolific sows born with signs of asphyxia, (n = 109; <6 on a score of respiration, meconium staining and activity) or very low birth weight (VLBW; n = 112; <1.05 kg) were selected for the study. Approximately half of each group (n = 55 VLBW piglets and n = 57 piglets with asphyxia) received 100% oxygen immediately after birth using a specially designed facemask for 45 seconds (VLBW) or 1 minute (asphyxiated). Physiological parameters (peripheral blood oxygen saturation (SpO₂) blood glucose concentration and rectal temperature) were measured before oxygen treatment 5 minutes after birth (SpO₂) and 24 hours later (SpO₂, blood glucose concentration, temperature). Weight at birth, at 24 hours and at 21 days of age, preweaning mortality, and estimated colostrum intake were also recorded. Results: A significant treatment effect on SpO₂ was observed (p = 0.013 and p < 0.001 for VLBW and asphyxiated piglets respectively). VLBW and asphyxiated piglets that received oxygen treatment had higher SpO₂ after treatment (measured 5 minutes after birth, 97.7 and 97.8% respectively) compared to immediately after birth (93.3 and 86.8% respectively) while untreated piglets showed no variation. Blood glucose concentrations increased in all piglets between birth and 24 hours of age (p = 0.003 and p < 0.001 for asphyxiated and VLBW piglets respectively) and this was higher in asphyxiated piglets that received oxygen than those that did not (5.6 (SE 0.2) mmol/L; p < 0.05). Estimated colostrum intake was higher in asphyxiated (401.6 (SD 24.4) g/kg) and VLBW (374.9 (SE 23.4 g/kg) piglets that received oxygen than those that did not (273.2 (SE 24.1) g/kg; p < 0.001 and 249.0 (SE 22.5) g/kg; p < 0.001 respectively). Similarly weight at weaning was higher in asphyxiated (5.8 (SE 0.2) kg) and VLBW (4.9 (SE 0.2) kg) piglets that received oxygen therapy than control animals (4.9 (SE 0.2) kg; = 0.005 and 4.1 (SE 0.2) kg; p = 0.008 respectively). Furthermore, oxygen treatment markedly reduced preweaning mortality from 9/52 (17%) untreated to 1/57 (1.7%) oxygen-treated piglets suffering asphyxia at birth (p = 0.006). Conclusions: Oxygen therapy improves physiological and productive parameters in piglets born with signs of asphyxia or VLBW. The incorporation of this strategy as part of the farrowing routine enhances the advantages of rearing hyperprolific sows.

Effect of increasing dietary energy density during late gestation and lactation on sow performance, piglet vitality, and lifetime growth of offspring

Genetic selection for hyperprolificacy in sows has resulted in a significant increase in the number of piglets born alive per litter but subsequently, decreased piglet vitality and growth. As a consequence, increasing sows' energy intake during lactation to help increase piglet vitality and growth is increasingly important. The objective of this study was to investigate the effect of increasing dietary energy density for lactating sows on weight and back-fat changes in sows, milk composition, and vitality and growth of progeny. Gestating sows (N = 100; Large White × Landrace) were randomly assigned to one of four energy dense diets at day 108 of gestation until subsequent service; 13.8 (LL), 14.5 (L), 15.2 (H), and 15.9 MJ DE/kg (HH). All diets contained 1.2% total lysine. Blood samples from sows were taken on day 108 of gestation and at weaning (day 26 of lactation) and colostrum (day 0) and milk samples (day 14) were collected during lactation. Sow lactation feed intakes were recorded daily. The number of piglets born per litter (total and live), piglet birth weight (total and live), intrauterine growth restriction (IUGR) traits and muscle tone were recorded in piglets at birth. Piglet tympanic ear temperature (TEMP) was recorded at birth and at 24 h. Pigs were weighed on days 1, 6, 14, 26, 33, 40, 54, 75, and 141 of life. Postweaning (PW) pigs were fed standard cereal-based diets. Pig carcass data were collected at slaughter (day 141). Lactation energy intake was higher for HH sows than for all other treatments (P < 0.01). Colostrum and milk composition and lactation feed intake were not affected by treatment. The number of piglets born per litter (total and live) and piglet birthweight (total and live) was similar between treatments. Piglets from LL sows had more IUGR traits (P < 0.01), while those from HH sows had better muscle tone (P < 0.01) than all other treatments. Piglets from LL sows (P < 0.01) and piglets from H sows (P < 0.01) had a higher 24 h TEMP than piglets from HH sows. H sows weaned a greater number of piglets than L sows (P < 0.05) and HH sows (P < 0.01), while L sows weaned lighter litters than H (P < 0.05) and LL sows (P < 0.05). Pig growth PW was unaffected by treatment. High energy dense diets increased energy intake in sows, without depressing appetite. Feeding an HH diet improved piglet muscle tone at birth, whereas feeding an H diet increased litter size at weaning. Inconsistent results were observed for other traits of piglet vitality and for preweaning litter growth performance.

