The Course of Parturition Affects Piglet Condition at Birth and Survival and Growth through the Nursery Phase

Effect of peripartum dexamethasone treatment on farrowing outcomes and newborn piglet traits in multiparous sows

This study assessed the effects of dexamethasone treatment on farrowing performance and piglet traits in the first 5 days of life in multiparous sows, a high-risk group for stillbirths and prolonged farrowing. In this study, 185 multiparous sows (parity 4.25 ± 0.14) were selected on the day of farrowing and divided into three treatments: CON - control, without dexamethasone treatment; DexaPF - treatment with dexamethasone (20 mg im per female) at the time of copious colostrum secretion (pre-farrowing); and DexaFO - treatment with dexamethasone (20 mg im per female) when the first piglet was born (farrowing onset). All sows and their litters were monitored for farrowing duration, obstetric interventions, colostrum yield and intake, newborn piglet traits, and piglet performance until 5 d of age. A subsample of 106 females (∼35 per treatment) had their blood glucose concentration checked hourly shortly after the first piglet was born until the end of farrowing. Additionally, blood samples from 42 litters were collected for immunocrit evaluation. The results showed no differences regarding farrowing duration (CON = 258.02 ± 13.81 min; DexaPF = 251.29 ± 13.60 min; DexaFO = 294.92 ± 13.89 min; P = 0.06) and obstetric intervention rates among treatments (CON = 36.58 ± 6.78 %; DexaPF = 42.16 ± 6.89 %; DexaFO = 48.05 ± 7.08 %; P = 0.45). The blood glucose concentration during farrowing was higher in DexaPF (94.56 ± 1.57 mg/dL; P < 0.001) than in CON (73.50 ± 1.72 mg/dL) and DexaFO (87.94 ± 1.80 mg/dL). No differences were observed regarding total piglets born and born alive, stillborn, newborn piglet vitality, colostrum intake, immunocrit, colostrum yield, and glycemia and rectal temperature at 24 h of age (P ≥ 0.13). Regarding meconium staining, higher percentages of piglets born without meconium staining were observed in DexaFO (54.77 ± 5.21 %; P = 0.02) compared with CON (48.58 ± 5.26 %), and no difference was observed for the DexaPF group (53.23 ± 5.21 %). In addition, a higher unbroken umbilical cord rate was observed in DexaFO (92.41 ± 1.31 %; P < 0.01) than the CON or DexaPF (86.91 ± 1.97 % and 89.31 ± 1.67 %, respectively). However, the treatments did not affect piglet performance (weight gain and survival) until 5 d of age (P ≥ 0.15). In summary, dexamethasone treatment in periparturient multiparous sows did not improve farrowing performance and key production parameters, such as the piglet weight gain and survival up to 5 d of age.

The effects of feeding sows at onset of farrowing supplemental energy (blend of carbohydrates and glycerol) on farrowing kinetics and piglet vitality

Delivering piglets is one of the most energy-demanding activities sows undergo in their lifetime. Sows can have myometrial contractions from 2 to 12 h before the first piglet is expelled as well as a nest-building behavior. Thus, when the first piglet is delivered, the female has already used part of her energy supply. When the sow gets exhausted due to lack of energy, the farrowing process can be interrupted, causing damage to the viability and vitality of the piglets. In the present study, we evaluated the effects of feeding sows an energy supplement at the onset of farrowing on farrowing kinetics and piglet vitality. The energy supplement consisted of a blend of carbohydrates and glycerol which provides 439 kJ of metabolizable energy per kg of metabolic weight. A total of 180 sows were used. At the onset of farrowing, sows were assigned to one of the following treatments: sows that were not supplied energy at the onset of farrowing, serving as controls (CON, n = 85); sows fed the energy supplement at the onset of farrowing (ESP, n = 95). Farrowing kinetics, blood glucose concentration, and piglet vitality were recorded for each sow. Blood glucose concentration was assessed by puncturing the auricular vein and using a portable glucometer at four different time points: after the birth of the 1st piglet (T0), and at 20 (T20), 40 (T40), 80 (T80), and 180 (T180) min after the birth of the 1st piglet. The vitality of the 1st, 6th, 12th, 17th, and 20th piglet born was evaluated using the Apgar score. Piglet birth weight and average colostrum intake were measured. The farrowing duration was 20 min shorter (P < 0.05) for ESP sows in comparison with CON sows. Sows from ESP treatment had higher (P ≤ 0.05) blood glucose concentration at T20 and T40 compared to the CON sows. The inter-piglet birth interval was shortened (P < 0.05) by 14 min between the 1st and 2nd piglet for the ESP treatment. The 17th and 20th piglets born from ESP sows had higher (P < 0.05) Apgar score compared to piglets of the same birth order from CON sows. Colostrum intake was higher (P < 0.01) for piglets born from ESP sows. Litter growth performance did not differ (P > 0.05). In conclusion, feeding a blend of carbohydrates and glycerol as an energy supplement for farrowing sows improved farrowing kinetics and piglet vitality score.

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.

Impacts of supplementing Cannabis sativa byproducts during the transition period on behaviour, feed consumption, constipation levels, colostrum production and piglet performance in hyperprolific sows

