Assessment of abdominal lesions in pigs with wounded umbilical outpouchings transported to slaughter.

BACKGROUND: Umbilical outpouchings (UOs) in pigs are of welfare and production concern in Danish pig herds. One of the challenges is the transportation of these animals due to the size of the UOs and ulcerations on them. With certain precautions and an approval from a veterinarian, pigs with UOs may be transported, however, UOs are associated with several intra-abdominal lesions, e.g. peritonitis and incarceration, which may worsen during the process of transportation. The prevalence and characterization of intra-abdominal lesions associated with UOs following transportation has not been investigated. Therefore, the objective of the present study was to evaluate lesions associated with the intestines and peritoneum in slaughter pigs with wounded UOs following transportation to an abattoir. RESULTS: A cross-sectional study involving three conventional Danish pig herds was conducted comprising 96 slaughter pigs with wounded UOs transported to an abattoir. Following slaughter the UOs with accompanying intestines were examined pathologically. Three distinct morphological categories were present: hernia, enterocystoma and herniating enterocystoma. Intra-abdominal lesions were present in 72% of the animals, representing 65% (44/68) of the hernias, 77% (10/13) of the enterocystomas, and 100% (15/15) of the herniating enterocystomas. Several different lesions were found like bleedings, acute/chronic peritonitis and hypertrophy of the intestinal muscular layers. CONCLUSIONS: The prevalence of intra-abdominal lesions in pigs transported with a wounded UO was found to be high independent of the underlying condition, and it is clear that these pigs possess a vulnerable group of animals, especially during physical stressful situations like transportation. More information is needed regarding the prevalence of intra-abdominal lesions in UO pigs without wounds on the UO. The results provide valuable knowledge, that can be used when examining and evaluating UO pigs before transportation.

Prevention of umbilical outpouchings and mortality in pigs: Meloxicam, tying, cutting, and chlorhexidine versus amoxicillin or no treatment? A clinical field trial.

BACKGROUND: Umbilical outpouchings (UOs) are common in Danish pigs. Neonatal antibiotics are therefore used with the hope of reducing umbilical infections and subsequently UOs. However, the effect of neonatal antibiotics on preventing UO has been the subject of mixed conclusions, and secondly, treating all animals with antibiotics might exacerbate the development of antimicrobial resistance. This study analysed the effects of different treatments on the prevalence of umbilical outpouchings and mortality from birth to nursery unit. All treatment was on the day of birth. The groups were: a negative control group, an antibiotic group receiving amoxicillin, and an experimental group where the piglets had their umbilical cord disinfected with chlorhexidine, followed by tying and clipping, and lastly, injection with meloxicam. The pigs were examined six weeks after weaning, and all pigs that died during the study were autopsied. RESULTS: There were 5494 pigs divided across the three groups. There were no statistically significant differences in UO prevalence between the groups: control 3.9%, antibiotic 4.2%, and experimental 4.0% (p = 0.87). The only variable affecting the prevalence of UOs in this study was sex with females being at higher risk. There were no statistically significant differences in mortality between the groups from birth until departure from the nursery unit: control 22.9%, antibiotic 21%, and experimental 21.4% (p = 0.33). The variables affecting mortality were sex, intrauterine growth restriction (IUGR), birth weight, and cross fostering. Males had higher odds of dying, as had piglets recorded with some degree of IUGR. Also, low birth weight increased the odds of dying for all weight quartiles compared to the fourth (the heaviest piglets > 1.6 kg), as well as cross fostering increased the odds ratio of dying. CONCLUSIONS: This study found no significant differences in the prevalence of UOs and mortality following different treatments at birth. The study showed that the prevalence of UO and mortality was not reduced following the administration of amoxicillin or meloxicam in combination with disinfection and tying of the umbilical cord.

Umbilical outpouchings in Danish piglets and weaners: prevalence and clinical characteristics-a cross-sectional study at herd level.

