Effect of oral progesterone and caffeine at the end of gestation on farrowing duration and piglet growth and survival

The profitability of pig production is constrained by high incidences of peri-parturient and pre-weaning piglet mortality. Supplementing sows with either progesterone or caffeine during the last week of gestation can reduce stillbirths and improve piglet performance. However, the consequences of combining these two substances has not been investigated. The aim of the current study was to determine the effect of oral supplementation of sows with progesterone (regumate) and caffeine at the end of gestation on the timing and progression of farrowing, as well as piglet survival and growth to weaning. From days 111 to 113 of gestation, 20 Large White pregnant sows (parity 3.0±0.45) received 5 ml of Regumate Porcine (0.4 w/v oral solution; MSD Animal Health) daily on top of their morning ration. Sows were stratified according to parity and predicted farrowing date, and allocated at random to receive a diet supplemented with either 0 g caffeine/kg diet (CONT) or 2.4 g of caffeine/kg diet (CAFF) from day 113 of gestation until parturition (n=10 sows/treatment). Treatment did not affect total litter size; however, CONT sows gave birth to more live and fewer dead piglets compared with CAFF sows; 14.5±0.73 v. 11.7±1.03 and 0.7±0.20 v. 3.2±0.77; P<0.05). Mean, minimum and maximum piglet birthweight were unaffected by treatment. Compared with the control, caffeine increased the proportion of piglets with a birthweight <1 kg (0.16±0.05 v. 0.05±0.02; P=0.072) and decreased the proportion of live born piglets surviving to day 5 postpartum (0.77±0.06 v. 0.90±0.02; P<0.05) and to weaning (0.74±0.06 v. 0.90±0.02; P<0.05). Overall, the current data provided the first evidence that caffeine supplementation of sows receiving progesterone to prevent premature farrowing impaired piglet survival during, and shortly after parturition. This negative outcome may be linked to extended farrowing durations and an increase in the proportion of very light piglets at birth. These data provide compelling, albeit preliminary, evidence that caffeine and progesterone should not be used together at the end of gestation.     

The effect of farrowing environment and previous experience on the maternal behaviour of sows in indoor pens and outdoor huts

Outdoor farrowing huts facilitate a less restricted maternal behaviour in sows compared with sows kept indoors in farrowing pens. The aim of our study was to investigate whether there are behavioural differences between primiparous sows kept outdoors in farrowing huts and indoors in pens, and whether the maternal behaviour during the second parity, when all sows were kept outdoors in farrowing huts, would differ between sows that have experienced the indoor or the outdoor environment, respectively, during their first parturition. A total of 26 Yorkshire×Swedish Landrace sows were studied. Of these, 11 sows were housed outdoors in farrowing huts during both parturitions (group=OUTOUT). The other 15 sows were kept indoors in a barn with single farrowing pens during their first parturition. During their second parturition, sows were kept outdoors in farrowing huts (group=INOUT). The behaviour was video recorded from 2 h prepartum to 48 h postpartum. The sows’ responsiveness to playbacks of a piglet’s screams was tested on days 2 to 3 postpartum. Parity 1: during the last 2 h prepartum, OUTOUT sows had a higher proportion of observations in the sternal lying position (P<0.01). During parturition, OUTOUT sows changed posture more often (P<0.05) and were lying less (P<0.05) than INOUT sows. All sows in both groups responded with ‘lifting head’ towards the playback of piglet scream, whereas 100% of OUTOUT sows and only 43% of INOUT sows thereafter were ‘getting up’ (P <0.01). Parity 2: There were no behavioural differences between INOUT and OUTOUT sows. In conclusion, it is not problematic for a second parity sow with initial maternal experience from an indoor farrowing pen to be kept outdoors in farrowing huts during its following farrowing.     