In the modern swine industry, inflammation and pain in sows after farrowing represent a crucial animal welfare concern. Cannabis sativa, a medicinal plant, has analgesic, anti-inflammatory and antipyretic properties and is rich in fibre. The objective of this study is to examine the impacts of supplementing sows with Cannabis sativa byproducts during transition periods (7 days before and after farrowing) on various aspects including postpartum behaviour, feed intake, constipation, farrowing duration, colostrum yield and piglet performance. The experiment involved a total of 100 Landrace × Yorkshire sows. The sows were distributed according to parity numbers into two groups, i.e., control (n = 54) and treatment (n = 46). The control group was provided with a lactation diet at 3.0-3.5 kg per day for a period of 7 days before and after farrowing. The treatment groups received the same quantity of the diet but with an additional supplementation of 150 g/d of Cannabis sativa byproduct. The byproduct was analysed and contained 0.24 % (w/w) cannabidiol (CBD), resulting in a daily intake of 360 mg of CBD per sow. The conventional lactational diet had a dietary fibre content of 4.3 %, whereas the diet supplemented with Cannabis sativa byproduct had a higher dietary fibre content of 16.9 %. Video cameras were used to observe and document the behaviour of sows within the initial 24 h after farrowing. The duration in which sows engaged in activities such as sleeping, sitting, standing, feeding and nursing their piglets was quantified. Additionally, the rectal temperature of the sows was measured, and a temperature equal to or exceeding 39.5 °C was considered indicative of fever. The faecal score of the sows was assessed, and a faecal score of ≤2 was classified as constipation. On the third day postpartum, the proportion of sows with fever in the treatment group was lower than that in the control group (20.0 % and 38.9 % respectively, P = 0.051). Sows receiving supplementation with Cannabis sativa byproducts exhibited increased durations of standing and feeding compared to those in the control group (P < 0.05). Notably, overall, sows without constipation issues spent more time consuming feed than those experiencing constipation (P = 0.006). The prevalence of constipation was significantly lower in the treatment group compared to the control group (17.4 % and 81.5 %, respectively, P < 0.001). Furthermore, the postpartum sows demonstrated increased feed intake following supplementation with Cannabis sativa byproducts (P < 0.05). Sow colostrum yield, piglet colostrum intake, piglet mortality and other piglet traits did not differ between the control and treatment groups (P > 0.05). In conclusion, supplementing Cannabis sativa byproducts during the transition periods in peri-parturient sows under tropical conditions resulted in a reduction in constipation issues and improved sow activities, such as increased time spent standing and consuming feed within the first 24 h postpartum.

Factors affecting birth weight and stillbirth in sows housed in a tropical environment

This study analysed data from a commercial swine herd in Thailand equipped with a free-farrowing housing system, comprising 17,196 piglets from 1318 litters, to explore the impact of sow and litter characteristics on the piglet birth weight and the incidence of stillbirth. The piglets were classified into four groups based on the total number of piglets born per litter (TB): ≤9 (n = 1434), 10-12 (n = 3232), 13-15 (n = 6537) and ≥16 (n = 5993). Sows were classified into four groups based on parity number: 1, 2-4, 5-7 and ≥8. The piglets were categorized into quartiles based on their birth order ranking: Q1 (n = 4786), Q2 (n = 4143), Q3 (n = 3808) and Q4 (n = 4456). Piglet birth weight was individually measured before colostrum ingestion. On average, TB, the number of live-born piglets and the incidence of stillbirth were 13.1 ± 3.7, 11.5 ± 3.8 and 6.3%, respectively. Among these litters, 26.6% had TB numbers ≥16. The average piglet birth weight was 1.37 ± 0.36 kg, with 18.3% of piglets weighing ≤1.0 kg at birth. Piglet birth weight was influenced by birth order ranking, as Q4 piglets were found to be heavier than piglets born in Q1-Q3 (p < .001). Moreover, the percentage of piglets with a birth weight of ≤1.0 kg increased from 5.9% in litters with TB of ≤9-25.3% in litters with TB of ≥16 (p < .001). Additionally, primiparous sows had lower piglet birth weights compared to sows with parity numbers 2-4, 5-7 and ≥8 (p < .001). Piglets born in the fourth quartile (Q4) had a higher risk of stillbirth compared to those born in the first (Q1), second (Q2) and third (Q3) quartiles (12.5% vs. 2.2%, 4.1% and 6.6%, respectively, p < .001). The incidence of stillbirth in litters with TB ≥16 was also higher than that in litters with TB ≤9 and 10-12 (p < .05). Furthermore, sows with parity numbers ≥8 had a higher incidence of stillbirth (9.7%) compared to primiparous sows (4.0%, p < .001), sows with 2-4 parity (5.2%, p < .001) and sows with 5-7 parity (7.6%, p = .003). In summary, a high incidence of stillbirth was found in piglets born in the last quartile of litters, in litters with >16 piglets and for sows with parity numbers ≥8. Piglets born in the last quartile of litters were heavier than those born in the first to third quartiles.

Physiology and management of the peri-parturient sow in the context of changing production conditions

Genetic selection has resulted in a considerable increase in litter size, paralleled by an increase in farrowing duration and perinatal mortality. This paper describes some of the physiological changes around farrowing, and how genetic trends and sow management interact with these. Compromised farrowing can be related to nutritional management, or to housing conditions and handling of periparturient sows. Transition diets, for example, can be formulated to support calcium homeostasis and alleviate constipation. The opportunity to express natural behaviours and minimize stress around farrowing can further optimize farrowing conditions and reduce piglet mortality. Loose farrowing systems are part of the answer to the challenges around farrowing; however, current systems do not perform consistently. In conclusion, increased farrowing duration and increased perinatal mortality may to some extent be inevitably related to trends in pig production; however, they can be improved by nutritional measures, housing conditions and farrowing management.

Relationship between piglets' survivability and farrowing kinetics in hyper-prolific sows

BACKGROUND

Prolonged farrowing and more piglets born with low birth weight are undesirable consequences of genetic selection for increased litter size. The objective of the present observational study was to evaluate the relationship between piglets' survivability and farrowing kinetics in hyperprolific sows. A total of 58 sows of different parities and 1190 piglets were included. The entire farrowing process was monitored and the following parameters were recorded: inter-piglet birth interval, birth order, total born, live born, dead born, and mummified piglets, obstetric intervention, weight at birth and 24h, colostrum yield and intake.

RESULTS

The sows included in this study had on average 20.6 ± 0.6 total piglets born, of which 16.4 ± 0.6 were live born, 3.3 ± 0.4 were stillborn and 0.9 ± 0.2 were mummified piglets. The average farrowing duration and average birth interval were 411.3 ± 31.6 and 20.6 ± 1.7 min, respectively. Farrowing duration was positively associated (p < 0.05) with parity, number of stillborn and mummified piglets. Piglet mortality 24h after birth was negatively affected (p < 0.01) by birth weight and positively affected (p < 0.01) by cumulative birth interval. The last tercile of piglets born (birth order ≥ 17) had the highest (p < 0.01) inter-piglet birth interval (IPBI) (43.4 ± 4.17 min) compared to piglets born in the first (birth order between 2 and 7) (26.5 ± 3.8 min) and second (birth order between 8 and 16) terciles (21.9 ± 3.8 min). Cumulative birth interval, birth weight, occurrence of stillborn piglets and manual intervention were positively associated (p < 0.05) with IPBI. Piglet birth weight was also positively associated (p < 0.01) to individual colostrum intake. Piglets ingesting more colostrum had lower (p < 0.01) mortality from 24h after birth until weaning. Sow's parity and cumulative birth interval were positively associated with the presence of stillborn piglets (p = 0.02 and p < 0.01, respectively).

