Arthritis In Lambs Research Articles

Flock-level risk factors for outbreaks of infectious arthritis in lambs, Norway 2018

BackgroundOutbreaks of infectious arthritis in young lambs associated with Streptococcus dysgalactiae subspecies dysgalactiae (SDSD) lead to reduced animal welfare, increased use of antibiotics and economic losses for sheep farmers. Understanding risk factors is essential when developing strategies to prevent such outbreaks. This questionnaire-based cross-sectional study classified sheep flocks of respondents as cases or controls. Flock-level risk factors for outbreaks of infectious arthritis were assessed using a multivariable logistic regression model.ResultsEighty-four of 1498 respondents (5.6%) experienced an outbreak of infectious arthritis in their flock in 2018, the year of study. Factors associated with a higher risk of outbreak were larger flock size (OR 1.3, 95% CI 1.1–1.4, per 100 lambs), plastic mesh flooring in the lambing pen (OR 3.0, 95% CI 1.7–5.3) and a lambing percentage greater than 200 (OR 2.0, 95% CI 1.1–3.5). Flocks where farmers observed infections around the ear tags of lambs also had an increased risk of outbreak (OR 2.6, 95% CI 1.6–4.3).ConclusionsThe risk factors identified in this study are characteristic of modern and intensively managed sheep farms in Norway. A distinguishing feature of Norwegian sheep farming is winter housing and indoor lambing. One might expect that this in itself is a risk factor because of high stocking densities during lambing. However, outbreaks of infectious arthritis in young lambs are reported by the industry to be a more recent phenomenon. The current study indicates that intensification of indoor management systems with larger flocks and higher production per ewe may predispose to outbreaks. The results provide a basis for further studies on transmission dynamics of SDSD in sheep flocks with indoor lambing.

Chlamydia pecorum-Induced Arthritis in Experimentally and Naturally Infected Sheep.

Chlamydia pecorum is an obligate intracellular pathogen with a wide host range including livestock such as sheep, cattle, goats, and pigs as well as wildlife species such as koalas. Chlamydial polyarthritis is an economically important disease resulting in swollen joints, lameness, stiffness, and weight loss in young sheep. In the present study, tissues from sheep experimentally or naturally infected with Chlamydia pecorum were assessed by histopathology and immunohistochemistry. Carpal, hock, and stifle joints as well as spleen, liver, kidney, lymph nodes, lung, and brain of 35 sheep from different inoculation groups were available. Two different C. pecorum strains (IPA and E58), different routes of administration (intraarticular or intravenous), UVA-irradiated IPA strain, and corresponding noninfected control groups were investigated. Similar investigations on tissues from 5 naturally infected sheep were performed. The most obvious inflammatory lesions were observed in synovial tissues and, notably, in the renal pelvis from the experimentally infected group and naturally infected animals. This resulted in chronic or chronic-active arthritis and pyelitis. Intralesional chlamydial inclusions could be demonstrated by immunohistochemistry in both tissues. Immunohistochemical evaluation of the presence and distribution of macrophages, T and B cells in synovial tissues revealed macrophages as the most prevalent inflammatory cell population. Previous observations indicated that C. pecorum isolates can infect circulating monocytes. Together with the finding of the histological lesions in synovial tissues and internal organs alongside the presence of C. pecorum DNA, these observations suggest chlamydial arthritis in lambs is the result of hematogeneous spread of C. pecorum.

Sustainable lamb production: Evaluation of factors affecting lamb growth using hierarchical, cross classified and multiple memberships models

