Management practices to optimize the parturition process in the hyperprolific sow

Seasonal effect on farrowing duration in sows within a temporarily confined farrowing system under tropical climates

Global warming negatively impacts sow reproduction, leading to health and welfare challenges and economic losses in the swine industry. The present study was a retrospective observational study that examined the effects of season, temperature, and humidity during parturition on farrowing duration and piglet birth intervals in sows housed in a temporarily confined system under a tropical climate. Data from 10039 farrowings of Landrace × Yorkshire sows (January-December 2023) included parity, farrowing date, parturition onset, total number of piglets born per litter (TB), number of piglets born alive per litter (BA), percentage of stillbirths (SB) and mummified fetuses (MF), and farrowing house temperature and humidity. The temperature-humidity index (THI) and averages for the 7 days before and on the day of farrowing were also calculated. The association between these parameters and the farrowing duration of sows was analyzed. Additionally, the proportion of sows experiencing prolonged farrowing (i.e., >300 min) associated with different factors were evaluated. On average, TB, BA, SB, and MF were 13.9 ± 3.6, 12.4 ± 3.9, 5.7 %, and 5.8 %, respectively. The average farrowing duration was 228.9 ± 194.8 min, with 21.1 % of sows experiencing prolonged farrowing (≥300 min). Dystocia occurred in 5.1 % of farrowings, and the average birth interval for each piglet was 18.7 ± 26.7 min. During the 7-day period before parturition, sows were exposed to an average barn temperature of 26.7 ± 1.9 °C, with daily minimum and maximum temperatures of 25.1 ± 2.2 °C and 29.9 ± 1.0 °C, respectively. The average barn humidity during the 7-day period before parturition was 80.2 ± 5.8 %, with values ranging from 62.1 % to 90.1 %. The farrowing duration of sows was positively correlated with average temperature (r = 0.044, P < 0.001), maximum temperature (r = 0.051, P < 0.001) and minimum temperature (r = 0.057, P < 0.001) during the 7-day period before farrowing. Moreover, every 10 % increase in relative humidity during the 7-day period before parturition caused an increase in the farrowing duration of 21 min (farrowing duration = 61.0 + (2.1 × humidity), P < 0.001). Every 1 °C increase in the average temperature during the 7-day period before parturition caused an increase in the farrowing duration of 4.3 min (farrowing duration = 113.49 + (4.3 × temperature), P < 0.001). In conclusion, 21.1 % of sows in tropical climates experience prolonged farrowing durations. Elevated temperatures, humidity, and THI during the 7 days prior to farrowing or on the day of farrowing significantly extended farrowing durations and birth intervals in sows. These findings highlight the critical importance of maintaining temperature and humidity levels as close as possible to the optimal range for lactating sows (i.e., 12-22 °C), particularly in tropical regions.

Influence of the intrauterine application of a phytotherapeutic agent and other parameters on the uterine involution of sows in a free farrowing system

Endometritis and postpartum dysgalactiae syndrome are common postpartum disorders in sows revealing antimicrobial treatment. This study evaluated the influence of the intrauterine application of a phytotherapeutic agent (EucaComp©) after farrowing containing essences of marjoram, marigold, melissa and eucalyptus and other sow-related parameters on the uterine involution. In total, 150 Landrace x Large white sows (parity 1-9) were divided randomly into three groups (no intervention (Control), 300 ml sodium chloride (Placebo) and 300 ml of phytotherapeutic agent (Phytotherapeutic)). Several sow-related parameters were assessed such as, parity, Body Condition Score (1-5), birth induction (Yes/No), and feed intake. On days 2, 3, 5, 7 and 21 postpartum, uterine involution was assessed by measuring the diameter on three locations of the uterine horns using ultrasound. The mean uterine diameter changed from 36.4 ± 6.5 mm on day 2-20.4 ± 5.9 mm on day 7 (reduction of 43.81 %) and 14.0 ± 3.2 mm on day 21 (reduction of 61.15 %). No significant differences between the groups and the regression of uterine involution were detected. However, birth induction had a positive effect on uterine involution, increasing the relative uterine involution by 8 %, whereas lack of appetite postpartum, lead to a decrease of 7 % until day 7. An suboptimal BCS (≤2; ≥4) and a parity ≥2 lead to a reduction of uterine involution regression on day 21 by 7 and 5 %. In conclusion, a single postpartal intrauterine application of a phytotherapeutic agent demonstrated no significant impact on uterine involution, while sow-specific and management factors remained pivotal.

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.

The parturition-relevant hormone profile in hyper-prolific sows under different housing conditions