Effects of Different Farrowing Environments on the Behavior of Sows and Piglets

Simple Summary

The farrowing crate has long been a severe welfare problem of sows as its space restriction greatly impairs the behavioral expression of sows and induces long-term stress. We aimed to investigate the behavioral pattern of sows and piglets reared under different farrowing systems a farrowing crate and free farrowing pens with sloping walls with or without nest materials. Sows and piglets in free farrowing pens had a higher level of activity and lower level of performing abnormal behaviors. Providing nest material enhanced the beneficial effect of free farrowing system on the behavior of sows and piglets. These results encourage us to introduce the free farrowing systems to the pig industry and thus improve the welfare condition of farrowing sows. However, improved managements should be investigated as the piglet loss in the free farrowing systems tended to be higher than that in the farrowing crate system.

Abstract

We investigated the effect of different farrowing systems on the behavior of sows and piglets. In total, 22 hybrid sows (Yorkshire × Landrace) were randomly assigned into three farrowing systems, farrowing crate (FC), free farrowing pen with sloping walls (FFS), and free farrowing pen with sloping walls and nest materials (FFSN). The FFS and FFSN sows were more active, and exhibited less abnormal behaviors compared with the FC sows before and after parturition. FFS and FFSN piglets were more active compared with FC piglets. The increased activity of the FFS and FFSN sows might encourage the activity of their piglets, resulting in more proximity to sow behavior of their piglets. Providing nest materials improved the investigative behavior of sows and piglets. The total mortality of piglets in the free farrowing systems tended to be higher compared with the farrowing crate system. In conclusion, free farrowing system has beneficial effects on the behavior of sows and piglets but extra care in management needs to be taken to avoid piglet loss. Adding nest material in the farrowing pens is suggested to enrich the behavioral pattern of sows and piglets.

Are Larger Litters a Concern for Piglet Survival or an Effectively Manageable Trait?

As sows continue to be selected for greater prolificacy, it is important to review problems that arise in larger litters, and whether these issues can be appropriately managed. Although a proportion of piglets in larger litters can be born underweight, proper supervision around farrowing and adequate colostrum intake has the potential to improve the survival of low-birth-weight piglets and their ongoing growth to weaning. As larger litters can impart greater stress and discomfort on sows, implementing a low-stress environment leading up to parturition may improve sow performance and subsequent survival of piglets. Additionally, treating sows with anti-inflammatory compounds, either dietary or pharmacologically, shows some promise for alleviating sow discomfort and improving piglet survival in larger litters. Understanding that selecting sows for larger litters not only affects piglet survival but the well-being of the sow, the decision to continue selecting for larger litters, regardless of management strategies, remains a topic of ethical concern.

L-arginine supplementation during the final third of gestation improves litter uniformity and physical characteristics of neonatal piglet thermoregulation