In light of current concerns about the sustainability of red meat production in a world with increasing global demand for food from animal origin there is a need for a better understanding of factors that influence the growth rate and feed conversion efficiency of animals on commercial farms. The primary objective of this observational study was to use longitudinal data to quantify the simultaneous effects of multiple ewe and lamb factors on lamb growth rate. A secondary aim was to evaluate model structures that specifically account for lamb grouping effects during the growth period and compare these to classical hierarchical growth rate models.A total of 4172 weight recordings from 805 lambs and data on disease events were collected over a 6-month period from a commercial pedigree sheep flock. Three mixed model structures were compared, hierarchical, cross classified and multiple membership, and final estimates determined within a Bayesian framework. The multiple membership structure provided the best model fit and was used for final inference; taking account of the effect of lamb grouping over time provided the best estimates of lamb growth rate.Ewe lameness and mastitis cases had a deleterious impact on lamb growth. Lambs from ewes identified with mastitis during lactation were on average 3.0 (standard error (SE) 1.6) kg lighter during the four month growth period than lambs from unaffected ewes. Lambs from ewes that were not lame during pregnancy were 3.0 (SE 1.2) kg heavier at eight weeks of age than lambs from ewes with a least one lameness case during the same period. Lambs from ewes lame either during the first 4 weeks or between 4–8 weeks of a lamb’s life (but not lame during pregnancy) were also significantly heavier at 56 days of age, than lambs reared by ewes that were lame during pregnancy (2.8 (SE 1.2) and 3.4 (SE 1.2) kg respectively).Cases of pneumonia and bacterial arthritis in lambs had a significant negative impact on lamb growth with affected lambs being on average 5.5 (SE 1.1) kg and 2.2 (SE 1.2) kg less than non-affected lambs respectively after the disease event. Prior to a case of lameness or pneumonia, lambs were significantly heavier than unaffected lambs suggesting a possible trade-off between growth and immune function.Overall, the study provides evidence that that a combination of ewe and lamb characteristics and disease events play an important role in determining lamb growth rate and that heavier lambs may be more susceptible to disease.

Trimming and production losses associated with bacterial arthritis in lambs presented to an abattoir in southern Australia

Bacterial arthritis in sheep is a painful and debilitating condition that is widespread across all sheep-raising regions and climatic zones of Australia. At slaughter, bacterial arthritis in sheep causes economic losses through the condemnation of all or parts of the carcass, as specified in the Australian Standard for the Hygienic Production and Transportation of Meat and Meat Products for Human Consumption. In this study, we investigated the economic cost of arthritis in lambs presenting to an abattoir in southern Australia using a combination of the prevalence of arthritis detected during meat inspection, condemnation rates, trim weight and carcass weight, and fat measurements. Data were collected on 354 lines of lambs representing 63287 carcasses. One hundred and sixty nine consignments, or approximately one-half of the consignments, had at least one carcass with arthritis/polyarthritis detected by meat inspection personnel. Four hundred and twenty-two, or 0.7%, of the carcasses had arthritis/polyarthritis in at least one joint. When arthritis was present, on average 2.0% of the line was affected. Three carcasses with arthritis were condemned and the remainder trimmed, with an average trim weight of 0.7 kg. In addition, arthritis reduced the growth of lambs by 1.2 kg hot standard carcass weight, approximately 2.7 kg liveweight (assuming 45% dressing percentage) and reduced fat cover by 1.8 mm.

Clinical, diagnostic and pathologic features of presumptive cases of Chlamydia pecorum-associated arthritis in Australian sheep flocks.

BackgroundArthritis is an economically significant disease in lambs and is usually the result of a bacterial infection. One of the known agents of this disease is Chlamydia pecorum, a globally recognised livestock pathogen associated with several diseases in sheep, cattle and other hosts. Relatively little published information is available on the clinical, diagnostic and pathologic features of C. pecorum arthritis in sheep, hindering efforts to enhance our understanding of this economically significant disease. In this case series, a combination of standard diagnostic testing used routinely by veterinarians, such as the Chlamydia complement fixation text (CFT), veterinary clinical examinations, and additional screening via C. pecorum specific qPCR was used to describe putative chlamydial infections in five sheep flocks with suspected ovine arthritis.Case presentationFive separate cases involving multiple lambs (aged six to ten months) of different breeds with suspected C. pecorum arthritis are presented. In two of the five cases, arthritic lambs exhibited marked depression and lethargy. Arthritis with concurrent conjunctivitis was present in four out of five lamb flocks examined. Chlamydia CFT demonstrated medium to high positive antibody titres in all flocks examined. C. pecorum shedding was evident at multiple sites including the conjunctiva, rectum and vagina, as determined via qPCR. Two of the five flocks received antimicrobials and all flocks recovered uneventfully regardless of treatment.ConclusionThis case series highlights the features a field veterinarian may encounter in cases of suspected ovine chlamydial arthritis. Our analysis suggests a presumptive diagnosis of chlamydial arthritis in lambs can be made when there is evidence of joint stiffness with or without synovial effusion and elevated chlamydia antibody titres. C. pecorum-specific qPCR was found to be a useful ancillary diagnostic tool, detecting Chlamydia positivity in low or negative CFT titre animals. Variables such as symptom duration relative to sampling, sheep breed and farm management practices were all factors recorded that paint a complex epidemiological and diagnostic picture for this disease. These case studies serve to provide a platform for further research to improve diagnostic testing and new treatment and control strategies for C. pecorum infections in sheep.