CONCLUSION

Reducing farrowing duration may be crucial to decrease stillbirth rate and neonatal mortality in hyperprolific sows. Moreover, special care must be provided to the lighter piglets within a litter to increase their colostrum intake and minimize piglet's mortality throughout lactation.

Offspring of hyper prolific sows: Immunity, birthweight, and heterogeneous litters

In Europe, in the last 3 decades, there has been a constant increase in litter size due to the use of superior maternal line genetics. Those sows giving birth to more piglets than their average number of functional teats are identified as hyperprolific sows (HPS). The large number of piglets born within a litter implies not only a challenge for their access to vital resources like colostrum and milk but has a direct effect on their average birth weight and heterogeneity. These conditions are detrimental to piglets' vitality in the first hours of life and also to their immunity development. An exceptionally large number of growing fetuses in HPS leads to intrauterine crowding and consequently to an increased number of piglets suffering from intrauterine growth retardation (IUGR), which put piglets at a high risk of mortality after birth and up to later stages of life. Increased heterogeneity of birth weight within large litters increases the competition for colostrum intake, with the smaller piglets being less competitive and vital, and therefore affecting negatively their immunity. Low birth weight, long interval to reach the udder, and long duration of farrowing, all have negative effects on piglets' immunoglobulin absorption. In HPS litters, colostrum management should be focused on low birth weight piglets, anticipating their impaired capabilities associated with ingesting adequate colostrum, by shortening the time to reach the udder and reducing competition among piglets. The vitality of neonate piglets, especially low in birth weight or affected by IUGR should be enhanced to improve their body temperature and their early life stage energy metabolism.

The impact of birth weight, birth order, birth asphyxia, and colostrum intake per se on growth and immunity of the suckling piglets

Colostrum is the only source of passive immunity and the major source of nutrients and is crucial for thermoregulation of newborn piglets in their early life. However, the amount of colostrum obtained by each piglet [colostrum intake (CI)] differs considerably in large litters as born by contemporary hyperprolific sow lines. This experiment aimed to investigate the impact of the following individual characteristics of piglets; birth weight, birth order and neonatal asphyxia at birth on CI, and further to determine the relationship between the CI and the passive immunity transfer, and the growth performance of piglets prior to weaning. Twenty-four Danbred sows of the second-parity and their progeny (n = 460) were used. As main inputs in the prediction model to assess individual piglet CI were piglet birth weight, their weight gain, and the duration of colostrum suckling of the piglets. The asphyxia (state of oxygen deprivation) was assessed by measuring blood lactate concentration immediately after birth, and piglets sampled at d 3 of age for determination of blood plasma concentrations of immunoglobulins (Ig) G, A, and M. Piglets' CI was negatively associated with asphyxia (P = 0.003), birth order (P = 0.005) and low birth weight have compromised the individual CI (P < 0.001). Average daily gain during the suckling period was greater among piglets with high CI (P = 0.001) and birth weight (P < 0.001). Body weight at weaning (d 24 of age) was positively associated with CI (P = 0.0004) and birth weight (P < 0.001). The probability of weaning was positively associated with CI and birth weight (P < 0.001) of the piglets. Concentrations of IgG (P = 0.02), IgA (P = 0.0007), and IgM (P = 0.04) in piglets' plasma at d 3 of age were positively associated with CI, and were negatively associated with birth order (P < 0.001). The present study demonstrated that piglets' individual characteristics at birth (birth weight, birth order, state of oxygen deprivation) have considerable effects on their CI. The knowledge gained from the results of this study gives a scientific base for development and implementation of more effective techniques in practice aimed to improve the piglets' robustness during the suckling period.

Physiological traits of newborn piglets associated with colostrum intake, neonatal survival and preweaning growth

Colostrum intake, which is critical for piglet survival after birth and growth up to weaning, greatly depends on piglet weight and vitality at birth. Our aim was to identify a set of biological variables explaining individual variations in colostrum intake, preweaning growth and risk of dying. Farrowing traits, morphological traits and colostrum intake were determined for 504 piglets born alive from 37 Landrace × Large White sows. A subset of 203 of these piglets was used to measure plasma neonatal concentrations of metabolites and hormones in blood collected from the umbilical cord at birth. From univariate analyses, we established that colostrum intake was positively associated with plasma neonatal concentrations of IGF-I, albumin, thyroid hormones (P < 0.001), and non-esterified fatty acids (P < 0.05), and was negatively associated with concentrations of lactate (P < 0.001). In a multivariable analysis, the variables explaining the variation in colostrum intake were piglet birth weight and rectal temperature 1 h after birth (positive effect, P < 0.001), time of birth after the onset of parturition, and fructose plasma concentrations at birth (negative effects, P < 0.001 and P < 0.05, respectively). Piglets that died within 3 days after birth had lower neonatal concentrations of albumin (P < 0.001), IGF-I and thyroxine (P < 0.01) than surviving piglets. Preweaning growth was positively associated with neonatal concentrations of IGF-I, thyroxine (P < 0.001), albumin and insulin (P < 0.05). Cortisol and glucose concentrations at birth were not related to colostrum intake, neonatal survival or preweaning growth. Multivariable analyses confirmed that colostrum intake was the predominant factor influencing piglet survival within 3 days after birth and preweaning growth. These results provide physiological indicators of piglet colostrum intake, besides birth weight. They also confirm the impact of time of birth during farrowing on colostrum intake and the crucial importance of physiological maturity at birth for postnatal adaptation.

Sow Nutrition, Uterine Contractions, and Placental Blood Flow during the Peri-Partum Period and Short-Term Effects on Offspring: A Review

The birth process is a crucial event for piglet survival. Along with increasing litter sizes, not only has the duration of parturition increased, but placental blood flow per piglet has reduced and placental area per piglet has become smaller, making these piglets more susceptible for hypoxia. Diminishing the risk of piglet hypoxia by either reducing the total duration of parturition or increasing fetal oxygenation may reduce the incidence of stillbirth and early post-partum mortality. This review discusses options to do so by nutritionally supporting the sow in the final pre-partum period, after discussing the role of uterine contractions and placental blood flow. Providing sufficient energy seems to be a logical first step, but also other nutrients needed for uterine contractions, such as calcium, or enhancing uterine blood flow by using nitrate seem promising. These nutrient requirements may depend on litter size.