The study assessed the effects of dietary L-arginine supplementation from days 85 to 115 of gestation on sow performance, litter quality, piglet physiology and survival variables in the first 24 hr of life. Twenty multiparous sows, with a history of hyperprolificacy (more than 14 piglets per litter), were used. A completely randomized experimental design was used, consisting of two treatments: feed supplemented or not with 1% L-arginine from days 85 to 115 of gestation. The experimental unit consisted of the sow and its respective litter, using 10 replicates per treatment. The sows were distributed into the treatments based on body condition and parity. Supplementation with L-arginine reduced the within-litter standard deviation and the within-litter coefficient of variation of piglet weight at 24 hr by 54 g and 4.14 percentage points respectively (p = .029; p = .035). Supplementation with 1.0% L-arginine decreased the percentages of piglets weighing less than 800 g by 5.60 and 5.08 points at birth and at 24 hr of life respectively. Piglets from sows supplemented with L-arginine had higher (p = .088) average rectal temperatures at birth and lower (p = .030) rectal temperature at 24 hr of life in comparison with control piglets. No significant differences in placental weight or estimated colostrum production and intake were observed in the first 24 hr of life. At 24 hr of life, piglets weighing less than 1,000 g and from supplemented sows had lower (p = .048) surface/mass ratios and higher body mass index (p = .070). Piglets from supplemented sows and who weighed 1601 to 1,800 g had lower body mass index and ponderal index (p = .002; p = .003). Supplementation with L-arginine during the final third of gestation reduces the incidence of unviable piglets (<800 g) and improved litter uniformity and piglets' body conformation within the first 24 hr of life.

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

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

Higher light intensity and mat temperature attract piglets to creep areas in farrowing pens

Loose farrowing pens have been considered as alternatives to crates to enhance sow welfare. A major concern with pen systems is often higher piglet pre-weaning mortality, especially due to crushing by the sow. An optimal management of light and mat surface temperature may promote greater piglet use of the creep, which has been associated with reduced piglet crushing. A total of 108 sows and their piglets were studied in sow welfare and piglet protection pens on a commercial piggery, across two replicates. Sows were randomly assigned to pens arranged within two creep treatments (bright creep: 300 lx v. dark creep: 4 lx), considering mat temperature as a covariate. Twelve sows and their litters in each treatment (24 in total) had their behaviour continuously recorded for 72-h postpartum (pp), and four focal piglets per litter were weighed on the first and third days pp. In situ behaviour observations were performed daily (from 0800 to 1700 h) on all sows and their litters, every 15 min over 72-h pp to record piglet time spent in the creep, latency to enter the creep for the first time, latency for the litter to remain in the creep for at least 10 min, and piglet and sow use of pen areas immediately in front of (A2) and farthest from the creep (A3). Piglets with access to bright creeps spent on average 7.2% more time (P&lt;0.01) in the creeps than piglets in pens with Dark creeps. In addition, for each degree increase in mat temperature, piglets spent on average 2.1% more time (P&lt;0.01) in the creep. Piglets in pens with bright creeps spent less time in A2 (P=0.04) and the least time in A3 (P=0.01). Light or mat temperature did not affect sow use of pen areas or piglet weight gain. Piglets with bright creeps tended (P=0.06) to take longer to enter the creep for the first time after birth, but the latency for 30.0% of the litter to remain clustered for 10 min tended (P=0.08) to be shorter in bright compared to dark creeps. Overall, piglet use of the creep increased with warm mat temperatures and brightness, which should be further investigated as potential strategies to promote piglet safety and reduce crushing in pen farrowing systems.

Does hut climate matter for piglet survival in organic production?

Piglet mortality in outdoor production systems varies across the year, and a reason for this variation could be fluctuations in hut climate, as ambient temperature might influence piglet survival, both directly and indirectly. Therefore, the aim of the current study was to investigate the impact of farrowing hut climate and year variation on stillbirth and liveborn mortality. A large-scale observational study was conducted at five commercial organic pig-producing herds in Denmark from June 2015 to August 2016. Both year variation (F 3,635=4.40, P=0.004) and farrowing hut temperature (F 2,511=6.46, P=0.002) affected the rate of stillbirths. The risk of stillborn piglets was lowest in winter and during this season larger changes in hut temperature between day 1 prepartum and the day of farrowing increased the risk of stillbirths (F 1,99=6.39, P=0.013). In addition, during the warm part of the year stillbirth rate increased at temperatures ⩾27°C. Year variation also affected liveborn mortality (F 3,561=3.86, P=0.009) with a lower rate of liveborn deaths in spring. However, the hut climate did not influence liveborn deaths. Consequently, other factors than hut climate may explain the influence of year variation on liveborn mortality. These could be light differences causing seasonality in reproduction and lactation.