Factors affecting piglet mortality during the first 24 h after the onset of parturition in large litters: effects of farrowing housing on behaviour of postpartum sows

The present study aimed to identify the factors that affect immediate (within 24 h after farrowing onset) postnatal piglet mortality in litters with hyperprolific sows, and investigate their associations with behaviour of postpartum sows in two different farrowing housing systems. A total of 30 sows were housed in: (1) CRATE (n=15): the farrowing crate closed (0.80×2.20 m) within a pen (2.50×1.70 m), and (2) OPEN (n=15): the farrowing crate open (0.80×2.20×1.80 m) within a pen (2.50×2.40 m) with a provision of 20 ls of hay in a rack. A total of 518 live born piglets, produced from the 30 sows, were used for data analyses during the first 24 h after the onset of parturition (T24). Behavioural observations of the sows were assessed via video analyses during T24. Total and crushed piglet mortality rates were higher in OPEN compared with CRATE (P<0.01, for both). During T24, the OPEN sows tended to show higher frequency of postural changes (P=0.07) and duration of standing (P=0.10), and showed higher frequencies of bar-biting (P<0.05) and piglet trapping (P<0.01), when compared with the CRATE sows. During T24, the mortality rates caused by crushing were correlated with the piglet trapping event (r=0.93, P<0.0001), postural changes (r=0.37, P<0.01), duration of standing (r=0.32, P<0.01) and frequency of bar-biting behaviour (r=0.51, P<0.01) of the sows (n=30). In conclusion, immediate postnatal piglet mortality, mainly due to crushing, may be associated with potential increases in frequency of postural changes, duration of standing and incidence of piglet trapping in postpartum sows in the open crate system with large litters.     

The effect of hessian and straw as nesting materials on sow behaviour and piglet survival and growth to weaning

Sows are strongly driven to build a nest prior to farrowing, and the performance of this behaviour is linked to the environment in which the animal is housed. The aim of this study was to investigate the impact of two nest-building materials, hessian and straw, on peri-parturient sow behaviour, plasma cortisol concentration and piglet survival and performance in farrowing crates. In the first experiment, sows (parity 1.7 ± 0.1) were allocated to four treatments: (n = 15), straw provided in the lead up to farrowing in an open farrowing pen, with the pen closed after farrowing (STRAW OPEN); (n = 14), straw provided in the lead up to farrowing in a closed farrowing pen (STRAW CLOSED); (n = 15), a closed farrowing pen with hessian sacks provided in the lead up to farrowing (HESSIAN) and; (n = 13), a closed farrowing pen with no nesting materials provided (CONTROL). A second experiment was performed on a separate farm to assess the effect of the same four treatments were applied to sows (parity 2.9 ± 0.1): SRAW OPEN (n = 68), STRAW CLOSED (n = 64), HESSIAN (n = 66) and CONTROL (n = 66), at a commercial level. The first experiment revealed that providing conventionally housed sows with straw or hessian in the lead up to parturition stimulated sows to perform nest-building behaviours similar to sows housed in an open pen with access to straw (nosing events; 16 ± 11 (CONTROL); 169 ± 36 (HESSIAN); 118 ± 29 (STRAW CLOSED); 199 ± 53 (STRAW OPEN); P < 0.05). Additionally, crated sows provided with straw had reduced cortisol levels immediately after farrowing compared to all other treatments (21.9 ± 6.1 ng/ml vs CONTROL; 49.3 ± 8.6 ng/ml; P < 0.01). Piglets born to STRAW CLOSED sows displayed the highest colostrum intake levels (404.8 ± 22.7 g vs CONTROL 361.9 ± 21.9 g; P < 0.01). The second experiment demonstrated a reduced incidence of piglet mortality both prior to fostering (0.7 ± 0.2; P = 0.001) and after fostering (0.7 ± 0.2; P = 0.001) in litters born to sows which were housed in conventional farrowing crates and provided with straw compared to CONTROL (prior to fostering 1.3 ± 0.2, and postfostering 1.1 ± 0.2). In conclusion, straw and hessian sacks are a suitable substrate for stimulating sows to exhibit nest-building behaviour under crated conditions. However, only the provision of straw in the crate environment improved piglet survival and positively affected sow welfare.     

