Effects of sow-crate design on sow and piglet behavior

The effects of sow-crate design on certain behaviors of sows and piglets at farrowing and again approximately 3 wk later were evaluated with a 2 x 2 x 4 factorial arrangement of crate width (narrow [N = 55 cm] or wide [W = 64] between lowest horizontal pipes), length (short [S = 183 cm] or long [L = 198] from rump stop to front gate) and side type (lower side of sow crate "fingered" [F], "bowed" bottom bar 20 cm above the floor [B], or straight bottom bar 20 cm [S20] or 25 cm above the floor [S25]). Farrowing-crate design influenced both sow and piglet behaviors both during and immediately after parturition and during nursing-suckling bouts approximately 3 wk later. Activities of 51 sows and their piglets were videorecorded during and immediately following parturition. Sow-crate design affected neither the interval between births of successive piglets in a litter nor the frequency of standing by the sow during parturition. Latency from birth to first mammary contact (LMC) was greater with S25-sided and S sow crates, and especially with S, W crates. A significant interaction occurred between sow-crate side type and dimensions; LMC was longer when S25 sides were combined with S or W crates. Data on suckling behavior were collected from 113 litters over three successive sucklings approximately 3 wk after farrowing. Sow-crate design had no effect either on the consistency with which a piglet suckled a particular teat or teat pair or on the frequency of multiple-teat use. Piglets maintained fewer functional teats with S, S20 crates. The distribution of functional teats between rows was less symmetric with S crates. Piglets nursed with their bodies over a side bar more frequently with B- and S20-sided crates. The sow permitted her piglets to suckle while she was in a vertical stance more frequently with S and N crates, and especially with S, N crates. Sow-crate design affected important behaviors of sows and piglets both during and immediately after parturition as well as during nursing-suckling bouts about 3 wk later.     

Impacts of a freedom farrowing pen design on sow behaviours and performance

The limited space in farrowing crate imposes many challenges, such as prolonged farrowing duration and high piglet stillbirth rate. Although the features of farrowing pens compensate for the drawbacks of farrowing crates, they are associated with high piglet crushing mortality caused by the greater space afforded to sows and their rolling-over behaviour. Therefore, a freedom farrowing pen was designed to overcome the drawbacks of both farrowing crates and farrowing pens. The main features of the freedom farrowing pen are its left anti-crushing bar and detachable right anti-crushing bar on the sides of the sow lying area. It also has a 10 cm-high anti-crushing bar in the non-lying area. Eighteen healthy, multiparous Yorkshire sows (3-7 parity) were averaged and randomly assigned to farrowing crates, farrowing pens, and freedom farrowing pens to compare the effects of the farrowing systems on sow behaviour and performance. Results showed that the farrowing duration and the mean piglet birth intervals were longer for the sows in farrowing crates than for those in farrowing pens and freedom farrowing pens (P<0.05), but there was no difference between the sows in farrowing pens and those in freedom farrowing pens (P>0.05). The piglet stillbirth rate was higher for the sows in farrowing crates than for those in farrowing pens and freedom farrowing pens (P<0.001). Crushing mortality was higher among piglets in farrowing pens (P<0.001), but there was no difference between piglets in freedom farrowing pens and those in farrowing crates (P>0.05). The freedom farrowing pen and the farrowing pen allowed sows to turn around and move freely, but because of the different structures of their anti-crushing bars, the increase in sow movement did not cause higher piglet crushing mortality (P>0.05). Sows in freedom farrowing pens were found to be more protective of their piglets.     

Effects of late introduction of sows to two farrowing environments on the progress of farrowing and maternal behavior