Causes of preweaning mortality in organic outdoor sow herds

The aims of the current study were to identify the causes of preweaning piglet mortality and investigate the effect of season and parity on the proportions of mortality causes. The study was conducted in nine herds over a one-year period, and dead piglets were collected for necropsy once during each of the four seasons. In total, 2672 piglets were necropsied of which 60% were live-born but died post-partum (pp), 32% were stillborn and 8% were euthanised. Intra-partum deaths accounted for 88% of stillborn piglets. Eighty-one percent of necropsied live-born piglets died within four days pp. Half of these had a body weight of <1 kg at the time of death. Crushed and starved piglets accounted for 83% and 9% of mortalities until day four pp, respectively. Thirty-three percent of the crushed piglets (age zero to four days) had not suckled prior to death and the proportion of these piglets was lower in summer compared to the remaining part of the year (OR = 0.6, 95% CI [0.5;0.9]) and was higher for multiparous sows compared to first parity sows (OR = 1.7, 95% CI [1.1;2.6]). In conclusion, sow parity and season affected the proportion of crushed piglets before four days of age. Furthermore, the group of crushed piglets was heterogeneous and consisted of both heavy well-fed piglets and small piglets with empty stomachs. Thus, management implementations to lower mortality may differ depending on sow parity, season and individual piglet characteristics.

Multi-level mixed models for evaluating factors affecting the mortality and weaning weight of piglets in large-scale commercial farms in central China

This study investigated the factors affecting piglet mortality (square root of mortality, SQRM) and average weaning weight (AWW) in commercial farms in central China. Information on sow diets, management and climate from 2478 weaning batches completed in 16 pig farms was collected from 2009 to 2013. Multi-level mixed models, which included batch level (level 1) and farm level (level 2), were used to analyze the factors associated with SQRM and AWW. The mean values of SQRM and AWW were 2.52% (SD = 0.96) and 7.31 (SD = 0.77), respectively. Lactation sow diets supplemented with oregano essential oils (OEOs) decreased the SQRM (P < 0.05) and increased the AWW of piglets (P < 0.01). The SQRM was lower in period 2 (June to September, hot) than in period 1 (February to May, warm) and period 3 (October to January, cold; P < 0.05 and 0.001, respectively). The AWW was lower in periods 2 and 3 than in period 1 (P < 0.01). In conclusion, supplying OEOs to lactation diets can increase the weaning weight and reduce the mortality of piglets. The sources of variations in SQRM and AWW are of greater concern in the warm season than in the hot season.

Influences of climatic parameters on piglet preweaning mortality in Thailand

The objective of the present study was to determine the influences of temperature, humidity, and temperature-humidity index (THI) on piglet preweaning mortality in a conventional open-housing system commercial swine herd in Thailand. The analyzed data included 11,157 litters from 3574 Landrace × Yorkshire crossbred sows. The daily temperature, humidity, and THI data were collected from a meteorological station near the herd. The associations between temperature, humidity, and THI for periods before and after farrowings and piglet preweaning mortality were analyzed. Piglet preweaning mortality (log transformation) and the proportion of litters with piglet preweaning mortality greater than 20% were analyzed by using general linear mixed models and generalized linear mixed models (GLIMMIX), respectively. On average, the piglet preweaning mortality and the proportion of litters with piglet preweaning mortality greater than 20% were 14.5% (14.2 to 14.8% CI) and 26.4% (25.5 to 27.2% CI), respectively. Piglet preweaning mortality was positively correlated with the mean temperature (r = 0.028, P = 0.003), humidity (r = 0.038, P < 0.001), and THI (r = 0.036, P < 0.001) during 0-7 days postpartum. In primiparous sows, piglet preweaning mortality increased from 12.1 to 18.5% (+ 6.4%, P < 0.001) when the mean temperature during 0-7 days postpartum increased from < 25.0 to ≥ 29 °C. However, the influence of the temperature during 0-7 days postpartum was insignificant in multiparous sows (P = 0.569, P = 0.593, and P = 0.539 in sows parity numbers 2, 3-5, and 6-9, respectively). Likewise, piglet preweaning mortality increased from 10.7 to 16.7% (+ 6.0%, P = 0.012) when humidity during 0-7 days postpartum increased from < 60 to ≥ 80% in primiparous sows but it was insignificant in sows parity numbers 3-5 (P = 0.095) and 6-9 (P = 0.219). Moreover, the proportion of the litters with piglet preweaning mortality greater than 20% in primiparous sows increased from 18.3 to 32.4% (+ 14.1%, P = 0.017) when the THI during 0-7 days postpartum increased from < 73 to ≥ 81. In conclusion, the negative influences of temperature, humidity, and THI on piglet preweaning mortality were more evident in primiparous than multiparous sows. These findings implied that strategies to reduce temperature for postpartum sows in the open-housing system in Thailand are inadequate, and the proper management of postpartum primiparous sows should be emphasized.

