Locomotive Disorders Associated with Sow Mortality in Danish Pig Herds

Unravelling novel and pleiotropic genes for cannon bone circumference and bone mineral density in Yorkshire pigs

Leg weakness is a prevalent health condition in pig farms. The augmentation of cannon bone circumference and bone mineral density can effectively improve limb strength in pigs and alleviate leg weakness. This study measured forelimb cannon bone circumference (fCBC) and rear limb cannon bone circumference (rCBC) using an inelastic tapeline and rear limb metatarsal area bone mineral density (raBMD) using a dual-energy X-ray absorptiometry bone density scanner. The samples of Yorkshire castrated boars were genotyped using a 50K single-nucleotide polymorphism (SNP) array. The SNP-chip data were imputed to the level of whole-genome sequencing data (iWGS). This study used iWGS data to perform genome-wide association studies and identified novel significant SNPs associated with fCBC on SSC6, SSC12, and SSC13, rCBC on SSC12 and SSC14, and raBMD on SSC7. Based on the high phenotypic and genetic correlations between CBC and raBMD, multi-trait meta-analysis was performed to identify pleiotropic SNPs. A significant potential pleiotropic quantitative trait locus (QTL) regulating both CBC and raBMD was identified on SSC15. Bayes fine mapping was used to establish the confidence intervals for these novel QTLs with the most refined confidence interval narrowed down to 56 kb (15.11 to 15.17 Mb on SSC12 for fCBC). Furthermore, the confidence interval for the potential pleiotropic QTL on SSC15 in the meta-analysis was narrowed down to 7.45 kb (137.55 to137.56 Mb on SSC15). Based on the biological functions of genes, the following genes were identified as novel regulatory candidates for different phenotypes: DDX42, MYSM1, FTSJ3, and MECOM for fCBC; SMURF2, and STC1 for rCBC; RGMA for raBMD. Additionally, RAMP1, which was determined to be located 23.68 kb upstream of the confidence interval of the QTL on SSC15 in the meta-analysis, was identified as a potential pleiotropic candidate gene regulating both CBC and raBMD. These findings offered valuable insights for identifying pathogenic genes and elucidating the genetic mechanisms underlying CBC and BMD.

The Linear-Logistic Model: A Novel Paradigm for Estimating Dietary Amino Acid Requirements

This study aimed to determine whether current methods for estimating AA requirements for animal health and welfare are sufficient. An exploratory data analysis (EDA) was conducted, which involved a review of assumptions underlying AA requirements research, a data mining approach to identify animal responses to dietary AA levels exceeding those for maximum protein retention, and a literature review to assess the physiological relevance of the linear-logistic model developed through the data mining approach. The results showed that AA dietary levels above those for maximum growth resulted in improvements in key physiological responses, and the linear-logistic model depicted the AA level at which growth and protein retention rates were maximized, along with key metabolic functions related to milk yield, litter size, immune response, intestinal permeability, and plasma AA concentrations. The results suggest that current methods based solely on growth and protein retention measurements are insufficient for optimizing key physiological responses associated with health, survival, and reproduction. The linear-logistic model could be used to estimate AA doses that optimize these responses and, potentially, survival rates.

Risk factors associated with sow mortality in breeding herds under one production system in the Midwestern United States

Sow mortality has significantly increased throughout the world over the past several years, and it is a growing concern to the global swine industry. Sow mortality increases economic losses, including higher replacement rates, affects employees' morale, and raises concerns about animal well-being and sustainability. This study aimed to assess herd-level risk factors associated with sow mortality in a large swine production system in the Midwestern United States. This retrospective observational study used available production, health, nutritional, and management information between July 2019 and December 2021. A Poisson mixed regression model was used to identify the risk factors and to build a multivariate model using the weekly mortality rate per 1000 sows as the outcome. Different models were used to identify the risk factors according to this study's main reasons for sow mortality (total death, sudden death, lameness, and prolapse). The main reported causes of sow mortality were sudden death (31.22 %), lameness (28.78 %), prolapse (28.02 %), and other causes (11.99 %). The median (25th-75th percentile) distribution of the crude sow mortality rate/1000 sows was 3.37 (2.19 - 4.16). Breeding herds classified as epidemic for porcine reproductive and respiratory syndrome virus (PRRSV) were associated with higher total death, sudden death, and lameness death. Open pen gestation was associated with a higher total death and lameness compared with stalls. Pulses of feed medication was associated with lower sow mortality rate for all outcomes. Farms not performing bump feeding were associated with higher sow mortality due to lameness and prolapses, while Senecavirus A (SVA)-positive herds were associated with a higher mortality rate for total deaths and deaths due to lameness. Disease interactions (herds Mycoplasma hyopneumoniae positive and epidemic for PRRSV; SVA positive herds and epidemic for PRRSV) were associated with higher mortality rates compared to farms with single disease status. This study identified and measured the major risk factors associated with total sow mortality rate, sudden deaths, lameness deaths, and prolapse deaths in breeding herds under field conditions.

Wheatgrass extract has chondroprotective and anti-inflammatory effects on porcine cartilage

Lameness is a commonly observed disorder in sows and negatively impacts both animal welfare and the profitability of the pig sector. The purpose of this study was to determine anti-inflammatory and/or chondroprotective effects of wheatgrass (WG) on porcine cartilage explants stimulated with lipopolysaccharide (LPS). Explants were aseptically prepared from the intercarpal joints of nine market-weight pigs and placed in culture at 37°C for a total of 120 hours. For the final 96 hours, explants were conditioned with an aqueous extract of WG (0, 5 or 15 μg/mL), and for the final 48 hours explants were stimulated with LPS (0 or 10 µg/mL). Media was removed and replaced every 24 hours. Samples from the final 48 hours were analyzed for biomarkers of cartilage inflammation [prostaglandin E2 (PGE2) and nitric oxide (NO)] and cartilage structure [glycosaminoglycan (GAG)], and cartilage explants were stained for an estimate of cell viability. Stimulation of explants with LPS significantly increased media concentrations of PGE2, GAG and NO compared with that from unstimulated explants. LPS stimulation did not significantly affect cell viability. Conditioning of explants with WG (5 μg/mL) significantly reduced LPS-stimulated cartilage release of PGE2, NO, and GAG (5 and 15 μg/mL), without impairing chondrocyte viability. These data provide evidence for a non-cytotoxic chondroprotective and anti-inflammatory effect of WG extract in cartilage and suggest a role of WG in protection against cartilage breakdown, inflammation, and pain associated with osteoarthritis.

Gross, histopathologic, microbiologic, and radiologic characterization of lesions associated with clinical lameness in a cohort of group-housed sows euthanized for lameness

Lameness in sows is reported as the most frequent cause of early culling from commercial farms and results in reduced productivity, economic losses, and a negative impact on animal welfare. Osteochondrosis was reported as the leading cause of lameness in North American sows and, although more recent European studies report infectious arthritis as the leading cause, lameness in US production facilities using group housing for gestating sows has not yet been evaluated. This study's aim was to characterize lesions associated with lameness in the appendicular musculoskeletal system of 26 sows euthanized for lameness using pathologic, radiologic, and microbiologic analyses. Of 178 total lesions, infectious lesions were most common (54%), predominated in distal limb segments (ie, at or distal to carpi and tarsi) and more often correlated with the clinically lame limb, whereas osteochondrosis and degenerative osteoarthritis predominated in proximal limb segments (ie, at or proximal to cubital and stifle joints) and rarely correlated with the clinically lame limb. The location and characteristics of infectious lesions, including mixed bacterial growth isolated from 22/22 orthopedic sites representing 19 sows with Trueperella pyogenes isolated in 16/22 (73%) of samples, suggest an etiologic component involving trauma. Radiography had a 70.6% sensitivity and 93.9% specificity for detecting infectious lesions affecting tarsocrural, antebrachiocarpal, and digital (ie, claw) regions combined. The frequency, type, and location of infectious lesions identified in this cohort of sows euthanized for lameness differ from previous reports, indicating the need for further investigation of the etiopathogenesis, earlier detection methods, and prevention.