To evaluate the effect of late introduction to farrowing pens on the progress of farrowing and maternal behavior, 20 primiparous and 20 multiparous sows were allocated randomly to 1 of 2 treatments: 1) early introduction to pen (EP, n = 20) and 2) late introduction to pen (LP, n = 20). To evaluate the difference between loose-housed sows and crated sows when introduced late to the farrowing environment, a third treatment was included: late introduction to farrowing crate (LC, n = 20). Sow behavior and piglet birth intervals were recorded using video recordings from 16 h before the birth of the first piglet (BFP) until 48 h after BFP. Behavioral data were analyzed using PROC MIXED in SAS and the percentage of stillborn piglets and the response of the sow to piglet scream were analyzed using PROC GENMOD in SAS. Before farrowing (16 to 3 h before BFP), sows introduced late to pens had more postural changes per hour than sows introduced early to pens (LP = 12.7, EP = 8.9; P = 0.04), whereas there were no differences between sows introduced late to crates and sows introduced late to pens (LC = 14.2, LP = 12.7; P = 0.53). Interbirth interval (P = 0.04), variation in the interbirth interval (P = 0.01), and percentage of stillborn piglets (P = 0.003) were affected by an interaction between parity and treatment. In multiparous sows there were no differences between treatments (P > 0.18) either in the progress of farrowing or in the percentage of stillborn piglets. For primiparous sows, there were no differences (P > 0.22) between sows that were introduced late to pens and sows that were introduced early to pens. Primiparous sows that were introduced late to crates compared with pens had longer interbirth intervals (LC = 29 +/- 4.9 min, LP = 16 +/- 2.9 min; P = 0.02), a greater variation of these intervals (LC = 35 +/- 8.3 min, LP = 16 +/- 3.6 min; P = 0.006), and a greater percentage of stillborn piglets (LC = 21%; 95% confidence interval ranging 14 to 30%, LP = 5%; 95% confidence interval ranging from 2 to 12%; P = 0.004). After farrowing, neither postural changes, time spent in lateral lying, number of near-crushing situations, nor the response to piglet scream test were affected by treatment (P > 0.09). When sows and gilts were introduced late to farrowing pens, neither progress of farrowing nor maternal behavior of importance for piglet crushing was influenced. However, crating primiparous sows that were introduced late to the farrowing environment compared with pen housing had detrimental effects on the progress of farrowing and the percentage of stillborn piglets.     

Rolling behaviour of sows in relation to piglet crushing on sloped versus level floor pens

The study focused on the rolling behaviour of sows and the crushing of piglets by sows' rolling behaviour. The experiment examined the influence of sloped floor in loose housed farrowing pens on the rolling behaviour of sows and crushing of piglets. The experimental unit was made up of 24 pens. There were two experimental pen designs with piglet creep in the corner of the pen and piglet creep across the end of the pen, respectively. Both of the experimental pen designs had a 10% sloped floor in the sow's resting area. The two control pen designs were identical to the experimental pen designs, but with a level floor. The behaviour of 85 sows and their litters was continuously video recorded. Behavioural observations were made from birth of the first piglet and until 3 days after birth of the first piglet. Rolling behaviour of sows caused significantly more trapped piglets under the sow than lying down from standing (P = 0.04). Rolling behaviour caused 64% of the trapped piglets and lying down from standing caused 36% of the trapped piglets. Rolling from udder to side without protection trapped significantly more piglets than rolling from udder to side near slanted wall or piglet protection rails and rolling from side to udder (P < 0.001). With a certain pen design sloped floor reduced rolling from udder to side without protection (P = 0.007) and reduced the number of trapped piglets (P = 0.01), but results concerning lying behaviour showed that sloped floor pushed sows to rest on the level part of the floor. The results indicate that rolling behaviour that crushes piglets can be reduced, and sows prefer to lie on a level floor.     

A cohort study of preweaning piglet mortality and farrowing accommodation on 112 commercial pig farms in England

A cohort study was carried out on 112 breeding pig farms in England to investigate the impact of type of farrowing accommodation on preweaning mortality in piglets. Four types of farrowing accommodation were studied; farrowing crates, indoor loose pens, crate/loose systems (where the sow was restrained in a crate during birth and the first days of lactation before being moved to a loose pen) and outdoor farrowing in arcs in paddocks. Four estimates of preweaning mortality were collected: an oral estimate from the farmer before the visit, an estimate from the 6-month rolling average from computer records, records from 20 litters observed when the farm was visited and prospective records collected from 20 farrowings after the visit. These four estimates were significantly correlated. The prospective records also included a farmer reported date and cause of death. From the prospective data there were 25,031 piglets from 2143 litters from 112 farms, 6.5% of piglets were stillborn while live born preweaning mortality was 12%. Mixed effect discrete time survival, binomial and competing risk, models were used to investigate the association between preweaning mortality and farrowing accommodation, controlling for sow parity, litter size and number of piglets stillborn and fostered. There was a reduced risk of stillbirths in outdoor farrowing systems compared with crated systems. Farmers reported that crushing of healthy piglets was the most frequent cause of death accounting for 55% of live born preweaning mortality. There was no significant difference in mortality in live born piglets by farrowing system. There was a significantly higher risk of farmer reported crushing of healthy live born piglets in outdoor arcs compared with piglets reared with sows in farrowing crates and a significantly reduced risk of death from causes other than crushing in piglets reared outdoors or in crate/loose systems compared with piglets reared in crated systems. We conclude that, in the farms in this study, farrowing crates reduced the risk of preweaning live born mortality attributable to crushing but piglets in this system were at increased risk of death from other causes. Consequently crates had no significant effect on overall preweaning mortality percentage. In all four commercial production systems; outdoor, farrowing crates, crate/loose farrowing systems and indoor loose housed systems, there were similar levels of mortality.     