Effect of low colostrum intake on gastrointestinal development and uterine and cervical morphometrical architecture in the neonatal gilt

To assess the importance of natural variation in colostrum intake on piglet gastrointestinal and reproductive development, two equally sized female piglets from each of 27 litters were selected, one with low (average 226 g) and one with high (average 401 g) colostrum intake. At weaning (23 d of age), piglets were euthanised to perform macromorphological measurements on ileum, colon, cervix and uterus tissues, and to obtain tissue samples from the cervix and uterus for histology. Sections of uterine and cervical preparations were analysed using digital image analysis. Despite being selected for the same birth weight (average 1.1 kg, standard deviation 0.18 kg), piglets with low colostrum intake weighed 5.91 ± 0.17 kg and piglets with high colostrum intake weighed 6.96 ± 0.19 kg at weaning (P < 0.05). Most of the micro- and macroscopic measures such as length and weight of ileum and colon, cervix and uterus, luminal size of cervix and uterus, number of cervical crypts and uterine glands, were greater in gilts with high colostrum intake. The histological architecture of the uterus and cervix in gilts with high colostrum intake showed more complexity, reflecting more advanced development in these piglets. In conclusion, these data demonstrate that independent of birth weight, natural variation in colostrum intake is related to the overall development of neonatal piglets, affecting body growth, as well as growth and development of the gut and reproductive tract.

Relationship between dexamethasone treatment around parturition of primiparous sows and farrowing performance and newborn piglet traits

This study evaluated the relationship between the steroidal anti-inflammatory action of dexamethasone treatment in primiparous sows and farrowing and piglet performance in the first 5 d of life. For this purpose, 234 gilts were selected on the day of farrowing and distributed among three treatments: CON - control, without dexamethasone treatment; DexaPF - treatment with dexamethasone (20 mg im) per female at the moment of copious colostrum secretion (pre-farrowing); and DexaFO - treatment with dexamethasone (20 mg im), per female when the first piglet was born (farrowing onset). All females and their litters were evaluated regarding farrowing duration, obstetric interventions, colostrum yield and intake, newborn piglet traits, and piglet performance until 5 d of age. A subsample of 79 females (∼26 per treatment) had their blood glucose concentration evaluated hourly shortly after the first piglet was born until the end of farrowing. Additionally, blood samples from 11 litters per treatment were collected for immunocrit evaluation. As a result, faster farrowing was observed in the DexaPF treatment (188.14 min; P = 0.002) compared with CON (229.99 min) and DexaFO (221.79 min). Additionally, lower obstetric intervention rates were observed in sows treated with dexamethasone (DexaPF = 7.69%; DexaFO = 5.13%) compared with CON (19.23%; P = 0.02). The sow's blood glucose concentration during farrowing was higher in DexaPF (90.55 mg/dL) than in CON (73.15 mg/dL) and DexaFO (80.06 mg/dL) treatments (P < 0.01). Besides the effect on farrowing duration, no differences among treatments were observed regarding piglets born alive and stillbirths, newborn piglet vitality, colostrum consumption, immunocrit, and colostrum yield (P ≥ 0.17). Regarding piglet traits, higher percentages of piglets born without meconium staining and lower percentages of piglets with meconium scores 2 and 3 were observed in the groups treated with dexamethasone (DexaPF and DexaFO; P < 0.01) compared with CON. However, piglet weight gain and survival rate until 5 d of age were not affected by the treatment (P ≥ 0.61). In summary, dexamethasone treatment before farrowing onset, in primiparous sows, had the potential to reduce the farrowing duration and the necessity of obstetric intervention, but it did not affect the main productive parameters such as the occurrence of stillbirths, piglet weight gain, and survival rates until 5 d of age.

The effect of piglet vitality, birth order, and blood lactate on the piglet growth performances and preweaning survival

BACKGROUND

Litter size is going up in modern pig production. Due to large litter size and increased farrowing duration, newborn piglets, during parturition, can suffer from asphyxiation. This alters their blood energy parameters and can contribute to their reduced vitality at birth, which is detrimental to their growth performance and survival. We aimed to evaluate the effects of vitality score, piglets' umbilical cord blood lactate, glucose, and butyrate, and birth order on growth performance and the preweaning mortality of piglets.

RESULTS

The more vital (vitality score 2, VS2) piglets had higher umbilical cord blood glucose and butyrate, lower blood lactate, and higher colostrum intake (CI) at birth, and showed higher body weight at birth and at weaning than did less vital piglets (vitality score 1, VS1). Umbilical cord lactate negatively correlated with vitality, colostrum intake, and growth before weaning. Among the four birth-order groups (BOGs), piglets born earlier during parturition had a higher mean vitality score than those born later. BOG1 and BOG2 had significantly higher CI (p < 0.05) than BOG3 and BOG4.

CONCLUSION

Changes in piglets' body weight, colostrum intake, and umbilical cord lactate are associated with piglet vitality and asphyxiation during farrowing. In addition, asphyxiation induced higher umbilical cord lactate may serve as an indicator of low vitality and low colostrum consumption. Overall, improvement in piglets' vitality and in the farrowing process can help in reducing piglet mortality.

Intrinsic challenges of neonatal adaptation in swine

Abstract. The losses of piglets in commercial pig farming remain at concerning levels and need to be addressed through the implementation of new sustainable breeding and management strategies. In fact, piglets are especially at risk in the first days of life. Both genetics and the farrowing process have been shown to impact piglet vitality. In addition, knowledge of the animal-intrinsic responses in adapting to extra-uterine life is particularly important but is scarcely described in the scientific literature. In this review, the three phases that constitute neonatal adaptation in the pig are systematically presented. The first phase of early adaptation involves primarily the development of cardiorespiratory function (within the first 10 min of life) as well as thermoregulatory processes and acid–base balance (up to 24 h of life). In the second phase, homeostasis is established, and organ maturation takes place (up to 14 d post natum). The final third phase aims at the development of neurological, immunological and muscular features (up to 28 d of life). The involvement of aggravating and ameliorating factors such as dystocia, low colostrum yield and heat supply is key to the development of strategies to reduce piglet losses and increase vitality. The insights are of particular value in addressing current concerns in pig farming and to further improve animal welfare in pig production across different management types.