Aim was to characterize birth-relevant hormone profiles of reproductively productive hybrid sows in the peripartum period. It was examined whether there are deviations in the hormone profile depending on the birth process (eutocia:dystocia) and the type of housing (box stall BS vs. farrowing pen FP vs. group housing GH).A total of 40 healthy, heavily pregnant hybrid sows (German Landrace x Large White) with a gestation number≥ 2 were available. The distribution between the housing types was: BS n=18, FP n=15, GH n=7. All births occurred after the biologically completed gestation period. Blood samples were taken via indwelling catheters (113th day ante partum to 4th day post partum). Progesterone (P4), oestradiol (E2), prostaglandin F2α and its metabolites (PGFM), relaxin, oxytocin, cortisol, adrenaline and noradrenaline were determined.The ratio of eutocia:dystocia was 15:25. Dystocia occurred regardless of type of housing. The only reason for dystocia was a weak labor (>60 min). The litter size was 17.73± 3.85 piglets. Differences in the hormone profiles between eutocia and dystocia were as follows: P4 tended to be higher in dystocia p=0.0776; oxytocin higher in eutocia (not significant), 12.5% of sows permanently with hypoxytocinemia; cortisol p=0.0503; noradrenaline p=0.0098. The type of housing had the following influence on the hormone profile: P4 p=0.046; E2 p=0.0009; PGFM p=0.0108; relaxin p=0.0022; noradrenaline p=0.0078.The parturition-relevant hormones are related to the parturition and to the type of housing during birth. The hormone profiles obtained could be of use in the discussion about the animal welfare-oriented housing system in the peripartum phase in pigs. The proportion of sows of the hyperproliferative line studied with permanent hypoxytocinaemia in stage II of parturition is remarkable. The ratio of eutocia:dystocia is unevenly distributed. Dystocia occurred regardless of the type of housing.

Prediction of Sow Farrowing Onset Time Using Activity Time Series Extracted by Optical Flow Estimation

Sow farrowing is a critical stage in pig farming, and predicting its onset can improve sow health and piglet survival. This study proposes a method based on optical flow estimation and time-series forecasting to predict sow farrowing onset. The RAFT optical flow algorithm is applied to visible-light videos of sows in late pregnancy to extract activity levels and generate time-series data. The reliability of the activity extraction algorithm is validated through correlation and trend analysis, showing strong inter-sow correlations with an average Pearson coefficient of 0.819. An in-depth analysis of sow_16 reveals a significant increase in activity 24 h before farrowing. Using these data, the CLA-PTNet model, incorporating CNN, LSTM, and attention mechanisms, is developed for continuous farrowing onset prediction. Experimental results demonstrate high predictive accuracy, with average MAE, RMSE, and R2 values of 5.42 min, 5.97 min, and 0.99, respectively, across four test sows. The method effectively captures activity pattern changes before farrowing, enabling precise predictions. This study offers an innovative, non-invasive solution for predicting sow farrowing onset, with significant application potential in farming practices.

Calcium chloride supplementation in sows: Enhancing farrowing efficiency and piglet viability during transition period

High-prolific sows have a high incidence of stillbirth and asphyxiated piglets due to calcium deficiencies. Calcium is important for enhancing farrowing efficacy and colostrum production. Calcium chloride (CaCl2), an acidogenic compound that lowers dietary cation-anion difference (DCAD), promotes calcium mobilization, thereby mitigating the risk of calcium deficiency. The objective of this study was to determine the effects of CaCl2 supplementation in sows during the transition period in working and non-working hours on sow performances, colostrum quantity and quality, urine pH, serum total calcium, and piglet characteristics. A total of 58 Landrace × Yorkshire crossbred sows and 382 piglets from a commercial swine farm in Thailand were included in the study. These sows were classified into two groups. Control (n = 29) were fed a standard lactation diet without a supplement and CaCl2 (n = 29) received the same quantity of standard lactation diet with 25 g/day of CaCl2 from day 109 of gestation until 7 days after farrowing (13.8 ± 0.3 days). The sow performances and farrowing time classified as either during working hours (WH) or non-working hours (NWH) were recorded. The piglet characteristics were classified based on birth order: i.e., 1-7 (n = 182) and ≥8 (n = 200). On average, the total number of piglets born per litter (TB) and the number of piglets born alive per litter (BA) were 15.0 ± 3.2 and 13.5 ± 2.9 piglets/litter, respectively. During NWH, CaCl2 group had a lower percentage of stillborn piglets per litter (SB) than Control group (5.5 ± 2.0 % vs. 13.9 ± 2.1 %, P = 0.030). While no difference was observed during WH (4.9 ± 2.4 % vs. 3.8 ± 2.2 %, P = 0.988). After supplementation with CaCl2 for 4 days, CaCl2 group had a lower urine pH than Control group (5.2 ± 0.1 vs. 6.3 ± 0.1, P < 0.001) but did not differ in the serum total calcium and colostrum quantity and quality (P > 0.05). The piglets in CaCl2 group required less farrowing assistance than those in Control group, particularly among piglets with birth order 1-7 (17.9 ± 5.7 % vs. 33.9 ± 5.3 %, P = 0.042). The incidence of broken umbilical cord was also lower in CaCl2 than in Control groups (P < 0.001), with a reduction in birth order 1-7 (30.1 ± 5.8 % vs. 61.1 ± 5.5 %, P < 0.001) and birth order ≥8 (48.2 ± 6.0 % vs. 65.4 ± 5.4 %, P = 0.034). Similarly, the incidence of meconium staining was lower in CaCl2 than in Control groups (P < 0.001), with a reduction in birth order 1-7 (28.9 ± 6.7 % vs. 70.2 ± 6.2 %, P < 0.001) and birth order ≥8 (63.4 ± 6.8 % vs. 89.2 ± 6.2 %, P = 0.005). In conclusion, CaCl2 supplementation in sows during the transition period significantly reduces SB, particularly during NWH and improves piglet characteristics at birth.