Modelling piglet growth and mortality on commercial hog farms using variables describing individual animals, litters, sows and management factors

Increases in sow prolificacy have reduced piglet vitality, growth capacity and weight at weaning and even pig weight at slaughter. The aim of this study was to develop a model that predicts likelihood of mortality and weight at weaning. A database containing 3214 records of birth weight, weight gain at 24h, rectal temperature at 24h, litter size, age at weaning, fostering status, manual assistance of birth and oxytocin use as well as the corresponding 227 records of sow parity and feed intake was analysed using logit functions for mortality and linear functions for weaning weight. The best model of mortality predicted increased likelihood as birth weight, rectal temperature and 0-24h weight gain decreased and sow parity and time between births increased (P<0.01, χ²=2910). The best model of weaning weight predicted increases with increasing birth weight, 0-24h body weight gain, age at weaning and sow parity and decreases with increasing litter size at 24h (P<0.01; AICC=4324; RMSE=0.82). This study confirmed that birth weight and weight gain during the first 24h are the principal factors influencing piglet growth and pre-weaning mortality.

Sow level risk factors for early piglet mortality and crushing in organic outdoor production

Piglet mortality is a major problem in organic pig production affecting both farm economy and animal welfare. Knowledge is scarce on the risk factors of piglet mortality in Danish commercial organic pig production. The objectives of this study were to evaluate season, litter size, parity, sow body condition and stillborn littermates as risk factors for early piglet mortality and crushing of liveborn piglets from parturition until castration at day 3 to 5 postpartum (pp). The study was conducted over a 1-year period in nine commercial Danish organic pig herds practicing outdoor farrowing all year round. Data included recordings on 3393 farrowings with 50 284 liveborn piglets of which 14.8% died before castration. A subset of the dead piglets were collected and necropsied to identify crushed piglets. The average number of liveborn piglets per litter was 14.8 (SD=3.7) and the average time from parturition until castration was 4.1 (SD=1.7) days. A negative binomial regression analysis was used to model the effect of the predictive variables on the early piglet mortality accounting for different time periods from parturition to castration. An increase in maternal body condition score (BCS) and parity significantly increased the risk of dying between parturition and castration. Early mortality was found to be lowest during spring (March to May) and highest during summer (June to August). Being born into a litter with one or more stillborn littermates increased the risk of early mortality. The risk factors for crushing of piglets were evaluated using a logistic analysis. A significant effect of parity and litter size was found where the odds of at least one piglet in a litter with mortality was diagnosed as crushed increased with increasing parity and litter size. In conclusion, being born during summer (June to August), high parity and maternal BCS and stillborn littermates were found to be risk factors for piglet mortality between parturition and castration. In addition, parity and increasing litter size were found to be risk factors for crushing of piglets in litters with mortality.