Defining "Normal" in Pig Parturition

Simple Summary

The dual considerations of efficient food production and good animal welfare have never been so important nor under such strong public scrutiny as they are in current times. Intensive animal production industries play an important role in feeding an ever-growing, increasingly affluent population that is hungry for animal proteins. The efforts to improve efficiency in these production systems must not come at the cost of animal welfare. One pain point in pig production is that of parturition, where factors such as litter size and sow-housing type have been shown to influence the process and outcome. However, there are still many gaps in knowledge surrounding the normal physiology and endocrinology in a farrowing and this review seeks to summarise what is known and highlight areas where further work is required.

Abstract

Animal production industries rely on efficient and successful reproductive outcomes, with pigs being no exception. The process of parturition in pigs (farrowing) can be especially prolonged, due to the large numbers of piglets being born (on average, approximately 13 piglets per litter in Australian conditions). Difficulties in farrowing (dystocia) lead to poor piglet outcomes and health problems in sows, in turn, causing economic loss for producers and welfare concerns for the animals. Despite the importance of this topic and publications in the area stretching back nearly 50 years, there is still no consensus on the prevalence of dystocia in pigs nor on how to identify a pig experiencing the condition. Understanding the process of parturition and the factors that influence its success is a crucial step towards the early identification of sows undergoing dystocia and development of best practices to assist them. This article describes the key factors that contribute to successful farrowing and identifies areas in which more research is required before the parturition process in the pig can be fully understood.

Premature delivery in the domestic sow in response to in utero delivery of AAV9 to fetal piglets

Numerous pediatric neurogenetic diseases may be optimally treated by in utero gene therapy (IUGT); but advancing such treatments requires animal models that recapitulate developmental physiology relevant to humans. One disease that could benefit from IUGT is the autosomal recessive motor neuron disease spinal muscular atrophy (SMA). Current SMA gene-targeting therapeutics are more efficacious when delivered shortly after birth, however postnatal treatment is rarely curative in severely affected patients. IUGT may provide benefit for SMA patients. In previous studies, we developed a large animal porcine model of SMA using AAV9 to deliver a short hairpin RNA (shRNA) directed at porcine survival motor neuron gene (Smn) mRNA on postnatal day 5. Here, we aimed to model developmental features of SMA in fetal piglets and to demonstrate the feasibility of prenatal gene therapy by delivering AAV9-shSmn in utero. Saline (sham), AAV9-GFP, or AAV9-shSmn was injected under direct ultrasound guidance between gestational ages 77-110 days. We developed an ultrasound-guided technique to deliver virus under direct visualization to mimic the clinic setting. Saline injection was tolerated and resulted in viable, healthy piglets. Litter rejection occurred within seven days of AAV9 injection for all other rounds. Our real-world experience of in utero viral delivery followed by AAV9-related fetal rejection suggests that the domestic sow may not be a viable model system for preclinical in utero AAV9 gene therapy studies.

Review: Improving the performance of neonatal piglets

Newborn piglets have a high incidence of preweaning mortality that is not only associated with low birth weights but also with the presence of intra-uterine growth-restricted (IUGR) piglets. Such IUGR piglets are commonly seen in litters from hyperprolific sows as a result of insufficient placental transfer of nutrients. Nutritional strategies can be used prior to and during gestation to enhance foetal development and can also be implemented in the transition period to reduce the duration of farrowing and increase colostrum yield. Recent findings showed that the energy status of sows at the onset of farrowing is crucial to diminish stillbirth rate. Newborn piglets often fail to consume enough colostrum to promote thermostability and subsequent growth, and this is particularly problematic in very large litters when there are fewer available teats than the number of suckling piglets. One injection of 75 IU of oxytocin approximately 14 h after farrowing can prolong the colostral phase, hence increasing the supply of immunoglobulins to piglets. Nevertheless, assistance must be provided to piglets after birth in order to increase their chance of survival. Various approaches can be used, such as: (1) optimising the farrowing environment, (2) supervising farrowing and assisting newborn piglets, (3) using cross-fostering techniques, (4) providing nurse sows, and 5) providing artificial milk. Although research advances have been made in developing feeding and management strategies for sows that increase performance of their newborn piglets, much work still remains to be done to ensure that maximal outcomes are achieved.

Genetic aspects of piglet survival and related traits: a review

In livestock, mortality in general, and mortality of the young, is societal worries and is economically relevant for farm efficiency. Genetic change is cumulative; if it exists for survival of the young and genetic merit can be estimated with sufficient accuracy, it can help alleviate the pressure of mortality. Lack of survival is a moving target; livestock production is in continuous change and labor shortage is a given. There is now ample evidence of clear genetic variance and of models able to provide genomic predictions with enough accuracy for selection response. Underlying traits such as birth weight, uniformity in birth weight, gestation length, number of teats, and farrowing duration all show genetic variation and support selection for survival or, alternatively, be selected for on their own merit.

Disentangling Litter Size and Farrowing Duration Effects on Piglet Stillbirth, Acid-Base Blood Parameters and Pre-Weaning Mortality

The current study evaluated interactions between farrowing duration and litter size on the level of asphyxia, vitality, percentage of stillbirth, and pre-weaning mortality of piglets. Farrowing duration was measured in 159 crossbred gilts and sows (Yorkshire × Dutch Landrace). Litter size ranged between 12 and 21 piglets. Blood acid–base parameters in umbilical cord blood and vitality scores of piglets were determined immediately after birth. Number of piglets born alive and stillborn as well as individual piglet weights at birth were recorded. Pre-weaning mortality (excluding stillbirth) was determined throughout lactation. Litter size as well as farrowing duration were categorized to evaluate the interaction between the two. There tended to be an interaction between litter size and farrowing duration for pre-weaning mortality (p = 0.10). In small litters (12–15 piglets), a prolonged farrowing duration (>250 min) tended to increase pre-weaning mortality compared with a short (<150 min) and medium farrowing duration (150–250 min), while for large litters (19–21 piglets), a medium to long farrowing duration tended to decrease pre-weaning mortality. No other interactions between litter size and farrowing duration were found. Piglets within large litters showed a higher umbilical cord lactate level (p < 0.01), lower average vitality score (p = 0.01), and a higher stillborn percentage (p < 0.01) compared with piglets within medium size (16–18 piglets) and small litters. Each additional piglet born to a litter linearly decreased average piglet birth weight (17.6 g, p < 0.01), increased farrowing duration (11 min, p < 0.01), and increased stillbirth (0.5%, p = 0.04). A medium farrowing duration resulted in a lower stillborn percentage compared with a short or prolonged farrowing duration, suggesting that farrowing duration might have an optimum. When analyzed linearly, stillborn percentage increased with 1.85% per every 100 min (p < 0.01) of farrowing duration. It can be concluded that both litter size and farrowing duration affect stillborn percentage, but independent from each other. However, these two factors tended to interact regarding pre-weaning mortality, suggesting that setting a certain threshold for maximal farrowing duration should be taken with care, because this appears to depend on litter size.