Welfare of pigs on farm

This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.

Study on ultrasonic wave propagation in equine leg bone for screening bucked shin

For simple, safe, portable, and inexpensive evaluation suitable for leg bone diseases of racehorses in the field, an ultrasonic measurement technique was applied to evaluate wave velocities. A digital model of the third metacarpal bone with the bucked shin was fabricated using high-resolution peripheral quantitative computerized tomography data of a racehorse. This model was anisotropic and heterogeneous, and was constructed using the measured ultrasonic wave velocities in the bone. With this model, ultrasonic wave propagation along the bone axis was simulated using the elastic finite-difference time-domain method. We found two main waves with different propagation velocities. The fast-waves showed a wave velocity close to the longitudinal wave in the axial direction. However, the apparent velocities changed dramatically owing to bone surface irregularities (changes of the shape) in the area of bucked shin. The slow-waves showed a wave velocity close to the shear wave, which was unaffected by the bone surface irregularities. The simple comparison of different wave behaviors may be a suitable parameter for the initial in vivo screening of bucked shin in the legs of racehorses, which can be performed in the field.

Causes of Sow Mortality and Risks to Post-Mortem Findings in a Brazilian Intensive Swine Production System

The present study was conducted to investigate the risk factors for post-mortem findings and causes of sow mortality. A post-mortem examination and microbiological investigation were conducted on 123 sows from a breeding herd with 15,000 dams. The mortality of spontaneous death in sows occurred mostly in the peripartum period (53%; p < 0.05). The spontaneous deaths were associated with heart failures, hemorrhagic and perforating gastric ulcers, and liver torsion, while in the euthanized sows, the post-mortem findings were associated with locomotor disorders. A higher body condition score (BCS ≥ 3.5) increased (p < 0.05) heart failure on the post-mortem examination. The excessive use of manual obstetric interventions increased sow deaths resulting from cervix/uterus ruptures and increased the odds of death (p < 0.05) due to metritis. Sow mortality had a multifactorial etiology. Infections were polymicrobial. The main microbial agents identified from a septic lesion in locomotor, genitourinary, and respiratory systems were Trueperella pyogenes, Escherichia coli, and Actinobacillus pleuropneumoniae, respectively. In conclusion, sow mortality involved multiple risk factors and several bacterial agents. These results indicate that better management practices can reduce sow mortality in swine production and increase sow welfare.

Comparative Study of the Effects of Two Dietary Sources of Vitamin D on the Bone Metabolism, Welfare and Birth Progress of Sows Fed Protein- and Phosphorus-Reduced Diets

To investigate the influence of two dietary sources of vitamin D on the vitamin D status, bone metabolism, welfare and birth progress of gestating and lactating sows, forty-nine multiparous sows were randomly assigned to one of two diets: “CON” (n = 25; 50 μg vitamin D3/kg feed) and “HYD” (n = 24; 50 μg 25-hydroxycholecalciferol/kg feed). The basal diets were protein- and phosphorus-reduced. The trial started on day 3 ante insemination of the sows and ended with weaning of the piglets on day 28 postpartum. Dietary supplementation of 25-hydroxycholecalciferol resulted in improved maternal vitamin D status (p < 0.001), fewer gait changes (p < 0.01) and longer standing time after feeding (day 5 ante partum; p < 0.05) compared to vitamin D3. However, the bone markers CrossLaps and osteocalcin were not affected. Overall, the present results suggest that sows fed 25-hydroxycholecalciferol instead of vitamin D3 showed improved locomotion and stance strength. However, this outcome is probably not related to altered bone metabolism. The underlying mechanisms must be investigated in further studies.

Description of on-farm treatment compliance and risk factors for culling in sows

Background

In commercial pig farming, sick or injured sows are often treated by producers or hired staff. To date, limited quantitative data exists on treatment compliance and the possible effect on sow longevity post-treatment. The objective of the study was to quantify on-farm compliance of treatment selection, frequency, and dosage, as well as to investigate the association between body condition scores (BCS) and other sow-level factors on post-treatment cull risk.

Results

On-farm treatment records, including culling reason or reason of death up to 6 months post-treatment, production records and sow characteristics were obtained for 134 sows over an 8-week period. Treatment compliance was based on the accuracy of recorded treatments compared to the herd veterinarian’s established treatment guidelines. Univariable and multivariable logistic regression models including treatment reason, treatment compliance, BCS, parity, production stage and production metrics, were constructed to investigate associations between those variables and sow culling or death. This study found low compliance for on-farm sow treatment protocols, with only 22.4% (30/134) of the sows receiving correct and complete treatment during the duration of the study. No effect of individual treatment components (drug, dosage, or frequency) on sow culling was observed. A trend for an interaction between treatment compliance and BCS was found, and parity and number of piglets born alive were identified as predictors for sow maintenance in the herd.

Conclusions

On-farm sow treatment compliance was low, resulting in that approximately 80% of the enrolled sows were not treated according to existing guidelines. Non-compliance of treatment guidelines did not seem to affect the risk of culling in treated sows but may have prolonged any associated pain, recovery time and negatively impacted the sow welfare during that time period.

Do Rubber Floor Mats Prevent Lameness in Gestating Sows Housed in Large Groups? A Field Experiment on Three Commercial Farms in France

Lameness and foot disorders are major health and welfare issues in intensive swine production systems. They are exacerbated when sows are housed in large groups on slatted concrete floors during gestation. Our study aimed to assess the effect of rubber mats in the lying area of the gestation pen on lameness and leg health in gestating sows housed in large pens in commercial conditions. The study was conducted on three commercial farms over two successive gestations. A total of 582 Large White × Landrace sows, housed in 10 static groups, were enrolled: 5 groups in pens with rubber mats and 5 groups on slatted concrete floors. Lameness, bursitis, leg injuries, claw growth defects and claw lesions were measured at the beginning, middle and end of each gestation period. The rubber mats decreased the risk of suffering from bursitis, but had no effect on the risk of lameness, leg injuries, claw growth defects or claw lesions. Sows housed on rubber mats were heavily soiled compared with those on slatted concrete floors because the mats were not perforated for slurry evacuation. Locomotion disorders and foot lesions remained prevalent despite the rubber mats in the lying area of the gestation pens, but adding rubber mats in service rooms and farrowing crates may produce better results.