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.     

Supplementing sow diets with palm oil during late gestation and lactation: effects on milk production,sow hormonal profiles and growth and development of her offspring

The supplementing of sow diets with lipids during pregnancy and lactation has been shown to reduce sow condition loss and improve piglet performance. The aim of this study was to determine the effects of supplemental palm oil (PO) on sow performance, plasma metabolites and hormones, milk profiles and pre-weaning piglet development. A commercial sow ration (C) or an experimental diet supplemented with 10% extra energy in the form of PO, were provided from day 90 of gestation until weaning (24 to 28 days postpartum) in two groups of eight multiparous sows. Gestation length of PO sows increased by 1 day (P<0.05). Maternal BW changes were similar throughout the trial, but loss of backfat during lactation was reduced in PO animals (C: −3.6±0.8 mm; PO: −0.1±0.8 mm; P<0.01). Milk fat was increased by PO supplementation (C day 3: 8.0±0.3% fat; PO day 3: 9.1±0.3% fat; C day 7: 7.8±0.5% fat; PO day 7: 9.9±0.5% fat; P<0.05) and hence milk energy yield of PO sows was also elevated (P<0.05). The proportion of saturated fatty acids was greater in colostrum from PO sows (C: 29.19±0.31 g/100 g of fat; PO: 30.77±0.36 g/100 g of fat; P<0.01). Blood samples taken on 105 days of gestation, within 24 h of farrowing, day 7 of lactation and at weaning (28±3 days post-farrowing) showed there were no differences in plasma concentrations of triacylglycerol, non-esterified fatty acids, insulin or IGF-1 throughout the trial. However, circulating plasma concentrations of both glucose and leptin were elevated during lactation in PO sows (P<0.05 and P<0.005, respectively) and thyroxine was greater at weaning in PO sows (P<0.05). Piglet weight and body composition were similar at birth, as were piglet growth rates throughout the pre-weaning period. A period of 7 days after birth, C piglets contained more body fat, as indicated by their lower fat-free mass per kg (C: 66.4±0.8 arbitrary units/kg; PO: 69.7±0.8 arbitrary unit/kg; P<0.01), but by day 14 of life this situation was reversed (C: 65.8±0.6 arbitrary units/kg; PO: 63.6±0.6 arbitrary units/kg; P<0.05). Following weaning, PO sows exhibited an increased ratio of male to female offspring at their subsequent farrowing (C: 1.0±0.3; PO: 2.2±0.2; P<0.05). We conclude that supplementation of sow diets with PO during late gestation and lactation appears to increase sow milk fat content and hence energy supply to piglets. Furthermore, elevated glucose concentrations in the sow during lactation may be suggestive of impaired glucose homoeostasis.     

Evaluation of an on-farm method to assess colostrum IgG content in sows

The objective of this work was to investigate the evaluation of swine colostrum immunoglobulin G (IgG) concentration using the Brix refractometer. Colostrum samples were collected across all teats, from 124 sows of mixed parities. According to sampling time, three categories were created: samples available from 9 h before the onset of parturition until the first piglet was born were classified as before farrowing; samples collected after the first birth until 4 h later were classified as during farrowing; and finally samples collected from this point until 14 h after parturition, were classified as after farrowing. Samples were drawn and divided into three portions; one was immediately analyzed, a second was refrigerated and the third was frozen at −20°C. Fresh and refrigerated colostrum samples were analyzed at the farm with a Brix refractometer. IgG content of frozen samples was analyzed using a Brix refractometer, with a subset of 42 samples also tested with a commercially available radial immune diffusion (RID) kit. The Brix percentage ranged from 18.3% to 33.2%. Brix percentage repeatability, assessed by the intraclass correlation coefficient (ICC), was very strong (fresh ICC=0.98, refrigerated ICC=0.88 and frozen ICC=0.99). One-way repeated-measures ANOVA showed that storage temperature did not affect BRIX percentage of colostrum IgG (P>0.05). ANOVA results show a significant effect of sampling time on colostrum immunoglobulin concentration, measured with both Brix and RID (Brix: P<0.003; RID: P<0.05). Immunoglobulin G concentration measured by RID ranged from 13.27 to 35.08 mg/ml. Pearson correlation coefficient revealed that Brix percentage was positively correlated (r=0.56, P<0.001) with RID results (regression equation: RID=1.01 (±0.2) Brix −1.94 (±5.66); R²=0.31). The results of this study indicate that the Brix refractometer provides a simple, fast and inexpensive estimation of colostrum IgG in sows.     

