Perinatal asphyxia pathophysiology in pig and human: A review

Blood haemoglobin concentrations in free farrowing sows and their piglets are associated with farrowing performance characteristics and sow traits

Haemoglobin concentration (HbC) in sows and/or their piglets might influence the farrowing process. The aim of this study was to investigate the association between the HbC of breeding sows and piglets and their performance characteristics at farrowing in a free farrowing system. In total 103 sows and their 1615 piglets were included. The investigated parameters included the HbC in all sows and the HbC in approximately 5 piglets per litter (n = 496). In addition, parity, litter size, litter weight, placenta weight, stillbirth rate, piglet expulsion duration, farrowing duration and other sow and piglet traits were evaluated. The mean HbC of the sows was 106.2 ± 10.36 g/l and of the litter was 93.6 ± 9.6 g/l. The univariant analysis revealed that sows with a HbC <100 g/l (low HbC) had a significantly higher median parity number (5.0, p = 0.003), litter size (18, p < 0.001) and placenta weight (4.9 kg, p < 0.001) compared to sows with a HbC ≥100 g/l (high HbC) (3.0; 15; 3.9 kg). The median piglet expulsion duration was significantly longer in low HbC sows (290min p = 0.005; compared to high HbC sows (224min). No significant correlation could be determined between the HbC of the sows and the HbC of their offspring (Pearson correlation: r = 0.124, p = 0.263). In the multivariable regression model, pre-partum HbC in sows decreased with an increase in litter size (beta = -0.88), was 6.62 g/l higher in low parity sows (1 + 2 vs > 2) and tended to be 3.02 g/l higher in sows that received obstetrical intervention. This study showed that the HbC of the sows and the piglets were significantly associated with several performance characteristics. It could serve as a useful indicator in farrowing management, contributing to better farrowing outcomes and promoting improved health and vitality in piglets.

Postnatal enteral plasma supplementation following birth asphyxia increases fluid retention and kidney health in newborn pigs

Birth asphyxia can result in kidney dysfunction, disturbances in systemic electrolytes and fluid balance in newborns. Currently, there is no proven dietary approach to support asphyxiated newborns. This study investigates whether oral plasma supplementation improves kidney function and overall health in asphyxiated newborns. Cesarean-delivered near-term pigs with or without an 8 min intrauterine clamping of the umbilical cord were fed a milk replacer dissolved in water for 24 h in Experiment 1. Pigs were fed 72 h with milk replacers dissolved in either maternal plasma or water in Experiment 2. Blood, urine, and kidney tissue were collected for further analyses. Asphyxia disrupted blood electrolyte balance. And plasma feeding led to higher fluid retention for both asphyxiated and control pigs. Additionally, plasma feeding may also affect kidney development and protect kidneys from asphyxia induced impairments. Birth asphyxia in pigs led to immediate disturbance of electrolyte balance, impaired fluid retention, and kidney impairments. Plasma feeding may improve postnatal newborn hydration and may also improve the condition of kidneys following asphyxia.

Commentary on the Adaptive Significance of Sociality Around Parturition Events, and Conspecific Support of Parturient Females in Some Social Mammals

In recent decades, it has become apparent that during parturition events in a number of social mammals, social support behaviours from group mates can be directed to parturient females (and their newborn neonates). Such behaviour has been documented in diverse taxa, across non-human primates, Elephantidae, Cetacea, and Chiroptera, living in a range of social group organisations, from matrilineal groups to cooperatively breeding groups and multi-male, multi-female groups. Since sociality, in association with parturition, has been demonstrated to confer several health benefits to human mothers and neonates, here, we also consider the potential adaptive significance of social support behaviours for other, non-human, social mammals. If appropriate social environments reduce a parturient female's dystocia risk and improve her responsiveness to her neonate following a successful birth, then the impacts of the peri-parturient social environment may ultimately have far-reaching impacts on the mother-neonate dyad's fitness. This seems a logical sequela since the health condition of a neonate at birth and the successful establishment of a strong maternal-neonate bond are often the most critical factors influencing mammalian offspring survival to independence. The principles of kin selection and alliance enhancement may serve to explain the fitness benefits to individuals who support group mates during their parturition and thus the selective advantage conferred to those exhibiting such behaviours. Older, multiparous females appear to hold a particularly important role in the assistance they can provide during the parturition of their group mates, given their greater level of experience of these events. Furthermore, a social birth may have an important influence on horizontal information transfer within a group. In particular, in long-lived, cognitively advanced social mammals (e.g., non-human primates, Elephantidae, Cetacea), witnessing birth events, early neonate responses, and maternal care, and engaging in allomaternal care with young neonates may be essential for nulliparous females' normal development. Such events may serve to prepare them for their own parturition and may improve their own parturition-related survivorship and that of their first-born offspring. Thus, it is vital that a better understanding is gained of the importance and salient features of social births in improving the health and survivorship outcomes for both the mother and her offspring in highly social species. The aim of this commentary is to assemble our current understanding of these highly interconnected themes. We suggest in the future, insights gained through observation of non-human social parturition in domestic and non-domestic species, by a wide and highly interdisciplinary range of stakeholders (including zookeepers, wildlife tourism guides, breeders of domestic animals, indigenous people, and ethologists), will be critical for enhancing our understanding of the influence of social environment on this rarely witnessed, yet highly important life event.

Risk factors associated with piglet pre-weaning mortality in a Midwestern U.S. swine production system from 2020 to 2022

Piglet pre-weaning mortality (PWM) is a significant issue in the U.S. swine industry, causing economic losses and raising sustainability and animal welfare concerns. This study conducted a multivariable analysis to identify factors associated with PWM in a Midwestern U.S. swine production system. Weekly data from 47 sow farms (7207 weaning weeks) were captured from January 2020 to December 2022. Initially, 29 variables regarding farm infrastructure, productivity parameters, health status, and interventions were selected for univariate analysis to assess their association with PWM. The initial multivariable analysis included the variables with P < 0.20 in the univariate analyses. A backward stepwise model selection was conducted by excluding variables with P > 0.05, and the final multivariable model consisted of 19 significant risk factors and 6 interaction terms. The overall average PWM for the study population was 14.02 %. Yearly variations in PWM were observed, with the highest recorded in 2020 (16.61 %) and the lowest in 2021 (15.78 %). Cohorts with a pond water source, lower farrowing rate (71.9 %), higher farrowing parity (5.1), shorter gestation length (116.2 days), and using oxytocin during farrowing had increased PWM. The higher productivity parameters such as mummies rate, stillborn rate, and average total born, the higher the PWM was. Additionally, health status and intervention-related factors were associated with PWM, where higher PWM rates were observed in herds facing porcine reproductive and respiratory syndrome virus (PRRSV) outbreaks, porcine epidemic diarrhea virus (PEDV) positive, the weeks before and during feed medication, and weeks without using Rotavirus vaccine or Rotavirus feedback. Altogether, these results corroborate that PWM is a multifactorial problem, and a better understanding of the risk factors is essential in developing strategies to improve survival rates. Therefore, this study identified the major risk factors associated with PWM for groups of pigs raised under field conditions, and the results underscore the significance of data analysis in comprehending the unique challenges and opportunities inherent to each system.