Colostrum intake and neonatal characteristics in piglets experiencing varying lengths of expulsion phase

The objective of this study was to investigate how the cumulative expulsion interval, litter size, and birth order influence the characteristics of newborn piglets from hyperprolific sows, as well as their intake of colostrum. Analysis was conducted on the temporal aspects of parturition in 254 sows, including 3920 piglets. Newborn piglet characteristics examined encompassed delivery time, birth order, birth status, umbilical cord rupture, meconium staining, delivery ease, birth weight, blood oxygen saturation, and heart rate. From the raw data, colostrum intake, birth interval, and cumulative birth interval of each piglet were computed. Piglets were sorted based on the cumulative expulsion interval into nine categories: 0-30, 31-60, 61-90, 91-120, 121-150, 151-180, 181-210, 211-240, and >240 min. Litter sizes were categorized into three groups: 10-13, 14-17, and ≥18 piglets per litter. The birth-order ranking referred to the piglet's position within a litter and was categorized into four quartiles: 1, 2, 3, and 4. On average, the expulsion interval, cumulative expulsion interval, and colostrum consumption were 14.8 ± 21.8 min, 138.6 ± 155.7 min, and 407.6 ± 162.1 g, respectively. In litters with ≥18 piglets, the percentage of piglets with inadequate colostrum intake (<300 g) was higher compared to litters with 10-13 piglets (33.1 % vs. 12.9 %, P < 0.001) and 14-17 piglets (23.9 %, P < 0.001). The occurrence of stillbirths in the fourth quartile of the litter was higher than in the first (16.0 % vs. 2.2 %, P < 0.001), second (4.0 %, P < 0.001), and third (7.8 %, P < 0.001) quartiles. Among litters with ≥18 piglets, those born in the third quartile exhibited lower colostrum consumption compared to those born in the first quartile (346.0 ± 9.9 vs. 391.4 ± 8.6 g, P = 0.028). Colostrum intake decreased with longer cumulative expulsion intervals, evident from a notable decline starting at 90 min post-farrowing compared to piglets born within the first 30 min (P = 0.004). Interestingly, colostrum consumption exhibited a negative correlation with the cumulative expulsion interval (P < 0.001), but not with individual piglet expulsion intervals (P = 0.460). Piglets born with meconium staining were most prevalent among those with a cumulative expulsion interval of >240 min. In summary, both the cumulative expulsion interval and birth-order ranking significantly impact the physiological characteristics of newborn piglets and their colostrum intake. Colostrum consumption decreases and newborn piglet characteristics change with higher cumulative expulsion intervals. Identifying piglets at high risk of hypoxia and implementing appropriate treatments and management strategies within an optimal timeframe could aid pig producers in reducing pre-weaning mortality among piglets born to hyperprolific sows.

An Investigation of Parturient Ocular Appearance in Sows

Protocols that enable prompt identification of sows in need of assistance during farrowing are important for optimal production outcomes. Change in the colour and appearance of the sclera of the eye can indicate increased stress. This warrants investigation into its use for the identification of sows in need of assistance at the time of parturition. To this end, a three-level ocular scoring system for the pig was devised and subsequently used in a preliminary investigation into the relationship between farrowing kinetics and visual changes in the sclera at farrowing. Data were collected and analysed from twenty randomly selected Large White × Landrace crossbred sows during farrowing. It was determined that sows with a severe ocular score were more likely to experience a prolonged farrowing duration (p = 0.013) and incur increased parturient straining of either total straining time (p = 0.011) or straining per piglet (p = 0.025). There was a significant association between ocular score and litter size (p = 0.043). Ocular score was not associated with sow parity (p = 0.728) and inter-piglet interval (p = 0.075). The proposed three-level scoring system successfully identified sows experiencing an abnormal parturition as defined by a prolonged farrowing duration and increased straining time. Findings from this study suggest the potential application of this simple ocular scoring tool for identifying sows experiencing an abnormal farrowing via in-person application or integration into remote monitoring systems in the future.

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.

Effect of Andrographis paniculata supplementation during the transition period on colostrum yield, immunoglobulin G, and postpartum complications in multiparous sows during tropical summer

OBJECTIVE

This study evaluated the effect of Andrographis paniculata (A. paniculata) supplementation in sow diets before and after farrowing on the sow and piglets' performances during early postpartum period and on sows' backfat and longissimus muscle losses during lactation.

METHODS

Seventy Landrace×Yorkshire sows and their offspring (1,186 piglets) were distributed into three groups: control (n = 31), treatment-250 (n = 18), and treatment-1000 (n = 21). From 110.2±0.7 days of gestation until farrowing (5.8 days) and throughout the lactation period (25.2 days), sows in the control group were given the conventional lactation diet, while sows in the treatment-250 and treatment-1000 groups received supplements of 250 ppm and 1,000 ppm of A. paniculata, respectively.

RESULTS

In sows with parity 3-5, piglets from the treatment-1000 group had higher colostrum intake than the control and treatment-250 groups (p<0.05), but not in sows with parity 6-9. Colostrum immunoglobulin G (IgG) increased in treated sows versus controls for parity 6-9 (p<0.05), but was consistent for parity 3-5. Piglet performance until day 3 postnatal was similar across groups (p>0.05). Treatment-250 sows had higher feed intake post-farrowing than treatment-1000 sows (p<0.05). Longissimus loss was less in both treatment groups than control (p<0.05), but backfat loss was similar across groups (p>0.05). Post-partum complications were consistent across groups (p>0.05). Farrowing duration and piglet birth intervals in sows with parity 6-9 were prolonged in the treatment-1000 group.