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

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

Short Communication: effect of positive handling of sows on litter performance and pre-weaning piglet mortality

Fear and environmental stressors may negatively affect the welfare of farm animals such as pigs. The present study investigated the effects of music and positive handling on reproductive performance of sows (n = 1014; parity 1 to 8) from a commercial pig farm practicing a batch farrowing system. Every 2 weeks, 56 sows were moved from the gestation unit to conventional-crated farrowing houses 1 week prior to expected farrowing. Treated (T; n = 299) and control (C; n = 715) sows were included in the study. In the farrowing houses, auditory enrichment (music from a radio) was provided to sows of T groups daily from 0600 to 1800 h until the end of lactation. Until the day of farrowing, T sows were additionally subjected, for 15 s per day per sow, to continuous back scratching by one member of farm staff. Litter performance and piglet mortality were recorded and analysed between T and C sows using linear mixed regression models. The number of liveborn piglets (C 13.85 v. T 13.26) and liveborn corrected for fostering (C 13.85 v. T 13.43) was significantly higher (P < 0.05) in C groups compared to the T groups. The number of stillborn piglets was 0.60 and 0.72 in T and C groups, respectively (P > 0.05). With regard to piglet mortality, a linear mixed regression model showed a significant overall effect of treatment in reducing piglet mortality (P < 0.01). Yet, the effect of treatment varied according to litter size (number of liveborn piglets) with a diminishing treatment effect in sows with a high litter size (P < 0.01). Pre-weaning survival was improved in the current study by the combined effect of daily back scratching of sows prior to farrowing and providing music to sows and piglets during lactation. Further research is needed to assess the separate effects of both interventions.     

Confinement of lactating sows in crates for 4 days after farrowing reduces piglet mortality

To reduce mortality among suckling piglets, lactating sows are traditionally housed in farrowing crates. Alternatively, lactating sows can be housed in farrowing pens where the sow is loose to ensure more behavioural freedom and consequently a better welfare for the sow, although under commercial conditions, farrowing pens have been associated with increased piglet mortality. Most suckling piglets that die do so within the first week of life, so potentially lactating sows do not have to be restrained during the entire lactation period. Therefore, the aim of the current study was to investigate whether confinement of the sow for a limited number of days after farrowing would affect piglet mortality. A total of 210 sows (Danish Landrace × Danish Yorkshire) were farrowed in specially designed swing-aside combination farrowing pens measuring 2.6 m × 1.8 m (combi-pen), where the sows could be kept loose or in a crate. The sows were either: (a) loose during the entire experimental period, (b) crated from days 0 to 4 postpartum, (c) crated from days 0 to 7 postpartum or (d) crated from introduction to the farrowing pen to day 7 postpartum. The sows and their subsequent litters were studied from introduction to the combi-pen ∼1 week before expected farrowing and until 10 days postpartum. Confinement period of the sow failed to affect the number of stillborn piglets; however, sows that were crated after farrowing had fewer live-born mortality deaths (P < 0.001) compared with the sows that were loose during the experimental period. The increased piglet mortality among the loose sows was because of higher mortality in the first 4 days after farrowing. In conclusion, the current study demonstrated that crating the sow for 4 days postpartum was sufficient to reduce piglet mortality.     