Increased feeding frequency prior to farrowing: effects on sow performance

Reducing the interval between the consumption of the last meal and the start of farrowing is suggested to increase the energy available to sows during farrowing, potentially reducing the farrowing duration and easing piglet births. The present study aimed to examine whether increasing feeding frequency from one to two feeds within standard production hours (0700 to 1500 hours) would produce a difference in farrowing duration and/or stillborn numbers. From entry to farrowing crates (110 ± 1 d gestation) to farrowing (116 ± 1 d gestation), multiparous sows (n = 118) were fed a daily fixed amount of feed either once at 0800 hours or in two meals at 0800 and 1300 hours. Sow weights and backfat depths were recorded on entry and exit from the farrowing crate. Litter size and weight were recorded 24 h after farrowing and on day 21 of lactation. Sows fed twice had a shorter farrowing duration and fewer stillborn piglets than those fed once (2.21 ± 0.56 h vs. 3.25 ± 0.52 h; P = 0.001). The interaction between treatment and farrowing duration showed that sows fed twice have a reduced farrowing duration and had significantly lower stillborn rates than those fed once or those fed twice with longer farrowing durations (P < 0.001). These findings suggest that increasing feeding frequency prior to farrow can reduce the farrowing duration and stillborn numbers in some sows, however, some sows remain with a high stillborn rate regardless of feeding frequency. Piglet average daily gain was greater in once-fed sows, but fewer of these sows remained in the herd at subsequent farrowing. Further, subsequent total born and born alive were higher in twice-fed sows. Feeding sows at a higher frequency can improve farrowing performance in some sows and could increase the longevity of the sow in the herd.

Effects of farrowing induction with prostaglandins on farrowing traits and piglet performance: A systematic review and meta-analysis

Induction of farrowing with prostaglandins is a way of increasing farrowing supervision and to provide adequate care for piglets in the first hours of life. However, some studies observed negative effects associated with induction, including decreased piglet viability, reduced birth weight and decreased colostrum yield. Furthermore, the farrowing response of sows to prostaglandins treatment varies among studies, largely influenced by the induction protocol applied. Thus, a systematic review and meta-analysis was carried out to evaluate the effects of farrowing induction with prostaglandins on stillbirth rate, birth weight, pre-weaning mortality, weaning weight, farrowing duration and colostrum and milk characteristics as well as the farrowing response to prostaglandin treatment. The interval from farrowing induction to onset of farrowing (IFIOF) was 31 h, and a twice application of prostaglandin increased by 37% the proportion of sows farrowing during the next working day. Prostaglandins had no effect on farrowing duration (P > 0.05). Piglet birth weight and weaning weight were only decreased (P < 0.05) when farrowing was induced ≥3 days before the expected farrowing date (based on herd average or in gestational length of the control group). Induction three or two days before the expected farrowing date had no effect on stillbirth rate; conversely, stillbirth rate was reduced by 28% (P < 0.05) when induction was performed one day before the expected farrowing date. Farrowing induction had no influence on pre-weaning mortality. The present study strengthened the observations that farrowing induction with prostaglandins is a valuable tool to reduce gestational length variation and to synchronize farrowing during the working day, allowing better assistance to sows and piglets. To obtain the maximum benefit of farrowing induction, it is recommended that induction should be performed one or two days before the expected farrowing date.

Piglet Viability: A Review of Identification and Pre-Weaning Management Strategies

Simple Summary

Neonatal piglet viability is decreasing in concert with the selection for ever-greater numbers of piglets born per sow per year. Their survival depends on the early intervention and management strategies used by production staff. This paper will review current and novel methods used to identify these piglets, some of the factors affecting their viability, and management strategies commonly used within production systems to improve their survival.

Abstract

Increased attention on the effects of the global push for a larger litter size has focused on the increased occurrence of piglets with decreased viability, which have lighter birthweights and a reduced ability to thrive in early life. To improve their odds of survival, interventions must be timely and targeted. This requires the early identification of low-viability pigs and appropriate strategies to manage them. Using novel measures such as abdominal circumference and crown to the rump length in conjunction with birth weight may provide an improved protocol for the identification of those at most risk of preweaning mortality. Further, identifying these at-risk piglets allows interventions to increase their colostrum intake and heat provisions shortly following birth. The appropriate management of the pre- and post-partum sows will improve the chances of decreasing the number of piglets born with lower viability. However, this outcome is constrained by limitations in resources such as technology and staffing. If these challenges can be overcome, it will allow for greater control and increased effectiveness in the implementation of current and new management strategies.

Synthetic Olfactory Agonist Use in the Farrowing House to Reduce Sow Distress and Improve Piglet Survival

The aim of the study was to investigate if the application of a synthetic olfactory agonist (SOA) would reduce indicators of stress in sows, in response to a stressor prior to parturition, and if it would improve farrowing house performance of sows and their piglets. Two studies were conducted: an intensive study with 47 sows, either having their first or second litter (Control n = 24; SOA n = 23); and a commercial validation study with 418 sows, either having their first litter or have had multiple litters (Control n = 210; SOA n = 208). Within the intensive study, sows were housed with or without a synthetic olfactory agonist suspended in the creep area of the farrowing crate, whereas within the commercial validation study, sows were housed with or without a synthetic olfactory agonist suspended over the adjoining creep area of two farrowing crates. Within the intensive study, despite a discernible increase in cortisol concentration in response to a stressor (snout rope test), cortisol response was not different between treatments (p > 0.05). Farrowing duration in first-litter sows exposed to the SOA was decreased (p < 0.001) whilst there was no impact on farrowing duration in second litter sows. Piglets were not attracted by the SOA to increase their utilisation of the creep area and spent more time in proximity to the sow (p < 0.05). Within the commercial validation study, no impacts were seen on piglet production measures (p > 0.05). Largely the use of an SOA within the farrowing house did not impact the sow or her piglets in either the intensive study or commercial validation study. Based on these current results, the use of SOA within the farrowing house is not supported.