Sow-level risk factors for stillbirth of piglets in organic sow herds

In Danish organic pig production, one-third of total born piglets die before weaning, and stillbirth has previously crudely been estimated to account for 27% of the total preweaning mortality. The objective of this study was to evaluate season, litter size, parity and body condition of the sow as risk factors for stillbirth in nine commercial Danish organic pig herds. The study was conducted over a 1-year period, and the data included registrations on 5170 farrowings with 82 906 total born piglets. The average number of total born piglets per litter was 16.0, and the number of stillborn piglets per litter was 1.1. A significant effect of season was seen with an odds ratio for stillbirth of 1.15 during summer (May to August) compared with the remaining part of the year. A non-linear effect of litter size was seen where an increase in litter size from 11 to 16 resulted in an odds ratio of stillbirth of 1.11. An increase in litter size from 16 to 21 resulted in an odds ratio of stillbirth of 1.45. A significant interaction between body condition and parity was present. In first parity sows, an increase in body condition score from 2 (thin) to 3 (moderate) and from 3 to 4 (fat) increased the probability of stillbirth with an odds ratio of 1.23 and 1.36, respectively. In sows with parity above 4, an increase in body condition score from 2 to 3 and from 3 to 4 decreases the probability of stillbirth with an odds ratio of 0.68 and 0.79, respectively. In conclusion, increasing litter size and being born during the summer months of May to August were found to be risk factors for stillbirth. Furthermore, an interaction between body condition and parity showed that thin sows with parity above 4 had a substantially increased risk of stillbirth compared with normal and fat sows with parity above 4. In contrast, for parity 1 sows risk of stillbirth was increased in fat sows.

Effect of radiant heat at the birth site in farrowing crates on hypothermia and behaviour in neonatal piglets

It has been documented that floor heating of the farrowing area in loose housed sows improves survival of piglets significantly. However, today, the majority of farrowing pens are designed with crating of sows and slatted floor at the birth site. The aim of this study was to investigate whether providing radiant heat at the birth site to new-born piglets in pens with crated sows reduced hypothermia, time to first milk intake and growth of the piglets during the 1(st) week. Second parity Danish Landrace×Yorkshire sows (n=36) were randomly divided into two groups: Control (CG) and heat (HG). In the area behind the sow (zone 1), two radiant heat panels were mounted above the slatted floor in the HG. The farrowings were attended, and the heaters were turned on at birth of first piglet and turned off 12 h after. Birth time, time to leave zone 1, time to first contact with udder and time to first suckling were registered by direct observation. The piglet's rectal temperature (RT) was measured 15, 30, 60, 120, 180, 240 min after birth and 12, 14 and 24 h after birth of first piglet. Piglets were weighed at birth, 24 and 48 h and 7 days after birth. Data were analysed in a mixed model in SAS. The drop in RT was lower in HG compared with CG (P=0.002), and the RT in HG remained higher than in CG from 30 to 240 min after birth (P<0.05), whereas no difference was found at 12 h after birth of first piglet (P=0.92). Piglets in HG stayed longer in zone 1 than those in CG (P=0.01), whereas time to reach udder (P=0.35) and to first suckling (P=0.56) did not differ. No difference in weight gain was found between piglets in HG and CG at 24 h (P=0.23), 48 h (P=0.28) and 7 days after birth (P=0.44). Birth weight had a positive effect on RT (P<0.001) and reduced time to leave zone 1 (P<0.01), reach udder (P<0.001) and time to first suckling (P<0.001). The results showed that radiant heating behind the sows reduced hypothermia in new-born piglets and indicate that providing heat during the first half hour after birth is important.

Relationship of sow udder morphology with piglet suckling behavior and teat access

The aim of this study was to investigate if there is a relationship between the latency to the first suckling and udder and teat morphology and to assess the extent to which piglet and sow characteristics influence teat pair position preference. Udder morphology trait measurements, piglet suckling behavior, and sow productive and behavioral traits were recorded from a population of 74 Large White X Landrace sows of different parities. The interteat distance within the same row was larger between the teats that were suckled at the first contact with the udder compared with the unsuckled teats (P = 0.04). There was a tendency for piglets to suckle first from teats placed closer to the abdominal midline. A high proportion of siblings (64%) suckled for the first time on a teat previously chosen by another piglet. Most neonates suckled first from a teat located in the posterior part of the udder (41%) or in the anterior part (33%), rather than the middle section. Latency from birth to suckling and the time from the first udder contact to locate a teat and suckle was shorter for piglets first suckling the anterior (28:03 and 9:48 minutes) and posterior teats (26:31; 8:38 minutes) than for those sucking the midsection teats (34:30 minutes, F7,256 = 1.99, P = 0.05; 10:30, F7,256 = 2.37, P = 0.05). To avoid possible confounds, other potential causes of delay in successful suckling were studied. The latency to suckle was not influenced by piglet vitality score at birth, weight, or provision of human assistance to place it at the udder. It was shorter when the piglets were born later in the litter (P < 0.001), from a litter with a low incidence of piglets born dead (P = 0.001) and from a sow with an induced farrowing (P = 0.007). Moreover, there was a tendency for piglets born from a multiparous sow (P = 0.06) and in a large litter size (P = 0.07) to have a longer latency to find a teat and suckle once they had made the first contact with the udder. Although suckling itself is clearly an instinctive behavior, acquisition of colostrum depends on many variables, relating not only to piglet characteristics but to sow behavioral and morphological characteristics as well. Future studies on sow characteristics are therefore recommended.

