Evaluation of the relationship between injuries and size of gestation stalls relative to size of sows

Comparison of the Welfare of Gestation Sows Raised in Different Production Systems in North Vietnam

Intensification and complexity of pig production systems may require different strategies for animal welfare improvement. We aimed to identify welfare issues of gestation sows and areas for improvement by comparing four production systems, including the smallholder pen-based system (SPS: 26 farms), smallholder stall-based system (SSS:14 farms), semi-intensive stall-based system (SES: 15 farms), and intensive stall-based system (ISS: 10 farms). Ten significant animal-based measures in the Welfare Quality® protocol were used for welfare assessment at the individual level. Stall-housed sows in SES and ISS faced more welfare problems where sows presented a higher prevalence of poor body condition (P < 0.001), wounds on body (P = 0.003), fear of humans (P < 0.001), and stereotypies (P < 0.001) than pen-housed sows in the SPS. Sows in the SPS presented the highest prevalence of panting (P < 0.001). Welfare improvement should be focused on minimizing the adverse effects of hot weather on sows in the SPS and SSS and redesigning a more welfare-friendly housing system that prevents sows from the risk of wounds on body and enables them to perform motivated behaviors in the SES and ISS.

Analysis of Hair Cortisol as an Indicator of Chronic Stress in Pigs in Two Different Farrowing Systems

Confinement to farrowing crates is known to prevent sows from performing natural behavior, impairing animal welfare and possibly causing chronic stress. Hair cortisol analyses are increasingly used to detect chronic stress in animals. In the present study, hair samples were collected in the neck of sows kept either in farrowing crates (FC, n = 31) or in a loose-housing system (LH, n = 30) in six batches. Cortisol was extracted and analyzed using chemiluminescence immunoassay. Mean hair cortisol concentrations (HCC) did not differ significantly between the systems (LH: 1.85 ± 0.82 pg/mg, FC: 2.13 ± 1.53 pg/mg, P = 0.631). HCC was also not affected by other factors, such as sows' parity, number of piglets, skin lesion score or sow's weight loss during the farrowing period. However, highly significant differences were found in hair growth rates between different regions within the 20 × 30 cm shaving area. While the hair in both lateral parts of the shaving area grew almost identically (left: 7.48 ± 3.52 mm, right: 7.44 ± 3.24 mm, P = 1.00), the hair grew more in the area above the spine (12.27 + 3.95 mm, P < 0.001). In both systems, the mean individual lesion score of sows declined from the beginning to the end of the housing period (P < 0.001). No difference was found between FC and LH sows at any time (P > 0.05). Since neither the amount of skin lesions nor HCC differed between LH and FC sows, it may be concluded that confining sows in farrowing crates did not affect chronic stress levels. However, results may be affected by a downregulation of the hypothalamic-pituitary-adrenal axis during long-term stress, resulting in lower cortisol levels over time. HCC in sows may also be influenced by a dominant stressor, such as farrowing or the presence of suckling piglets. Thus, for a comparison of different farrowing systems regarding chronic stress, the use of hair cortisol measurement seems to be limited. The present results revealed that differences in hair growth rate within the same body region exist. This important finding should be considered when collecting hair samples in pigs, since hair cortisol concentrations may vary depending on hair growth and length.

Comparison of three different farrowing systems: skin lesions and behaviour of sows with special regard to nursing behaviour in a group housing system for lactating sows