The effects of chronic environmental stress on parturition and on oxytocin and vasopressin secretion in the pig

Previous work has suggested that an acute behavioural confinement in mid-partum can inhibit oxytocin secretion and prolong delivery in the pig, an effect that is opioid mediated. The present experiment investigated the effect of longer-term (chronic) behavioural confinement, that has previously been shown to elevate total plasma cortisol, on speed of delivery and on plasma oxytocin and lysine vasopressin concentrations during the peri-parturient period in primiparous pigs (gilts). Five days before their expected parturition (farrowing) date, gilts with preplaced jugular catheters were either confined to farrowing crates that severely restricted maternal behaviour, or housed in pens that permitted free movement and maternal behaviour (e.g. nest building). Blood samples were taken continuously from 24 h before the birth of the first piglet (BFP) to 6 h post-BFP, and for oxytocin on Days 1, 2, and 7 following parturition (Days P1, P2, P7). Both oxytocin and vasopressin were strongly influenced by parturition (P<0.001). There was no overall effect of chronic crating on either hormone, but crated and penned gilts did show significant differences with respect to the pattern of both oxytocin and vasopressin concentrations over time (P<0.05 in both cases). Oxytocin and vasopressin first increased in crated and penned gilts from 3 h pre-BFP (P<0.05). Crated gilts subsequently showed greater increases in both oxytocin and vasopressin over the first hour of delivery than penned gilts (mean oxytocin (pmol 1⁻¹): 53.3±8.5 vs. 39.7±5.0 for crated vs. penned gilts; mean vasopressin (pmol l⁻¹):4.4±0.7 vs. 2.0±04 for crated vs. penned gilts; both P<0.05). For oxytocin, crated gilts then showed subsequent declining concentrations relative to penned gilts (P<0.05). For vasopressin, penned gilts reached similar concentrations as crated gilts in the third hour post-BFP before vasopressin concentrations in both groups declined. Crated gilts also gave birth to piglets faster in the early stages of delivery (e.g. mean interval between Piglets 2 and 3 (min): 9.6±2.5 vs. 25.6±8.54 for crated and penned gilts, respectively: P<0.02). We conclude that confinement of gilts to a farrowing crate for 5 days neither adversely affects the progress of delivery in the primiparous pig nor the secretion of posterior pituitary hormones involved in parturition.     

The influence of azaperone treatment at weaning on reproductive performance of sows: altering effects of season and parity

Azaperone treatment can control aggression and decrease stress due to weaning, re-grouping and hierarchical fighting of gilts and sows. However, the effects of this butyrophenone neuroleptic and sedative administered at weaning on pig reproductive function are poorly characterized. In this year-long study, a total of 619 cross-bred sows (Polish Large White×Polish Landrace) kept on a commercial farm received an i.m. injection of azaperone (Stresnil®; 2 mg/kg BW) just before weaning and were artificially inseminated during the ensuing estrus with 3×10⁹ spermatozoa per dose of an inseminate; 1180 sows served as untreated controls. Immediately after weaning, the sows were moved to four pens of seven to nine animals each. A teaser boar was used twice daily to check for estrus and sows were bred at heat detection. Subsequently, all sows stayed in individual stalls until pregnancy testing on day 30 post-artificial insemination and were then re-grouped until farrowing. The proportion of pigs that were in estrus within 6 days post-weaning was significantly lower in azaperone-treated groups of animals than in controls (71.4% v. 84.2%). Overall, the azaperone-treated sows had a significantly longer weaning-to-estrus interval (WEI; 8.7±10.1 v. 6.3±8.1 days; mean±SD) and a significantly larger litter size (LS: 11.8±3.0 v.11.3±3.2; azaperone-treated v. control sows). Treatment of the winter-farrowing sows was associated with increased LS (12.8±2.6 and 11.3±3.1 piglets/sow, respectively; P<0.05) and longer (P<0.05) weaning-to-effective-service intervals (11.7±19.3 and 8.4±12.3 days, respectively) as well as farrowing intervals (155.7±19.7 and 152.2±16.1 days, respectively) compared with untreated controls. In the summer months, significantly longer WEIs (12.1±21.0 v. 8.4±16.9 days) were accompanied by a significant decline in LS only in azaperone-treated sows that were inseminated within 6 days post-weaning (10.8±2.9 v. 11.5±3.3 piglets/sow; azaperone-treated v. controls). Azaperone-treated second parity sows had greater LS (P<0.001) along with prolonged WEIs (P<0.05) in comparison to their respective controls, regardless of the timing of estrus. An application of azaperone at weaning increased the annual piglet productivity of winter-farrowing animals and of second parity sows but depressed it significantly in summer. The extra cost and labor due to delayed onset of estrus may cancel out any reproductive benefits of azaperone treatment.     