BACKGROUND: Umbilical outpouchings (UO) in pigs present a welfare concern because of ulceration risk and complications. Danish legislation requires pigs with larger UOs to be housed in sick pens with soft bedding, and some UO pigs might not be suited for transport. Because of this, many UO pigs are euthanized, adding to the costs of pig production. The true prevalence of UO is unknown as no scientific reports with randomly sampled herds exist. This study aimed to estimate the prevalence of UO in Danish piglets and weaners and describe their clinical characteristics: size, texture, reducibility, and occurrence of ulcers. Lastly, risk factors for the occurrence of ulcers on UOs were investigated. RESULTS: A cross-sectional study was conducted in 30 Danish conventional herds, with at least 800 weaned pigs and 200 sows. The herds were selected randomly from the Danish Husbandry Register and visited once between September 2020 and May 2021. Piglets were examined during their last week in the farrowing unit, and weaners were examined between weeks three and eight after weaning. The abdominal area was palpated on all pigs, and all irregularities were recorded; the results presented are umbilical outpouchings measuring at least 2 × 2 cm. The within-herd prevalence of piglets with UO averaged 4.2% with a range from 0.8 to 13.6% between herds. The within-herd prevalence of weaners with UO averaged 2.9%, ranging from 1.0 to 5.3% between herds. Approximately 80% of the UOs were classified as small or medium (< 7 cm piglets/ < 11cm weaners). Large outpouchings had significantly higher odds of ulcer occurrence (OR = 9.9, p < 0.001). CONCLUSION: UOs are common in Denmark, with a prevalence of 2.9% in weaners and an estimated annual production of 32 million Danish pigs almost a million pigs are affected yearly. Most of these pigs will have a small or medium UO. If the pigs have large UOs the odds of ulcer occurrence increase significantly. Numerous of these pigs are wasted, challenging sustainability and economy. UOs might also affect the welfare of the pigs. More research is therefore needed, especially in the prevention of UOs.

Determination of an optimal ELISA cut-off for the diagnosis of Toxoplasma gondii infection in pigs using Bayesian latent class modelling of data from multiple diagnostic tests.

Toxoplasma gondii infection in pigs is commonly diagnosed using serological tests that detect IgG antibodies targeted against the parasite. Such tests include enzyme-linked immunosorbent assay (ELISA), modified agglutination test (MAT), and western blot (WB), which are commercially available as rapid test kits. In this study, we evaluated the manufacturer recommended cut-off of ELISA-PrioCHECK test kit and determined a new optimal cut-off for identifying T. gondii infections in pigs. Assessment of the commercial ELISA kit was done by including data from two additional serological tests, MAT, and WB, applied to seven pig population categories with varying prevalences. A total of 233 plasma samples that were previously used in other studies for investigating T. gondii seroprevalence in pigs in Denmark were randomly selected for inclusion, including 95 samples that had previously been analysed with all three tests and an additional 138 samples that were analysed using the three serological tests for this study. In the absence of a gold standard test, a latent class model was fit to the data to obtain estimates of sensitivity and specificity for each of the tests along with prevalence in each of the populations. A cut-off that maximized the sensitivity and specificity of the ELISA test was then selected. The optimal cut-off value for percent of positive control (PP) in ELISA-PrioCHECK was estimated to be 27.7 PP, which is higher than the cut-off value of 20 PP that is recommended by the manufacturer. At this cut-off, the estimated sensitivities of ELISA, MAT and WB were 99.2% (96.3-100.0%), 96.3% (88.0-100.0%), and 89.8% (80.0-98.0%), respectively. The estimated specificities of ELISA, MAT and WB were 95.2% (92.5-97.6%), 99.6% (97.5-100.0%), and 98.2% (95.9-100.0%), respectively. Our findings have broad relevance to the use of the ELISA-PrioCHECK test kit for detecting Toxoplasma gondii infection in pigs.

Seroprevalence of Toxoplasma gondii infection in sows and finishers from conventional and organic herds in Denmark: Implications for potential future serological surveillance.