While group housing (GH) is mandatory in the European Union for the greater part of pregnancy, single housing in farrowing crates (FCs) during lactation that restrict sows in most of their natural behaviour patterns is still practised on a large scale. Research is urgently needed to develop alternative farrowing systems that improve sows' welfare. Therefore, sows in three different farrowing systems - pens with FC, loose housing (LH) pens and GH for six sows - were compared regarding the level of skin injuries and their active and resting behaviour. A skin injury score was assessed for 15 body parts of 102 sows in six batches on 3 days (days 1, 14 and 34). In total, the active and resting behaviour of 77 sows in six batches was examined on 3 days (days 18, 25 and 32) between 0700 h and 1900 h by means of a scan sampling method. The suckling behaviour and the level of cross-suckling were analysed in GH by means of direct observation in four batches during three 4-h sampling periods (days 17, 24 and 31). No significant differences were found in total skin injuries when the sows entered the systems (day 1), but GH sows showed significantly higher total skin injuries compared to FC and LH sows in the middle (day 14) and at the end (day 34) of the lactation period. A significant difference between FC and LH sows was never seen. Differences were found for the proportion of different body postures between the three systems. The odds for lying in lateral recumbency versus standing and sitting versus standing were significantly higher for FC and LH sows compared to GH sows. Additionally, sows were significantly more likely to be standing as opposed to lying in lateral recumbency as the lactation period progressed. Cross-suckling was a frequent behaviour in GH, seen in 35.0% of all successful suckling bouts. However, only an average of 0.56 piglets per successful suckling bout was observed cross-suckling, suggesting only a few piglets were engaged in cross-suckling. In conclusion, the skin injury score was only moderately increased in GH compared to FC and LH and comparable to pregnant group-housed sows, both free farrowing systems seemed to be an environmental enrichment for lactating sows and good management cannot prevent the occurrence of cross-suckling in a GH system, but can probably reduce it.

Analysis of influencing factors of boar claw lesion and lameness

This study aimed to investigate the factors affecting boar claw lesions and lameness. A total of 1299 boars were examined for claw lesions and lameness, including 788 boars reared in individual pens with solid concreted floor (IPS) and 511 boars raised in individual stalls with slatted floor (ISS). Flooring type showed significant impacts on all claw lesion types (P < 0.01). Except for swelling ankle, boar age had significant effects on all other claw lesion types (P < 0.01). In addition, only heel overgrowth and erosion, cracked wall horizontal, heel-sole crack, dew claws, and toes were significantly related to boar breeds (P < 0.05). Furthermore, IPS lame boars had higher prevalence of lameness in the hind limb (P < 0.05), whereas in ISS lame boars, there were no significant differences in prevalence of lameness between the fore and hind limbs (P > 0.05). Boar lameness was moderately correlated with swelling ankle (Φ = 0.5571). In conclusion, claw lesions can be influenced by flooring type, boar age and breed, and could serve as a predictor for boar lameness.

Wider stall space affects behavior, lesion scores, and productivity of gestating sows

Limited space allowance within the standard gestation stall is an important welfare concern because it restricts the ability of the sow to make postural adjustments and hinders her ability to perform natural behaviors. Therefore, we evaluated the impacts of increasing stall space and/or providing sows the freedom to access a small pen area on sow well-being using multiple welfare metrics. A total of 96 primi- and multiparous crossbred sows were randomly assigned in groups of 4 sows/treatment across 8 replicates to 1 of 3 stall treatments (TRT): standard stall (CTL; dimensions: 61 by 216 cm), width-adjustable stall (flex stall [FLX]; dimensions: adjustable width of 56 to 79 cm by 216 cm), or an individual walk-in/lock-in stall with access to a small communal open-pen area at the rear of the stall (free-access stall [FAS]; dimensions: 69 by 226 cm). Lesion scores, behavior, and immune and productivity traits were measured at various gestational days throughout the study. Total lesion scores were greatest for sows in FAS and least for sows in FLX ( < 0.001). Higher-parity sows in FAS had the most severe lesion scores (TRT × parity, < 0.0001) and scores were greatest at all gestational days (TRT × day, < 0.05). Regardless of parity, sows in FLX had the least severe scores ( < 0.0001). As pregnancy progressed, lesion scores increased among sows in CTL ( < 0.05). Sow BW and backfat (BF) were greater for sows in FLX and FAS ( < 0.05), and BCS and BF were greater for parity 1 and 2 sows in FAS than the same parity sows in CTL (TRT × parity, < 0.05). Duration and frequency of some postural behaviors and sham chew behavior were affected by TRT ( < 0.05) and time of day (TRT × day, < 0.05). These data indicate that adequate stall space, especially late in gestation, may improve the well-being of higher-parity and heavier-bodied gestating sows as assessed by changes in postural behaviors, lesion severity scores, and other sow traits. Moreover, compromised welfare measures found among sows in various stall environments may be partly attributed to the specific constraints of each stall system such as restricted stall space in CTL, insufficient floor space in the open-pen area of the FAS system, and gate design of the FLX (e.g., direction of bars and feeder space). These results also indicate that parity and gestational day are additional factors that may exacerbate the effects of restricted stall space or insufficient pen space, further compromising sow well-being.

