The effect of providing shredded paper or ropes to piglets in farrowing crates on their behaviour and health and the behaviour and health of their dams

The objective of this study was to evaluate the effect of providing paper or rope, alternative enriching substrates to straw, to piglets in farrowing crates on piglet and sow welfare.Sixty multiparous sows and their litters were housed in crates that were either barren (BARREN), enriched with shredded paper (PAPER) or natural fibre rope (ROPE). Enriching substrates were introduced when piglets were 10 days old. The proportion of sows with udder and teat lesions before parturition and at weaning was recorded. Piglet facial lesions were scored according to severity on days 11, 18 and 27. Sow and piglet behaviour was recorded using scan sampling on days 14, 18, 22 and 26. Furthermore, the behaviour of one male and one female focal piglet per litter was recorded continuously for 10 min twice per day on days 14, 18, 22 and 26. On day 27 post-partum, focal piglets were observed for 5 min in a novel arena and for a further 5 min after a novel object was introduced.On day 27, there was a tendency for more BARREN sows to have teat lesions (P = 0.07). PAPER litters tended to have a smaller proportion of piglets with facial lesions (P = 0.06). ROPE piglets were active in the enriched area of the crate in more observations than BARREN and PAPER piglets (P < 0.01). PAPER piglets spent less time inactive (P < 0.01), less time exploring the pen-fittings (P < 0.01) and more time interacting with the enriching substrate (P < 0.001) than piglets in the other two treatments. In the first 5 min in the novel arena BARREN piglets froze more than PAPER and ROPE piglets (P = 0.05).In conclusion, shredded paper improved piglet welfare and was easily incorporated into the farrowing crates.     

The effects of confinement on periparturient behaviour and circulating prolactin,prostaglandin F2α and oxytocin in gilts with access to a variety of nest materials

In a 2×2 factorial experiment, the effects of gestation and farrowing housing on (1) periparturient behaviour and circulating prolactin, prostaglandin F_2α (PGF_2α) and oxytocin in gilts with access to peat, straw and branches, and (2) correlational relationships between the periparturient behaviour and hormones were studied. The treatments consisted of housing in stalls or pens from mating to day 110 of gestation followed by farrowing crates or pens until after parturition. Landrace×Yorkshire gilts were observed from video recordings (n=25) from 20 h prepartum and blood sampled via jugular catheters (n=16) from 24 h prepartum until 2 h after the birth of the first piglet.There was an interaction between gestation and farrowing housing affecting the start of nest-building (P=0.03). Gilts that experienced a change in type of housing accommodation commenced nest-building closer to parturition than gilts that were penned both during gestation and at farrowing (both P<0.05). There were no effects of the housing environment on the timing of termination of nest-building, behaviour during parturition, or the course of parturition. However, relative to base level, crated gilts sat more from 16 to 6 h prepartum, whereas this was the case for penned gilts only from 9 to 7 h prepartum. Crated gilts also tended to change posture more often (P=0.07) and lie more in sternal recumbency (P=0.095). This suggests that familiarity with the environment in combination with space to move about and/or availability of materials is important in the timing of nest-building. Confinement during farrowing did not appear to impair feed-back from the materials and the nest, although increased number of postural changes may reflect the motivation but inability to nest-build, or general discomfort in the crate.There was a development over time in postural and nest-building behaviours as well as in plasma concentrations of prolactin, PGF_2α (measured by the metabolite PGFM) and oxytocin, but there were only few effects of housing treatments on hormones or associations between behaviour and hormones. The results suggest that nest-building occurs independently of a prepartum rise in prolactin, but that oxytocin may be associated with the termination of nest-building as there was a negative correlational relationship with nosing (P<0.01) and arranging nest-building materials (P<0.001).Farrowing crate housing appeared to have fewer effects on periparturient behaviour and course of parturition than reported in previous studies where effects of confinement and provision of nest-building materials may have been confounded. Thus, provision of nest-building materials to crated sows may have beneficial effects on sow behaviour and welfare.     