Factors contributing to stillbirth in young hyper-prolific sows in a tropical free-farrowing system

The present study investigated factors associated with the incidence of stillbirth in young hyper-prolific sows within free farrowing systems in tropical environments. A total of 714 live-born and 54 stillborn piglets from 57 Landrace × Yorkshire sows, with an average parity of 2.7 ± 1.0 (range: 1 - 4), were comprehensively investigated. Reproductive variables of the sows, including gestation length, farrowing duration, the total number of piglets born per litter, and the birth order and status of each piglet, were recorded. Differences in the physiological characteristics of live-born and stillborn piglets, such as birth interval, cumulative birth interval, body weight at birth, crown-rump length, body mass index (BMI), ponderal index (PI), meconium staining score, and the percentage of piglets with a broken umbilical cord, were analysed. Piglets were divided into four groups based on the quartiles of birth order (Q1-Q4). On average, the duration of farrowing was 173.3 ± 85.9 min, and the total number of piglets born and number of piglets born alive-per litter were 14.1 ± 3.8 and 12.5 ± 3.5, respectively. The incidence of stillbirth was 6.7% (54/801 piglets). The higher percentages of stillbirths were detected in sows with large litter sizes (≥17 piglets, 10.9%) compared to those with small (≤13 piglets, 6.1%) and moderate (14 - 16 piglets, 2.8%) litter sizes (p < .001). The incidences of stillbirth in Q3 and Q4 of the litters were higher than in Q1 and Q2 (p < .001). Compared to live-born piglets, stillborn piglets had higher cumulative birth interval (103.0 ± 3.71 vs. 142.4 ± 9.35 min, p < .001), BMI (17.1 ± 0.15 vs. 18.4 ± 0.39 kg/m2, p = .002), PI (63.7 ± 0.59 vs. 70.8 ± 1.59 kg/m3, p < .001), meconium staining scores (1.78 ± 0.04 vs. 2.04 ± 0.10, p = .021), and the percentage of piglets born with a ruptured umbilical cord (45.2% vs. 66.0%, p = .004). An increase in the incidence of stillbirth was detected at 60, 120, 150, 180, and ≥ 210 min after the first piglet was born, compared to those born within the first 30 min of farrowing (p < .05). In conclusion, the study found that stillbirths in young, hyper-prolific sows were linked to several factors: large litter sizes (≥17 piglets per litter), prolonged cumulative birth intervals (142.4 min), elevated BMI of 18.4 kg/m2, high PI values of 70.8 kg/m3, increased meconium staining scores, and a higher occurrence of ruptured umbilical cords. To reduce the risk of stillbirth, particularly among piglets with high body indices born later in the birthing process, it is recommended to enhance farrowing supervision for young sows, starting at a cumulative birth interval of 60 min.

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.

Enteral plasma supports brain repair in newborn pigs after birth asphyxia

Newborns exposed to birth asphyxia transiently experience deficient blood flow and a lack of oxygen, potentially inducing hypoxic-ischaemic encephalopathy and subsequent neurological damage. Immunomodulatory components in plasma may dampen these responses. Using caesarean-delivered pigs as a model, we hypothesized that dietary plasma supplementation improves brain outcomes in pigs exposed to birth asphyxia. Mild birth asphyxia was induced by temporary occlusion of the umbilical cord prior to caesarean delivery. Motor development was assessed in asphyxiated (ASP) and control (CON) piglets using neonatal arousal, physical activity and gait test parameters before euthanasia on Day 4. The ASP pigs exhibited increased plasma lactate at birth, deficient motor skills and increased glial fibrillary acidic protein levels in CSF and astrogliosis in the putamen. The expression of genes related to oxidative stress, inflammation and synaptic functions was transiently altered in the motor cortex and caudate nucleus. The number of apoptotic cells among CTIP2-positive neurons in the motor cortex and striatal medium spiny neurons was increased, and maturation of preoligodendrocytes in the internal capsule was delayed. Plasma supplementation improved gait performance in the beam test, attenuated neuronal apoptosis and affected gene expression related to neuroinflammation, neurotransmission and antioxidants (motor cortex, caudate). We present a new clinically relevant animal model of moderate birth asphyxia inducing structural and functional brain damage. The components in plasma that support brain repair remain to be identified but may represent a therapeutic potential for infants and animals after birth asphyxia.

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.

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.

Assessment of Vitality, Blood Profile, and Degree of Meconium Staining on the Skin in Newborn Dogs According to Its Birth Weight

Neonatal mortality in dogs reaches up to 40%. Due to the high rates, promptly detecting the causes and preventing newborns from dying are extremely important. Vitality evaluation, blood parameters, and the degree of meconium staining on the skin are valuable resources in canine perinatology. In this study, 435 puppies from 85 bitches close to parturition were recruited and divided into four quartiles according to the puppy's birth weight: Q₁ (127-200 g) n = 110 puppies, Q₂ (201-269 g) n = 108 puppies, Q₃ (270-388 g) n = 108 puppies, and Q₄ (389-464 g) n = 109 puppies. This experimental article aimed to report the effect of birth weight on the blood profile variables, the vitality of newborn puppies, and the meconium staining degree, integrating these three aspects. It was concluded that the weight of newborns was correlated with the degree of meconium staining, presenting more cases of severe meconium staining in the puppies of the highest birth weight group. The weight of the newborns was correlated with a higher number of stillbirths and alterations in the blood variables, showing the most severe cases of metabolic acidosis, hypoxia, and hypoglycemia in the puppies of the Q₄ quartile. On the contrary, no statistically significant correlations were found between the weight of newborns and vitality. Nevertheless, the analysis of the results showed that the most vigorous puppies were found at Q_1; however, at minute 60 after birth (AB), all the puppies in the four quartiles standardized their vitality scores.