Effects of gestation housing system and floor type during lactation on locomotory ability; body, limb, and claw lesions; and lying-down behavior of lactating sows

This study evaluated the influence of housing system during gestation and floor type during lactation on the welfare and lying-down behavior of lactating sows. Multiparous sows (n = 85) were housed either in individual gestation stalls (n = 42) or loose (n = 43) in a single dynamic group with 2 electronic sow feeders moved to farrowing crates on either slatted steel (n = 48) or cast iron (n = 37) flooring. Lameness (0 = normal to 5 = severely lame) was scored on transfer to the farrowing crate (-5 d). Limb and body lesions were recorded on -5 d, 24 h after entering the farrowing crate (-4 d), 10-d postpartum, and before weaning. Claw lesions were recorded on -5 d and before weaning, whereas all behavioral observations were made on -5, -4, and 10 d. Median (Me) scores were calculated for claw, body, and limb lesions and classified as either less than or equal to the Me or greater than the Me lesion scores. Sows were classified as nonlame (≤ 1) or lame (≥ 2). Loose-housed sows had an increased (P < 0.01) risk of lameness; a reduced (P < 0.05) risk for claw lesions, particularly white line damage, horizontal wall cracks, and dewclaw injuries; and a reduced (P < 0.05) risk for calluses and bursitis on the limbs compared to stall-housed sows. Sows housed on cast iron floors during lactation had a reduced (P < 0.01) risk for heel overgrowth and erosion and heel-sole cracks compared with sows on slatted steel floors. There was no (P > 0.05) association between flooring type during lactation and body lesion score. On -4 d, loose-housed sows had a shorter latency to lie down (P < 0.01), spent more time inactive (P < 0.05), and shifted weight between the limbs more often (P = 0.05) while standing compared with stall-housed sows. Lame sows had a shorter (P < 0.01) latency to lie down compared to nonlame sows on -5 and -4 d. In conclusion, there was an increased risk of lameness in sows housed loose compared to those housed in gestation stalls on transfer to the farrowing crate. Claw health deteriorated in the farrowing crate regardless of gestation housing or floor type but the deterioration in claw health was increased on slatted steel compared to on cast iron.

Measuring changes in physical size and predicting weight of sows during gestation

Changes in physical body size during gestation were monitored using 529 sets of sow measurements. All sows were from the same herd and production system with a range in parity from 1 to 8. Sows were individually weighed, P2 backfat thickness was determined by ultrasound and morphometric measurements of body size were taken five times during gestation: day 0 (at service), day 25, day 50, day 80 and day 110. The morphometric measurements included sow height (from floor to last rib at the midline, from floor to ventral surface and from floor to hip), heart girth, depth of last rib, length (from snout to tail and from anterior scapula to tail) and width (at ham, at last rib and at shoulder). Regression analyses were used to model the relationship between day of gestation or parity number and morphometric measurements of body size. Regression equations were also developed to estimate sow weight from physical measurements, day of gestation and parity. As expected, sow dimensions, in general, increased as pregnancy progressed and also with increasing parity number. The relationships between day of gestation and body dimensions were described by linear and quadratic regression models, which had a range of adjusted R2 values up to 0.99. Similar relationships to parity number had a range of R2 values between 0.51 and 0.96. Sow depth, which can be used as an estimate of the width of the sow when lying, equalled the maximum width of the gestation stall (650 mm) at day 103 of gestation. However, by day 40 of gestation, predicted mean sow depth (570 mm) equalled the width at the rear of the crate. The implication of this is that after day 40 of gestation, the average sow was too wide for the rear of the crate when lying in a recumbent position. On day 110 of gestation, 95% of the mean sow body depths would be accommodated in stalls that were 674 mm wide; however, the range in body sizes with increasing parity number suggests the use of more than one stall width would be appropriate. Sow weight could be estimated with an adjusted R2 value of 0.81 and with a residual standard deviation (r.s.d.) of 16.5 kg using heart girth alone, or more accurately using a model with parity, day of gestation, P2 backfat depth and heart girth as the parameters (R2 = 0.89, r.s.d. 12.4 kg).