Early piglet mortality in loose-housed sows related to sow and piglet behaviour and to the progress of parturition

The aim of the present study was to identify characteristics of sow behaviour and parturition related to early piglet mortality in loose-housed farrowing sows. Data from 152 farrowings that originated from three different herds with loose-housed sows during parturition were used. Graphical chain models were used to model the relationships between perinatal behaviour, periparturient individual conditions (time of day of parturition, rectal temperature 1–3 days postpartum) and causes of early piglet mortality. Modelling was based on the correlation between variables within herd and farrowing batch.The analysis showed that different causes of mortality were linked to different behavioural variables during the periparturient period and that they grouped into three independent categories. The first category was associated with stillbirth and death due to other causes. Stillbirth was positively related to the variation of the inter-birth interval and negatively related to the percentage of piglets that suckled during the first 8 h after birth of first piglet (BFP). Death due to other causes was negatively related to the suckling activity during the post-partal period (9–24 h after BFP). The second category was associated with piglet crushing, which was positively related to much lateral lying the last 4 h before BFP. Finally, the third category was associated with death due to lack of colostrums ingestion of colostrum, which was linked to the time of parturition and sow rectal temperature on days 1 and 2 after farrowing. Sows that gave birth during the morning compared to evening/night had more dead piglets due to lack of colostrums ingestion. Death due to lack of colostrums ingestion was also higher in sows with high rectal temperature on the day after BFP. The results further showed that litter size not only influenced mortality but also behavioural variables. High litter size was related to high nest building activity before BFP, low but more variable inter-birth intervals, and much lateral lying after BFP. The study points towards several areas of interest for further research that can help understand early piglet mortality. These include causes of variation in the progress of parturition, causes of individual differences in sow activity and responsiveness to piglets, and early management of farrowing. In addition, the study suggests possible indicators of problematic farrowings rendering liveborn piglets at risk. These include prepartum lateral lying in the sow, low suckling activity and rate of stillbirth.     

Impact of social stress during gestation and environmental enrichment during lactation on the maternal behavior of sows

The impact of a social stress in gestation and an enriched pen in lactation on components of sow maternal behavior was studied in a 2 × 2 factorial experiment. At breeding, 41 sows were assigned to a social mixing stress treatment (T) during mid-gestation or a control group (C). During lactation, half of the T and C sows were housed in straw enriched pens (E) (1.57 m × 4.10 m) and the others in standard farrowing crates (S) (0.68 m × 2.10 m). The mixing stress consisted in introducing each T sow to the home pen of two unfamiliar sows twice for 1 week, from d 39 to 45 and 59 to 65 of gestation. Aggressive behavior was observed and lesion scores were taken to confirm that a social stress occurred. During lactation, the responses of sows to a simulated piglet crush test on d 3 and an isolated piglet playback test on d 21 were observed. Postural budgets of sows were automatically detected using accelerometers on d 5 and 19 of lactation. Sow-initiated social contacts with the piglets were observed continuously from video recordings on d 6 and 20 of lactation. Data were analyzed with a mixed models procedure. The social stress treatment had an impact on the response of sows to isolated piglet vocalizations with T sows showing longer latencies to respond vocally than C sows (P = 0.035). In early lactation, T sows spent more time lying ventrally than C sows (P = 0.007). Furthermore, the social stress had an impact on the space use in the enriched housing, with T sows spending less time in the nesting straw area of the pen than C sows (P = 0.018). Housing also impacted maternal behavior with E sows tending to spend more time lying ventrally than S sows in late lactation (P = 0.067) and tending to have more social contacts with their piglets than S sows in early lactation (P = 0.058). In conclusion, the social stress during gestation had a slight negative impact on sow maternal behavior, and while an enriched farrowing pen allowed for more opportunities to express maternal behavior, it did not counteract the negative effects of gestation stress.     

Parturition in gilts: duration of farrowing, birth intervals and placenta expulsion in relation to maternal, piglet and placental traits

Large White x Meishan F2 crossbred gilts (n = 57) were observed continuously during farrowing while the placentae of their offspring were labeled in order to examine the duration of farrowing and placenta expulsion in relation to maternal-, piglet- and placental traits and the duration of birth interval in relation to birth weight, birth order and placental traits. Independently from each other, litter size, gestation length and offspring directed aggression significantly (P 0.05) affected duration of farrowing. An increase in litter size was associated with an increase of duration of farrowing and an increase in gestation length was associated with a decrease of duration of farrowing. Aggressive gilts took longer to farrow, compared to non-aggressive ones. After taking into account litter size, gestation length and offspring directed aggression, placental thickness (i.e., placental weight corrected for placental surface area) was significantly (P < 0.05) related to duration of farrowing, i.e., litters with on average thicker placentae took longer to farrow. The latter effect is the result of the fact that individual placental thickness significantly (P < 0.01) affected individual birth interval, independent of birth weight. The piglet has to break its own membranes to be able to start its journey through the uterus towards the birth channel. Apparently, a thicker placenta offers more resistance and thus prolongs the process of birth. Independent of placental thickness, birth interval significantly (P < 0.01) decreased with an increase in birth order (first born to last born). The high variation of birth intervals for the last born piglets, caused a slight increase in average birth interval for the latter piglets. Litters with on average more areolae per placenta took significantly (P < 0.001) less time to be born than litters with on average less areolae per placenta (independent of total number of piglets born and other placental traits), while birth intervals within litters were not affected by this trait. Thus, these results are probably due to a gilt trait rather than a piglet trait. Since the number of areolae represent the number of uterine glands present, the gilt trait might be uterine development. Duration of placenta expulsion significantly (P < 0.01) increased with an increase of duration of farrowing. Furthermore, the first placenta was expelled significantly (P < 0.01) earlier relative to last piglet when duration of farrowing was protracted, while there was no relation of the time interval between first placenta and last piglet and the duration of placenta expulsion. In conclusion, the most important finding of this study is that placental thickness rather than birth weight appears to play an important role in the duration of birth intervals and as a result, of duration of parturition in gilts.     