Pigs are one of several host species for Toxoplasma gondii parasites, and consumption of infected pork may lead to toxoplasmosis in humans. We estimated seroprevalence in sows and finishers from conventional and organic herds in Denmark and discussed the strategies for reducing the risk from pork. We collected 447 blood samples from 59 herds, and additional meat-juice samples from 212 of the same pigs. Using a T. gondii IgG commercial ELISA test, we found 2% (95% CI = 0.4%-5%) apparent seroprevalence of T. gondii in conventional finishers, 11% (95% CI = 6%-17%) in organic finishers, 19% (95% CI = 11%-30%) in conventional sows and 60% (95% CI = 47%-72%) in organic sows. The odds of an animal testing positive for T. gondii was 16 times higher (95% CI = 4.6-74.3) in organic compared to conventional herds. The odds were 22 times higher (95% CI = 6.5-88.3) if the animal was a sow compared to a finisher. Meat-juice ELISA values were significantly correlated with plasma results (P < 0.001), but on average 64% of the blood-plasma ELISA values. Lowering the recommended cut-off from 20 to 13 percent positive values of the positive control for meat-juice ELISA, resulted in the meat-juice ELISA identifying 93% of the plasma positives as positive and 99% of the plasma negatives as negative. The time taken to detect one or more infected pigs from a T. gondii positive herd at slaughter was estimated using abattoir data on pigs (17,195,996) and batches (165,569) delivered to Danish abattoirs in 2018. The time to detection was affected by the seroprevalence, frequency at which the pigs were delivered, the number of samples tested per batch delivery and the batch sizes. Time to detection was long in conventional finisher herds due to low prevalence, and in sow herds because of intermittent delivery of a low number of sows. In organic finisher herds, time to detection was short due to medium prevalence and frequent delivery of a high number of finishers. Conventional finisher herds may be classified as low-risk, organic finisher herds as medium-risk, and conventional and organic sow herds as high-risk herds. Risk-mitigation strategies at processing plants (freezing or curing) or at the consumer level (heat treatment) for meat originating from high-risk herds, surveillance of medium-risk herds, and auditing for controlled housing (high biosecurity) in low-risk herds may be cost-effective alternatives to serological surveillance of all Danish pig herds.

Herd and sow-related risk factors for mortality in sows in group-housed systems.

Mortality of sows is a major problem for pig production worldwide. In this study, we used hierarchical multivariable logistic analyses to investigate different risk factors for mortality at the sow and herd level in herds with group-housed pregnant sows. Data included 3652 pregnant and 1266 lactating sows from 34 sow herds. A clinical examination for 16 clinical signs was carried out for each sow, and information about 16 herd related factors was obtained by interviews. Farm records were used to obtain information about whether or not sows died suddenly or were euthanized within 3 months after the clinical examination. Factors increasing the risk of sow mortality in the gestation unit were solid pen floors (OR=1.87), presence of vulva bites (OR=1.73) and unwillingness to stand when approached (OR=1.62). Factors increasing the risk of sow mortality in the lactation unit were pale vulva color (OR=12.69), body leanness (OR=4.11), and presence of shoulder ulcers (OR=2.89). The estimated between herd variation was small. Thus, the findings for the sow level variables may be generally applicable for sows in herds with group housed systems.

An object-oriented Bayesian network modeling the causes of leg disorders in finisher herds.

The implementation of an effective control strategy against disease in a finisher herd requires knowledge regarding the disease level in the herd. A Bayesian network was constructed that can estimate risk indexes for three cause-categories of leg disorders in a finisher herd. The cause-categories of leg disorders were divided into infectious causes (arthritis caused by infectious pathogens), physical causes (e.g. fracture and claw lesions), and inherited causes (osteochondrosis). Information about the herd (e.g. the herd size, floor type and number of suppliers) and information about individual pigs (e.g. results from diagnostic tests) were used to estimate the most likely cause of leg disorders at herd level. As information to the model originated from two different levels, we used an object-oriented structure in order to ease the specification of the Bayesian network. Hence, a Herd class and a Pig class comprised the basic components of the object-oriented structure. The causal structure of the model was based on evidence from published literature. The conditional probabilities used in the model were elicited from experts within the field and from the published literature. To illustrate the behaviour of the model, we investigated the value of different levels of evidence in two fictitious herds with different herd characteristics related to the risk of leg disorders (e.g. purchase policy, production type and the stocking density in pens). The model enabled us to demonstrate the value of performing systematic collection of additional information (i.e. clinical, pathological and bacteriological examination) when identifying causes of leg disorders at herd level.