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.

Vitality in Newborn Farm Animals: Adverse Factors, Physiological Responses, Pharmacological Therapies, and Physical Methods to Increase Neonate Vigor

Vitality is the vigor newborn animals exhibit during the first hours of life. It can be assessed by a numerical score, in which variables, such as heart rate, respiratory rate, mucous membranes' coloration, time the offspring took to stand up, and meconium staining, are monitored. Vitality can be affected by several factors, and therapies are used to increase it. This manuscript aims to review and analyze pharmacological and physical therapies used to increase vitality in newborn farm animals, as well as to understand the factors affecting this vitality, such as hypoxia, depletion of glycogen, birth weight, dystocia, neurodevelopment, hypothermia, and finally, the physiological mechanism to achieve thermostability. It has been concluded that assessing vitality immediately after birth is essential to determine the newborn's health and identify those that need medical intervention to minimize the deleterious effect of intrapartum asphyxia. Vitality assessment should be conducted by trained personnel and adequate equipment. Evaluating vitality could reduce long-term neonatal morbidity and mortality in domestic animals, even if it is sometimes difficult with the current organization of some farms. This review highlights the importance of increasing the number of stock people during the expected days of parturitions to reduce long-term neonatal morbidity and mortality, and thus, improve the farm's performance.

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.

Dietary Supplementation of Eubiotic Fiber Based on Lignocellulose on Performance and Welfare of Gestating and Lactating Sows

The present study aimed to evaluate the effects of partially fermentable insoluble dietary fiber supplementation on the behavior, surface temperature, and reproductive parameters of gestating and lactating sows, as well as on the performance of their litters. Four hundred hyper-prolific sows were assigned in a randomized block design with two treatment groups during the gestation phase: Control (C), corn-soy based diets, or corn-soy based diets with daily 55 g supplementation of eubiotic fiber (F) from the 85th day of gestation until the farrowing (late pregnancy). During the lactation phase, the sows were assigned in a 2 × 2 factorial design using the following treatment groups: (1) CC, no fiber included during gestation and lactation. (2) FC, daily inclusion of 55 g of fiber only during late pregnancy. (3) CF, daily inclusion of 55 g of fiber only during lactation. (4) FF, daily inclusion of 55 g of fiber during late pregnancy and lactation. Sows that received dietary fiber supplementation during the final third of gestation increased feed intake during lactation. Piglets from sows supplemented in both phases showed a significant increase in weight at weaning. The dietary supplementation of eubiotic fiber for sows in the end period of gestation and lactation improved performance and welfare, with positive consequences for developing their litters.

Pen Versus Crate: A Comparative Study on the Effects of Different Farrowing Systems on Farrowing Performance, Colostrum Yield and Piglet Preweaning Mortality in Sows under Tropical Conditions

The present study was performed to determine the farrowing performance of sows, newborn piglet characteristics, colostrum yield, milk yield and piglet preweaning mortality in a free-farrowing pen compared to a conventional farrowing crate system in a tropical environment. A total of 92 sows and 1344 piglets were included in the study. The sows were allocated by parity into two farrowing systems, either a free-farrowing pen (n = 54 sows and 805 piglets) or a crate (n = 38 sows and 539 piglets). Backfat thickness and loin muscle depth of sows at 109.0 ± 3.0 days of gestation were measured. Reproductive performance data including total number of piglets born (TB), number of piglets born alive (BA), percentage of stillborn piglets (SB) and percentage of mummified foetuses (MF) per litter, farrowing duration, piglet expulsion interval, time from onset of farrowing to the last placental expulsion, piglet preweaning mortality rate, percentage of piglets crushed by sows and number of piglets at weaning were analysed. In addition, piglet colostrum intake, colostrum yield, Brix index and milk yield of sows were evaluated. On average, TB, BA, farrowing duration, colostrum yield and milk yield during 3 to 10 and 10 to 17 days of lactation were 14.7 ± 2.8, 12.8 ± 3.1, 213.2 ± 142.2 min, 5.3 ± 1.4 kg, 8.6 ± 1.5 kg, and 10.4 ± 2.2 kg, respectively. Sows kept in the free-farrowing pen tended to produce more colostrum than crated sows (5.5 ± 0.2 vs. 4.9 ± 0.2 kg, p = 0.080). Piglets born in the free-farrowing pen had a higher colostrum intake than those in the crate system (437.0 ± 6.9 and 411.7 ± 8.3 g, p = 0.019). However, the piglet preweaning mortality rate (26.8 ± 2.9 vs. 17.0 ± 3.8, p = 0.045) and the proportion of piglets crushed by sows (13.1 ± 2.1 vs. 5.8 ± 2.7, p = 0.037) in the free-farrowing pen were higher than those in the crate system. Interestingly, in the free-farrowing pen, piglet preweaning mortality rate in sows with high backfat thickness was higher than that in sows with moderate (37.8 ± 5.1% vs. 21.6 ± 3.6%, p = 0.011) and low (21.0 ± 6.2%, p = 0.038) backfat thickness. Moreover, the incidence of crushing in sows with high backfat thickness was higher in the free-farrowing pen than in the crate system (17.6 ± 3.6 vs. 4.0 ± 5.7, p = 0.049), but this difference was not detected for sows with moderate and low backfat thickness (p > 0.05). Milk yield of sows during 3 to 10 days (8.6 ± 0.2 vs. 8.6 ± 2.3, p > 0.05) and 10 to 17 days (10.2 ± 0.3 vs. 10.4 ± 0.4, p > 0.05) did not differ between the two farrowing systems. In conclusion, piglets born in the free-farrowing pen had a higher colostrum intake than those in the crate system. However, the piglet preweaning mortality rate and the proportion of piglets crushed by sows in the free-farrowing pen were higher than in the crate system. Interestingly, a high proportion of piglet preweaning mortality in the free-farrowing system was detected only in sows with high backfat thickness before farrowing but not in those with low and moderate backfat thickness. Therefore, additional management in sows with high backfat thickness (>24 mm) before farrowing should be considered to avoid the crushing of piglets by sows.

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

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.