Effect of insemination of estrus-induced prepuberal gilts on ensuing reproductive performance and body weight

Prepuberal gilts reared and managed to 85-90 kg live weight in a common system were allocated at random to one of three first-mating treatments in an experiment conducted over a period of more than 5 years. In two of the treatments, gilts received a single i.m. injection of 400 IU equine chorionic gonadotropin (eCG) and 200 IU human chorionic gonadotropin (hCG) (PG600; Intervet) and were either inseminated 4 and 5 days later on a fixed-time basis regardless of oestrus (treatment A), or at the second oestrus following treatment (treatment B). The third group of gilts remained untreated and was inseminated on the first spontaneous oestrus (treatment C). Thereafter, all gilts were managed in the same way and those observed in oestrus were re-inseminated. Significantly more gilts returned to oestrus after the first service in treatment A (35%) than in treatment B and C (12 and 17%, respectively; P<0.01). Gilts farrowed to the first or repeat inseminations at a significantly younger age (P<0.01) in treatment A (304 days) than treatment B (324 days) and C (320 days). The age difference at farrowing remained in surviving gilts at the end of their third parity. The first farrowing performance of the gilts was significantly affected by treatment in terms of litter size at birth (A 7.0, B 8.4 and C 8.3 live piglets per gilt; P<0.01), litter size at weaning (A 6.2, B 7.2 and C 7.2 live piglets per gilt, P<0.05), and piglet birth weight (A 1.4, B 1.3 and C 1.3 kg; P<0.05) but piglet survival rate and weaning weight were not affected by treatment. The live weights of the gilts were significantly different between the treatments at first insemination (A 95.7, B 106.5 and C 109.2 kg; P<0.01) but not when the first litter was weaned (A 133.6, B 135.1 and C 136.6; P>0.05). After the first farrowing there were no differences between the treatments in terms of the survival rate, productive or reproductive performance of the gilts/sows and their offspring. Without conducting a detailed cost-benefit-calculation it was deduced that, from an economical point of view, differences between treatment A and treatments B and C are negligible because the savings associated with farrowing at a younger age on this treatment just about compensated for any additional costs associated with the treatment and the lower number of piglets born at the first farrowing.     

Effect of birth litter size, birth parity number, growth rate, backfat thickness and age at first mating of gilts on their reproductive performance as sows

The present study was performed to evaluate retrospectively the influence of birth litter size, birth parity number, performance test parameters (growth rate from birth to 100kg body weight and backfat thickness at 100kg body weight) and age at first mating (AFM) of gilts on their reproductive performance as sows. Traits analysed included remating rate in gilts (RRG), litter size, weaning-to-first-service interval (WSI), remating rate in sows and farrowing rate (FR). Data were collected from 11 Swedish Landrace (L) and 8 Swedish Yorkshire (Y) nucleus herds and included 20712 farrowing records from sow parities 1-5. Sows that farrowed for the first time during 1993-1997, having complete records of performance test and AFM, were followed up to investigate their subsequent reproductive performance until their last farrowing in 1999. Analysis of variance and multiple regression were applied to continuous data. Logistic regression was applied to categorical data. The analyses were based on the same animals and the records were split into six groups of females, i.e. gilts, primiparous sows, and sows in parities 2-5, respectively. Each additional piglet in the litter in which the gilt was born was associated with an increase of her own litter size of between 0.07 and 0.1 piglets per litter (P<0.001). Gilts born from sow parity 1 had a longer WSI as primiparous sows compared with gilts born from sow parity 4 (0.3 days; P<0.05) or parity 5 (0.4 days; P<0.01). Gilts with a higher growth rate of up to 100kg body weight had a larger litter size (all parities 1-5; P<0.05), shorter WSI (all parities 1-5; P<0.05) and higher FR (parities 2 and 5; P<0.05) than gilts with a lower growth rate. Gilts with a high backfat thickness at 100kg body weight had a shorter WSI as primiparous sows (P<0.001) compared with low backfat gilts, and 0.1 piglets per litter more as second parity sows (P<0.01). A 10 day increase in AFM resulted in an increase in litter size of about 0.1 piglet for primiparous sows (P<0.001) and a decrease (P<0.05) for sow parities 4 and 5.     