Effects of stall dimensions on the welfare of pregnant sows

The welfare of sows in gestation accommodation, and in particular the use of gestation stalls, is a major issue of concern among the animal-welfare community and pig producers. The objective of the present experiment was to investigate the effects of width (0.6 m v. 0.75 m) and length (2.0 m v. 2.2 m v. 2.4 m) of gestation stalls, plus a tether-stall negative-control treatment, on sow welfare measured via parameters of behaviour, stress physiology, immunology and gait score. The research involved 56 multiparous sows, housed alongside 56 non-experimental sows that were included to facilitate measurement of social behaviour. Posture and social behaviour were recorded after 7 weeks in treatment and animals were surgically catheterised in Week 8 for blood sampling, to measure daytime profiles of cortisol concentrations and responses to an adrenocorticotropic hormone (ACTH) challenge. The cell-mediated immune response to a bean extract was examined in Week 9. Sows spent more time standing during 2 h in the morning in 0.75-m- than 0.6-m-wide stalls (P < 0.05). This effect was greatest in 2.0-m-long stalls. Although the angle of head turn by sows was greater in 0.75-m- than 0.6-m-wide stalls (P < 0.001), social interactions were unaffected by stall dimensions. Sows in 0.6-m-wide stalls had lower total (P < 0.01) and free (P < 0.001) cortisol concentrations, reduced responsiveness to ACTH (P < 0.05) and increased immunoresponsiveness (P < 0.05) than did the sows housed in 0.75-m-wide stalls. There was no effect of stall length on total cortisol concentrations; however, free cortisol concentrations were greater in 2.4-m than in both 2.0- and 2.2-m treatments (P < 0.05). Sows in 2.2-m-long stalls showed significantly lower responsiveness to ACTH (P < 0.01), and greater immunoresponsiveness (P < 0.05) than did the sows in 2.0- and 2.4-m-long stalls. There were no interactions between stall width and length. The results indicated lower stress responses in both 0.6-m-wide and to some extent in 2.2-m-long stalls. Although these effects are not intuitively obvious, it is suggested that within the stall dimensions studied, 0.6 m × 2.2 m stalls will minimise stress effects. The opportunity was taken in the present experiment to test the scientific validity of these welfare measures by examining how well the measures predict the welfare status of the animal. Tethers and stalls are expected to provide variation in the welfare status of sows due to variation in the level of restriction and it was found that for four of the six biological variables (basal free and total cortisol concentrations, cortisol response following ACTH injection and deteriorated gait), expected differences were detected for sows housed in stalls (0.6-m width, 2.0-m length) and tethers.