Use of 25-hydroxyvitamin D3 in diets for sows: A review

Dietary supplementation with 25-hydroxyvitamin D₃ (25OHD₃), as an alternative source of vitamin D, is becoming increasingly popular due to its commercialization and more efficient absorbability. The addition of 25OHD₃ rather than its precursor vitamin D₃ can circumvent the 25-hydroxylation reaction in the liver, indicating that supplementation of 25OHD₃ can rapidly improve the circulating vitamin D status of animals. Emerging experiments have reported that maternal 25OHD₃ supplementation could increase sow performances and birth outcomes and promote circulating vitamin D status of sows and their offspring. Increased milk fat content was observed in many experiments; however, others demonstrated that adding 25OHD₃ to lactating sow diets increased the contents of milk protein and lactose. Although an inconsistency between the results of different experiments exists, these studies suggested that maternal 25OHD₃ supplementation could alter milk composition via its effects on the mammary gland. Previous studies have demonstrated that adding 25OHD₃ to sow diets could improve the mRNA expressions of insulin-induced gene 1 (INSIG1) and sterol regulatory element-binding protein 1 (SREBP1) in the mammary gland cells from milk and increase the mRNA expressions of acetyl-CoA carboxylase α (ACCα) and fatty acid synthase (FAS) in the mammary gland tissue. Maternal 25OHD₃ supplementation promotes skeletal muscle development of piglets before and after parturition, and improves bone properties including bone density and bone breaking force in lactating sows and their piglets. Interestingly, 25OHD₃ supplementation in sow diets could improve neonatal bone development via regulation of milk fatty acid composition related to bone metabolism and mineralization. In this review, we also discuss the effects of adding 25OHD₃ to sow diets on the gut bacterial metabolites of suckling piglets, and propose that butyrate production may be associated with bone health. Therefore, to better understand the nutritional functions of maternal 25OHD₃ supplementation, this paper reviews advances in the studies of 25OHD₃ for sow nutrition and provides references for practical application.

Causes of spontaneous sow deaths in the farrowing units of 10 Danish sow herds

This study established the causes and timing of spontaneous sow deaths in the farrowing units of ten Danish sow herds. Herds participated for seven to 15 months during 2018-19. We received data (production data and detailed information on the sows that died) on a total of 126 sows. Fifty-three sows were necropsied, and tissues were evaluated histopathologically. Twenty-four percent of the sows died 0-5 days postpartum. The main cause of death in the study was liver lobe torsion, which was diagnosed in 22 of 53 necropsied sows (42%). Deaths caused by liver lobe torsions were less often seen during the 0-5 day postpartum period compared to deaths caused by other reasons (P = 0.002). Seven of the necropsied sows (13%) died from endotoxaemic shock from retained foetuses. This cause of death was seen in seven of ten herds. These sows typically died 1-3 days postpartum. Pneumonia accounted for 13% of deaths in the necropsied sows, but the majority of these sows originated from one herd experiencing a respiratory outbreak caused by the introduction of M. hyopneumonia. Less prevalent causes of death in the study were torsion of the intestinal segment (8%), suspected cardiovascular collapse (8%), rupture of blood vessels (uterine and nonuterine) (8%), gastric ulcer (4%), sepsis (2%) and liver abscess (2%). We concluded that liver lobe torsion needs further attention to establish the background of this surprisingly prevalent cause of death. Furthermore, a need for procedures that ensure efficient farrowing was identified.

Rearing in female-only groups and dietary mineral supplementation improves sow welfare in the early parities and lifetime performance

The lifetime performance of commercial sows relies on longevity, which is dependent on good health and reproductive performance. However, there is a high rate of wastage of sows in the early parities, which is influenced by the way they are managed and housed during rearing. This study investigated the carry-over effect of gilt rearing strategy on the measures of welfare and performance. Eighty sows were reared using a two by two factorial design: rearing group composition [GC; female-only (FEM) or mixed-sex (MIX) from weaning] with or without supplementary minerals (CON = control diet; SUPP = control + Cu, Zn, and Mn) from 5 wk into the finisher stage. Once served, gilts were managed in a dynamic group gestation pen and fed a standard gestating sow diet. Locomotory ability was scored (0 to 5) and salivary cortisol measured five times during the first gestation, and human approach tests were carried out on day 108. Hooves were scored for injuries and legs for bursas at day 70 of the first gestation, at first weaning, and at the second farrowing. Sow behavior in the hoof scoring crate (movement, vocalization, and handling ease) was also recorded. The number of piglets born alive and dead during the first five parities was recorded as was the performance of the first litter to finish. Data were analyzed using general or generalized linear mixed models, as appropriate, using SAS (v 9.4). There was no effect (P > 0.05) of rearing treatment on locomotory ability, bursa score, the total number of piglets born, or on offspring growth. However, there was an interaction between GC and supplementary minerals (P < 0.05) on salivary cortisol levels with MIX × SUPP sows having the highest levels. Total hoof scores and heel erosion scores were higher in sows reared in MIX groups (P < 0.01), and CON sows tended to have higher horizontal crack scores (P = 0.06). Sows from MIX kicked more at weaning than FEM (P < 0.05) and tended to be more fearful in the forced human approach test (P = 0.1) where they are scored on their reaction to being approached. They also had more stillborn piglets across all five parities than FEM (P < 0.05). Overall, rearing replacement sows in FEM groups and dietary mineral supplementation had minimal but beneficial effects on their subsequent welfare and performance.

Dietary fatty acid content and thickness of plantar pads in gilts

The objective of this study was to test a diet enriched in the most abundant components of foot fat pads (oleic and palmitic acid) to increase its thickness in gilts. We evaluated the effects of two oleic and palmitic acid dietary concentrations (control and test) and three treatment durations (35, 45, and 65 d) on 116 gilts (Landrace × Large White), all 180-d-old and slaughtered at the end of the study. Both test and control diets contained 5.9% total fat. The control diet contained 0.9% oleic acid and 0.6% palmitic acid; the test diet contained 1.9% and 1.2%, respectively. Body weight (BW), backfat (BF), lateral, and medial plantar pad thickness from the left rear leg were measured. No significant differences were detected for BW or BF between the test and control groups. The lateral pad was always thicker than the medial one (P < 0.001). No significant difference for plantar pad thickness was detected for the 35 d treatment. For the other treatments, thickness increased with respect to the control group (P < 0.01); the percentage of increase ranged from 20.8% (lateral side, 45 d treatment) to 37.8% (lateral side, 65 d treatment). Its effects on foot health must still be demonstrated.

Computed tomographic development of physeal osteochondrosis in pigs

BACKGROUND

Articular osteochondrosis follows a dynamic development pattern. Lesions arise, in incidence peaks compatible with failure of cartilage canal vessels during incorporation into bone, and can also resolve. Lesions that resolve before examination at a single time point will constitute false-negative diagnoses. The aim of the study was to identify physeal osteochondrosis lesions in pigs and monitor their development by computed tomography (CT), to determine if they follow a similar dynamic development pattern to articular osteochondrosis.

RESULTS

Thirteen physes were evaluated bilaterally in up to eight biweekly CT scans from 18 male Landrace pigs age 70-180 days (total: 112 scans), generating 2912 scores. There were 1754 (60%) lesion-negative scores and 1158 (40%) lesion-positive scores. Positive scores comprised 138 lesions present at the start and 235 lesions that developed during the study, from 4 to 32 lesions per physis (median: 15 lesions). There were 1-2 peaks in the incidence curves for 12/13 examined physes, the exception being the proximal humerus. Positive scores also included 785 times that lesions persisted, from 1.3-4.8 examination intervals per lesion (median: 2.8 intervals). Negative scores included 190 times that lesions resolved, from 19 to 100% of lesions per physis (median: 65%). Lesions resolved by filling with bone from marginal sclerosis and reparative ossification centres. In the distal scapula and distal fibula, perichondrial new bone formation occurred that led to permanent enlargement of physeal regions. Angular limb deformity was not identified in any pig.