Animal Welfare Compromises Associated with Causes of Death in Neonatal Piglets

Simple Summary

The pre-weaning piglet mortality percentage is a commonly reported metric on commercial pig farms. The mortality percentage tells us how many piglets died, but not what their welfare status was as it relates to their cause of death. This pilot study aimed to evaluate the likely experience of piglets that died, following confirmation of the cause of death via postmortem investigation. The Five Domains Model was then used to collate scientific evidence of the likely experience of these piglets before death from acute disease, starvation, crushing, savaging and euthanasia, to understand the impact of different causes on their welfare. The resulting findings raised the question of differentiating ‘smothering’ as a cause of death from ‘crushing,’, and that co-morbidities (such as hypothermia) may alter the welfare experience due to their influence on consciousness before death.

Abstract

This pilot study aimed to assess the welfare impacts of different causes of pre-weaning deaths in piglets. Piglets that died between 0–7 days after birth (n = 106) were collected from two commercial pig farms and subject to post-mortem examination to confirm their cause of death as well as any contributing factors. Using the Five Domains Model, the most likely affective experiences associated with the pathological findings were carefully inferred to better understand affective experience as it related to known causes of liveborn piglet mortality. The most common causes of liveborn piglet mortality were starvation (23%), crushing (23%) and non-viable (21%). Thirty one piglets had evidence of starvation, but it was only considered the primary cause of death in 15 piglets, as cofactors such as poor viability (n = 13) were also present in many piglets with evidence of starvation. All 15 piglets that were crushed died within 24 h after birth and most had evidence of thoracic and/or abdominal internal bleeding. This study found that common causes of liveborn piglet death were associated with compromises in Domains 1 (Nutrition/hydration), 3 (Health/function), and4 (Behavioural interactions), with the most likely resulting affective states described in Domain 5 (Mental state). This highlights the interaction between physical/functional and situation-related (behavioural) aspects that influence an animals’ welfare status.

Killing underweighted low viable newborn piglets: Which health parameters are appropriate to make a decision?

Background

The aim of this study was to estimate the mortality risk and associated factors within the first days of life for underweight or low-vital neonatal piglets. This risk estimation should start a discussion concerning the preconditions for timely killing of compromised newborn piglets to prevent unnecessary pain and suffering. In an observational study, various clinical and laboratory variables were examined in 529 piglets out of four farms. Body weight, crown-rump-length, rectal temperature, a 4-stage vitality score, an intrauterine-growth-retardation score, glucose, lactate, haemoglobin and immunocrit were assessed on the first day of life. Vitality was scored by three factors: movement, abdominal palpation, and colour of the skin. Afterwards the death of the piglets (by killing or spontaneously) was monitored until day 5 of age.

Results

Body weight, rectal temperature and vitality score were significantly associated with probability of death. Piglets with rectal temperatures ≤ 37.5 °C, a body weight < 0.86 kg and impaired vitality scores were found to have the highest probability of death until day 5 of age.

Conclusion

The clinical findings, identified by this model, allow a first estimation of mortality risk for newborn piglets within the first days of life. In a further step veterinarians, farmers and ethicians now need to clarify what probability of death should justifiy the killing of a newborn piglet.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40813-022-00265-y.

Early Blood Analysis and Gas Exchange Monitoring in the Canine Neonate: Effect of Dam’s Size and Birth Order

Simple Summary

The complications that are observed during parturition are events that affect the vitality of the newborn and can also compromise their health by predisposing them to fetal hypoxia, increasing newborn mortality. Blood gas analysis to measure the main biomarkers associated with hypoxia evaluates the physiological and metabolic alterations derived from this state, and these could help identify if said markers respond to maternal or neonatal causes. This study aimed to assess the effect of the dam’s size, the birth order, and the presentation of blood gas alterations. Recognizing if these elements are intertwined may enhance newborns’ life expectancy by enabling the planning of a perinatal protocol to avoid serious metabolic consequences that are derived from prolonged hypoxia.

Abstract

In canines, size at birth is determined by the dam’s weight, which would probably affect the newborn’s viability due to litter size and birth order. Fetal hypoxia causes distress and acidemia. Identifying physiological blood alterations in the puppy during the first minute of life through the blood gas exchange of the umbilical cord could determine the puppy’s risk of suffering asphyxiation during labor. This study aimed to evaluate the effect of the birth order and dam’s size during spontaneous labor and the alterations during the first minute of life. The results indicate that the dam’s size and the birth order have considerable physiological and metabolic effects in the puppies, mainly in birth order 1 (BO1) in small-size dogs, while in the medium size, the last puppy presented more alterations, probably because of a prolonged whelping which could have fostered hypoxic processes and death. Likewise, with large-size dogs, intrapartum asphyxiation processes were registered during the first minute of life in any birth order.

Pathophysiology of Perinatal Asphyxia in Humans and Animal Models

Perinatal asphyxia is caused by lack of oxygen delivery (hypoxia) to end organs due to an hypoxemic or ischemic insult occurring in temporal proximity to labor (peripartum) or delivery (intrapartum). Hypoxic-ischemic encephalopathy is the clinical manifestation of hypoxic injury to the brain and is usually graded as mild, moderate, or severe. The search for useful biomarkers to precisely predict the severity of lesions in perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE) is a field of increasing interest. As pathophysiology is not fully comprehended, the gold standard for treatment remains an active area of research. Hypothermia has proven to be an effective neuroprotective strategy and has been implemented in clinical routine. Current studies are exploring various add-on therapies, including erythropoietin, xenon, topiramate, melatonin, and stem cells. This review aims to perform an updated integration of the pathophysiological processes after perinatal asphyxia in humans and animal models to allow us to answer some questions and provide an interim update on progress in this field.

Parturition in Mammals: Animal Models, Pain and Distress

Parturition is a complex physiological process and involves many hormonal, morphological, physiological, and behavioural changes. Labour is a crucial moment for numerous species and is usually the most painful experience in females. Contrary to the extensive research in humans, there are limited pain studies associated with the birth process in domestic animals. Nonetheless, awareness of parturition has increased among the public, owners, and the scientific community during recent years. Dystocia is a significant factor that increases the level of parturition pain. It is considered less common in polytocous species because newborns' number and small size might lead to the belief that the parturition process is less painful than in monotocous animal species and humans. This review aims to provide elements of the current knowledge about human labour pain (monotocous species), the relevant contribution of the rat model to human labour pain, and the current clinical and experimental knowledge of parturition pain mechanisms in domestic animals that support the fact that domestic polytocous species also experience pain. Moreover, both for women and domestic animal species, parturition's pain represents a potential welfare concern, and information on pain indicators and the appropriate analgesic therapy are discussed.