CONCLUSION

Supplementing with 1,000 ppm A. paniculata for 5.8 days pre-farrowing and 25.2 days post-farrowing enhanced sow colostrum IgG and piglet colostrum intake, while also reducing longissimus loss in sows. However, for sows of parity 6-9, this supplementation led to prolonged farrowing, increased intervals between piglet births, increased stillbirth, and reduced piglet birth weight. These effects should be considered when using A. paniculata supplementation.

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

BACKGROUND

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

RESULTS

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

CONCLUSIONS

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

The impact of the interval between the last meal and the onset of farrowing on the duration of farrowing, stillbirth rates, and colostrum production in highly productive sows in a tropical climate

The present study investigated impact of the interval between the last meal and the onset of farrowing on the duration of farrowing, stillbirth rates, and colostrum production in highly productive sows in a tropical climate. The study involved a total of 92 Danish Landrace x Yorkshire sows (herd A) and 114 French Landrace × Yorkshire sows (herd B). In herd B, a total of 61 sows had their blood samples collected within 1 hr after the onset of farrowing to evaluate their blood glucose levels. The interval between the last meal and the onset of farrowing averaged 5.9 ± 4.5 and 5.4 ± 4.1 hr in herds A and B, respectively. Neither the duration of farrowing nor the occurrence of stillborn piglets in both herds was affected by the time gap between the last meal and the onset of farrowing. At the onset of farrowing, the average blood glucose level in sows was 77.1 ± 19.3 mg/dL, with a range of 27 to 115 mg/dL. There was a positive correlation observed between the blood glucose concentration and the colostrum yield of the sows (r=0.261, P=0.042). In conclusion, the time interval between the last meal and the onset of farrowing did not have any impact on the farrowing performance of sows. However, a higher concentration of blood glucose at the onset of farrowing was associated with an improvement in the colostrum yield of the sows.

Influence of prepartum feed levels on colostrum production and farrowing performance in highly prolific sows in a tropical environment

Currently, there is a lack of data on the effects of altering feed levels on sow performance and piglet characteristics during the transition period in tropical environments. The present study determined the effect of sow feed levels during the transition period on colostrum yield, colostrum immunoglobulin (Ig) G, colostrum intake of piglets, farrowing duration, proportion of stillborn piglets per litter (SB) and the incidence of farrowing assistance in highly prolific sows. A total of 114 Landrace × Yorkshire crossbred sows and their offspring (n = 2 072) were included in the experiment. Sows were assigned to different feed supply levels from entry to farrowing at 110 days of gestation until farrowing based on their parity number. Three feed-level groups were the control group who received 3.0 kg/day of lactation feed (n = 40), treatment 1 group who received 3.6 kg/day of gestation feed (n = 39) and treatment 2 group who received 4.0 kg/day of lactation feed (n = 35). Colostrum samples (5 ml) were obtained from the sows within 3 h after the onset of farrowing for IgG assay. Piglets were weighed immediately after birth and then again 17-24 h later to estimate their colostrum intake. Colostrum yield was determined by aggregating the colostrum intake of piglets within the litter. The total number of piglets born, SB and farrowing duration were 18.2 ± 3.8, 7.5% and 259.1 ± 138.1 min, respectively. Among these sows, 28.9% experienced a farrowing duration exceeding 300 min and 50.9% required assistance during farrowing. Interestingly, piglets in the treatment 2 group demonstrated a greater colostrum intake (403.1 ± 14.9 g) compared to the control group (360.6 ± 15.1 g, P = 0.046) and the treatment 1 group (361.0 ± 12.9 g, P = 0.033). On average, colostrum yield of sows in the treatment 2 group tended to be higher than in the control group (+0.5 kg, P = 0.081), but did not differ from the treatment 1 group (+0.3 kg, P = 0.191). No significant differences in farrowing duration, SB, farrowing assistance, or colostrum IgG concentration were found across various feed-level groups (P > 0.05). In conclusion, the study showed that raising lactation feed by 1.0 kg/day prefarrowing increased piglet colostrum intake and tended to boost sow colostrum production, without significantly affecting farrowing duration, stillbirth rates, or need for assistance.

Preweaning piglet survival on commercial farms

Preweaning piglet mortality (PWM), a trait highly related to litter size, is one of the main concerns associated with productive efficiency and animal welfare in commercial pig farms. The objectives of this work were to study piglet survival at the farm level, to establish a survival rate (SR) as a target indicator to be improved, and to model it based on other reproductive parameters. Analyzed data corresponded to 580 Spanish commercial farms with a total inventory of 809,768 sows. These farms showed a mean SR of 85.70% piglets born alive (BA), which decreased to 81.81% when total piglets born (TB) were considered. The SR was strongly associated with prolificacy (P < 0.01), the parities with the highest prolificacy being those that had the lowest SR. Thus, the highest correlations were for the SR of piglets BA in the third and fourth parities (r = -0.460 and r = -0.452, respectively, P < 0.01), and for the SR of piglets TB in the fourth parity (r = -0.546, P < 0.01), which was the one with the highest prolificacy. The values corresponding to the quartile of farms with the highest SR within the most productive farms were established as targets to be improved, which were ≥88.5% of piglets BA and 83.2% of piglets TB. Nevertheless, the direct associations shown between the piglet's survival and prolificacy and other productive factors, such as the age of piglets at weaning, the farrowings per sow and year and the farrowing interval, suggest the convenience of modeling the risk of PWM on farms to have its own target of survival index to be improved.

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.