Oestrous behaviour in relation to fertility and fecundity of gilts

The reproductive performance of 2484 gilts was recorded over a 12-month period at a large intensive piggery in southern Australia. Between 29 and 35 weeks of age, gilts were examined daily for response to the back-pressure test (BPT). Those subjectively assessed as showing a moderate or high response were taken to a boar for mating. Gilts that had showed a moderate response to the BPT on their first day of mating had lower average litter size than gilts showing a high BPT response (9.05 and 9.35 piglets, respectively; P < 0.05). A quantitative assessment of sexual receptivity was made while the gilt was with the boar. Gilts that were mated while showing low sexual receptivity on the first day of mating had poorer farrowing rate (78.1 vs. 83.1%, respectively; P < 0.05), as well as lower litter size (9.03 vs. 9.35 piglets, respectively; P < 0.05) than gilts that were mated when showing high sexual receptivity. A moderate BPT response was followed by either low sexual receptivity or failure to mate on 81.4% of occasions, compared with 12.8% for a high BPT response. Since 75% of gilts that showed a moderate BPT response on the first day of mating showed a high response on the following day, it was concluded that mating should only be attempted when gilts exhibit a high response to the BPT. The mean farrowing rate and litter size for gilts at their first farrowing was 82.4% and 9.31 piglets (8.62 alive and 0.69 dead), respectively.     

The influence of drinker location and colour on drinking behaviour and water intake of newborn pigs under hot environments

The effect of drinker location within the farrowing crate in relation to its microenvironment and the effect of dispenser colour on drinking behaviour and water intake of newborn pigs for the first two days of their lives were studied. In the first trial, 16 sows were randomly assigned to four treatment groups with the piglet's water dispenser placed in the front right (FR), front left (FL), back right (BR) or back left (BL) corner of the farrowing pen, respectively. In the second trial nine sows were randomly assigned to three treatment groups with the piglets’ water dispenser, placed in the front left corner of the farrowing pen, and coloured as red (CR), green (CG) or blue (CB), respectively. Trials commenced between 08:00 and 10:00 h on the first morning after the litters were born and the piglets’ age was considered to be zero (“age”) by that time.The average age of the piglets at their first visit to water dispensers was 15.9 ± 1.8 h. The newborn pigs visited the drinker more frequently (P < 0.001) during daytime than during night, with two peaks soon after sow feeding time. The duration of drinking time was long at the time of higher (noon) and shorter at the time of lowest (early morning) temperatures (P < 0.01) in the farrowing house, respectively. The greatest attention at the drinkers occurred soon after suckling (P < 0.001). The longest time spends at the drinker during the first visits and decreased as the pigs visited dispensers repeatedly. The profile of visit frequency and duration differed between piglet sexes (P < 0.001). The pigs that did not visit the drinker grew slower and were lighter at 48 h of age than the pigs visited the drinker. First visit and overall mean visit age were significantly shorter for BL than for FR and BR groups. Piglets visited the FL drinker for shorter time than the others. Water consumption per pig/24 h was lower for FL and higher for BL groups (P < 0.05). Water consumption was higher for CR and CB groups than for CG group. The overall mean visit age was shorter for CG than for CB group. Significant interactions were observed between sex and colour groups for the number of visits (P < 0.05). The results of the present study revealed that water dispenser use by newborn piglets is characterised by diurnal and between two successive milk consumptions distributions. Water consumption by piglets from birth to 48 h of their lives is strongly influenced by water dispenser location in the farrowing pen and the dispenser colour. It also appears that males and females behave differently to the three colour dispensers used in this study.     