Validation of Brix refractometer to estimate colostrum immunoglobulin G content and composition in the sow

Colostrum is an essential source of immunoglobulin G (IgG) for neonate piglets. However, colostrum IgG content and nutritional composition can vary considerably among sows due to age, parity, feeding regime and immunological background. Currently, there is no practical way to obtain information about colostrum IgG concentration at herd level. We evaluated sows’ colostrum IgG content on-farm using a Brix refractometer and its performance was compared with that of an IgG ELISA. In addition, nutritional compositions of the colostrum samples were analyzed using Fourier transform IR spectroscopy. Colostrum samples (5 to 6 ml) (n=153) were obtained within 0 to 3 h of farrowing. However, to obtain a 24 h IgG profile for 11 sows, colostrum samples were collected at 0, 2, 4, 6, 8, 10, 16 and 24 h after farrowing. A 0.3 ml of freshly drawn colostrum sample was used for the on-farm measurement of Brix percentages using a digital refractometer shortly after collection. The remaining fractions of the samples were frozen and submitted to laboratory analysis for total IgG, using a commercially available pig IgG ELISA kit. For nutritional composition analysis, a 35 ml colostrum sample (n=34) was obtained immediately after birth of first piglet from the first three pairs of frontal teats. Colostrum concentrations of IgG averaged 52.03±30.70 mg/ml (mean±SEM) at 0 to 3 h after farrowing. Concentration of IgG decreased on average by 50% during the 1st day of lactation (P<0.01). Sow parity did not influence colostrum concentrations of IgG. Differences in colostrum composition were recorded between two herds and among the parity groups (P<0.05). The Brix refractometer measurement of colostrum and the corresponding log transformed IgG measurements from the ELISA were moderately correlated (r=0.63, P<0.001, n=153). Based on the classification we suggest here, low levels of IgG (14.5±1.8 mg/ml) were recorded for colostrum samples with Brix readings below 20%. Borderline colostrum IgG content (43.8±2.3 mg/ml) had Brix readings of 20% to 24%, adequate colostrum IgG content (50.7±2.1 mg/ml) had Brix % readings of 25% to 29% and very good IgG colostrum content (78.6±8.4 mg/ml) had Brix readings >30%. Colostrum IgG concentration is highly variable among sows, Brix measurement of a sows’ fresh colostrum is an inexpensive, rapid and satisfactorily accurate method of estimating IgG concentration, providing indication of differentiation between good and poor IgG content of colostrum.     