Factors associated with farrowing assistance in hyperprolific sows

OBJECTIVE

The present study was performed to determine risk factors associated with the frequency of farrowing assistance in hyperprolific sows in a tropical environment and to investigate the impacts of farrowing assistance on piglet colostrum consumption and sow colostrum yield.

METHODS

Farrowing data from 352 Landrace×Yorkshire crossbred sows and 5,554 piglets in five commercial swine herds in Thailand were investigated. The sows were classified according to parity numbers: 1 (n = 72), 2 to 4 (n = 128), 5 to 6 (n = 84), and ≥7 (n = 68) and the total number of piglets born per litter (TB): 10 to 13 (n = 90), 14 to 16 (n = 117), and ≥17 (n = 145). The incidence of farrowing assistance and associated parameters were investigated.

RESULTS

The TB and farrowing duration averaged 15.8±0.2 and 279.9±11.2 min, respectively. The percentage of sows that required farrowing assistance was 29.8% and varied among herds from 5.7% to 53.3% (p<0.001). The percentage of piglets born after birth assistance using manual intervention was 8.4%. Sows with parity numbers 1 and 2 to 4 had a lower frequency of farrowing assistance than sows with parity numbers ≥7 (p<0.01). The colostrum yield of sows that required farrowing assistance did not differ from sows that farrowed without assistance (5.3±0.2 and 5.1±0.1 kg; p = 0.288); however, the colostrum consumption of piglets born from sows that required farrowing assistance was lower than those born from sows that farrowed without assistance (302.2±15.7 and 354.2±5.6 g; p<0.001). Blood oxygen saturation of the piglets born after birth assistance tended to be lower than the piglets that farrowed without birth assistance (87.8%±1.3% vs 90.4%±0.4%; p = 0.054).

CONCLUSION

The frequency of farrowing assistance in sows varied among herds and was influenced by parity number. The piglets born after receiving birth assistance should receive special care to improve their blood oxygen saturation and enhance colostrum intake.

Bump Feeding Improves Sow Reproductive Performance, Milk Yield, Piglet Birth Weight, and Farrowing Behavior

The late gestation period is crucial for fetal growth and development, impacting swine enterprises' profitability. Various nutritional strategies have been explored to enhance reproductive performance in sows, but findings regarding birth weight and litter size have been inconsistent. This study investigated the effects of increased feeding allowance during the late gestation period on the reproductive performance and farrowing behavior of primiparous and multiparous sows. A total of 28 sows (Landrace × Yorkshire) were used in this experiment, and fed 2.50 kg/d or 3.50 kg/d from 84 days of gestation until farrowing. Farrowing behavior was monitored using a DeepEyesTM M3SEN camera. The data were analyzed using the 2 × 2 factorial within Statistical Analysis System (SAS, 2011, Version 9.3) software. The results indicated that regardless of the parity number, sows fed a high diet exhibited a numerical increase in the total number of born piglets and a significant increase in milk yield (p = 0.014) and piglet birthweight (p = 0.023). Backfat thickness loss was significantly higher in sows with a 2.50 kg feeding allowance (p = 0.022), and the total number of piglets born, live births, and litter size were numerically higher in sows fed 3.50 kg per day. Moreover, stillborn piglets, mortality rate, and re-estrus days were numerically lower in sows with a high feeding allowance. The diet and parity did not individually affect the average duration of farrowing and farrowing intervals. However, the duration of postural changes in sows after farrowing was significantly reduced (p = 0.012). The principal component analysis revealed 81.40% and 80.70% differences upon partial least-squares discriminant analysis. Therefore, increasing feeding allowance during the late gestation period, regardless of parity, could positively influence sows' reproductive performance and piglets' growth performance during the lactation phase.

Effect of Immunocastration on Culled Sows-A Preliminary Study on Reproductive Tract, Carcass Traits, and Meat Quality

The Bísaro pig is a Portuguese autochthonous breed greatly appreciated for its meat quality and is mainly reared outdoors. Immunocastration could be a solution to avoid undesirable pregnancies and boar taint in cull sows. The present study tested three immunocastration protocols (with Improvac®) according to their reproductive cycle. The first inoculation was performed two weeks after farrowing (IM1, n = 5), at the beginning of estrus (IM2, n = 5), and one week after the end of estrus (IM3, n = 5), followed by a second administration four weeks apart. A control group (C, n = 5) was also included in the same housing conditions. The sample collection included the reproductive tract for morphometric evaluation, neck fat for the quantification of boar taint compounds, and a portion of the Longissimus thoracis et lumborum for meat quality trait assessment. The reproductive tracts from intact sows (C) were significantly heavier compared to the immunocastrated groups (p < 0.05) (1.403 kg C to 0.508 kg IM1, 0.590 kg IM2, and 0.599 kg IM3), suggesting the regression of the reproductive tract to nonstimulated conditions due to immunization against GnRH. The IM1 group exhibited significantly smaller reproductive tract measurements compared to group C for most of the evaluated segments (p < 0.05). No marked differences were observed in the meat quality traits. Therefore, immunocastration can be used in culling sows to avoid ovarian activity, and it is not detrimental to pork quality traits.

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.