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.

An Experimental Model for Iron Deficiency Anemia in Sows and Offspring Induced by Blood Removal during Gestation

Anemia is a common condition in sow herds. We aimed to study the effects of severe iron deficiency during gestation on sow and piglet health outcomes with an experimental model for blood-removal-induced iron deficiency anemia. In total, 18 multiparous sows (8 in trial I and 10 in trial II) were allocated to either a blood removal group or a control group. Hematologic parameters were monitored at regular intervals and the tissue iron concentrations were measured for the sows and newborn piglets after farrowing. In trial I, the mean liver iron content was reduced to 46.7 µg/g in the blood removal sows compared to 252.6 µg/g in the controls (p < 0.001). In trial II, sows in the blood removal group had lower iron content in the liver (147.8 µg/g), kidney (46.3 µg/g) and spleen (326.5 µg/g) compared to the control sows (323.2 µg/g, 81.3 µg/g and 728.9 µg/g, respectively; p = 0.009, 0.016, 0.01, respectively). In trial I, piglets from sows in the blood removal group had significantly decreased hematocrit (Hct), red blood cells (RBC) and a tendency for reduced hemoglobin (Hb) compared to the control piglets. We established a blood removal model that resulted in mild- to severe degrees of sow anemia and reduced tissue iron stores at farrowing.

Dietary Yucca schidigera Extract Supplementation During Late Gestating and Lactating Sows Improves Animal Performance, Nutrient Digestibility, and Manure Ammonia Emission

This study was conducted to investigate the effect of dietary Yucca schidigera extract (YSE) supplementation to sow performance, nutrients digestibility and ammonia emission of manure. Total 80 sows were randomly divided into 4 groups and fed with either control, control + 0.06% YSE, control + 0.12% YSE or control + 0.24% YSE diet from day 80 of gestation to day 21 of lactation. The results showed that dietary YSE supplementation resulted in trends toward a reduced number of stillbirth piglets (P = 0.08), weak piglets (P = 0.06), pre-weanling mortality (P = 0.04) and diarrhea (P = 0.03), and improved apparent digestibility of dry matter (P = 0.04). Besides, YSE supplementation significantly increased catalase activity (P = 0.02) while decreasing malonaldehyde levels (P = 0.04) in sow blood. Furthermore, the loss of total nitrogen, urea nitrogen and ammonia nitrogen in sow manure were significantly reduced with supplementation of YSE. In summary, supplementation of YSE in sow diet during late gestation and lactation could improve sow and litter performance, nutrient digestibility, and reduce nitrogen loss in sow manure during storage.

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.

Effects of induction on the farrowing process and piglet blood parameters at the time of farrowing

Historically, sows have been induced to farrow using prostaglandin followed by an injection of oxytocin 24 h later. Benefits of induction can include decreased rate of stillbirths, dystocia, and postnatal mortality along with increasing the likelihood of farrowings being attended. Several studies have indicated that oxytocin administration may negatively impact fetal oxygen supply during parturition, potentially from umbilical cords breaking prior to birth, resulting in increased preweaning mortality. Therefore, the objective of this study was to determine if various induction protocols impact umbilical cord breakage and fetal blood parameters at birth. Fifty-eight primiparous and multiparous sows were assigned to one of three treatments: no induction (NO; n = 24) or 2 cc prostaglandin administered on day 114 of gestation followed by either 1 cc of oxytocin 24 h later (OXY24; n = 13) or 0.5 cc of oxytocin at 6 and 12 h after prostaglandin (OXY6; n = 21). Details of the farrowing process were recorded, and umbilical cord blood was collected from piglets at birth and evaluated on an iSTAT machine using an Abbott EC8+ test cartridge. There were no differences in total born, number born alive, stillborns, mummies, or assistance needed during farrowing. Induced sows were more likely to farrow by day 115 compared to naturally farrowing sows (P = 0.02). Sows in the OXY24 treatment tended to have longer farrowings when compared to both NO and OXY6 (4.8 vs. 3.6 vs. 3.9 h; P = 0.09). Colostrum from OXY6 sows tended to have a greater amount of lactose present than NO and OXY24 (P = 0.05). Colostrum from sows with longer gestation lengths had a higher percentage of fat (P = 0.03). Piglets born from NO sows had higher base excess, total carbon dioxide, and glucose, which suggests that these piglets had prolonged moments of asphyxiation (P < 0.01). OXY24 piglets had the lowest blood pH which is indicative of hypoxic birthing conditions (P < 0.01). Preweaning mortality was driven largely by a low birth weight coupled with low colostrum intake (P = 0.03). All piglets, regardless of treatment, displayed signs of stress during farrowing. Induction did not influence preweaning mortality but has the potential to decrease the incidence by increasing attended farrowings.

Intravenous infusion of glucose improved farrowing performance of hyperprolific crossbred sows

The sow at parturition is challenged with respect to energy status due to increases in energetic expenses associated with 1) nest building 2) uterine contractions, and 3) colostrum production. A previous study indicated that sows were depleted of glucogenic energy around farrowing. The aim was to investigate whether intravenous infusion of glucose from observed nest-building behavior to 24 h postpartum affected the farrowing kinetics and colostrum production in sows. Ten multiparous sows (DanBred landrace × DanBred Yorkshire) were fitted with a jugular vein catheter on each side (one for infusion and the other one for blood sampling). Sows were infused with either 0.9% saline (CON; n = 5) or 10% glucose (GLU; n = 5) solution at a constant rate of 125 mL/h. From day 108 of gestation, sows were fed once daily with 3.33 kg of a standard lactation diet. During farrowing, sows were monitored to register the onset of farrowing, time of birth, birth status (live or dead), sex, stillbirth rate (SR), and weight of newborn piglets. Farrowing assistance (FA) was provided when the birth interval exceeded 60 min. In late gestation, 1 mL of blood was collected every third hour for blood gas analysis and every sixth hour for harvesting plasma. During farrowing, 1 mL (for blood gas) and 9 mL of blood were collected at 0, 3, 6, 9, 12, 15, 18, 21, and 24 h in milk (HIM). Colostrum and milk samples were collected at 0, 6, 12, 18, 24, and 36 HIM and also at 3, 10, 17, and 24 d in milk. Compared with CON sows, GLU infusion decreased the SR (16.1% vs. 7.4%; P = 0.03), FA (21% vs. 9.0%; P = 0.01), and surprisingly also blood glucose at the onset of farrowing (5.53 vs. 5.09 mmol/L; P = 0.03), respectively. A tendency to higher plasma lactate at the onset of farrowing (P = 0.05) but decreased piglet mortality from 0 to 24 h (P = 0.06) was also found for GLU sows. No effects of treatment on farrowing duration or mean birth intervals were found. Lactate in whole blood (P = 0.003) and plasma (P = 0.002) was increased for GLU sows as compared with CON sows during the colostrum period. No effect of GLU infusion was seen on colostrum and milk composition and yield. The increase in lactate was most likely due to a shift toward a greater proportion of glucose oxidation and insufficient O2 supply to fuel uterine contractions. In conclusion, infusion of glucose reduced the frequency of SR and FA, and improved energy status of the sow which seems to be crucial to enhance total piglet survival.