Short confinement of sows after farrowing,but not pen type affects live-born piglet mortality

Over the last decades, permanent crating of farrowing and lactating sows has led to serious public concerns with regard to sow welfare. As one alternative, it has been suggested to restrict crating to the period when suckling piglets are at the highest risk to die. Therefore, the aim of this study was to investigate live-born piglet mortality with regard to different confinement periods (CFP) as well as farrowing pen types. On three research farms (A, B and C), four confinement periods were compared: In CFP 0 (control), sows were not confined at all, sows in CFP 3 were crated after the end of farrowing for three days. In CFP 4, sows were confined one day before the due date of farrowing until three days after parturition and sows in CFP 6 were crated one day before expected farrowing until five days after parturition. Furthermore, five different pen types designed for temporary crating (PT; 5.5–7.3 m²) were compared. In total, production data from 638 litters were analysed. For each piglet found dead (n = 1 580), the cause of death was determined by the farm personnel and verified by necropsy (all three farms) and additional video analysis (farms A and B only). Data were analysed using logistic mixed models with CFP 0 and pen type Fluegel as reference categories (CFP 0 was control and this pen type was present on all three farms and the largest number of litters was born in this pen type). Live-born piglet mortality was lower in temporarily crated sows than in sows without confinement (CFP 0; P < 0.015). Pairwise posthoc tests did not reveal differences between CFP 3, CFP 4 and CFP 6 (odds ratios 0.75, 0.59 and 0.69), nor between pen types. Additional factors associated with increasing live-born piglet mortality were larger litter size, higher sow parity as well as the administration of hormones around farrowing. Factors influencing mortality due to crushing were similar to those for total live-born mortality with the exception of CFP 3 not differing significantly from CFP 0. It can be concluded, that confinement of the sow for three days after farrowing is an effective measure to reduce live-born piglet mortality in the pen types tested. An extension of the confinement period to five days after parturition does not result in a further reduction of live-born mortality rate.     

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.     

Sow and piglet factors determining variation of colostrum intake between and within litters

Colostrum intake has a short- and long-term beneficial impact on piglet performance and mortality. Sows’ colostrum production and piglets’ colostrum intake are limited and highly variable. The present study investigated sow and piglet factors explaining the variation of colostrum intake between and within litters. The CV for colostrum intake and birth weight (BW_b) of all piglets within a litter was calculated to evaluate the variation of colostrum intake and BW_b within a litter (colostrum and litter BW_b heterogeneity, respectively). A total of 1937 live-born piglets from 135 litters from 10 commercial herds were included. Colostrum intake per piglet averaged 371±144 g and was affected by breed (P=0.02). It was lower when oxytocin was administered to the sow during parturition (P=0.001) and with increased litter size (P<0.001). It was higher when the interval between birth and first suckling decreased (t_FS, P<0.001). Colostrum intake was positively influenced by BW_b (P<0.001) and this association was more pronounced in piglets from Topigs (P=0.03) and Hypor (P=0.03) sows compared with piglets from Danbred sow breeds. The positive relationship between colostrum intake and BW_b was more pronounced when t_FS lasted longer (P=0.009). Heterogeneity in colostrum intake averaged 31±11%, it increased when oxytocin was applied during farrowing (P=0.004) and when stillbirth occurred (P=0.006). Colostrum heterogeneity was positively associated with litter size (P<0.001) and litter BW_b heterogeneity (P=0.01). The positive relationship between colostrum and litter BW_b heterogeneity was more pronounced when oxytocin was applied during farrowing (P=0.04). The present study demonstrated that oxytocin should be used cautiously in sows during farrowing. Farrowing and colostrum management should prevent or counteract the adverse influences of stillbirth, large and heterogeneous litters on colostrum intake and colostrum heterogeneity. The study also confirmed the expected association between BW_b and colostrum intake and indicated that the impact of BW_b on colostrum intake was different among breeds (Hypor v. Danbred) and dependent on piglets’ latency to first suckling. Hence, colostrum management should focus on low birth weight piglets, especially in some breeds, and low colostrum intake in low birth weight piglets can be counteracted by shortening the t_FS.     