Preweaning performance in intrauterine growth-restricted piglets: Characteristics and interventions

Intrauterine growth restriction (IUGR) is frequently observed in pig production, especially when using highly prolific sows. IUGR piglets are born with low body weight and shape indicative of differences in organ growth. Insufficient uteroplacental nutrient transfer to the fetuses is the leading cause of growth restriction in the pig. Supplementing the sow's gestation diet with arginine and/or glutamine improves placenta growth and functionality and consequently is able to reduce IUGR incidence. IUGR piglets are at higher risk of dying preweaning and face higher morbidity than their normal-weight littermates. A high level of surveillance during farrowing and individual nutrient supplementation can reduce the mortality rates. Still, these do not reverse the long-term consequences of IUGR, which are induced by persistent structural deficits in different organs. Dietary interventions peri-weaning can optimize performance but these are less effective in combating the metabolic changes that occurred in IUGR, which affect reproductive performance later in life. IUGR piglets share many similarities with IUGR infants, such as a poorer outcome of males. Using the IUGR piglet as an animal model to further explore the structural and molecular basis of the long-term consequences of IUGR and the potential sex bias could aid in fully understanding the impact of prenatal undernutrition and finding solutions for both species and sexes.

One Health challenges for pig reproduction

The current state of the world challenges pig reproduction as an important part of One Health, which involves interrelationships between animal, human and environmental health. The One Health concept underlines a comparative aspect in reproductive physiology and disease occurrence, bridging knowledge from one species to another. Seasonal changes in the environment affect pig reproduction and climate change may further strengthen those effects. Endocrine-disrupting chemicals (EDCs), and specifically phthalates and heavy metals, interfere with endocrine function, and thereby sexual behavior, fertilization capacity and steroidogenesis. Reproductive infections and extended semen storage are important indications for antimicrobial use. Innovative solutions are needed to explore alternatives to antimicrobials. Efforts to ensure reproductive efficiency have prolonged farrowing as litter size has doubled over the past three decades, compromising immune transfer and welfare. Physiological, metabolic and programming related events around parturition are key areas for future One Health research in pig reproduction. In conclusion, climate change challenges reproductive management and breeding. More resilient pigs that can tolerate harsh environment but maintain high reproductive performance are needed. EDCs continue to grow as an environmental challenge for reproductive management and alternatives to antibiotics will be required.

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

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

Managing Reproduction in Hyperprolific Sow Herds

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

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.

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.

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.

Factors Associated with Farrowing Duration in Hyperprolific Sows in a Free Farrowing System under Tropical Conditions

The ongoing selection for increased litter size has had significant impacts on sow husbandry practice. The present study investigated factors associated with farrowing duration and the proportion of sows that had prolonged farrowing in modern hyperprolific sows kept in a free farrowing system in a tropical environment. Farrowing data from 2493 Landrace x Yorkshire cross-bred sows in a commercial swine herd in Thailand were included in the study. The time of farrowing, parity number, litter size, and the birth status of each piglet were recorded. Farrowing duration was analysed using multiple analyses of variance. Total number of piglets born per litter (TB), parity, and time onset of farrowing were included in the statistical models. On average, TB, piglets born alive, and farrowing duration were 13.7, 12.1, and 221.0 min, respectively. Of these sows, 26.4% had TB ≥ 16 and 21.7% had a prolonged farrowing duration (≥300 min). Farrowing duration was positively correlated with TB (r = 0.141, p < 0.001), percentage of stillborn (SB) piglets per litter (r = 0.259, p < 0.001), percentage of mummified foetuses (MF) per litter (r = 0.049, p = 0.015), piglet birth weight (r = 0.068, p < 0.001), and litter birth weight (r = 0.041, p = 0.043). The proportion of SB per litter was higher and piglet birth weight lower in litters that had ≥16 TB than those with 8−12 TB (p < 0.05). The farrowing duration of sows with parity numbers 5−7 (247.7 ± 5.1 min) and 8−10 (237.1 ± 5.1 min) was longer than that of sows with parity numbers 1 (188.3 ± 5.2 min) and 2−4 (214.3 ± 3.9 min) (p < 0.05). Sows that had started farrowing during working hours had longer farrowing durations (229.3 ± 3.6 min) than those that had started farrowing during non-working hours (217.6 ± 3.4 min, p = 0.017). In multiparous sows, the duration of farrowing was positively correlated with the maximum temperature (r = 0.056, p = 0.012) and the maximum temperature−humidity index (r = 0.059, p = 0.008) in the 7 days before farrowing. The present data confirm that TB, sow parity, and time of onset of farrowing are significant risk factors for a prolonged farrowing.

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.

Defining the Effect of Oxytocin Use in Farrowing Sows on Stillbirth Rate: A Systematic Review with a Meta-Analysis

The objective of this systematic review and meta-analysis was to identify the benefits and possible adverse side effects of oxytocin use during farrowing. Randomized controlled trials that were published in English within the last 50 years were eligible for inclusion. Eligible research needed to contain the PICO elements: population (P)-sows at farrowing; intervention (I):-oxytocin given to sows-comparator (C): sows at farrowing not given oxytocin, as well as sows given different dosages and/or different timing of administration; and outcomes (O):-stillbirths, sow mortality, and piglet viability. Four bibliographic databases were used: PubMed, CAB Direct, Web of Science Core Collection, and ProQuest Dissertations, and Theses Global. In addition, we performed a manual search of the table of contents in the American Association of Swine Veterinarians database for relevant conference proceedings and reports. To assess the risk of bias at the study level, a modified version of the Cochrane 2.0 ROB was used. Meta-analyses were performed to examine the average stillbirth rate, farrowing duration, and birth interval between piglets using random-effect standardized mean difference (SMD) models. To explore heterogeneity, a sub-group analysis was performed on the objectives of the study, dose, time, and route of administration. Of the 46 studies eligible for meta-analyses, only 25 had sufficient information. The pooled analyses of the random effect model demonstrated that the average number of stillborn pigs was lower in the comparator group (SMD = 0.23; CI95% = 0.1, 0.36), and both the farrowing duration (SMD = -8.4; CI95% = -1.1, -0.60) and the birth interval between piglets (SMD = -1.41; CI95% = -1.86, -0.97) were shorter in the oxytocin group. The majority of the studies had an overall risk of bias of 'some concerns'. It was concluded that the use of oxytocin increases the overall number of stillborn piglets, but decreases the farrowing duration and time interval between piglets. However, future studies should focus on the effect of oxytocin on the experience of dystocia among sows.