The influence of the thermal environment and other early life events on growth rate of piglets during lactation

The effects of early life events on average daily weight gain from birth to day 21 (ADG) of suckling pigs kept at different room temperatures (15°C, 20°C and 25°C) from birth to weaning were investigated. Data were collected from litters born by 61 sows in a loose housing system. The ADG for piglets with low birth weight (estimated for birth weights below the 10% percentile) was estimated to be 20 to 30 g higher per day at room temperature 20°C to 25°C compared with 15°C. In contrast, the ADG during the lactation period decreased for larger piglets (estimated for birth weights above the 10% percentile) by 28 g/day at room temperature 25°C compared with 15°C. Thus, high ambient temperatures (20°C to 25°C) are favourable for the growth in smaller piglets during lactation. Neither latency to first suckle nor birth-induced hypoxia, measured as concentration of umbilical cord lactate, affected the growth rate of the piglets. Lowest rectal temperature during the first 24 h after birth had a long-term negative effect on ADG (P<0.05), so that piglets with a lowest rectal temperature of 32.8°C (10% percentile) had an ADG which was on average 19 g lower per day than piglets with a rectal temperature of 37.3°C (90% percentile). Our results showed that hypothermia at birth, low birth weight and high number of suckling piglets lead to reduced ADG during the suckling period. The results suggest that keeping the room temperature at 20°C during lactation to some extent could compensate for the otherwise negative effects of low birth weight on ADG in piglets without decreasing the ADG of high birth weight piglets. However, to avoid hypothermia in the smallest piglets it may be beneficial to increase the room temperature above 20°C during the farrowing period of loose housed sows.

Individual physical characteristics of neonatal piglets affect preweaning survival of piglets born in a noncrated system

The aim of this study was to investigate the effects of individual physical characteristics on preweaning survival and growth of piglets born in a noncrate system. Data were collected from 3,402 neonatal piglets from 203 Landrace × Yorkshire sows housed in noncrate pens in a commercial Danish sow herd. Piglets were categorized into groups according to their survivability: surviving to weaning (SURV), stillborn (STILL), or dead between birth and weaning (DBW), which was subdivided into dead d 0 to 1 after farrowing (DEAD1) or dead d 2 to 26 after farrowing (DEAD26). Linear models were used to determine which physical characteristics affected survivability and growth of piglets. Results showed that characteristics related to the individual piglets had a greater degree of explanatory power in relation to survival than variables related to the sow. Survival of piglets increased if piglets were females (P < 0.001), had a greater body mass index (P < 0.001), and were born to sows of parity 3 or more (P = 0.017). Piglets with a greater birth weight were more likely to survive (P < 0.001), but birth weight was inferior to body mass index in explaining differences between SURV and DBW. Piglets that died 2 to 26 d after birth had a lower birth weight (P < 0.001), were born to sows of parity 1 or 2 (P = 0.014), and were born after a shorter gestation (P = 0.011) compared with SURV. Piglets that died on d 0 to 1 after birth had a lower body mass index (P < 0.001), displayed a greater degree of growth restriction (P = 0.004), and were born in large litters (P = 0.005). The gender of the piglets affected survivability at both d 0 to 1 (P < 0.001) and d 2 to 26 (P < 0.001). Piglets in DEAD1 differed from STILL by having a shorter crown to rump length (P < 0.001), a birth weight that deviated more from the mean weight of the litter (P = 0.001), and being more likely to be born before d 116 of gestation (P = 0.008). The only physical characteristic that was important for growth performance in the suckling period was birth weight (P < 0.001), yet using only birth weight as an indicator for survivability was too simplistic. The results of this study emphasize that individual characteristics of neonatal piglets could serve as indicators of survivability of piglets born in noncrate systems; however, the results suggest that the importance of characteristics differed in different periods of the preweaning period.

