Infectious and rearing-system related risk factors for chronic pleuritis in slaughter pigs

Chronic pleuritis (CP) in Danish pigs for slaughter is by far the most frequent finding at the routine post-mortem meat inspection. An initial investigation published in 1990 demonstrated infectious and management-related risk factors. Serological testing for additional infectious agents, as well as the need to consider the effect of disease clustering at the herd level, required a re-analysis of the data.

Our re-analysis used a representative sample of 4800 pigs originating from 623 Danish herds. Each pig was examined for the presence of CP and progressive atrophic rhinitis (PAR). The gender of the pig, the weight of the carcass, and the herd of origin were also recorded. Individual blood samples were examined for seropositivity for Actinobacillus pleuropneumoniae (AP) serotypes 2, 6, 7, 12, Haemophilus parasuis, Mycoplasma hyopneumoniae (MYC) and swine influenza (SI). Herd-level information retrieved through a questionnaire included health status, production type, herd size (i.e. pigs per year) and vaccination procedures.

Associations between CP and infectious, individual and herd-related factors were investigated by logistic regression with random effects. Among pigs from herds with conventional health status, seropositivity for AP serotypes 2 and 6, and MYC had odds ratios (ORs) of CP of 9.0, 1.6 and 1.8, respectively. Neither seropositivity for AP serotype 7 nor SI were associated with CP by themselves, but interacted: OR of CP of 5.3 (1.8) when present at the same time among pigs exhibiting (not exhibiting) PAR. An association of PAR with CP was found, and PAR interacted with AP serotype 7: OR=10.0 (4.3) when both factors were present among pigs exposed (non-exposed) to SI. The OR (0.97) for an increase of carcass weight by 1 kg was negligible.

In pigs from specific pathogen-free (SPF) herds, seropositivity for MYC and herd size were associated with CP. Moreover, for a herd size of 1000 pigs, CP was associated with exposure to MYC by an OR of 3.3 (decreasing to 1.9 when the herd size was increased by 1000). Farrow-to-finish as opposed to finishing herd had an OR of CP of 3.2.

In conventional herds, seropositivity for AP serotype 2 and MYC were associated with 51% and 29% of the occurrence of CP. In SPF herds, farrow-to-finish as opposed to finishing herds was associated with 47% of the occurrence of CP. Seropositivity for MYC was associated with 33% (39%) of the occurrence of CP in herds with a size > (≤) 1500 pigs.     

Nuclear membrane proteins with potential disease links found by subtractive proteomics

To comprehensively identify integral membrane proteins of the nuclear envelope (NE), we prepared separately NEs and organelles known to cofractionate with them from liver. Proteins detected by multidimensional protein identification technology in the cofractionating organelles were subtracted from the NE data set. In addition to all 13 known NE integral proteins, 67 uncharacterized open reading frames with predicted membrane-spanning regions were identified. All of the eight proteins tested targeted to the NE, indicating that there are substantially more integral proteins of the NE than previously thought. Furthermore, 23 of these mapped within chromosome regions linked to a variety of dystrophies.     

Integration by case,place and process: transdisciplinary research for sustainable grazing in the Lachlan River catchment,Australia

In a context of global agricultural intensification, integrating conservation and agricultural production is a major challenge. We have tackled the problem using a transdisciplinary research framework. Our work focuses on part of the upper Lachlan River catchment in southeastern Australia. The region is dominated by livestock grazing, and is part of an internationally recognised threatened ecoregion because most native woodland vegetation has been cleared. In productive areas, most remnant vegetation occurs as scattered and isolated paddock trees, which are dying from old age and not regenerating due to agricultural practices. The policy context and industry trends present additional risks for sparse trees. These declining trees provide many ecosystem services, including enhanced water infiltration, shade for livestock, aesthetic and cultural values, and habitat for native species. Our research aims to identify management options and policy settings that enable landscape-scale tree regeneration while maintaining grazing production. Our findings highlight tensions between the trajectory of tree cover in the region and stakeholder values. Under status quo management, many scattered and isolated paddock trees will be lost from farms, although most farmers would like to see them persist. Case studies on selected farms reveal management strategies that may be more sustainable in terms of tree regeneration and agricultural productivity, such as rotational grazing. In addition to these applied insights, our work provides a case study illustrating how a transdisciplinary study can be conducted efficiently by a small team. Our pragmatic approach has successfully combined targeted disciplinary activities with strategic collaborations and stakeholder engagement, all united by shared landscape, case graziers, and outreach activities.     