Treatments and therapeutic protocols for the recovery of an asphyxiated new-born: A review of pre-clinical and clinical studies in human neonates and in different animal models

The objective of this review is to ascertain the advantages and disadvantages of several treatments and therapeutic protocols that have been used for the prevention and treatment of perinatal asphyxia in human neonates and in different animal models. Perinatal asphyxia is one of the main causes of mortality worldwide and is an important factor in triggering physio-metabolic disorders that result in serious neurological consequences and learning disorders not only in human foetuses and neonates, but also in animals. In recent years, the search for new pharmacological protocols to prevent and reverse physio-metabolic disorders and brain damage derived from perinatal asphyxia has been and continues to be the subject of intense research. Currently, within these pharmacological protocols, therapeutic strategies have been evaluated that use respiratory and hormonal stimulants, as well as hypothermic therapies in combination with other putative neuroprotective agents. Similarly, energy supplements have been evaluated with the objective of preventing perinatal asphyxia and treating new-borns with this condition, and to decrease the incidence of neonatal and foetal deaths associated with it. However, despite these promising advances, this pathology has persisted, since the administration of these therapies in low doses may not exert a neuroprotective effect or, in high doses, can trigger adverse effects (such as reduced cardiac contractility, reduced cerebral blood flow, poor perfusion, sympathetic and neuroendocrine stimulation, and increased blood viscosity) in human foetuses and neonates as well as in different animal models (rats, piglets, sheep and rabbits). Therefore, it is important to determine the minimum effective dose with which these therapies exert a neuroprotective effect, as well as the mode of administration, the duration of therapy, etc. Therefore, until a powerful strategy is found to improve the consequences of suffocation, this topic will continue to be the subject of intensive research in the future.

Effect of 1,25-Dihydroxyvitamin D3-Glycosides on the Farrowing Process and Piglet Vitality in a Free Farrowing System

Vitamin D improves the reproductive efficiency in animals. This study aimed to examine the effects of 1,25-dihydroxyvitamin D3-gylcosides (1,25-vitD) on the farrowing process in sows and the vitality of their piglets. In total, 100 sows were allocated into two groups at insemination (‘1,25-vitD’ and ‘negative control’). The 1,25-vitD group received 260−300 mg/sow/day 1,25-vitD in their feed during the gestation period. Backfat thickness, fecal score, and the farrowing process was evaluated. The piglets were categorized into live born or stillborn, and vitality was evaluated by assessing the umbilical cord and the meconium score. The number of total-born piglets in sows of ‘1,25-vitD’ was higher and the farrowing duration was shorter than in the negative control group without showing significance in the univariable analysis. In a linear multiple regression model including the variables ‘farrowing duration’, ‘total born piglets’ and ‘1,25-vitD’ differences became evident. We found that 1,25-vitD was associated with a reduced farrowing duration (p = 0.055). Moreover, significantly more mummies (p < 0.01) and short ruptured umbilical cords (p < 0.05) were observed in the 1,25-vitD group. This study showed an effect of 1,25-vitD on the farrowing process. However, more research is needed to better describe the mechanism of 1,25-vitD in detail.

Selection for litter size and litter birthweight in Large White pigs: Maximum, mean and variability of reproduction traits

Gradually increasing trend of litter size poses a challenge to pig farmers in terms of managing larger litters. Therefore, it seems that a balanced approach that optimises litter size, litter birthweight, and uniformity of those traits is needed in order to address animal welfare and farm management concerns. This study aimed to investigate this issue by defining several traits for total number born (TNB), number born alive (NBA) and litter birthweight (LW). First, the highest value from at least five records per sow was selected as maximum (max) value for each reproduction trait. Second, a mean (mean) for each reproduction trait was calculated per sow. Last, the variability of reproduction traits between parities of the sow was calculated as log-transformed variance of residuals of all observations per sow for each reproduction trait (LnVar). In total, 23 193 Large White sows from Topigs Norsvin with 152 282 litter records were used for analysis in ASReml 4.1. Also, a simulation of breeding schemes was performed with the use of SelAction 2.1 and estimates from genetic analysis. Maximum value of reproductive traits had a much higher heritability than repeated observations or mean of reproduction traits, e.g., 0.31 for maxTNB vs. 0.12 for TNB and 0.07 for meanTNB, which allows for a faster response under selection. The maximum value traits, however, were found to carry more risks, i.e. higher ratio of stillborn (not for maxNBA) and increased variability of traits. Thus, using them in breeding programme should be carefully considered. The genetic coefficient of variation on SD level estimated to indicate the genetic magnitude for variability phenotypes indicated a maximum change of 6-9% in genetic SD of TNB, NBA and LW. The genetic correlations between mean and corresponding variability traits varied from 0.66 to 0.74, whereas the correlation between other mean and variability traits ranged from 0.33 to 0.99. The simulation indicated that even with selection targeted against the variability of reproduction traits, a very limited change should be expected due to a complex genetic and phenotypic relationship between the traits. In the scenarios with selection against LnVarTNB and LnVarLW, this was a decrease of 0.1-0.6% per year, whereas in scenario with selection against LnVarNBA, the range was 0.6-1.1% per year. It is still possible to increase litter size and birthweight further, however, a balance between mean and variability of reproduction traits is required, which can be obtained only by a very well designed breeding programme.