A cross-sectional study to collect risk factors associated with stillbirths in pig herds

The aim of this study was to identify risk factors for stillborn piglets at herd level in commercial pig herds. A written questionnaire, containing semi-open questions directly or indirectly related to stillborn piglets, was sent to 250 randomly selected pig herds (>150 sows) in northern Belgium. In total 111/250 questionnaires were returned (response rate of 44.4%) and 107 were valid for analysis. The average reported frequency of stillbirth was 7.5% (S.D. 2.8%). The relationship between risk factors and stillbirths was evaluated with a generalized linear effects model with the percentage of stillborn piglets as outcome variable. Type of breed used on the farm was significantly (P < 0.01) associated with the percentage of stillborn piglets. A high temperature in the farrowing unit (≥22 °C compared to <22 °C) was associated with significantly (P < 0.01) more stillbirths, whereas showering sows with warm water before parturition resulted in significantly less stillbirths (5.8%) than no showering (7.7%) (P < 0.01) and was not significantly different from showering with cold water (7.0%) (P = 0.26). When supervision of farrowing was performed occasionally, significantly more stillbirths (8.1%) were observed in comparison with no attending to farrowing (6.5%) (P < 0.01) or frequent supervision of farrowing (6.9%) (P < 0.01). Significant interactions were found between breed and showering sows prior parturition or supervision of sows at parturition, and between temperature in the farrowing unit at parturition and showering procedure of the sows. In conclusion, this study has clearly demonstrated that breed is a major factor involved in the frequency of stillbirth. Additionally, some management practices before or at parturition may reduce the number of stillborn piglets.     

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

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

The behaviour and welfare of sows and piglets in farrowing crates or lactation pens

Temporary confinement during parturition and early postpartum may provide an intermediary step preceding loose housing that offers improvement in sow and piglet welfare. Three experiments were conducted to investigate the implications of replacing farrowing crates (FCs) with an alternative housing system from 3 days postpartum until weaning. In each experiment sows farrowed in FCs and were randomly allocated at day 3 of lactation to either a FC or a pen with increased floor space (lactation pen (LP)) until weaning. In experiment 1, piglet growth and sow and piglet skin injuries were recorded for 32 sows and 128 focal piglets in these litters. Behaviour around nursing and piglet behavioural time budgets were also recorded for 24 of these litters (96 focal piglets for time budgets). In experiment 2, measures of skin injury and behavioural time budgets were conducted on 28 sows and 112 focal piglets. The behavioural response of sows to piglet vocalisation (maternal responsiveness test (MRT)) was also assessed. In experiment 3, piglet mortality from day 3 of lactation until weaning was recorded in 672 litters over 12 months. While housing did not affect piglet weight gain in experiment 1, or piglet skin injuries in experiments 1 or 2, sows in both experiments sustained more injuries in LP than FC (experiment 1, 2.9 v. 1.4; experiment 2, 2.5 v. 0.8 lesions/sow; P<0.05). Sow–piglet interactions were more frequent in LP than FC at days 11 and 18 postpartum in both experiment 1 (day 11, 1.4% v. 1.2%; day 18, 1.7% v. 1.0% of observations; P=0.05) and 2 (day 11, 1.0% v. 0.3%; and at day 18 were 1.0% v. 0.6% of observations; P<0.01), and LP sows were more responsive in the MRT in experiment 2 (2 v. 0 median number of tests in which sows react, P<0.01). In experiment 1 piglets played more (0.7% v. 0.3% of observations, P=0.05) and manipulated others less (0.3% v. 0.7% of observations, P=0.04) in LP, but more piglets missed nursing bouts (0.2 v. 0.1 piglets/bout, P<0.01) compared with FC. There was no effect of housing on piglet mortality from day 3 of lactation until weaning in experiment 3 (0.63 and 0.64 deaths/litter for LP and FC, respectively, P>0.05). Thus, housing sows and litters in LP from day 3 of lactation minimises piglet mortality while improving maternal behaviour in sows and social behaviour in piglets.     

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.