Effects of Birth Order on Performance and Affective State of Pigs

In pigs, higher birth order is associated with higher pre-weaning mortality. However, knowledge on the effect of birth order on welfare of surviving piglets is limited. The aim of this study was to explore the possible link between birth order and both newborn piglet performance and later affective state. Firstly, the following data were collected in 393 piglets from 27 litters: stillbirth, intactness of the umbilical cord and birth weight. Subsets of piglets were used to measure suckling latency (n = 67) and teat order (n = 21). Secondly, a subset of first-born (n = 9) and last-born (n = 7) piglets were trained to perform an active-choice judgement bias task (JBT). During discrimination training preceding the JBT, the pigs learned to associate two tone cues with the availability of either a large (4 M&amp;M's® Milk Chocolate candies) or small (1 M&amp;M's) reward, provided at two different locations. After training, ambiguous intermediate tones were introduced and the pig's choice of location was scored as either optimistic or pessimistic. Results showed that last-born piglets had a higher birth weight than middle-born piglets, while first-born piglets did not significantly differ from last- or middle-born piglets. They also latched to more caudal teats than first-born piglets. The last-born and first-born piglets showed a similar learning rate during discrimination training, and a similar latency to approach reward locations, and had a similar optimistic bias in the JBT.

Associations between piglet umbilical blood hematological criteria, birth order, birth interval, colostrum intake, and piglet survival

A total of 656 pigs (623 live-born and 33 stillborn) from 43 sows were used to evaluate hematological criteria at birth and their association with piglet survival. At birth of each piglet, birth time and order within the litter, weight, umbilical cord status (intact or ruptured) and whether the pig was live-born or stillborn were recorded. A 200µL sample of blood from the umbilical cord was collected and immediately analyzed for concentrations of glucose, oxygen partial pressure (pO2), carbon dioxide partial pressure (pCO2), pH, base excess (BE), bicarbonate (HCO3), saturated oxygen (sO2), total carbon dioxide (TCO2), sodium, potassium, ionized calcium (iCa), hematocrit (Hct), and hemoglobin (Hb) on a hand held iStat portable clinical analyzer (iStat Alinity, Abbott Point of Care Inc., Princeton, NJ). Piglets were categorized into quartiles based on birth order and cumulative birth interval (CumBI). Live-born pigs had higher (P < 0.01) umbilical cord blood pH, HCO3, BE, sO2, TCO2, and birth weight compared with stillborn pigs, but lower (P < 0.01) pCO2, K, iCa, and glucose compared with stillborn pigs. Pigs with intact umbilical cords at birth were associated with higher (P < 0.01) blood pH, HCO3, BE, and TCO2 compared with piglets born with a ruptured umbilical cord. Pigs with intact umbilical cords were associated with lower (P < 0.01) Hct and Hb concentrations and born earlier (P < 0.01) in the birth order compared with pigs born with a ruptured umbilical cord. Pigs that did not survive to weaning had lower (P < 0.01) umbilical cord blood pH, HCO3, BE, sO2, TCO2, Na, glucose, and birth weight, and 24 hr weight compared with pigs alive at weaning. Pigs born in the first quartile for CumBI had higher (P <0.05) pH compared with pigs in the other three quartiles. Umbilical cord blood HCO3, BE, and TCO2 decreased (P <0.05) with each change in CumBI quartile from first to last. Blood glucose was lowest (P <0.05) in pigs born before 44 min and highest in pigs born after 164 min. Umbilical cord blood pH, HCO3, BE, TCO2, Na, glucose, Hct, and Hb were positively associated (P <0.001) with colostrum intake, indicating increased blood values resulted in higher colostrum intake. Although a pig may be live-born, their survival to 24 hr and to weaning is reduced when blood pH, HCO3, BE, and sO2 are lower reiterating the importance of management practices that can reduce the birth interval between pigs and the number of pigs experiencing moderate to severe hypoxia.

Caffeine: A potential strategy to improve survival of neonatal pigs and sheep

Caffeine is commonly used to treat pre-and postnatal injuries, including apnoea in premature infants, as well as neurological impairment caused by hypoxia or asphyxiation often associated with difficult birthing. As an adenosine antagonist, caffeine is metabolised rapidly and transported into many tissues. Caffeine stimulates the brain respiratory centre, improving respiratory function in immature infants or neonates, provides neuroprotection to the fetal brain, and initiates non-shivering thermoregulation increasing metabolic rates. Recently, potential benefits of caffeine for animal production have been investigated. This has particularly occurred in pig production, where large litters are associated with relatively long parturition durations, and piglets born near the end of the parturition period have an increased risk of mortality due to asphyxia-related birthing injury. Similarly, in sheep, dystocia or prolonged parturition is a significant problem, where neonatal injury, dystocia and death in utero contributes to approximately 46 % of lamb mortalities. Within these two livestock production systems, large prevalence's of neonatal mortality is a persistent issue contributing to lost revenue, as well as being a significant animal welfare concern. Pre-partum maternal caffeine supplementation is a promising strategy to reduce neonatal mortality; however, there needs to be refinement of appropriate quantities administered, duration and administration pathway to provide producers with an efficient and cost-effective method to reduce mortality rates and increase production output. The information in this review details effects, benefits and important considerations regarding caffeine use in animal production, and identifies areas of limited knowledge where further research is needed.

[Clinical, ethologic, endokrinologic, and metabolic aspects of the peripartal period in pigs]

The aim of this review article is to provide an overview of the literature relevant to the peripartal period in swine. As in all other mammals, the farrowing process in pigs is divided into 3 phases (I-III; opening, expulsion, and postnatal stage), during which various essential endocrine and metabolic mechanisms initiate or maintain parturition. These include the hormones progesterone, cortisol, prostaglandin F_2α, oxytocin, estradiol, relaxin as well as electrolytes, enzymes, and metabolites such as calcium, magnesium, inorganic phosphate, glucose, creatine kinase, lactate, non-esterified free fatty acids, and β-hydroxybutyrate. Exogenous or endogenous disruptive factors may result in a delay or even stagnation of labor. For example, the form of husbandry may represent a possible exogenous disruptive factor. Endogenous disruptive factors may arise from insufficient storage and/or distribution of the above-mentioned labor-associated parameters. Subsequent dystocia leads to temporary or permanent consequences for maternal reproductive fitness and impairs piglet vitality at the time of birth, possibly resulting in lower survival rates.