Effect of carbetocin administration during the mid-period of parturition on farrowing duration, newborn piglet characteristics, colostrum yield and milk yield in hyperprolific sows

Control of the farrowing process is crucial to reduce the risk of post-parturient disorders in sows and newborn piglet mortality. Carbetocin is a long-acting oxytocin-like compound that has been introduced to domestic animal obstetrics. The aims of the present study were to evaluate the effects of carbetocin administration during the mid-period of parturition on farrowing duration as well as colostrum and milk production and its side effects on neonatal piglet characteristics in hyperprolific sows. The study included 89 Landrace x Yorkshire crossbred sows and 1534 piglets. Sows were randomly distributed into two groups: CONTROL (n = 46), where sows were allowed to farrow naturally, and TREATMENT (n = 43), where sows were administered 0.5 μg/kg carbetocin intramuscularly after the birth of the 7th piglet. In each litter, the piglets were classified into two groups according to birth order: 1-7 and ≥8. The colostrum yield of sows and the colostrum intake of each individual piglet were calculated. Litter weight gain of the piglets from 3 to 5 days of lactation was used to estimate milk yield. Farrowing duration tended to be reduced from 338.4 ± 35.2 min in the CONTROL group to 255.3 ± 36.4 min in the TREATMENT group (P = 0.105). However, the colostrum yield in the TREATMENT group was lower than that in the CONTROL group (3828 ± 149 and 3041 ± 158 g, respectively, P < 0.001). Nevertheless, milk yield during 3-5 days of lactation in the TREATMENT group did not differ significantly compared to that in the CONTROL group (7.53 ± 0.01 and 7.54 ± 0.01 kg/day, respectively, P = 0.643). The incidence of stillbirths in the TREATMENT group was not significantly different from that in the CONTROL group (8.3 and 7.4%, respectively, P = 0.944). However, the incidence of piglets born with umbilical cord rupture in the TREATMENT group with birth order ≥8 was higher than that in the CONTROL group in the same birth order (16.6 and 5.7%, P < 0.001). Across groups, colostrum intake of piglets born with birth order ≥8 was lower than that of piglets born in the birth orders 1-7 (187.4 ± 8.7 and 241.5 ± 9.0 g, P < 0.001). Interestingly, the colostrum intake of piglets with birth orders 1-7 in the TREATMENT group was also lower than that of piglets with the same birth order in the CONTROL group (214.9 ± 12.9 and 268.1 ± 12.5 g, respectively, P = 0.003). Colostrum intake was lowest in the piglets with birth order ≥8 in the TREATMENT group (159.6 ± 12.3, P < 0.001). Carbetocin administration after the birth of the 7th piglet reduced the birth interval of piglets but increased the incidence of piglets born with umbilical rupture and reduced colostrum intake. Therefore, colostrum supplementation and care of the newborn piglets immediately after birth are strongly recommended after carbetocin administration.

Evaluation of different point-of-care tests to characterize the vaginal discharge of sows after parturition and parameters' correlation with subsequent reproductive performance

The lochia is the physiological uterine discharge post-partum, whereas abnormal fluids are often indicators of puerperal disorders in sows, which negatively influence the further reproductive performance. The aim of the study was to characterize the vaginal discharge in sows employing simple and feasible tests and to correlate the evaluated parameters with the subsequent reproductive performance of these sows. The birth process of 48 clinically healthy free farrowing sows was monitored and several parameters characterizing the vaginal discharge such as total amount, colour, amount of cells (somatic cell count) and cell characteristics (cytology) were collected daily from first to fifth day after parturition. Finally, the reproductive performance of the following gestation was evaluated and compared to the characteristics of the lochia. The amount of vaginal discharge was significantly increased on the second (p < 0.01), third (p = 0.019) and fourth (p = 0.011) day post-partum compared to day one. Furthermore, a decrease in the percentage of neutrophilic granulocytes from day one to three (p = 0.038), four (p = 0.038) and five (p = 0.048) post-partum was observed. The percentage of neutrophilic granulocytes in the yellowish vaginal discharge was increased compared to whitish (p = 0.02) or clear (p = 0.027) vaginal discharge. In addition, obstetrics (p = 0.003) and an increased farrowing duration (p = 0.017) significantly increased the amount of vaginal discharge. Sows with a high amount of vaginal discharge had a significant higher body temperature than sows with no (p = 0.014) or low amount (p < 0.01) of vaginal discharge. No correlation was detected between the evaluated parameters of the lochia and the subsequent reproductive performance. It is hypothesised that the amount of vaginal discharge alone is not a predictor for the performance of sows during their next gestation. However, it might serve as indicator for acute endometritis. In summary, the different parameters of the vaginal discharge determined by means of point-of-care tests might be useful to strengthen a presumptive diagnose of endometritis in sows during the first five days after parturition.