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.

Handling Associated with Drenching Does Not Impact Survival and General Health of Low Birth Weight Piglets

The increase in litter sizes in recent years has resulted in more low birth weight (LBW) piglets, accompanied by a higher mortality. A potential intervention to overcome this is drenching bioactive substances. However, if the act of drenching provokes additional stress in LBW piglets, it might counteract the supplement's effect and be detrimental for the piglet's survival. To study the effect of the drenching act, piglets from 67 sows were weighed within 4 h after birth. The mean litter birth weight (MLBW) and standard deviation (SD) were calculated. LBW piglets (n = 76) were defined as weighing between (MLBW-1*SD) and (MLBW-2.5*SD). They were randomly allocated to two treatments: "sham" (conducting the act of drenching by inserting an empty 2.5 mL syringe in the mouth during 20 s, once a day, d1 till d7; n = 37) or "no treatment" (no handling; n = 39). On day 1, 3, 9, 24 and 38, piglets were weighed and scored for skin lesions. Blood samples were collected on day 9 and 38 and analyzed to determine glucose, non-esterified fatty acids (NEFA), urea, immunoglobulin G (IgG), insulin-like growth factor 1 (IGF-1) and a standard blood panel test. There was no difference between sham drenched and untreated piglets regarding any of the parameters. In conclusion, this study showed that drenching does not impose a significant risk to LBW piglets and can be applied safely during the first 7 days after birth.

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

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

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.

Supplying sows energy on the expected day of farrowing improves farrowing kinetics and newborn piglet performance in the first 24 h after birth

The farrowing process is one of the most energy-demanding activities for the modern hyperprolific sow. This study evaluated the effects of supply of energy on the expected date of farrowing on the farrowing kinetics and piglets' performance during the first 24 h after birth. A total of 80 sows were used. The sows and their respective litters were considered as the experimental unit. On the expected day of farrowing, the sows were allocated to one of the following groups: sows that did not have access to feed from farrowing induction until the end of the farrowing process (CON, n = 40); sows fed 500 g of energetic supplement, which consisted of 250 g of the basal lactation diet plus 250 g of cane sugar, 18 h after farrowing induction (SUP, n = 40). The farrowing duration, farrowing assistance, birth interval, number of total born, stillborn and mummified piglets were recorded for each sow. Piglets were weighed individually at birth and 24 h later. The interval from birth to first suckle was evaluated individually for each piglet in 16 randomly selected litters (eight litters per treatment group). Blood glucose concentrations of six sows were measured shortly after expulsion of the first piglet. Farrowing duration, farrowing assistance and stillborn rate tended to be greater (P = 0.06, P = 0.09 and P = 0.07, respectively) in sows from the CON group compared to sows from the SUP group. However, there was no difference (P > 0.05) between the groups for birth interval. Colostrum intake was greater (P < 0.05) for piglets from the SUP group compared to piglets from the CON group. Additionally, BW gain of the piglets suckling the SUP group was greater (P < 0.05) than those suckling the CON group at 24 h after birth. The blood glucose concentrations during the expulsive stage of farrowing were greater (P < 0.05) in the SUP group than for sows from the CON group. In conclusion, supplying modern hyperprolific sows energy on the expected day of farrowing is a valuable nutritional intervention to improve the farrowing kinetics and piglets' performance in early life.

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.

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.

Dietary supplementation with garcinol during late gestation and lactation facilitates acid-base balance and improves the performance of sows and newborn piglets1

The present study was conducted to evaluate the effects of dietary garcinol supplementation during late gestation (from the 90th day of pregnancy; day 90) and lactation on the acid-base balance of the umbilical cord blood and performance of sows and piglets. Sixty sows (Duroc × Yorkshire × Landrace; second- or third-parity; n = 20) were randomly divided into 3 gestation (day 90 of pregnancy) or lactation treatments, control diet (CON; basal diet), basal diet with 200 mg garcinol, and basal diet with 600 mg garcinol per kg of feed. The body weight (BW); backfat thickness and litter size of the sows; and birth weight, weaning weight, and mortality of piglets were recorded. Sows' blood and piglets' umbilical cord blood were collected for the measurements of hematological parameters and antioxidative and immune indexes, and acid-base balance parameters, respectively. The colostrum and milk and fecal samples of the sows were also collected for analysis of milk composition and apparent total tract nutrient digestibility. Garcinol had no effect on the BW and backfat thickness of the sows but significantly increased the birth weight and weaning weight of piglets (P < 0.05) and decreased the mortality (P < 0.05). Moreover, the white blood cell counts and neutrophil count, mean cell hemoglobin, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in the plasma of the sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group, whereas the malondialdehyde (MDA) content was decreased (P < 0.05). The garcinol treatment significantly increased the pH, HCO3- and base excess values (P < 0.05), whereas it decreased the pCO2 and lactate content (P < 0.05) in the umbilical blood. Dry matter (DM), ash, and ether extract in the colostrum were similar between groups (P > 0.05), whereas the garcinol significantly increased the crude protein (CP) in the milk. In addition, the content of immunoglobulin A (IgA) and immunoglobulin G (IgG) in the plasma of piglets and in colostrum and milk of sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group. The apparent total tract nutrient digestibility was similar between treatments. Collectively, this study indicates that sows fed with garcinol in late gestation and lactation showed improved maternal health and antioxidative status, milk protein content, acid-base balance in the umbilical cord blood, and growth performance in piglets, showing promise in natural plant extract nutrition for sows.