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.

Effects of dietary inulin during late gestation on sow physiology, farrowing duration and piglet performance

In this study there was evaluation of effects of dietary inulin during late gestation on sow physiology, farrowing duration and piglet performance. At day 80 of gestation sows were randomly assigned to four groups：basal diet (CON); or basal diet with 0.8 %; 1.6 %; or 2.4 % inulin. The feeding of the diet with 1.6 % inulin resulted in larger weights of the litter at birth a shorter duration of the farrowing period, lesser average birth interval between piglets, lesser number of piglets dead at birth, and fewer piglets/sow dead at birth (P < 0.05). When sows were fed 0.8 % and 1.6 % IN, there was a larger litter weight at weaning, sow average daily feed intake and piglet average daily gain during lactation compared with values for these variables in the CON group (P <  0.05). Additionally, there was an increase in serum concentration of free fatty acid, total cholesterol, and high-density lipoprotein cholesterol with increasing amounts of inulin in the diet (linear, P <  0.05). Sows fed 1.6 % IN had greater serum concentrations of glucose than those in the CON group (P <  0.05). Furthermore, there was a linear increase in serum activity of total antioxidant capacity, total superoxide dismutase and glutathione peroxidase with increasing amounts of inulin in the diet (P <  0.05). In conclusion, results of the present study indicated feeding inulin during late gestation improved reproductive performance of sows, thus, may be a novel additive for the pig industry in improving efficiency of pork production.

Sow and piglet traits associated with piglet survival at birth and to weaning

AbstractUnderstanding the relationship between sow and piglet characteristics that are associated with stillborn rate and preweaning mortality is beneficial as litter size continues to increase. Two experiments were previously conducted to evaluate prefarrowing nutrition regimens on sow and litter characteristics. These two datasets (experiments 1 and 2) were then used to identify sow and piglet characteristics associated with stillborn rate and piglet survival to weaning. A total of 1,201 sows that gave birth to 19,168 pigs comprised the dataset. The following characteristics were used in multivariate logistic regression analysis for traits associated with stillborn rate or survival to weaning: parity, litter weight, mean piglet birth weight, sow backfat, and BW at day 113 of gestation, gestation length, farrowing duration, litter size, piglet birth order, farrowing assistance, pig to teat ratio, colostrum intake, and colostrum yield. Sows within each experiment (herd) were categorized into quartiles for each of the independent variables to quantify the relationship to stillborn rate or survival to weaning. Increased stillborn rate was associated (P < 0.01) with heavier litter weights, lighter piglet birth weights, and larger litters in both experiments. In experiment 1, increased stillborn rate was associated (P < 0.01) with longer farrowing duration. Increased stillborn rate was associated with sows with less backfat depth at day 113, older parity, or increased farrowing assistance in experiment 2. In both experiments, pigs born later in the birth order had an increased (P < 0.01) risk of being stillborn. In both experiments, heavier piglet birth weight, greater colostrum intake, and lower total born were associated (P < 0.01) with increased survival to weaning. In experiment 2, pigs born in the first 75% of the litter, or in a litter with lower pig to teat ratio were associated (P < 0.01) with increased survival to weaning. Although the stillborn rate was similar between experiments (6.5% vs. 6.6%), differences in the traits associated with stillborn rate between studies indicate that some associated traits may be herd dependent. However, improving piglet birth weight, placing an emphasis on assisting pigs born later in the birth order and increasing colostrum intake will increase piglet survival from birth to weaning.

Parturition and Its Relationship with Stillbirths and Asphyxiated Piglets

Simple Summary

Piglets that experience a long labour are more likely to die during birth or immediately following birth, or to grow slowly during life. This is because the longer the piglet experiences contractions during labour, blood supply and oxygen delivery to the brain will be impaired. Even before the first piglet in the litter is born, sows that will have a delayed labour can be identified. This means that the key to saving piglets that are at risk of death because of long labours lies in managing the sow before she gives birth.

Abstract

The transition from an intra- to extrauterine existence is extremely challenging for the pig. This is evidenced by the fact that conservative estimates place intrapartum piglet death at between 5% and 10%. The main cause of this loss is the parturition process itself, with a long farrowing duration resulting in reduced oxygenation to the piglet via uterine contractions stretching, and in some cases, causing rupture of the umbilical cord. Sows that experience a long expulsive stage of parturition are likely compromised before the birth of the first piglet, and so any strategy to reduce stillbirth should be applied before this. Even in piglets born alive, 15% to 20% will have suffered asphyxiation because of a long cumulative farrowing duration. These individuals are significantly disadvantaged with regards to behavioural progression, colostrum intake, growth and survival extending past the lactation phase, and so require more labour and resources than littermates in order to make them viable. Given these immediate and longer-term impacts, identifying ways to correctly manage the sow before parturition leading to a reduction in farrowing duration should be a priority in order to maximise piglet performance.

Caffeine administered to pregnant sows improves piglet vitality, gas exchange and body weight gain

Intra-partum asphyxia is the most common non-infectious etiology limiting the performance of neonate piglets. Previous studies indicate caffeine (orally and subcutaneously) reverses the effects of intra-partum asphyxia in neonate piglets. In this study, there was investigation of whether use of a novel therapeutic protocol for administering caffeine subcutaneously to pregnant sows would improve the newborn piglets' vitality, physio-metabolic profiles and body weight gain. Sows were randomly divided into two groups (n = 10 each). Caffeine or NaCl 0.9% was administered 2 days pre-farrowing. Physio-metabolic profiles were measured using blood from the anterior vena cava. The vitality of piglets was evaluated immediately after birth. Piglets (n = 180) were weighed at birth and on days 7, 14 and 21 of lactation. Caffeine positively affected the vitality of the piglets, as indicated by greater vitality scores than that for the control group (8.72 ± 0.12 compared with 7.28 ± 0.16, P < 0.001). Metabolic values were similar between groups, but pO₂ values were greater in the piglets with greater vitality scores treated with caffeine (19.10 ± 0.82 compared with 14.49 ± 1.42, P < 0.01), indicating increased respiratory rates. Body weight gain at day 21 was greater in the piglets treated with caffeine that had greater vitality scores than the control piglets having greater vitality scores (6.87 ± 0.18 compared with 6.52 ± 0.25 kg, P < 0.05). Caffeine administration before birth improves the vitality and respiratory capacity of piglets, increasing their adaptation to extra-uterine environment.