IGF-1 concentrations after weaning in young sows fed different pre-mating diets are positively associated with piglet mean birth weight at subsequent farrowing

Pre-mating diets can influence piglet birth weight and within-litter birth weight variation and thereby piglet survival and development. The major objective of this study was to evaluate the litter characteristics of young sows whose pre-mating diets received different supplementation. The supplements included a top-dressing of 200 g, consisting of either wheat (CON) or wheat plus microfibrillated cellulose, _L-carnitine or _L-arginine at one of two supplementation levels (low and high) in late lactation and during the weaning-to-oestrus interval (WEI). The second objective was to investigate the role of body condition loss and IGF-1 concentration during the WEI for subsequent litter characteristics. In total, sows after their first (N = 41) and second (N = 15) lactation were used. One week before weaning, the sows were allocated to the seven treatments based on the number of piglets and BW loss from farrowing until 1 week before weaning. Pre-mating diets did not affect litter characteristics at subsequent farrowing. However, at subsequent farrowing, sows after their first lactation had a lower total number of piglets born per litter (18.3 v. 20.3), higher mean piglet birth weight (1 365 v. 1 253 g), lower CV of birth weight (20.0 v. 26.1%) and lower percentage of piglets < 1 000 g (11.5 v. 24.4%) than sows after their second lactation. Litter weight at second parturition was positively related to IGF-1 during the WEI after first lactation (P < 0.04). Within parity, piglet mean birth weight was positively related to IGF-1 at oestrus (P < 0.02). Surprisingly, within parity, a higher relative loin muscle depth loss during previous lactation was related to lower CV and SD of birth weight (P < 0.05, for both). In conclusion, pre-mating diets did not affect litter characteristics at subsequent birth. However, a higher IGF-1 concentration during the WEI was positively associated with subsequent litter weight and piglet mean birth weight. Further studies should elucidate the role of IGF-1 during the WEI for subsequent litter characteristics and dietary interventions to stimulate IGF-1.     

The effect of environment on plasma cortisol and β-endorphin in the parturient pig and the involvement of endogenous opioids

Previous work has indicated that plasma cortisol increases during farrowing in the pig suggesting increasing physiological stress. The aim of this study was to determine changes in plasma cortisol and β-endorphin over farrowing in the pig to obtain a more detailed profile of pituitary and adrenal release at this time and also to investigate the involvement of endogenous opioids in the mediation of the HPA axis. Indwelling jugular catheters were implanted, under general anaesthesia, in 31 Large White×Landrace gilts approximately 15 days before the expected parturition day (EPD). Gilts were moved into either a farrowing crate, without straw (n=15), or a straw-bedded pen (n=16) 5 days before the EPD. Samples were taken during the pre-farrowing period and then during farrowing itself. At 7.5 min after the birth of the first piglet (BFP), gilts either received naloxone, an opioid antagonist, (1 mg kg⁻¹ body weight, i.v.) or a control dose of saline. Plasma β-endorphin increased following the BFP but remained fairly constant over the third and fourth hour of farrowing. Plasma cortisol continued to increase over the 4 h following the BFP. Changes seen in these hormones were generally insensitive to the environment and there was little evidence of opioid mediation of the HPA axis at parturition. From these results it is suggested that certain aspect(s) of parturition itself stimulate the HPA axis. However it is unknown if the rise in plasma cortisol is a result of some stress-inducing factor of the parturition process or whether it reflects a metabolic function. The study also demonstrates the lack of any inhibitory mediation of the HPA axis by endogenous opioids at parturition.     

Higher preweaning mortality in free farrowing pens compared with farrowing crates in three commercial pig farms

If loose-housed farrowing systems are to be an alternative to traditional farrowing crates, it is important that they can deliver the same production results as can be achieved in farrowing crates under commercial conditions. The aim of this study was to compare preweaning mortality in farrowing crates and free farrowing pens (FF-pens) within herds that had both systems. The study was conducted over 2 years in three commercial Danish herds that had FF-pens as well as traditional farrowing crates in their farrowing unit. Piglet mortality was analysed in two periods: before litter equalisation and after litter equalisation. Linear models were used to analyse effects of housing (crate or pen), herd (Herd A, B or C), parity (parities 1, 2, 3 to 4 or 5 to 8) as well as the effect of number of total born piglets on mortality before litter equalisation, and the effect of equalised litter size on piglet mortality after litter equalisation. All corresponding interactions were included in the models. Before litter equalisation piglet mortality was higher (P<0.001) in pens (13.7%) than in crates (11.8%). Similarly, piglet mortality after litter equalisation was higher in pens than in crates in all three herds, but the difference between pens and crates were dissimilar (P<0.05) in the different herds. In addition, piglet mortality, both before (P<0.001) and after litter equalisation (P<0.001), grew with increasing parity of the sows. Mortality before litter equalisation moreover increased with increasing number of total born piglets per litter (P<0.001), and mortality after equalisation increased when equalised litter size increased (P<0.001). No significant interactions were detected between housing and parity or housing and litter size for any of the analysed variables. In conclusion, there is knowledge how to design pens for free farrowing; but this study showed a higher preweaning mortality in the FF-pen. Nonetheless a noteworthy proportion of the sows in the FF-pens delivered results comparable to those farrowing in crates. This indicates that FF-pens are not yet a robust type of housing for farrowing sows.     