CONCLUSIONS

Physeal osteochondrosis followed a similar dynamic development pattern to articular osteochondrosis. There were peaks in the incidence curves, compatible with failure of vessels during incorporation into bone. In some physes, osteochondrosis led to permanent enlargement, potentially relevant for decubital ulcers. The relationship between physeal osteochondrosis and angular limb deformity must be examined further in pigs over 6 months old in future.

Factors influencing claw lesion scoring in sows

Claw lesions have a multifactorial origin and may affect sow welfare and farm profitability. However, estimating the precise impact is hampered by several factors that interfere with the accuracy of claw lesion assessment. The objective of this study was to determine the impact of observer, scoring condition and claw cleanliness on claw lesion scoring in sows. The first experiment evaluated the impact of observer by calculating the inter- and intra-observer reliability during three test sessions using photographs. The second experiment evaluated the impact of observer, scoring condition (Feet First© chute of Zinpro Corp., "sow chute" vs. Mobile Claw Scoring Device, "MCSD"), and claw cleanliness (clean or soiled claws) on claw lesion scoring. For this experiment, 20 hybrid mid-gestating sows were hoisted up using the sow chute in which the MCSD was positioned. Lateral and medial claw digits of both hind claws were scored for heel horn erosion and separations along the heel/sole junction and white line. Scores were given by drawing a vertical bar on a 160 mm tagged visual analogue scale (tVAS); the severity of a claw lesion type was determined by measuring the distance from 0 mm. Four scores per sow were collected and analysed: clean claws × MCSD video recordings, soiled claws × MCSD video recordings, clean claws × visual scoring in a sow chute, and soiled claws × visual scoring in a sow chute. In both experiments, observer had an impact on the claw lesion scores. The inter-observer reliability was highest for overgrown dewclaws and lowest for the horizontal wall cracks (0.84 and 0.35, resp.). The highest intra-observer reliability was found for overgrown dewclaws and heel horn erosion (0.89) and lowest for vertical wall cracks (0.64). Furthermore, scoring condition and claw cleanliness influenced the scores in the second experiment and the limits of agreements were high (23.5-58.9 mm). The improved concordance correlation coefficient (iCCC) was highest for the heel horn erosion scores. In conclusion, the impact of observer seemed less relevant for claw lesion scoring; however, claw cleanliness and scoring condition were important and cannot be used interchangeably.

Pathological findings in spontaneously dead and euthanized sows - a descriptive study

Background

A high rate of euthanized and spontaneously dead sows causes production losses and likely indicates underlying welfare problems. Identification of predisposing factors to on-farm deaths requires a thorough understanding of the causes. Post-mortem examination is needed for a proper diagnosis. The aims of this descriptive study were to determine causes of spontaneous deaths and euthanasia in sows in a convenience sample of Finnish herds and to describe pathological findings in the locomotor system and in teeth and gums.

Results

This study described post-mortem findings in 65 sows found dead or euthanized on 15 farms. All but one of the sows presented with two or more pathological findings. The majority of primary pathologic-anatomic diagnoses (PAD-1) were inflammatory. The most prevalent diagnoses were arthritis and peritonitis (9% of sows each). The locomotor system was the body part most commonly affected by lesions. Findings in the locomotor system unassociated with death were present in 85% of the animals, additionally 29% of PAD-1 s concerned the locomotor system. The prevalence for both degenerative joint disease and tooth wear was 71%. Farmers had noted clinical signs within 30 days of death in every euthanized sow and in half of the spontaneously dead ones. The farmer’s impression of the cause of death agreed at least partly with the PAD-1 in 44% of the cases.

Conclusion

Multiple pathologies were the norm in the present animals. This may indicate an extended course of illness and therefore also an unnecessary delay in medical treatment or euthanasia. The prevalence and clinical relevance of the most common disorders, including degenerative joint disease and tooth wear, need to be elucidated.

Lowering dietary cation-anion difference increases sow blood and milk calcium concentrations

A study was conducted to evaluate the effects of feeding an acidogenic diet with a low dietary cation-anion difference (DCAD) on acid-base balance, blood, milk, and urine Ca concentrations of sows during lactation. A total of 30 multiparous sows (parity: 4.5 ± 2.9, Smithfield Premium Genetic, Rose Hill, NC) were allotted to 1 of 2 dietary treatments: CON (control diets were corn-soybean meal based with a calculated DCAD of 170 and 226 mEq/kg during late gestation and lactation, respectively) or ACI (acidogenic diets had a DCAD 100 mEq/kg lower than the control diets). The lower DCAD was achieved by the addition of an acidogenic mineral. The DCAD was calculated as mEq (Na + K - Cl)/kg diet. Sows had a daily access to 2-kg feed from day 94 of gestation to parturition and ad libitum access to feed during lactation. Blood and urine pH and Ca, serum macrominerals, serum biochemistry, Ca-regulating hormones, and milk composition were measured. Sows in ACI had a lower (P < 0.05) blood pH than sows in CON at day 1 of lactation. Sows in ACI had a lower (P < 0.05) urine pH at day 108 of gestation, days 1, 9, and 18 of lactation compared with sows in CON. Sows in ACI had greater (P < 0.05) concentrations of serum total Ca at days 1 and 18 of lactation than sows in CON. There was a greater (P < 0.05) concentration of colostrum Ca in ACI than in CON. There was no difference in urine Ca concentration between treatments during lactation. Concentrations of parathyroid hormone and 1,25-dihydroxycholecalciferol were not different between treatments at either day 1 or 18 of lactation. Sows in ACI tended to have a smaller (P = 0.086) concentration of total alkaline phosphatase in serum at day 18 of lactation compared with sows in CON. At day 1 of lactation, the concentration of serum Cl in ACI was greater (P < 0.05) than that in CON. Feed intake, BW loss, and litter performance were not different between treatments. Collectively, feeding an acidogenic diet with a low DCAD to sows can induce a mild metabolic acidosis at farrowing, reduce the urine pH consistently, and increase serum total Ca and colostrum Ca concentrations during lactation but without altering the parathyroid hormone and 1,25-dihydroxycholecalciferol levels during lactation.

The Effect of Group Composition and Mineral Supplementation during Rearing on Measures of Cartilage Condition and Bone Mineral Density in Replacement Gilts

Lameness is a major cause of poor longevity and poor welfare in replacement gilts. The problem is exacerbated by inappropriate housing and diet during the rearing period. Replacement gilts are often reared with male finisher pigs destined for slaughter. If they are not castrated, they perform high levels of potentially injurious sexual and aggressive behaviour. Furthermore, finisher pig diets are not designed to meet the needs of developing gilts and may not supply the necessary minerals to support good limb health. The objective of this study was to evaluate the effect of supplementing the diet of replacement gilts with copper, zinc and manganese and separating them from males during the rearing period on locomotory ability, bone mineral density and cartilage lesion scores. A 2 × 2 factorial design experiment investigated the effect of female-only or mixed-sex rearing, with or without supplementary minerals (Copper, Zinc and Manganese). In total, 384 maternal line gilts were assigned to 32 pens of 12 and were locomotion scored during the rearing period. A sub-sample (n = 102) of gilts were culled at breeding age and the front right limb was removed at slaughter. Areal bone mineral density (aBMD) was measured using dual energy X-ray absorptiometry, after which the limb was dissected to score the condition of the cartilage. The addition of trace minerals to the diet resulted in increased aBMD in the humerus (P < 0.05) compared to the control diet. Rearing gilts in female-only groups reduced the number of cartilage lesions overall (P < 0.05), and on the humeral condyle (P < 0.05). Rearing replacement gilts in female-only groups and with mineral supplementation had benefits for limb health.