Periparturient cortisol, acute phase cytokine, and acute phase protein profiles of gilts housed in groups or stalls during gestation

Use of gestation stalls in pork production remains a controversial topic in animal welfare. Immune status and measures are frequently used to assess stress levels and thus well-being of confined animals. The important welfare issue of close confinement among gestating gilts was tested by quantifying cortisol, acute phase cytokine, and acute phase protein pro-files before and after farrowing of gilts housed in 2 systems. Landrace x Yorkshire crossbred gilts housed in groups of 4 (group, n = 8) in pens (3.9 x 2.4 m with 4 individual feeding spaces, 9.36 m(2) total or 2.34 m(2)/gilt) were compared with gilts housed in standard industry stalls (stall, n = 16; 2.2 x 0.6 m, 1.32 m(2)/gilt). Floors were fully slatted, and a substrate was not provided for either system. Cortisol was determined from saliva on d 105 of gestation, 1 h after moving the gilts into farrowing stalls (d 111), and 24 h and 7 d after farrowing. Cortisol was greater (P = 0.04) for group gilts compared with stall gilts 1 h after moving them into farrowing stalls and 24 h after farrowing. Cortisol concentrations decreased (P = 0.001) over time. Leukocyte mRNA expression of IL-1, IL-1 receptor antagonist, and tumor necrosis factor-alpha was determined by quantitative, reverse transcription PCR on d 35, 63, and 91 of gestation and 72 h after farrowing. Cytokine mRNA expression of peripheral blood mononuclear cells did not differ between housing systems for IL-1, its receptor antagonist, or for tumor necrosis factor-alpha. Acute phase proteins, including fibrinogen, haptoglobin, and alpha(1)-acid glycoprotein were determined for plasma samples taken at d 35, 63, and 91 of gestation and 72 h and 14 d after farrowing. In contrast to cortisol, plasma fibrinogen concentrations increased (P < 0.005) over time. Haptoglobin did not differ between treatments (P > 0.10). Stall gilts tended to have greater (P = 0.07) plasma alpha(1)-acid glycoprotein concentrations than group animals at d 35 of gestation and d 14 after farrowing. These data showed a trend (P < 0.07) for alpha(1)-acid glycoprotein concentrations to return to baseline more quickly in group-housed gilts, which did not appear to be directly related to increased cortisol just before farrowing. In conclusion, few differences in the acute phase response were detected between housing systems, suggesting that the resting immunological responses are only mildly affected by gestation stalls.

Association between limb conformation and retention of sows through the second parity

OBJECTIVE

To determine the association between limb conformation scores in gilts and retention through the second parity.

ANIMALS

961 gilts.

PROCEDURE

Gilts were monitored for 1 year. Baseline data recorded were conformation scores for the forelimbs and hind limbs and backfat thickness. Primary outcome was time to removal from a herd, and the secondary outcome was time to removal as a result of lameness.

RESULTS

662 of 961 (68.89%) females remained in herds through the second parity, whereas 299 (31.11%) were removed before the second parity. Survival time for females on the basis of conformation scores for the forelimbs and hind limbs differed significantly for total sow removals and removals as a result of lameness. Females with poor conformation scores for the hind limbs had an increased risk of being removed, compared with risk for females with better conformation scores. Risk of removal specifically as a result of lameness increased as conformation score for the hind limbs became poorer. Proportion of the total population that was removed and could be attributed to undesirable limb conformation was 16.13% for forelimbs and 12.90% for hind limbs.

CONCLUSIONS AND CLINICAL RELEVANCE

Females with undesirable conformation were removed earlier than females with desirable conformation. This was particularly true for females with low conformation scores for the hind limbs. Selection of gilts on the basis of limb conformation may result in reduced attrition of females and improved performance of herds over time.

Evaluation of well-being, productivity, and longevity of pregnant sows housed in groups in pens with an electronic sow feeder or separately in gestation stalls

OBJECTIVE

To compare well-being, performance, and longevity of gestating sows housed in stalls or in pens with an electronic sow feeder (ESF).

ANIMALS

382 pregnant sows of parities 1 through 6.

PROCEDURE

Sows were housed in separate stalls (n = 176) or group pens (206) with an ESF. Well-being of sows was assessed at various time points in terms of injuries, salivary cortisol concentration, and behavior in a novel arena or to a novel object. Farrowing performance and longevity of sows were also assessed.