An assessment of the most profitable length of lactation for producing piglets of 20 kg body weight

Based on data derived from experiments and surveys carried out in several countries, the most profitable length of lactation for producing piglets of 20 kg body weight is assessed. The assessment is limited to a comparison of the numbers of piglets (20-kg) produced per sow per year at lactation periods varying from 6 to 56 days with the associated amounts of sow and piglet feed consumed and its costs. For the various lactation periods considered, several equations are used to estimate the numbers of 20 kg piglets produced and the amounts and costs of sow and piglet feed consumed per piglet raised to this body weight. According to the assessment, and taking into account reasonable piglet prices, the margins over feed costs per sow per year are highest with a lactation period of 21–25 days.     

The association between sow and piglet behavior

Sows in modern pig industry are often housed individually in farrowing crates a few days before farrowing until weaning. These farrowing crates limit movements of the sow and therefore also limit them in expressing their behavior. These limitations may lead to distress with the sow and can result in stereotypical behaviors. Because it is possible that the general behavior of the mother sow also influences her piglets, the hypothesis of the present study was that there is an association between the general behavior of sows and the behavior of their piglets. Our results showed that there was indeed an association between the postures and activities of sows and the behavior of their piglets, not only for nursing–suckling behavior. Results also indicated that piglets prefer resting when sows are resting. When sows were standing up, piglets were running around more. Although there were indications that piglets were more at ease when sows were bar biting compared with when they were sham chewing, a specific relationship between sow stereotypical behavior and piglet behavior could not be demonstrated in the present study. Though, it should be taken in mind that relatively low frequencies of stereotypical behaviors were observed. Furthermore, it could be that not only the prevalence of a specific stereotypical behavior is important but also a specific threshold of that specific behavior should be exceeded to induce effects on the suckling piglets. Alternatively piglets could coinduce stereotypical behavior of the mother sow.     

Exposure to maternal feces in lactation influences piglet enteric microbiota,growth, and survival preweaning

It is known that gilt progeny performance is reduced compared with sow progeny. Previous research suggests that the presence of maternal feces in early life improves the health and survival of offspring. Therefore, we aimed to determine whether contact with feces from multiparous (MP) sows would improve the growth and survival of piglets born and reared on primiparous (P1) sows and if so, whether these differences are associated with the gut microbiota. Four treatments were applied for 10 days: Donor (n = 29) piglets had limited access to maternal feces as, each morning, sow feces were removed and placed in the crate of a P1 sow (P1-FT; n = 30 piglets) and P1-Con (n = 29) and MP-Con (n = 33) piglets had access to their own mothers’ feces. All piglets were weighed on days 1, 3, 10, and 18. Fecal samples were collected from a subset of sows (n = 10/treatment) 3 days post farrow and from two female piglets/litter on days 10 and 18 (n = 20/treatment) and subject to 16S rRNA amplicon analysis. Escherichia, Clostridium, Campylobacter, and Treponema were more abundant in MP sows, while P1 sows had a higher abundance of Lactobacillus and Prevotella. At 10 days, P1 progeny fecal microbiota differed, and growth and survival were reduced when compared with MP progeny. No treatment effect was observed for P1-FT piglets (P > 0.05). Donor piglets had a different fecal microbiota and improved weight and survival then all other treatments (P < 0.05). Overall, the removal of sow feces from the farrowing crate improved piglet microbiota development, growth, and survival.     