Structural characterization of piglet producing farms and their sow removal patterns in Finland

Background

The main objectives of this observational, cross-sectional study were to characterize piglet producing farms in Finland and to investigate how farm profiles are associated with sow culling and mortality.The study was conducted on 43 farms during 2014. A questionnaire survey was administered in-person and supplemented with observations in the housing facilities. Annual removal figures and average monthly sow inventories were retrieved from a centralized animal data recording system (National Swine Registry) administered by the Finnish Food Authority. Multiple correspondence analysis and hierarchical clustering were used to explore the complex underlying data-driven patterns.

Results

Sow removal varied markedly between farms with an overall average culling percentage of 38.0% (95% CI 34.1-42.0) and a relatively high average mortality percentage 9.7% (95% CI 7.9-11.5). We identified three farm clusters, which differed both in their typologies and removal patterns. Cluster 1 included farms with features indicative of a semi-intensive or intensive kind of farming, such as larger herd and room sizes, higher stocking density and more sows per caretaker. Most of the cluster 1 farms exceeded the investigated cut-off levels for culling and mortality. Cluster 2 farms were estimated to have the best animal welfare among the sample farms based on a combination of environmental indicators (e.g. amount of bedding, rooting and nesting materials, space allowance, pen cleanliness) and the lowest level of sow mortality as an animal-based indicator. Cluster 3 farms followed a strategy of a rather non-intensified system based on the predominance of smaller herd size, lower stocking density and less sows per caretaker, combined breeding and gestation rooms and rare use of farrowing induction. This cluster showed the lowest culling levels within the sample.

Conclusions

This study captures the diversity among Finnish sow farms and provides a baseline assessment of their practices and facilities. Our results support the notion that farm typologies are associated with sow culling and mortality. In summary, the control of suboptimal sow removal cannot be based on single improvements only, because of other limitations within the individual farm resources.

On-Farm Claw Scoring in Sows Using a Novel Mobile Device

Claw lesions and lameness in sows are important problems in the industry as they impair sow welfare and result in economic losses. Available scoring techniques to detect claw lesions are all limited in terms of collecting data during all reproductive phases and recording all claws. The Mobile Claw Scoring Device (MCSD) was designed to address these limitations. After considering different practical situations and a design phase, two prototypes were constructed and tested. Improvements were incorporated into a final aluminium apparatus, consisting of two cameras with light-emitting diode (LED) lights mounted in a two-segment aluminium box and covered with laminated tempered glass plates. The operating system slides underneath the claws and takes video images. This final prototype was optimised and validated in an experiment with 20 hybrid sows, comparing scores for soiled claws using the MCSD against scores for clean claws using the Feet First^© sow chute (as gold standard). Fifty percent of the scores differed between both scoring tools, with mainly medial claw digits deviating, but this seemed biologically irrelevant. The MCSD seems to be an appropriate alternative for on-farm claw scoring and is distinguishable from other claw scoring techniques; however, it needs further optimisation to improve the similarity between the two techniques.

Removing prophylactic antibiotics from pig feed: how does it affect their performance and health?

BACKGROUND

Antibiotics (AB) are an important tool to tackle infectious disease in pig farms; however some research indicates that their frequent mis/over-use may contribute to the development of antibiotic resistance and the WHO has declared that this issue should be addressed. Little is known about the long term consequences of withdrawing prophylactic AB from pig feed; hence we aimed to assess its effects on performance and health of pigs from weaning to slaughter. Six batches of 140 pigs each were monitored on a commercial farm through the weaner and finisher stages to slaughter. In-feed antibiotics were not added to the feed for half of the pigs (NOI) and were added in the other half (ABI) within each batch for the whole weaner stage. Individual pigs in both treatments were treated with parenteral administrations if and when detected as ill or lame. Productive performance, parenteral treatments and mortality were recorded on farm and the presence of respiratory disease was recorded at slaughter. Pen was considered the experimental unit.

RESULTS

ABI pigs showed higher growth (P = 0.018) and feed intake (P = 0.048) than NOI pigs in the first weaner stage but feed efficiency was not affected (NOI = 1.48 vs. ABI = 1.52). Despite an initial reduction in performance, NOI pigs had similar performance in finisher stage (ADG: NOI = 865.4 vs. ABI = 882.2) and minimal effects on health compared to ABI pigs. No difference between treatments was found at the abattoir for the percentage of pigs affected by pneumonia, pleurisy, pleuropneumonia and abscesses (P > 0.05). Mortality rate was not affected by treatment during the weaner stage (P = 0.806) although it tended to be slightly higher in NOI than ABI pigs during the finisher stage (P = 0.099). Parenteral treatments were more frequent in NOI pigs during the weaner stage (P <  0.001) while no difference was recorded during the finisher stage (P = 0.406).

CONCLUSIONS

These data suggest that the removal of prophylactic in-feed antibiotics is possible with only minor reductions in productive performance and health which can be addressed by improved husbandry and use of parenteral antibiotics.

Articular cartilage gene expression patterns in the tissue surrounding the impact site following applications of shear and axial loads

BACKGROUND

Osteoarthritis is a degradative joint disease found in humans and commercial swine which can develop from a number of factors, including prior joint trauma. An impact injury model was developed to deliver in vitro loads to disease-free porcine patellae in a model of OA.

METHODS

Axial impactions (2000 N normal) and shear impactions (500 N normal with induced shear forces) were delivered to 48 randomly assigned patellae. The patellae were then cultured for 0, 3, 7, or 14 days following the impact. Specimens in the tissue surrounding the loading site were harvested and expression of 18 OA related genes was studied via quantitative PCR. The selected genes were previously identified from published work and fell into four categories: cartilage matrix, degradative enzymes, inflammatory response, and apoptosis.

RESULTS

Type II collagen (Col2a1) showed significantly lower expression in shear vs. axial adjacent tissue at day 0 and 7 (fold changes of 0.40 & 0.19, respectively). In addition, higher expression of degradative enzymes and Fas, an apoptosis gene, was observed in the shear specimens.

CONCLUSIONS

The results suggest that a more physiologically valid shear load may induce more damage to surrounding articular cartilage than a normal load alone.

Partial substitution, with their chelated complexes, of the inorganic zinc, copper and manganese in sow diets reduced the laminitic lesions in the claws and improved the morphometric characteristics of the hoof horn of sows from three Greek herds

BACKGROUND

Hoof lesions in sows have been associated with lameness and poor hoof horn quality. The mechanical strength and quality of hoof horn is determined by the density and diameter of horn tubules, which were recently associated with the severity of lesions on the hoof wall of sows. Histologic changes that have previously been described in cases of bovine laminitis, have also been observed in the dermis and epidermis of the sows' claws. Trace elements, particularly zinc, copper and manganese, occupy important roles as enzyme catalysts in the process of keratin synthesis which determines the quality and the integrity of the hoof epidermis. Therefore, the objective of this study was to investigate the effect of diet supplementation with chelated zinc, copper and manganese, partially substituting their inorganic form, on sow claw health and hoof horn quality assessed by macroscopic, histologic and morphometric examination.