Effects of prostaglandin F2alpha treatment of pseudopregnant pigs on nest building and interactions with newborn piglets

Previous studies showed that prostaglandin (PG)F2alpha treatment stimulated nest building behaviors in prepartum and pseudopregnant pigs. This experiment studied behaviors of PGF2alpha-treated pseudopregnant nulliparous pigs (gilts) exposed to newborn piglets. Penned pseudopregnant gilts (days 46-53) were injected with either 10 mg PGF2alpha (n = 8) or saline (n = 8) im, and behavior was recorded for 2 h (period A). Between 2 and 6 h (period B), gilts were given two male piglets (< 12 h old) and a novelty object (house brick) and recordings continued. During period A, PGF2alpha animals showed greater frequencies of standing, pawing, rooting, lifting, and carrying straw (indices of nest building) and scratching than saline treated animals. During period B, one PGF2alpha- and two saline-treated gilts attacked piglets, which were removed from the pen and the gilts excluded from further analysis. There were no treatment differences in period B in gilt posture, nest building behavior, or interactions with piglets or novelty object, except for a reduced frequency to trap piglets beneath their bodies and an increased frequency to attempt to escape from the pen in PGF2alpha-treated animals. Piglet position relative to the gilts' head and udder was unaffected by treatment. Gilts in both groups approached and nosed piglets more within the first 30 min of period B than subsequently. PGF2alpha-induced nest building had only a weak impact upon subsequent interactions between gilts and piglets, suggesting that mechanisms controlling porcine nest building and maternal behavior in this model were not directly linked.     

Piglet use of the creep area—Effects of breeding value and farrowing environment

The objective of this study was to investigate piglet use of the creep area, comparing litters of sows with a high vs. low breeding value for piglet survival in the first 5 days postpartum, that were either housed in crates or individual pens during farrowing and lactation. Seventy-five Yorkshire × Danish Landrace sows were video recorded for 4 days after farrowing, and the analysis was conducted using instantaneous sampling every 10 min commencing 24 h after the birth of the first piglet for a period of 72 h. Breeding value for piglet survival had no effect on piglet use of the creep area or time spent in any location of the farrowing environment. Farrowing environment had significant effects on piglet location; during all days there were significantly more piglets in the creep area in the crates compared to the pens (P < 0.01), and this difference was larger at 24–48 h than at 49–72 h and at 73–96 h after birth (P < 0.05). Piglets in pens spent significantly more time resting near the sow, excluded nursing (P < 0.001), and this percentage decreased over time after farrowing (P < 0.001) in both the crates and the pens. In conclusion, piglet use of the creep area was higher in the crate compared to the pen particularly during the second day of life. This may partly be due to a much larger proportion of uncomfortable, slatted floor in the crates, and the shorter distance from the sow to the creep area in the crate.     

Consistency is key: interactions of current and previous farrowing system on litter size and piglet mortality

Global interest in alternative indoor farrowing systems is increasing, leading to a growing number of farms utilising such systems alongside standard crates. There is evidence that interchanging sows between different farrowing systems affects maternal behaviour, whilst the subsequent effect of this on piglet mortality is unknown. The current study hypothesised that second parity piglet mortality would be higher if a sow farrowed in a different farrowing system to that of her first parity. Retrospective farm performance records were used from 753 sows during their first and second parities. Sows farrowed in either standard crates (crates), temporary crates (360s) or straw-bedded pens (pens), with mortality recorded as occurring either pre- or post-processing. Inter- and intra-parity sow consistency in performance were also investigated. Overall, total piglet mortality reduced from the first to the second parity, being significantly higher in the crates and higher in the 360s during the first or second parity, respectively. In the second parity, an interaction of the current and previous farrowing systems resulted in the lowest incidence of crushing for sows housed in the same system as their first parity for the crates and pens, but not the 360s. Post-processing mortality was significantly higher in the crates if a sow previously farrowed in the 360s and vice versa. Sows which previously farrowed in a pen had a significantly larger litter size and lower pre-processing mortality from crushing in their second parity than sows previously housed in the crates or the 360s. No inter-parity consistency of sow performance was found, whilst intra-parity consistency was found in the first but not second parity. In conclusion, returning sows to the same farrowing system appears to reduce piglet mortality, whilst farrowing in a pen during the first parity significantly increased second parity litter size without increasing piglet mortality.     