Floor heating at farrowing in pens for loose-housed sows

The effects of floor heating at parturition on sow and piglet behaviour in pens were examined in a Danish production herd. A total of 50 gilts and sows were split into two groups; one (n = 25) experienced no treatment; one (n = 25) was exposed to floor heating in the area of the sow around parturition. The sows and piglets were recorded on video 24 h a day for behavioural analyses.Floor heating tended to improve piglet weight at weaning (P = 0.05) but did not affect average daily gain. Piglets in pens with floor heating were more often in proximity of the sow at posture changes than piglets from pens without floor heating on day one postpartum (P = 0.01). Floor heating did not affect duration of parturition or any of the recordings of sow behaviour significantly.     

Preweaning housing effects on behavior and physiological measures in pigs during the suckling and fattening periods

The effect of the preweaning housing system on the stress response of pigs before weaning and during fattening was studied in 33 litters of domestic pigs. Three preweaning housing systems were compared: barren crate (standard farrowing crate without straw), enriched crate (20% larger crate, with straw), and as a control, a farrowing pen (pen, 60% larger than the barren crate, with straw). At 25 d of age, pigs were tested with an isolation test and 1 d later with a human approach test (HumanT). Pigs were weaned at 28 d of age. At 3 and 6 mo of age, pigs were tested with an isolation-human approach test. The latency and frequency of squeal calls and locomotor activity were analyzed for all 3 tests, whereas physical contact with the human was also analyzed for the HumanT and isolation-human approach test. At 6 mo of age, the pigs were transported to a slaughterhouse. One day before transport, immediately after transport, and 1 h after transport, saliva samples were taken for cortisol analysis. The pH of the LM was also measured 45 min after slaughter. Preweaning housing system affected (P < 0.05) the probability of squeal vocalizations, the latency of locomotion, and the duration of locomotion during the HumanT. Pigs from the enriched pens vocalized less, had a longer latency to move, and performed less overall locomotion than pigs from the barren crates. Preweaning housing system did not affect behavior of fattening pigs. Cortisol concentrations before and after transport were not affected by preweaning housing system. An interaction of cortisol concentrations and housing systems was observed between the control sample and the sample taken immediately after transport in pigs from the barren crates (P < 0.05) compared with pigs from the enriched housing systems. Meat from pigs reared in the barren crate tended to have lower pH (P < 0.10) and that of pigs reared in enriched crates had lower pH (P < 0.05) than meat of pigs reared in enriched pens. No differences were observed between pigs from barren or enriched crates. Our results suggest that enrichment of the preweaning environment through enlarged space, provision of straw, and free movement for the sow had a positive effect on the coping behavior of pigs before weaning and prevented an increase in salivary cortisol concentration immediately after transport and a decrease in meat pH 45 min postmortem at the age of 6 mo. Minimal enrichment of the commercial farrowing crate did not affect behavior and physiological measures in pigs before and after weaning.     

Factors affecting piglet mortality in loose farrowing systems on commercial farms

Crating sows in farrowing systems greatly restricts their normal behaviour (e.g. movement, nest-building, leaving the nest site for defecation), which is usually justified by the assumption that piglet mortality is higher with loose-housed sows. Based on experiments showing that this is not the case, farrowing crates were banned in Switzerland in 1997, with a 10-year transitional period. Since then, many farms have introduced loose farrowing systems, enabling an analysis of risk factors for piglet mortality in crateless farrowing systems based on a large sample size. Data from a Swiss sow recording scheme (UFA2000) were analysed using generalised linear mixed-effects models with an underlying Poisson distribution. Average total piglet mortality for the years 2002 and 2003 on 99 farms (N = 12457 litters) with loose farrowing systems amounted to 1.36 liveborn piglets per litter. The number of crushed piglets was 0.64 piglets per litter, whereas the number of piglets that died for other reasons was 0.72 piglets per litter.Herd size, pen size, possibility of confinement of the sow, presence of piglet protection bars and year of data collection did not significantly influence total piglet losses, losses due to crushing and losses due to reasons other than crushing. With greater litter size at birth, significantly more losses occurred due to all reasons (total, crushed, others). Total piglet mortality and losses for reasons other than crushing were significantly higher in older sows. Losses were therefore mainly attributable to sow-related characteristics rather than to the design of the farrowing pen.     