RESULTS

Clinically, the total claw lesion score was significantly lower in claws of sows which received the "organic" diet compared to those of sows on the "inorganic" diet. Histologically, lamellar hyperplasia was the most frequently recorded change in the epidermis of the sows' claws regardless of the diet's mineral source. The claws of the sows which received the organic diet were more likely to have none or less histologic changes than at least one or more, respectively, compared to those of the sows on the "inorganic" diet. Morphometrically, the density and vertical and horizontal diameters of the horn tubules was significantly higher and smaller, respectively, in the hoof horn of sows which received the "organic" compared to those which received the "inorganic" source diet.

CONCLUSIONS

Partial substitution of the inorganic zinc, copper and manganese in sows' diet with their chelated complexes, provided a comparative advantage against a conventional, inorganic mineral source diet, at least under the conditions examined in the current study, in terms of macroscopic, histologic and morphometric criteria, characterizing the health and horn quality status of sows' hooves.

Pre-clinical and clinical walking kinematics in female breeding pigs with lameness: A nested case-control cohort study

Gait profiles were investigated in a cohort of female pigs experiencing a lameness period prevalence of 29% over 17 months. Gait alterations before and during visually diagnosed lameness were evaluated to identify the best quantitative clinical lameness indicators and early predictors for lameness. Pre-breeding gilts (n= 84) were recruited to the study over a period of 6 months, underwent motion capture every 5 weeks and, depending on their age at entry to the study, were followed for up to three successive gestations. Animals were subject to motion capture in each parity at 8 weeks of gestation and on the day of weaning (28 days postpartum). During kinematic motion capture, the pigs walked on the same concrete walkway and an array of infra-red cameras was used to collect three dimensional coordinate data of reflective skin markers attached to the head, trunk and limb anatomical landmarks. Of 24 pigs diagnosed with lameness, 19 had preclinical gait records, whilst 18 had a motion capture while lame. Depending on availability, data from one or two preclinical motion capture 1-11 months prior to lameness and on the day of lameness were analysed. Lameness was best detected and evaluated using relative spatiotemporal gait parameters, especially vertical head displacement and asymmetric stride phase timing. Irregularity in the step-to-stride length ratio was elevated (deviation  ≥ 0.03) in young pigs which presented lameness in later life (odds ratio 7.2-10.8).

Field study of hind limb claw lesions and claw measures in sows

We investigated the associations of hind limb claw lesions with claw measures and reproductive performance of sows on a commercial breeding farm. We used a five-point scale (score of 0-4) for each hind limb claw region to generate a claw lesion score (CLS). Of 110 sows, 1.8% had no hind claw lesions, and the remaining 98.2% had at least one. The proportions of sows with a CLS of 2 and 3 were 49.1% and 3.6%, respectively. The junction region had the highest frequency of a CLS of ≥ 2 (P < 0.05). The mean toe length was 45.0 ± 0.4 to 46.4 ± 0.4 mm. Sows with the highest CLS of ≥ 2 in the lateral claw had longer sole dimensions than did sows with the highest CLS of ≤ 1 (P < 0.05). There were no significant differences in claw width or height between sows with the highest CLS of ≥ 2 and ≤ 1. There was also no difference in reproductive performance between sows with the highest CLS of ≥ 2 and ≤ 1. In conclusion, most sows had hind claw lesions. The association between CLS and claw measures indicates that the sole length can be used as an indicator of claw lesions.

Triennial Growth Symposium--Effects of dietary 25-hydroxycholecalciferol and cholecalciferol on blood vitamin D and mineral status, bone turnover, milk composition, and reproductive performance of sows

To evaluate the role of vitamin D3 during gestation and lactation of sows, 2 independent experiments were performed with the aim of investigating sow reproductive performance, milk composition (study 1 only), and changes in blood status of 25-hydroxycholecalciferol (25-OH-D3), 1,25-dihydroxycholecalciferol (1,25-(OH)2-D3; study 2 only), minerals, and bone markers of sows during gestation and lactation. Study 1 comprised 39 primi- and multiparous crossbred sows fed 1 of 3 barley meal-based diets fortified with 200 IU/kg vitamin D3 (NRC, 1998; treatment DL), 2,000 IU/kg vitamin D3 (cholecalciferol; treatment DN), or 50 μg 25-OH-D3 (calcidiol; treatment HD)/kg feed. This study was conducted over a 4-parity period under controlled conditions. Study 2, running over 1 parity only, was performed in a commercial farm with 227 primi- and multiparous sows allocated to 2 dietary treatments: control (CON), receiving 2,000 IU vitamin D3/kg (equivalent to 50 μg/kg) feed (114 sows), and test (HYD), supplemented with 50 μg 25-OH-D3/kg feed (113 sows). Blood samples of sows were collected at 84 and 110d postcoitum and 1, 5, and 33 d postpartum (study 1) and at insemination and 28 and 80 d postinsemination as well as d 5 and 28 postpartum (study 2). Colostrum and milk samples in study 1 were obtained at 1, 9, and 33 d of lactation after oxytocin administration. Plasma 25-OH-D3 concentrations were increased (P < 0.05) in sows receiving 25-OH-D3 (HD and HYD) at any time of sampling whereas circulating plasma concentrations of 1,25-(OH)2-D3, Ca, and P were not affected by treatment. Milk concentrations of Ca and P were similar, but 25-OH-D3 content (except in colostrum) was clearly increased (P< 0.05) when 25-OH-D3 was fed. Most characteristics of sow reproductive performance responded similarly to the 2 sources and levels of vitamin D3, but weight gain of piglets between birth and weaning was decreased (P< 0.05) in offspring of DL and HD sows compared with animals of treatment DN (study 1). In study 2 total litter weight and birth weight per piglet were increased (P< 0.05) with 25-OH-D3 supplementation in comparison with the control (CON). Overall, feeding sows with 25-OH-D3 was considered to improve maternal supply with vitamin D3 and thereby maintain Ca homeostasis during gestation and lactation.