Heat stress of gilts around farrowing causes oxygen insufficiency in the umbilical cord and reduces piglet survival

Late gestating sows are susceptible to high ambient temperatures, possibly causing farrowing complications and reducing piglet survival. This experiment aimed to quantify in the days leading up to farrowing the impact of sow heat stress (HS) on farrowing physiology and survival of the piglets. Pregnant primiparous sows (gilts) were allocated to either thermoneutral control (CON, n = 8; constant 20 °C) or cyclical HS conditions (n = 8; 0900 h to 1700 h, 30 °C; 1700 h to 0900 h, 28 °C) from d 110 of gestation until farrowing completion. Gilt respiration rate, skin temperature and rectal temperature were recorded daily, and farrowing duration was quantified by video analyses. Blood samples were collected from the piglet umbilical vein at birth. At 48 h of age, piglet growth was quantified by morphometric analyses. The thermal exposure model induced HS and respiratory alkalosis in the gilts, as indicated by increased respiration rate, rectal temperature, skin temperature (all P < 0.001), plasma cortisol (P = 0.01) and blood pH (P < 0.001). Heat-stressed gilts took longer to start expelling placentae (P = 0.003), although the active farrowing duration was not significantly different between treatments. Stillbirth rates were higher in the HS group (P < 0.001), with surviving piglets at birth having lower umbilical vein partial pressure of oxygen (P = 0.04), oxygen saturation rate (P = 0.03) and tending to have increased lactate concentrations (P = 0.07). At birth, piglet skin meconium staining scores were greater in the HS group (P = 0.022). At 48 h of age, piglets from the HS group had reduced small intestinal length (P = 0.02), reduced jejunal crypt depth (P = 0.02) and lighter absolute brain weight (P = 0.001). In contrast, piglet BW, growth rate, relative organ weight and small intestinal mucosal barrier function did not change between treatments. Collectively, these findings demonstrated gilt HS during late gestation caused farrowing complications and reduced the umbilical oxygen supply to the piglets at parturition, leading to increased risks of piglet stillbirth with implications on impaired neonatal survivability and development.     

Relationships between ovulation rate and litter size in purebred Landrace and Yorkshire gilts

The aim of the present study was to investigate the ovulation rate and its relationship to number of total piglets born in purebred gilts under tropical climatic conditions. This study was conducted in two swine breeding herds (A and B) in the northeastern part of Thailand. The sources of swine genetic material originate from West Europe. Gilts were mated (AI) on the second or later observed estrus at a body weight of at least 130 kg. In most cases, they were mated at third estrus. One hundred and twenty-seven gilts, 24 Landrace and 24 Yorkshire from herd A, and 42 Landrace and 37 Yorkshire from herd B were used. Gilts were examined once by laparoscopy under general anesthesia between days 8 and 15 after mating. The ovaries were examined and the pathological findings were recorded. The number of corpora lutea was counted, and was assumed to equal the ovulation rate. Subsequent mating results and farrowing data were recorded. The data were analyzed with analysis of variance. Single or double unilateral cysts and par-ovarian cysts did not affect mating results. Landrace gilts were significantly younger at first mating than Yorkshire gilts (244 versus 249 days, P < 0.05). At first mating, Yorkshire gilts had a significantly higher ovulation rate compared to Landrace gilts (15.3 versus 13.8, P < 0.001). There was no difference in the number of total piglets born per litter between the two breeds, but the total prenatal loss from ovulation to farrowing was significantly higher in Yorkshire than in Landrace gilts. Both the low ovulation rate and the high prenatal loss contribute to the low litter size in gilts raised under tropical climatic conditions.     