Influence of thermal environment on sows around farrowing and during the lactation period

Our objective was to investigate the effects of floor heating duration (HEAT: 35°c for 12 or 48 h) after birth of first piglet (BFP) under different room temperatures (ROOM: 15°C, 20°C, 25°C) on sows during farrowing and lactation. The study included 8 to 11 repetitions for each combination of ROOM and HEAT. There were no treatment effects on indicators of birth problems (duration of parturition, interbirth intervals, umbilical cord lactate concentration), BW changes of the sow, and litter size and weight until weaning. Sows at 15°C compared with 20°C and 25°C spent more time nest building (P = 0.015). The feed intake was reduced the first 7 d after farrowing in sows at 25°C (P = 0.014); however, both daily feed intake (P = 0.018) and water consumption (P < 0.001) of these warm sows exceeded that at lower temperatures during the last part of the lactation. Sows at 15°C received more medical treatments until weaning at heat = 48 h only (ROOM and HEAT interaction, P = 0.005). Room temperature influenced prefarrowing water consumption (25°C > 20°C and 15°C; P < 0.017), sow surface temperature (15°C < 20°C < 25°C; P < 0.001), respiration rate (25°C > 20°C > 15°C; P < 0.001), and rectal temperature during the first 12 h after bfp (15°C < 25°C; P = 0.009); additionally, long floor heating duration (HEAT = 48 h) increased the respiration rate by 50% d 1 and 2 after bfp (p < 0.001). The proportion of lying time on the unheated slatted floor increased with room temperature (P < 0.001) and, transiently, also for the heat = 48 h treatment 13 to 48 h after BFP (P < 0.001). The majority of piglets (82% to 95%) were born on the heated solid floor, regardless of room temperature (P = 0.46). Sows spent approximately twice as much time standing and walking at 15°C during 13 to 48 h after BFP at HEAT = 12 h only (ROOM and HEAT interaction; P = 0.002). In conclusion, long-term indicators of reduced sow performance were unaffected by room temperature, probably because the farrowing and lactating sows in the current pen design were able to perform thermoregulatory behavior and successfully adapt to room temperatures between 15°C and 25°C.     

Immunoglobulins in piglets from sows heat-stressed prepartum

Sows were subjected to moderate heat stress in a chamber (32 C) from d 100 of pregnancy until less than 8 h before delivery of first piglet, while control sows were in a thermoneutral chamber (21 C) or farrowing house (22 C). Blood serum and colostrum at parturition of heat-stressed sows and their piglets' serum at birth had elevated cortisol concentrations. Total protein, globulin and immunoglobulin G (IgG) concentrations in sow serum tended to decrease as parturition time was approached; albumin did not change. Total protein and IgG concentrations in colostrum at parturition and in milk 24 and 48 h later tended to be lower in heat-stressed sows. Concentrations of these four protein fractions (total, globulin, IgG and albumin) in piglet serum at birth did not differ among treatment groups, but soon after colostrum ingestion they increased markedly in all groups. Therefore, in all groups total protein remained constant while globulin and IgG decreased. Globulin concentration on d 1 was lowest in piglets from heat-stressed sows, but its rate of decrease after d 1 was not affected by sow treatment. Immunoglobulin G concentration was 11 mg/ml lower, but its rate of decrease through postnatal d 20 was slower in piglets from heat-stressed sows than in those from control sows; a 10-mg/ml difference in IgG concentration on postnatal d 1 has been associated with increased preweaning mortality in piglets. Higher cortisol concentration in serum and lower IgG in colostrum of sows under heat stress was associated in their piglets with higher serum cortisol at birth and lower serum IgG for the first 20 d postnatum.     

Selection for litter size at day five to improve litter size at weaning and piglet survival rate