Tissue mineral concentrations and osteochondrosis lesions in prolific sows across parities 0 through 7

Mortality in swine herds is often associated with lameness, and trace minerals are implicated in maintaining integrity of skeletal tissues. The objectives of this study were to determine if prolific sows displayed evidence of trace mineral depletion with age and to determine the prevalence of osteochondrosis (OC) lesions. Reduced mineral concentrations with age would support recommendations for an increase in the amount of dietary minerals. Tissue samples were collected from 66 sows selected to represent a cross-sectional profile of a prolific herd fed diets with inorganic sources of trace minerals fortified at concentrations typically found in commercial diets. Females ranged from nulliparous (parity 0) to parity 7 with a lifetime average of 12.9 ± 0.5 pigs born alive per litter. Minerals were assessed in humerus, scapula, ovary, liver, and muscle (psoas major) tissues. Percent bone ash increased (P < 0.05) with parity from 64 to 66% but differed among bone sections. The Ca (39.0%) and P (18.9%) concentrations in bone ash were essentially constant in all sections and parities. Bone Cu, Fe, Mn, and Zn concentrations varied among sections, but differences due to parity (P < 0.05) were only detected in Fe. Bone Fe decreased from approximately 49 μg/g ash in parity 0 and 1 sows to approximately 29 μg/g ash in parity 7, likely reflecting loss of hemopoietic tissue with age. No evidence was detected in liver for depletion of trace minerals across parity; however, liver Cu and Zn concentrations tended to increase with age. Liver Mn concentrations varied with parity, but no consistent trend with parity was evident. Ovary Cu and Mn concentrations varied dramatically as a function of the reproductive status, but no evidence was detected for depletion with parity. Articular surfaces of the distal scapula and proximal and distal humerus were evaluated grossly for prevalence of OC; bones were then sectioned to evaluate lesions in subchondral bone and physis. Incidence of OC lesions on the articular-epiphyseal cartilage complex varied among bone sites, but differences across parities were not detected. In a subset of sows with subchondral bone lesions, the lesions appeared severe enough to contribute to clinical lameness, particularly in the distal humerus site. However, none of the sows exhibited lameness at slaughter. As no reductions in mineral concentrations with age were detected, recommendations to increase dietary mineral supplementation with age were not supported.

Validation of a lameness model in sows using physiological and mechanical measurements

The objective of this study was to develop a validated, transient, chemically induced lameness model in sows using subjective and objective lameness detection tools. Experiment 1 determined an effective joint injection technique based on volume and placement of dye using feet collected from 9 finisher pigs and 10 multiparity cull sow carcasses. Experiment 2 confirmed the injection technique in live animals and produced a transient clinical lameness in 4 anesthetized sows injected with amphotericin B (15 mg/mL) in the distal interphalangeal joints of the claw. Clinical lameness was assessed by a categorical lameness scoring system, and a postmortem visual confirmation of joint injection technique was obtained. In Exp. 3, 6 sows were injected with 0, 10, or 15 mg/mL amphotericin B in either the left or right hind foot and were monitored until clinical resolution. Treated sows demonstrated elevated clinical lameness scores. These changes resolved by 7 d after lameness induction. Control sows injected with sterile saline developed a clinical lameness score of 0.5, which resolved 72 h post injection. In Exp. 4, 36 sows were injected with 10 mg/mL amphotericin B in 1 of 4 injection sites (left front claws, right front claws, left rear claws, and right rear claws). All injected sows exhibited a decrease in maximum pressure, stance time, and number of sensors activated on the GaitFour (P < 0.05) sensor system. A static force plate also demonstrated a decrease in weight (kg) being placed on the injected foot when all feet were injected (P ≤ 0.05). Injection of amphotericin B induced a predictable acute lameness that resolved spontaneously and is an effective method to model lameness in sows.

The interrelationships between clinical signs and their effect on involuntary culling among pregnant sows in group-housing systems

Sows suffering from clinical signs of disease (e.g. lameness, wounds and shoulder ulcers) are often involuntarily culled, affecting the farmer's economy and the welfare of the animals. In order to investigate the interrelationships between clinical signs of individual pregnant group-housed sows, we performed an explanatory factor analysis to identify factors describing the patterns of variation of clinical signs. Moreover, we investigated how these emerging factors affected the probability of a sow to be either (i) euthanized, (ii) suddenly dead, (iii) sent to slaughter due to clinical signs of disease such as claw lesions or wounds or (iv) involuntarily culled (representing a pool of sows that were either euthanized, dead or sent to slaughter due to disease). Data from 2.989 pregnant sows in group-housing systems from 33 sow herds were included in the study. A thorough clinical examination was performed for each sow by using a protocol including 16 different clinical signs. Farmers recorded all cullings and deaths and the reasons for these actions in a 3-month period after the clinical examination. Among the observed sows, 4.2% were involuntarily culled during the 3-month period. From the explanatory factor analysis, we identified three factors describing the underlying structure of the 16 clinical variables. We interpreted the factors as 'pressure marks', 'wounds' and 'lameness' Logistic analyses were performed to investigate the effect of the three factors and the parity number of each sow on the four outcomes: (i) euthanized, (ii) suddenly dead, (iii) sent to slaughter due to clinical signs of disease and (iv) involuntarily culled. The analyses showed that 'lameness' significantly increased the risk of sows to be involuntarily culled (P = 0.016) or sent to slaughter due to clinical signs of disease (P = 0.026). Lameness is generally considered to be an important welfare problem in sows, which could explain the increased risk seen in this study. By contrast, 'pressure marks' and 'wounds' did not have any significant effect on the four outcomes (P > 0.05).

Genome-wide association study identifies Loci for body composition and structural soundness traits in pigs

BACKGROUND

The recent completion of the swine genome sequencing project and development of a high density porcine SNP array has made genome-wide association (GWA) studies feasible in pigs.

METHODOLOGY/PRINCIPAL FINDINGS

Using Illumina's PorcineSNP60 BeadChip, we performed a pilot GWA study in 820 commercial female pigs phenotyped for backfat, loin muscle area, body conformation in addition to feet and leg (FL) structural soundness traits. A total of 51,385 SNPs were jointly fitted using Bayesian techniques as random effects in a mixture model that assumed a known large proportion (99.5%) of SNPs had zero effect. SNP annotations were implemented through the Sus scrofa Build 9 available from pig Ensembl. We discovered a number of candidate chromosomal regions, and some of them corresponded to QTL regions previously reported. We not only have identified some well-known candidate genes for the traits of interest, such as MC4R (for backfat) and IGF2 (for loin muscle area), but also obtained novel promising genes, including CHCHD3 (for backfat), BMP2 (for loin muscle area, body size and several FL structure traits), and some HOXA family genes (for overall leg action). The candidate regions responsible for body conformation and FL structure soundness did not overlap greatly which implied that these traits were controlled by different genes. Functional clustering analyses classified the genes into categories related to bone and cartilage development, muscle growth and development or the insulin pathway suggesting the traits are regulated by common pathways or gene networks that exert roles at different spatial and temporal stages.

CONCLUSIONS/SIGNIFICANCE

This study is one of the earliest GWA reports on important quantitative traits in pigs, and the findings will contribute to the further biological function analysis of the identified candidate genes and potential utilization of them in marker assisted selection.

A survey of bone integrity from cull sows in Ireland

The objective of this study was to examine the differences in sow metacarpal properties through various parities and to compare the incidence of locomotory problems between stalled and loose-housed sows. Metacarpals (n = 110) of sows from six farms were collected at slaughter and stored at -20°C. Bones from one forelimb of sows in stalls (n = 36) and loose-housed (n = 20) were collected and their articular surfaces examined for Osteochondrosis Dissecans (OCD), these sows were also scored for lameness pre-slaughter. Metacarpals were CT scanned for cross sectional area and moment of inertia. Cylindrical sections from the diaphysis were used for mechanical testing and calculating bone strength indices. The results show there was little change in bone mineral status throughout the range of parities examined and overall metacarpal integrity was not compromised by multiple production cycles. There were no differences detected in the incidence of lameness or joint pathology between housing systems.