RESULTS

Total injury scores (TIS) of sows in pens were significantly higher at initial introduction and mixing. In stall-housed sows, TIS was significantly higher during late gestation. The TIS and cortisol concentration were significantly lower in stall-housed sows, compared with values for sows in pens. As parity increased, the likelihood of higher median TIS decreased significantly in pen-housed sows and increased significantly in stall-housed sows. The TIS of sows in pens was negatively correlated with body weight and backfat thickness, whereas these correlations were positive in stall-housed sows. Farrowing performance and results for novel arena or objects did not differ. Proportion of sows removed was significantly higher for pens than for stalls; lameness was the major reason for removal for both systems.

CONCLUSIONS AND CLINICAL RELEVANCE

Stalls impose space restrictions for larger sows, resulting in injuries during late gestation. Interventions are needed to minimize aggression during initial introduction and mixing and at the ESF in pens to reduce severe injuries or lameness of gestating sows.

Sow housing: opportunities, constraints, and unknowns

As Webster has stated, we have real opportunities to provide incremental improvements to a whole range of welfare factors. We need a disciplined approach that takes into account the skills of farmers, veterinarians, and the whole range of other specialists involved in animal agriculture. Improvement is best based on a model of discovery, transparency, and dialogue. Combative models impede discovery and dialogue, and the animals are the most likely to suffer when we create such a scenario. Veterinarians have a real opportunity to aid swine farms in identifying opportunities and allowing for a transparent portrayal of activities on the farm.

The physical size of gestating sows1

Two hundred ninety-six gestating sows were used to determine the physical dimensions of sows in commercial settings. Sows were examined from five farms within a single production model that included identical feed formulation, management practices, herd health, and similar, but not identical, genotypes. Sows were individually weighed, backfat thickness was determined by ultrasound, and body dimensions were determined. Sow body length, height, width (lateral length, left to right from mid-line), and depth (measured as distance from ventral to dorsal extremes) were also determined. Regression procedures were used to model the changes in sow body size in relation to parity, BW, and stage of gestation within and among genotypes. Farm-to-farm variation in sow dimensions for the same genotype was also determined. Least squares means, SD, and 95% upper confidence limits of this sample are presented. Sows increased (P < 0.001) in body dimensions by predicable levels with parity (r2 = 0.92) up to Parity 6, and with advancing pregnancy (r2 = 0.99). Sows of different but related genotypes differed (P < 0.01) in body length, width, height, and depth. Sows of the same genotype, fed the same feed formulation, differed in body dimensions when managed on different farms. Based on mean values and a 95% confidence interval, stall width would need to be at least 72.4 cm to accommodate all sows on the farm. These data and models can be used to design stall sizes and farm floor space needs to meet current animal welfare recommendations. To accommodate the body size of pregnant sows on commercial farms, stall sizes for the majority of sows would need to increase, as would the total floor space needed for a given number of gestating sows individually penned in conventional production systems to meet recently published guidelines.

Comparison of injuries in sows housed in gestation stalls versus group pens with electronic sow feeders

OBJECTIVE

To compare the location and severity of injuries in pregnant sows housed in individual gestation stalls with that in pregnant sows housed in dynamic groups in pens with electronic sow feeders.

DESIGN

Prospective study.

ANIMALS

100 pregnant sows of parity 1 to 3 and various body weights.

PROCEDURE

Fifty sows each were randomly allotted to gestation stalls or group pens with electronic sow feeders. Injuries were scored on the basis of location, number, and depth of wounds. Injury scores for sows in both housing systems were compared during a period of 90 days. The influence of factors such as duration of stay in the housing system, parity, and body weight on sow injuries was also examined.

RESULTS

Injury scores were higher in group pens with electronic sow feeders. As body weight increased, injury scores decreased for sows housed in group pens with electronic sow feeders and increased for sows housed in gestation stalls. There was a significant negative association between second parity and total injury scores.

CONCLUSIONS AND CLINICAL RELEVANCE

Modifications in housing system design and management procedures are needed to reduce injuries in pregnant sows.