Selection for total number of piglets born (TNB) since 1992 has led to a significant increase in this trait in Danish Landrace and Danish Yorkshire but has also been accompanied by an increase in piglet mortality. The objective of this study was to estimate the genetic and phenotypic parameters for litter size and survival to find alternative selection criteria to improve litter size at weaning. Data from Landrace (9,300 litters) and Yorkshire (6,861 litters) were analyzed using REML based on a linear model including genetic effects of sow and service-sire. The estimates of heritability (based on the sow component) for TNB, number born alive (NBA), and number alive at d 5 after birth (N5D) and at weaning (about 3 wk, N3W) ranged from 0.066 to 0.090 in Landrace and 0.050 to 0.070 in Yorkshire. Genetic correlations between TNB and N3W were 0.289 in Landrace and 0.561 in Yorkshire, but between N5D and N3W the estimated genetic correlation was 0.995 in both populations. The approximate estimates of heritability for survival rate per litter at birth (SVB = NBA/TNB), from birth to d 5 (SV5 = N5D/NBA), and from d 5 to weaning (SVW = N3W/N5D) were 0.130, 0.131, and 0.023, respectively, in Landrace, and 0.095, 0.043, and 0.009, respectively, in Yorkshire. Genetic correlations between TNB and survival rates at different stages were negative. On the other hand, genetic correlations between N5D and survival rates and between N3W and survival rates were strongly or moderately positive, except for the correlations with SVW in Yorkshire. The results suggest that selection for N5D could be an interesting alternative to improve litter size at weaning and piglet survival for Danish Landrace and Danish Yorkshire.     

An exploratory study on the effects of a straw dispenser in farrowing crates

The effect of a straw dispenser in farrowing crates was investigated to determine the extent to which the provision of small quantities of straw has an influence on both sows and piglets. Sows and suckling piglets are often housed in barren environments with limited opportunities to show behavior they are highly motivated to perform. Enriching the environment might be a solution; for example, by providing materials that can be manipulated. In this study, 20 sows received a straw dispenser with chopped straw (treatment group) and 20 other sows did not receive any enrichment (control group). The treatment group was split up in 2: in treatment group A, the straw dispenser was placed in front of the sow, above the feed trough; and in treatment group B, the straw dispenser was placed next to the sow. Sows from the treatment groups received the straw dispenser from arrival in the farrowing crate until weaning. The total straw use within the treatment group was very variable but did not differ before and after farrowing. Sows took on average 53.0 g (±8.85) straw from the straw dispenser during the whole period in the farrowing crate. The frequency of undesirable and stereotypical behavior performed by the sows did not differ between treatment and control groups, and the same is seen with nest-building behavior before farrowing. By positioning the dispenser in front of the sow, the frequency of lateral lying increased, which means the udder was exposed more toward the piglets. This was reflected in the higher frequency of udder activity, performed by piglets from this treatment group. By positioning the dispenser next to the sow, sows showed more ventral lying behavior, because of disturbance of lying behavior by piglets. Piglets from this treatment group also showed less udder activity and possibly because of this, more pain-related behavior. These piglets performed more playing behavior in the third week of life compared with other groups, but it cannot be stated with certainty that this is a positive effect. A lower weight gain and weaning weight were seen in piglets within treatment group B. Possible explanations are the higher level of activity among these piglets as the straw dispenser was positioned within their reach or decreased milk consumption because of decreased udder activity and increased ventral lying by the sows. It can be concluded that the straw dispenser has positive effects on the behavior and welfare of sows and piglets, but positioning the straw dispenser in reach of both sow and piglets is not preferred as it is associated with undesirable effects on behavior such as ventral lying in sows and pain-related behaviors in piglets.     

Postweaning growth check in pigs is markedly reduced by intermittent suckling and extended lactation