Effects of supplementing late-gestation sow diets with zinc on preweaning mortality of pigs under commercial rearing conditions

The objective of this experiment was to determine preweaning survival of pigs when sows were supplemented with 3 dietary levels of zinc (Zn) in late gestation. Gilts and sows (n = 339) were assigned to 1 of 3 dietary treatments based on parity. Dietary treatments were 1) Control—sows fed a corn–soybean meal-based diet containing 125 ppm total supplemental Zn supplied by ZnSO₄ (75 ppm Zn) and AvailaZn (50 ppm Zn, CON); 2) Intermediate—as Control + 240 ppm supplemental Zn as ZnSO₄ (INT); and 3) High—as Control + 470 ppm supplemental Zn as ZnSO₄ (HI). Final supplemental Zn concentrations of the 3 dietary treatments were 1) CON—125 ppm; 2) INT—365 ppm; and 3) HI—595 ppm. Sows received dietary treatments from about day 85 of gestation until farrowing. Individual piglet birth weights were recorded within 12 h of parturition. Instances of piglet mortality were recorded daily. The statistical model considered fixed effects of treatment and random effects of parity. Piglets from sows fed the INT diet had heavier (P < 0.05) birth weights than those fed CON (1.42 vs. 1.38 kg, respectively), while offspring from sows fed HI tended to have heavier (P < 0.10) birth weights (1.40 kg) than pigs from INT sows. Furthermore, incidence of low birth weight pigs was less (P < 0.05) for sows consuming INT compared with sows fed CON and HI. Despite differences in birth weight, there were no differences (P > 0.05) in total pigs born, born alive, or weaned, nor differences in individual piglet gain or weaning weight across treatments. Mortality of low birth weight pigs was lowest (P < 0.05) for offspring from sows fed HI (28.1%) compared with offspring from sows fed INT (36.1%) and CON (38.3%). Similarly, overall piglet mortality tended to decrease (P < 0.10) as dietary Zn content increased (CON: 15.0%, INT: 13.2%, and HI: 12.2%). A subset of pigs (n = 420, n = 140/treatment) were selected at weaning to evaluate effects of dietary treatment on postweaning performance. There were no significant effects of sow Zn supplementation on final body weight, days to market, or carcass characteristics of market pigs. Overall, effects of supplemental dietary Zn at 365 and 595 ppm in late gestation improved preweaning survival of low birth weight piglets and reduced overall preweaning mortality of piglets.

Stress during pregnancy affected neonatal outcomes and changed cortisol and leptin levels both in mothers and newborns

BACKGROUND

The present study aimed to determine the effect of perceived stress during pregnancy on neonatal outcomes and cortisol and leptin levels in mothers and their newborns.

METHODS

This longitudinal study was carried out on 110 pregnant women in Miandoab city, Iran. Mothers, who had singleton pregnancies and gestational age of 24 to 28 weeks, were included in the study. The participants were asked to fill out Cohen's Perceived Stress Scale (PSS). The mothers were then tracked in gestational ages of 28-32 weeks, 32-36 weeks, and the time of delivery. The maternal and umbilical cord blood samples were obtained during labor in order to measure leptin and cortisol levels.

RESULTS

Umbilical cortisol level was significantly higher in newborns who had meconium stained amniotic fluid than those who did not. Maternal blood leptin levels at delivery were significantly higher in the mothers whose neonates had respiratory distress, low birth weight, low head circumference, low Apgar score, and were premature than those whose neonates did not have such problems. The level of leptin in umbilical cord blood was significantly higher in neonates who had respiratory distress than those who did not. The results also showed a significant correlation between maternal cortisol levels and PSS during weeks 24-28 and the entire pregnancy. A significant relationship was observed between umbilical leptin and maternal leptin levels.

CONCLUSIONS

It can be concluded that stress during pregnancy is accompanied by fetal distress. The probable reason for newborns distress may be related to increased maternal leptin levels.

Caffeine supplementation at birth, but not 8 to 12 h post-birth, increased 24 h pre-weaning mortality in piglets

Pre-weaning mortality represents a major economic loss and welfare concern for the global pork industry. Caffeine administration prior to, or after, parturition positively affects metabolic parameters associated with survival in newborn animals. However, its effects on piglet viability and survival when administered within the first 24 h of life have not been evaluated. This study determined the effect of caffeine treatment during the 24 h postpartum period on piglet viability, growth and survival. Piglets received 30 or 0 mg of caffeine orally at birth or 8 to 12 h following birth and again at 24 h. Vitality, meconium staining and blood lactate were assessed at birth. Time to first reach the udder and suckle was recorded. Body weight and rectal temperature were measured at 10 min, 24 and 72 h after birth. A blood sample for analysis of serum immunoglobulin G was collected at 24 h, and BW and survival were monitored to 20 days of age. Caffeine had no effect on body temperature, blood glucose, serum immunoglobulin G concentration or weight (P > 0.05). However, when caffeine was administered at birth, it significantly increased 24 h mortality in piglets (P < 0.05). Piglet mortality between birth and weaning also tended to be higher for piglets receiving caffeine at birth (P = 0.063). These data demonstrate that caffeine administration to piglets at birth, but not 8 to 12 h after birth, impaired piglet survival. Further research into caffeine dosage and timing postpartum is required to establish its efficacy.

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.

Relation between Apgar scoring and physical parameters in 44 newborn Amiata donkey foals at birth

The assessment of the behavior and physiological parameters of neonatal foals is essential in the detection of early signs of illness. Modified Apgar scoring systems from human medicine exist and have been validated in foals as a guide for assessing neonatal viability after birth. This study evaluated the viability of 44 Amiata donkey foals at birth, by assessing the Apgar score and comparing the relationship between viability and various physical parameters. A total of 44 Amiata donkey foals and 27 jennies were enrolled in this study. An expert operator examined each foal within 5 min of birth. A complete physical examination was performed, along with an existing four-parameter Apgar score. The presence of the suckling reflex was evaluated. The interval time needed to acquire sternal recumbency and quadrupedal position, as well as nurse from the mare, were recorded. In addition, heart rate (HR), respiratory rate (RR), and rectal body temperature (BT) were measured. Results were expressed as median ± standard error, minimum and maximum values. The effects of the Apgar score on time to reach sternal position and quadrupedal standing, time to nurse from the mare, RR, HR, and BT were estimated along with the differences related to Apgar scoring and gender. Differences between female and male donkey foals regarding the time to acquire sternal position and quadrupedal standing, time to nurse from the mare, RR, HR, and BT were also assessed. Differences between female and male donkey foals regarding the Apgar score was evaluated using a chi-Square test. Finally, the reference values for Amiata donkeys were also calculated. Twenty/44 (45.4%) foals were colts and 24/44 (54.5%) were fillies born from 27 jennies. None of the foals showed an Apgar score lower than 6. Twenty-nine out of 44 foals showed an Apgar score of 8/8, 10/44 a score of 7/8, while 5 foals (11.3%) showed a score of 6/8. No differences between fillies and colts in relation to the Apgar score were obtained.