Sow postural changes, responsiveness to piglet screams, and their impact on piglet mortality in pens and crates

Free farrowing pens (pens) improve the welfare of sows but may increase sow activity and negatively influence piglet production. The aim of this study was to assess the effect of pens and crates on sow postural changes, piglet trapping, sow responses to piglet screams, piglet mortality, and piglet BW gain. It was predicted that provision of greater space (in pens) would increase not only the frequency of sow postural changes and the probability of trappisng but also sow responses to the screams of piglets; thus, the outcome would be no differences in fatal piglet crushing or overall mortality between the housing systems. Sows were randomly moved to either a farrowing pen (n = 20) or farrowing crate (n = 18). Sow behavior was recorded and analyzed for 72 h from the birth of the first piglet (BFP). Sow postural changes included rolling from a ventral to lateral position and vice versa and going from standing to sitting, standing to lying, and sitting to lying. Occurrences of piglet trapping and sow responsiveness to real crushing situations were analyzed. Sow responsiveness was assessed in response to audio playbacks (PB) of piglet screams on d 3 postpartum (48 to 72 h after BFP; PB crush calls) and real piglet crushing during the first 72 h after BFP (real crush calls). Piglet BW gain was estimated 24 h after BFP, piglet BW was recorded at weaning, and piglet crushing and piglet mortality were recorded during the 72 h after BFP. Data were analyzed using PROC MIXED and PROC GENMOD of SAS. Sows in pens showed more postural changes (P = 0.04) and tended to have greater incidences of piglet trapping (P = 0.07) than those in crates. Sow response to PB crush calls was greater in pens (P = 0.04) but did not differ for real crush calls between pens and crates (P = 0.62). There was no effect on the probability of piglet crushing (P = 0.38) and mortality (P = 0.41) during the 72 h after BFP nor in piglet mortality at weaning (P = 0.81) between pens and crates. Piglet BW gain at 24 h after BFP (P = 0.01) and piglet BW at weaning (P = 0.02) were greater in pens. Sows in pens showed more postural changes and tended to trap more piglets; however, the response to real crush calls did not differ between the two housing systems. Despite this, there was no increase in piglet crushing or mortality in pens, which might be influenced by the better piglet body condition observed in pens, which in turn could influence their ability to avoid crushing by the sow.

Invited review: piglet mortality: management solutions

Preweaning mortality varies greatly among herds and this is partly attributed to differences in farrowing house management. In this review, we describe the various management strategies than can be adopted to decrease mortality and critically examine the evidence that exists to support their use. First, we consider which management procedures are effective against specific causes of death: intrapartum stillbirth, hypothermia, starvation, disease, crushing, and savaging. The most effective techniques include intervention to assist dystocic sows, measures to prevent and treat sow hypogalactia, good farrowing house hygiene, providing newborn piglets with a warm microenvironment, early fostering of supernumerary piglets, methods that assist small and weak piglets to breathe and obtain colostrum, and intervention to prevent deaths from crushing and savaging. The provision of nest-building material and modifications to the pen to assist the sow when lying down may also be beneficial, but the evidence is less clear. Because most deaths occur around the time of farrowing and during the first few days of life, the periparturient period is a particularly important time for management interventions intended to reduce piglet mortality. A number of procedures require a stockperson to be present during and immediately after farrowing. Second, we consider the benefits of farrowing supervision for preweaning mortality in general, focusing particularly on methods for the treatment of dystocia and programs of piglet care that combine multiple procedures. Third, we discuss the need for good stockmanship if farrowing supervision is to be effective. Stockmanship refers not only to technical skills but also to the manner in which sows are handled because this influences their fearfulness of humans. We conclude that piglet survival can be improved by a range of management procedures, many of which occur in the perinatal period and require the supervision of farrowing by trained staff. Although this incurs additional labor costs, there is some evidence that this can be economically offset by improved piglet survival.