The objective of this study was to determine whether intermittent suckling (IS) combined with an extended lactation can reduce postweaning growth check in pigs. Three weaning regimens [conventional weaning (CW), IS with 6-h separation intervals (IS6), and IS with 12-h separation intervals (IS12)] were compared. In CW (n = 17 litters), litters had continuous access to the sow until weaning (d 21, d 0 = farrowing). In IS6 and IS12, litters were separated from the sow for 12 h/d, beginning at d 14 and lasting until weaning (d 41 to 45). Litters were with the sow from 1400 to 2000 and from 0200 to 0800 (IS6, n = 14) or between 2000 and 0800 (IS12, n = 14). Litter size was standardized within 2 d after farrowing by crossfostering, resulting in an average litter size of 10.9 +/- 1.8 piglets. Piglets had ad libitum access to creep feed from d 7 onward. One week after the onset of IS (d 20), creep feed intake was increased in litters from both IS groups compared with CW litters (P < 0.05). Both IS groups consumed considerable amounts of creep feed before weaning (d 41 to 45). Total feed intake before weaning was greater (P = 0.004) in IS12 (3,808 +/- 469 g/piglet) than in IS6 (2,717 +/- 404 g/piglet). In comparison, CW litters consumed 18 +/- 9 g/piglet before weaning (d 21). Irrespective of weaning regimen, total feed intake of litters before weaning was highly correlated with post-weaning feed intake (P < 0.001). Furthermore, in all treatment groups, total preweaning feed intake was correlated with postweaning growth (P < 0.10). Irrespective of treatment, piglets suckling anterior teats grew faster than piglets suckling middle or posterior teats during the first 2 wk of lactation. Body weights at the end of the experiment (d 55) were similar among weaning regimens. Onset of IS induced a growth check in both IS groups (34% for IS12 and 22% for IS6). Only a mild growth check was observed after weaning of IS litters (14% for both IS groups). However, a serious growth check (98%) was observed after weaning of CW litters. Results of the current study indicate that IS stimulated feed intake during lactation, providing a more gradual transition to weaning. Because the IS6 regimen did not prevent the growth check after the onset of IS and is rather laborious, we suggest that IS12 might be preferable for a practical implementation of IS.     

Effect of nipple drinker water flow rate and season on performance of lactating swine.

A cooperative study involving six experiment stations and 236 crossbred litters was conducted to determine the effect of nominal nipple drinker water flows of 700 mL/min and 70 mL/min (actual = 701 and 76 mL/min, respectively) during winter (November through February; 124 litters) and summer (June through August; 112 litters) seasons on performance of lactating sows and their litters. Within a season, sows were paired according to expected farrowing date and assigned at random to crates. Water flow rate treatments were assigned at random to sows within pairs. Sows were housed in farrowing crates from d 109 of gestation until either d 21 (two stations) or d 28 of lactation (four stations). Within 24 h after farrowing, litters were adjusted to contain 8 to 12 piglets. Sow feed intake (SFI) and litter weight (LW) were recorded weekly. Sow weights were recorded at d 109 of gestation, d 0, and d 21 of lactation. Sows lactating beyond 21 d were also weighed on d 28. Analysis of covariance was applied to sow weight change, average daily SFI, and LW data where litter size after crossfostering was the covariate. Average ambient temperature 30 cm above the floor at 0830 and 1600 was 24.6 +/- 0.15 degrees C and 29.4 +/- 0.14 degrees C, respectively, during summer and 20.7 +/-0.13 degrees C and 21.8 +/- 0.11 degrees C during winter trials. Restricted drinker water flow rate decreased SFI (P < 0.01; 4.59 vs. 3.94 kg/d, respectively, for 700 and 70 mL/min) and increased BW loss (P < 0.01; 0.56 vs 0.89 kg/d, respectively for 700 and 70 mL/min) but did not affect litter size (P > 0.87) or LW (P > 0.89) during the first 21 d of lactation. During d 22 to 28, the 70 mL/min flow decreased SFI (P < 0.01; 5.02 vs. 4.47 kg/d respectively, for 700 and 70 mL/min). Over the 21-d lactation period, the 70 mL/min treatment depressed (P < 0.01) SFI more during the winter (5.12 vs. 4.24 kg/d for 700 and 70 mL/ min, respectively) than during the summer (4.05 vs 3.65 kg/d for 700 and 70 mL/min, respectively). Season affected SFI (P < 0.01; 4.68 vs. 3.85 kg/d, respectively, for winter and summer), sow weight loss (P < 0.001; 0.46 vs 0.83 kg/d, respectively, for winter and summer), and LW at 21 d (P < 0.05; 52.8 vs. 49.6 kg, respectively, for winter and summer) but not (P > 0.96) the number of pigs per litter. Results of this study suggest that ample access to drinking water and controlling ambient temperature during summer months are essential for sow and litter performance.     