A randomised controlled trial investigating the effects of administering a non-steroidal anti-inflammatory drug to beef calves assisted at birth and risk factors associated with passive immunity, health, and growth

BACKGROUND

The objectives of this study were to investigate the impact of pain mitigation at birth to assisted beef calves and determine the risk factors associated with transfer of passive immunity (TPI), health, and growth.

METHODS

Two hundred and thirty cow-calf pairs requiring calving assistance were enrolled. Calves were randomised to receive meloxicam (0.5 mg/kg) or an equivalent volume of placebo subcutaneously at birth. Calf blood samples were collected between one and seven days of age to determine serum immunoglobulin (IgG) concentration. Colostrum intake, treatment for disease, mortality, and weaning weights were recorded. Multilevel linear or logistic regression models were used to determine the effects of meloxicam and to identify risk factors.

RESULTS

There was no effect of meloxicam on serum IgG concentrations, average daily gain (ADG), or risk of inadequate TPI (serum IgG concentration <24 g/l), treatment for disease, or mortality (P>0.05). Bottle or tube feeding calves were associated with decreased serum IgG concentrations (P=0.01) compared with nursing. Calves with an incomplete tongue withdrawal reflex had higher odds of being treated for disease compared with those with complete withdrawal (P=0.009). Being born meconium-stained and having decreased serum IgG concentrations were associated with an increased risk of mortality (P=0.03). Being born of a mature cow, having a higher birth weight, and increased serum IgG concentrations were associated with greater ADG to weaning (P<0.05).

CONCLUSION

Vigour assessment at birth along with good colostrum management may be important to improve TPI and health in high-risk calves such as those assisted at birth.

Prolonged second stage labour and consequences of hypoxia in the neonate: A review

Hypoxia due to dystocia and its repercussions are serious issues concerning the health of neonates. In order to gain a better understanding of the cause and especially the effects and potential long-term disorders, a critical analysis of peer-reviewed literature was made. As shown by many authors, initially the most devastating peripartal cause of ill health in neonates is associated with the serious effects of prolonged and severe acidosis. Other life threatening complications are related to disorders such as meconium aspiration syndrome (MAS), neonatal respiratory distress syndrome, hypoxic ischaemic encephalopathy and necrotising enterocolitis. Despite the astonishing ability of neonates to compensate mixed metabolic and respiratory acidosis with breathing onset directly postpartum, the longer second stage labour takes and the more extreme the acidosis is, the more detrimental its consequences. Lungs are especially vulnerable in this phase of life, aspired meconium can result in increased expression of pro-inflammatory chemotactic cytokines, phospholipase A2 and PGE2 levels , exacerbating inflammatory reactions of lung tissue and exerting a deleterious effect on alveolar cells. Neonates experiencing dystocia could greatly benefit from administration of buffering substances and non-steroidal anti-inflammatory drugs.

Attenuation of Acute Renal Injury After the Post-resuscitation Administration of Doxycycline in Surviving Newborn Piglets With Severe Hypoxia-Reoxygenation

Background: Asphyxiated neonates often have myocardial dysfunction and renal insufficiency. Previously we demonstrated that doxycycline improved cardio-renal function through matrix metalloproteinase (MMP)-2 inhibition in an acute swine model of neonatal hypoxia-reoxygenation. The prolonged cardio-renal protective effects of doxycycline in neonates still remained unknown. We therefore hypothesized that the protective effects of doxycycline persisted in surviving subjects. Methods: Newborn piglets were instrumented and subjected to 1 h of hypoxia followed by reoxygenation with 21-25% oxygen and observed for 4 days. Intravenous doxycycline (30 mg/kg) or normal saline (1 mL, saline-control group) was given at 5 min of reoxygenation (n = 8/group) in a randomized, blinded fashion. Sham-operated piglets (n = 5) received no hypoxia-reoxygenation. At 96 h after reoxygenation, the left ventricular function was assessed by Millar® catheter. Renal injury was investigated by measuring plasma creatinine, urinary N-acetyl-D-glucosaminidase activity, renal tissue lactate and MMP-2 activity. Results: Both hypoxia-reoxygenation groups had similar hypoxic stress with severe lactate acidosis, and hemodynamic recovery. Doxycycline-treated piglets had higher urine output with lower urine N-acetyl-D-glucosaminidase, plasma creatinine, and renal MMP-2 activity (vs. saline-controls; all p < 0.05). These markers were all negatively correlated with urine output. Conclusions: In newborn piglets surviving hypoxia-reoxygenation, we observed a weak but significant and persistent attenuation of renal injury and improved recovery with the post-resuscitation administration of doxycycline.

Neurophysiological development of newborn pigs: effect of the sow

The objective of the present study was to determine the effect of sow parity on neonatal piglet health and vitality at birth. We evaluated 1505 neonate piglets, which were born of York–Landrace sows with the following parity distribution: primiparous (n = 202), second (n = 207), third (n = 211), fourth (n = 222), fifth (n = 225), sixth (n = 218) and seventh parity (n = 220). Piglets born to primiparous and seventh-parity sows had the lowest and highest birthweights respectively, and showed the most marked imbalances in blood gas exchanges, acid–base balance and energy profiles, as well as the highest percentage of severe meconium staining of the skin and the lowest vitality scores (P &lt; 0.05). In contrast, the neonates from the fourth-parity sows had the highest vitality scores, required less time to reach the mother’s teat, and had the highest percentage of adhered umbilical cords and newborns with dyspnoea, apnoea and abnormal heartbeat (P &lt; 0.05). The results of this study suggest that during eutocic farrowings, the sow’s parity number has the following effects on newborn piglets: reduced vigour and longer latencies to begin breathing, stand and take the teat. These effects are due to the presence of imbalances in gas exchanges, the acid–base balance and energy profiles that occurred when the mother was a primiparous or older sow. These signs indicate that the newborn piglet survived a process of intrapartum asphyxia.