Age-related differences in collagen crimp patterns in the superficial digital flexor tendon core region of untrained horses

Objective To measure collagen fibril crimp angles and lengths as well as collagen fibril mass-average diameters in central and peripheral regions of the superficial digital flexor tendon of wild horses, to ascertain any age-related changes in either region in the absence of imposed galloping exercise.
Design Measurements from a random cull of wild horses.
Sample population Superficial digital flexor tendon samples were taken from 23 wild horses ranging in age from two to ten years.
Procedure Horses were divided into 'young' (< 5 years, n = 10), 'middle-aged' (5 to < 10 years, n = 9) and 'old' groups (10+ years, n = 4) and the mean crimp angle, mean crimp length and collagen fibril mass-average diameter calculated for the central region, and for the peripheral region of each group. Differences between groups and regions were analysed using two-tailed t tests.
Results The crimp angle for the central region was found to decrease with age, so that in old horses it was smaller than that for the tendon periphery (P < 0.05). The crimp angle for the latter region did not alter significantly with age. Crimp period lengths and collagen fibril mass-average diameters did not show significant changes with age in either region.
Conclusion Reduction of the crimp angle in the core of the superficial digital flexor tendon occurs normally with age, as tendons of older animals would have undergone a higher number of loading cycles. It is possible that athletic training increases the frequency and/or the magnitude of high loading cycles experienced by the tendon, and may accelerate and worsen the normal load-related ageing process in the superficial digital flexor tendons of young performance horses, particularly in the central regions where lesions usually occur.     

Effect of combined antibiotic therapy on fertility in brood bitches infected with Brucella canis

Bitches with naturally occurring Brucella canis infection were treated with combined antibiotic therapy consisting of tetracycline, dihydrostreptomycin, and trimethoprim-sulfadiazine. After treatment, all but 1 bitch became abacteremic, and serologic titers declined for a variable length of time (3 months to 1 years). Abortion did not occur while these bitches were abacteremic. Although sequential antibiotic therapy for 6 weeks did not eradicate Brucella canis from affected bitches, it did not prevent abortion. The number of live pups whelped and weaned by treated bitches was comparable with that in bitches before they became infected.     

Expression of ABC-Transport Proteins in Canine Mammary Cancer: Consequences for Chemotherapy

Intrinsic or acquired drug resistance is a major barrier for chemotherapy of cancer. Importantly, the presence of ATP-binding cassette, ABC-transport proteins in tumour cells circumvents an intracellular accumulation of chemotherapeutic drugs. In this study, 103 canine mammary tumour probes were investigated for mRNA expression of seven ABC-transporters by RT-PCR. All tumour samples expressed multidrug resistance-associated protein 1 (MRP1) and breast cancer resistance protein (BCRP). MRP7 was detected in 97.1% of tumour probes, MRP3 in 96.1%, Pgp in 92.2%, MRP5 in 85.4% and MRP6 in 64.1%. More of the half of tumour samples (56.1%) expressed all of the examined ABC-transport proteins. Approximately one-third of the tumour samples (32.7%) were lacking in one transporter and only 11.2% possessed from three to five transporters. The canine transporter cBCRP was functionally analysed in stable transfected Madin-Darby canine kidney-II cells using an MTT viability test. cBCRP transfected cells showed a 5.4-fold resistance to 10 μ m doxorubicin. Cell survival in the presence of methotrexate was not affected by cBCRP. In conclusion, absence of efficiency of chemotherapy of canine mammary cancer can be caused by expression of seven various ABC-transport proteins. Because cBCRP is expressed in all examined tumour probes and induces resistance to doxorubicin, the application of doxorubicin for treatment of canine mammary is inappropriate.     