Variables related to the progress of parturition and probability of stillbirth in swine

Sow and piglet variables related to probability of stillbirth and to viability score were analyzed in litters from 98 multiparous Yorkshire sows. Immediately after the birth of each piglet, viability was scored using Randall's method. Sow variables related to the probability of stillbirth were average birth weight of the litter (p = 0.0001), sow age (p = 0.001), sow condition score (p = 0.003), length of gestation (p = 0.005), and number of piglets in the litter (p = 0.01). Sow variables related to average viability score were average birth weight of the litter (p = 0.001), standard deviation in birth weight in the litter (p = 0.02), sow age (p = 0.03), sow condition score (p = 0.03), and length of gestation (p = 0.03). Piglet variables related to probability of stillbirth were piglet hemoglobin (p = 0.0001), position in the birth order (p = 0.0001), broken umbilical cord (p = 0.0004), and preceding birth interval (p = 0.0004). Piglet variables related to viability score were piglet hemoglobin (p = 0.0001), position in the birth order (p = 0.0001), broken umbilical cord (p = 0.0001), preceding birth interval (p = 0.0001), and birth weight (p = 0.004). Preceding birth interval was related to whether the piglet was live or stillborn (p = 0.0001), to position in the birth order (p = 0.003), and to the sex of the piglet (p = 0.03).

The results demonstrated that sow and piglet variables were highly correlated to probability of stillbirth and to viability score. In addition it was also found that the probability of stillbirth was not associated with the duration of farrowing but with the number of piglets in the litter and piglet hemoglobin level. This study also found that lower weight piglets tend to have poor viability, but are not more prone to stillbirth as commonly suggested. These low viability piglets may survive if the necessary care is given during the farrowing process.

     

Effect of oxygen inhalation at birth on the reduction of early postnatal mortality in pigs

Asphyxia during delivery is considered a main cause of stillbirth in pigs, but piglets suffering from intermittent asphyxia during delivery are also less viable at birth and less prone to adapt to extrauterine life. In an effort to improve pig viability, one attractive solution would be to increase oxygen supply through oxygen inhalation by the newborn pig. The objective of this study was to test effects of oxygen inhalation immediately after birth on various physiological parameters and piglet survival. The experiment was performed on 252 Piétrain x Large White piglets, half of them reoxygenated immediately after birth. They were maintained during 20 min in a chamber where oxygen concentration was monitored at 40% and were then put back with the sow and the control pigs. Oxygen inhalation affected piglet metabolism. Through stimulation of oxidative metabolism (reduction of circulating levels of lactate) and lowering of the level of postnatal hypothermia (particularly for the lightest pigs), oxygen inhalation increased piglet viability and reduced mortality during the 1st d of life by 75% (2 vs 8%). No additional effects were observed during the following days and overall mortality between birth and weaning at 21 d was reduced from 12 to 8%.     

Group size and floor-space allowance can affect weanling-pig performance

Crossbred weanling piglets (n = 1,920; mean initial BW, 5.3 +/- .7 kg) were used in two 9-wk trials employing a randomized block design in a 2 x 2 factorial arrangement of treatments to determine effects of group size (20 [Small = S] or 100 [Large = L] pigs/pen) and floor-space allowance (calculated requirement [CR] or calculated requirement less 50% of estimated "free space" [CR-50]) on growth performance. Free space was estimated for each group size. From wk 1 through 4 after weaning, S and L groups at CR were allowed a floor space of .17 m2/pig, and at CR-50, S and L groups were allowed .15 m2/pig and .13 m2/pig, respectively. From wk 5 through 9 after weaning, all CR treatment pigs were provided a floor space of .38 m2/pig, and for the CR-50 treatment, S and L pigs were allowed .32 m2/pig and .28 m2/pig, respectively. Piglets had free access to feed and water. Feeder-trough space per pig was the same for both group sizes. Feed-intake data were collected for only wk 1 through 4. Group size by floor-space allowance interactions (P < .05) were found for gain/feed ratio (G/F) for wk 1 and wk 2 through 4, but not for wk 1 through 4. Piglets in L groups were lighter (P < .001) at the end of wk 1, 4, and 9 by 2, 4, and 5%, respectively, and had lower ADG (6%; P < .001) throughout the trial than S piglets. During wk 1 through 4, feed intake was lower (7%, P < .001) in L piglets than in S piglets, but G/F was similar (P > .05). Piglets in CR groups had greater ADG (5%; P < .01) throughout the trial, with a greater G/F (P < .05) for wk 1 through 4, and were heavier (P < .01) than those in CR-50 groups at the end of wk 4 (3%) and 9 (4%). Pigs in L groups had a greater within-pen coefficient of variation in BW at the end of wk 9 than pigs in S groups. Large groups and reduced floor-space allowance reduced piglet growth performance in the nursery.