Steroidome and metabolome analysis in gilt saliva to identify potential biomarkers of boar effect receptivity

Optimal management of gilt reproduction requires oestrus synchronization. Hormonal treatments are used for this purpose, but there is a growing demand for non-hormonal alternatives, especially in organic farms. The boar effect is an important alternative opportunity to induce and synchronize oestrus without hormones. Before puberty, gilts exhibit a ‘waiting period’ during which boar exposure could induce and synchronize the first ovulation. We searched for salivary biomarkers of this period of boar effect receptivity to improve detection of the gilts to stimulate with the perspective of enhancing the efficacy of the boar effect. Saliva samples were collected from 30 Large-White × Landrace crossbred gilts between 140 and 175 days of age. Gilts were exposed twice a day to a boar and subjected to oestrus detection from 150 to 175 days of age. Among the 30 gilts, 10 were detected in oestrus 4 to 7 days after the first introduction of the boar and were considered receptive to the boar effect, 14 were detected in oestrus more than 8 days after first boar contact, and six did not show oestrus and were considered non-receptive. Saliva samples from six receptive and six non-receptive gilts were analyzed for steroidome and for metabolome using gas chromatography coupled to tandem mass spectrometry and ¹H nuclear magnetic resonance spectroscopy, respectively. Four saliva samples per gilt were analyzed: 25 days and 11 days before boar introduction, the day of boar introduction, 3 days later for receptive gilts or 7 days later for non-receptive gilts. Twenty-nine steroids and 31 metabolites were detected in gilt saliva. Salivary concentrations of six steroids and three metabolites were significantly different between receptive and non-receptive gilts: progesterone and glycolate 25 days before boar introduction, 3α5β20α- and 3β5α20β-hexahydroprogesterone, dehydroepiandrosterone, androstenediol, succinate, and butyrate 11 days before boar introduction, and 3β5α-tetrahydroprogesterone on the day of boar introduction. Thus, nine potential salivary biomarkers of boar effect receptivity were identified in our experimental conditions. Further studies with higher numbers of gilts and salivary sampling points are necessary to ascertain their reliability.     

Induction of lactational estrus in organic piglet production

The longer lactation period required in organic piglet producing herds reduces the potential number of produced litters per sow per year compared with that of conventional production. Induction and use of lactational estrus may be a way to increase the productivity in organic production. However, if lactational estrus is to be beneficial under practical husbandry conditions, it is crucial that the majority of sows are successfully mated within a few days to make batch farrowing procedures possible. The objective of this study was to investigate the occurrence and timing of lactational estrus in an organic outdoor system based on ad libitum feeding, individual housing until Day 35 in lactation, followed by grouping and introduction of a boar and weaning of piglets after 8 wk. Five groups with four sows ((Danish Yorkshire × Danish Landrace) × Danish Duroc) in each were observed, and rank was determined by a food competition test. All sows showed lactational estrus, and 84% of these sows showed estrus within 1 wk, on average 43.5 d and 7.3 d after farrowing and boar introduction, respectively. The number of days from boar introduction to estrus increased significantly with increasing feed competition rank (the lowest number being the top rank position). Eighty-four percent of all sows were diagnosed pregnant 5 wk after estrus. Behavioral observations revealed that the average total number of copulations per estrus sow was 2.3 with a range of 0 to 5 copulations. The findings of the current study indicate that it is possible to combine lactational estrus and batch farrowing procedures to increase the number of weaned piglets per year per sow in organic piglet production based on 8 wk of lactation or more.     

Dietary supplementation with maize distillers dried grains with solubles during late gestation and lactation: Effects on sow and litter performance,and on colostrum and milk composition

The objectives of this study were to determine the effects of maize distillers dried grains with solubles (DDGS) during late gestation and lactation on sow and piglet performance, and on colostrum and milk composition. Thirty-six second- and third-parity (2.43 parity) sows (Yorkshire) were allotted to 1 of 3 groups and fed diets containing 0 (control), 200 or 400 g DDGS/kg during the last 20 d of gestation and throughout a 21 d of lactation. Experimental diets contained 12.9 MJ metabolizable energy/kg and 9.7 g lysine/kg. The colostrum and milk samples were obtained on d 0 (farrowing) and d 21 (weaning). There were no differences (P>0.05) in the sows’ average gestation lengths, weaning-to-estrus interval, average daily feed intake, and the lactation backfat and body weight change between dietary treatments. There were no dietary effects (P>0.05) of DDGS on the numbers of total, born alive piglets, average birth weights, piglets per litter at weaning or piglets average daily gain during lactation. No differences (P>0.05) were observed in total solids, protein, fat and lactose among the sows fed the DDGS diets compared with the control. The composition of total solids and protein of sows colostrum and milk were higher at farrowing (d 0) than at weaning (d 21) (P<0.001). However, the fat and lactose content of sows colostrum and milk were increased (P<0.001) from d 0 (farrowing) to d 21 (weaning). In conclusion, the results suggest that 400 g DDGS/kg (87 g lysine/kg) supplemented with 5.2 g lysine/kg included in late gestation and lactation diets is sufficient to replace all the dietary soybean meal without significantly affecting sow and litter performance or colostrum and milk composition.