A cross-sectional study of prevalence and risk factors for foot lesions and abnormal posture in lactating sows on commercial farms in England

A cross-sectional study of lactating sows in 71 commercial pig herds in England was carried out to estimate the prevalence of foot lesions and abnormal posture and investigate the associated risks. Observational data were collected on the standing posture, lesions on the hind left foot, and the pen the sow was housed in for 233 sows. The prevalence of foot lesions was 76.8% and 10.8% of lactating sows had abnormal posture. Sows housed on slatted floors during pregnancy had an associated increased risk of heel flaps but a reduced risk of toe erosion, compared with sows housed on solid concrete floors with bedding during pregnancy. There was an increased risk of abnormal posture in lactating sows housed on slatted floors during pregnancy compared with those housed on solid concrete floors with straw bedding during pregnancy. In addition, there was an increased risk of abnormal posture in lactating sows with wounds on the limbs and erosions on the toe and the heel/sole. The positive association between abnormal posture and foot lesions suggests that these lesions might be painful. Housing sows on solid floors during pregnancy might reduce the risk of abnormal posture, and certain foot lesions, in sows during lactation. However, posture is a less sensitive measure of lameness than gait, and the nature of the causal relationship between foot lesions and lameness requires further investigation.

Oral ketoprofen is effective in the treatment of non-infectious lameness in sows

The efficacy of ketoprofen in the treatment of non-infectious lameness in sows was examined in a double-blinded study. Two dose rates of oral ketoprofen were compared to placebo treatment over five consecutive days. Lameness was assessed with a five-grade scoring system prior to and on the last day of the treatment. The rate of treatment success was 54.3% for the ketoprofen 4mg/kg group (n=46), 53.2% for the ketoprofen 2mg/kg group (n=47) and 20.8% for the pigs in the placebo group (n=48). The difference between both ketoprofen groups and the placebo group was significant (P=0.001), but there was no difference between the two ketoprofen groups (P=0.78). Oral ketoprofen was well tolerated and no adverse events were observed. As lameness is a very common problem in sows, oral ketoprofen appeared to be a practical way to alleviate pain and improve the welfare of sows.

Investigation into the pathology of shoulder ulcerations in sows

The pathogenesis and pathology of 421 cases of shoulder ulcerations in sows were examined and compared with 95 normal shoulders. The ulcerations started on the surface as a result of thrombosis and gradually progressed inwards to the tuber spina scapula. At each stage the lesions contained multiple bacterial colonies, and as the ulcerations progressed the amount of granulation tissues and fibroplasia increased. In 45 of the 95 normal shoulders there were areas of acute haemorrhage, oedema and fibroplasia, which followed the cords of normal fibrous tissue. However, in these cases the tissue was never necrotic, and the reaction was comparable with the subcutaneous lesions caused by blunt trauma to the skin.

A cross-sectional study of the prevalence of lameness in finishing pigs, gilts and pregnant sows and associations with limb lesions and floor types on commercial farms in England

The prevalence and risks for abnormal gait in finishing pigs (Sus scrofa), gilts and pregnant sows from a representative cross-section of indoor and outdoor herds in the United Kingdom were investigated. The prevalence of abnormal gait in finishing pigs, maiden gilts, pregnant gilts and pregnant sows from 88 herds was 19.7, 11.8, 14.4 and 16.9%, respectively. In a multivariable analysis of 98 herds, there was an increased risk of abnormal gait in pregnant sows housed on slatted floors compared with pregnant sows housed on solid concrete floors with straw bedding or sows housed outdoors on soil. The lowest prevalence of abnormal gait in finishing pigs occurred in pigs housed outdoors (3.4 vs 19.7% in indoor-housed finishing pigs) however, the difference was not significant because only three farms in the study housed finishing pigs outdoors. In indoor-housed finishing pigs, there was an increased risk of abnormal gait in pigs housed on solid concrete floors with sparse bedding, partly-slatted floors or fully-slatted floors compared with those housed on solid concrete floors with deep bedding in all areas. However, there were no significant associations between floor type and abnormal gait in gilts. There was an increased risk of abnormal gait associated with increasing callus, bursitis and capped hock score on the limbs of finishing pigs. This might have occurred because limb lesions cause discomfort or because lame pigs spend more time lying and this increases the risk of limb lesions developing.

Large-scale association study for structural soundness and leg locomotion traits in the pig

BACKGROUND

Identification and culling of replacement gilts with poor skeletal conformation and feet and leg (FL) unsoundness is an approach used to reduce sow culling and mortality rates in breeding stock. Few candidate genes related to soundness traits have been identified in the pig.

METHODS

In this study, 2066 commercial females were scored for 17 traits describing body conformation and FL structure, and were used for association analyses. Genotyping of 121 SNPs derived from 95 genes was implemented using Sequenom's MassARRAY system.

RESULTS

Based on the association results from single trait and principal components using mixed linear model analyses and false discovery rate testing, it was observed that APOE, BMP8, CALCR, COL1A2, COL9A1, DKFZ, FBN1 and VDBP were very highly significantly (P < 0.001) associated with body conformation traits. The genes ALOX5, BMP8, CALCR, OPG, OXTR and WNT16 were very highly significantly (P < 0.001) associated with FL structures, and APOE, CALCR, COL1A2, GNRHR, IHH, MTHFR and WNT16 were highly significantly (P < 0.01) associated with overall leg action. Strong linkage disequilibrium between CALCR and COL1A2 on SSC9 was detected, and haplotype -ACGACC- was highly significantly (P < 0.01) associated with overall leg action and several important FL soundness traits.

CONCLUSION

The present findings provide a comprehensive list of candidate genes for further use in fine mapping and biological functional analyses.

Post mortem findings in sows and gilts euthanised or found dead in a large Swedish herd

Background

The aim of this study was to get information on post mortem diagnoses of sows found dead or euthanised and to understand the diagnoses aetiology (causative background). Moreover, the study was to evaluate the association between the clinical symptoms observed on farm and post mortem findings.

Methods

A large Swedish herd was studied from January to September 2006. During the 32-week period 3.9% of the removed sows and gilts (old enough to be mated) were found dead, 12.0% were euthanised and the rest were sent to slaughter. Of 32 sows/gilts found dead 17 (53%) were post mortem examined, and of 98 sows euthanised 79 (81%) were examined. The 96 examined carcasses were after 70 sows and 26 gilts. The findings at examination were together with data from the herd monitoring program PigWin Sugg the base for the descriptive statistics presented.

Results

The average parity number at removal was 2.8 for those found dead and 2.1 for those euthanised. The highest number euthanised and found dead was in parity 0 (gilts). The main proportion of post mortem examinations was made on sows being in the period = 28 d of gestation at death (37.5%), followed by weaning to next service period (24.0%). Arthritis, with an incidence of 36.4% was the most common main finding of pathological-anatomical diagnosis (PAD). Of sows/gilts found dead were circulatory/cardiac failure (23.5%) and trauma related injuries (23.5%) most common PAD. The most commonly observed clinical symptom and reason for euthanasia of the sows/gilts was lameness. Notably, in 43% of the cases with PAD arthritis, the clinical symptoms suggested it being a fracture. Further one or more abscesses (38.5%) and teeth injuries (31.0%) were common findings when also incidental findings were included.

Conclusion

This post mortem study based on carcasses from sows/gilts found dead or euthanised showed that arthritis was a significant problem in the studied herd and that post mortem examination was important to get proper diagnosis.