Changes in mineralised tissue at the site of origin of condylar fracture are present before athletic training in Thoroughbred horses

Abstract

AIM: To show that changes are present at the site of origin of metacarpal condylar fracture in young Thoroughbred horses before they enter race training.

METHOD: Bone slices, 2 mm thick, in three mediolateral planes through the centre of rotation of the metacarpo-phalangeal joint (MCPJ) of both distal third metacarpal bones (Mc3) of 12 Thoroughbred horses aged 17 months, were imaged using point-projection digital X-ray imaging (µXR).

RESULTS: In some horses, linear or ovoid radiolucency was found in articular calcified cartilage (ACC) and subchondral bone of the palmaro-distal aspect of the sagittal groove, exactly at the site of more advanced stages of condylar fatigue fracture. An incidental finding was ovoid radiolucency in the apex of the dorso-distal aspect of the sagittal ridge, with or without fragmentation or disturbance of the subchondral mineralised tissue line, resembling equine osteochondrosis.

CONCLUSIONS AND CLINICAL RELEVANCE: The findings imply that the aetiology of condylar fatigue fracture in young Thoroughbred horses includes abnormality in development of the bone and joint that is present before athletic activity occurs.     

Bodyweights and growth rates of spring- and autumn-born Thoroughbred horses raised on pasture

AIM: To examine the growth of spring- and autumn-born Thoroughbred foals raised on pasture.

METHODS: Bodyweight and growth rates were measured in pasture-raised Thoroughbred horses, born in either spring (n=56) or autumn (n=7), from birth to approximately 13 and 17 months of age.

RESULTS: Birthweight tended to be lower in autumn- than spring-born foals (54.4, SD 7.92 kg vs 57.3, SD 5.90 kg; p=0.08). Between birth and 6 months of age, there was no difference in growth rate at equivalent ages between horses born in spring and autumn. Spring-born horses, which were weaned in the autumn, had lower post-weaning growth rates than autumn-born horses that were weaned in the spring. At time of the late yearling sales (March–April) in the Southern Hemisphere, unadjusted mean bodyweights of autumn-born horses (379.3, SD 24.8 kg) were lower (p=0.017) than those of the spring-born horses (437.2, SD 35.3 kg), although values in the autumn-born horses were all within two standard deviations (SD) of the mean of the spring-born animals. When adjusted for the covariates of birthweight and gender, the difference between spring- and autumn-born horses at that time was not significant (p=0.25).

CONCLUSIONS AND CLINICAL RELEVANCE: Some autumn-born foals could be marketed for late yearling sales in the Southern Hemisphere, on the basis of bodyweight. Furthermore, they might also be competitive in the Northern Hemisphere industry (sales or racing), as they would be competing against horses of the same official age.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. Conclusions

This paper summarises and presents in context the main findings of an extensive series of studies of early training lasting 13 weeks in which the tissue responses of 2-year-old Thoroughbred horses were assessed using a combination of methods. Negligible clinical injury was detected and thus the study fulfilled the intention of investigating adaptive change rather than injury. Cancellous and cortical bone, some digital tendons, and articular cartilage responded to early training exercise to a greater or lesser degree. Clinical examination and ancillary diagnostic aids currently in veterinary clinical use are not sufficient to detect early abnormalities in metacarpo-phalangeal joint (MCPJ) cartilage found in both trained and untrained horses. Future work should centre on detection of such changes, on the precise registration of training workload, and on the manipulation of the responses of musculoskeletal tissues by careful investigation of the effects of introducing conditioning exercise at a young age.