Docked tail length is a risk factor for bacterial arthritis in lambs

Arthritis is commonly observed in lambs at slaughter, resulting in losses due to carcase downgrading, trimming or condemnation. The condition arises on-farm and is thought to be influenced by a number of predisposing factors, which vary in their ability to be addressed by sheep producers. The aim of this study was to investigate whether there is a link between tail length and arthritis in lambs. If there is, leaving a longer tail stump when docking may be a cost-effective way of reducing the prevalence of joint infections in lambs. The study was conducted at an abattoir in South Australia and included 63,287 carcases. This study found a correlation between short-docked tails (fewer than three coccygeal vertebrae remaining) and bacterial arthritis in lambs. Other risk factors for arthritis included breed and the regional source of the lambs, but not age. The constraints of data collection within the abattoir did not allow the effects of tail docking method, sex or whether male lambs had been castrated on the prevalence of bacterial arthritis to be determined. The bacterium most commonly isolated from abnormal joints was Erysipelothrix rhusiopathiae, followed by Streptococcus spp., including Streptococcus suis.

Structural Consideration of the Formation of the Activation Complex between the Staphylokinase-Like Streptococcal Plasminogen Activator PadA and Bovine Plasminogen

The characteristics of a streptococcal plasminogen activator (PA) displaying specificity for ruminant plasminogen (Plg) were defined using molecular approaches. The 16-kDa secreted protein PadA was found to be prevalent in Streptococcus dysgalactiae subspecies dysgalactiae isolated from cases of bovine mastitis and septic arthritis in lambs. PadA was able to activate bovine, ovine and caprine Plg, but not human Plg. Amino acid sequence analysis identified a limited level of homology to other streptococcal PAs, including streptokinase; however, PadA was found to align well with and match in size the staphylococcal PA, staphylokinase. Recombinant PadA was used to investigate interaction with bovine Plg, leading to formation of an activator complex that was capable of recruiting and converting further substrate Plg into plasmin. Individual non-overlapping peptides of PadA or bovine microplasminogen were found to block the interaction between PadA and bovine Plg, preventing the formation of the activation complex. Homology modelling based upon structures of staphylokinase complexed with human microplasminogen supported these findings by placing critical residues in close proximity to the plasmin component of the activation complex.

Effect of mulesing and shearing on the prevalence of effect of mulesing and shearing on the prevalence of Erysipelothrix rhusiopathiae arthritis in lambs.

To examine the effects of management practices and environment on the prevalence of arthritis in lambs. A case-control study was conducted on groups of lambs from 122 Western Australian sheep flocks. Arthritis was diagnosed by visual assessment of lambs at abattoirs by qualified meat inspectors. The prevalence was estimated from data collected from producers on culling practices for arthritis. Data on management practices and environmental variables were collected by personal interview. Stepwise logistic regression was used to measure the effects of the most important factors on the prevalence of arthritis. Mulesing and shearing lambs increased the odds of high prevalence of arthritis by 7 (95% CI 1.9 - 25.6) and 4.3 (95% CI 0.9 - 19.6) times, respectively compared to unmarked and unshorn lambs. Lambs slaughtered between December and June had 3.7 (95% CI 0.8 - 16.6) times greater odds of having a high prevalence of arthritis than lambs slaughtered in the remainder of the year. This study indicates that, to decrease the risk of high prevalence of arthritis, lambs raised for meat production should not be mulesed or shorn. Recommended improvements to hygiene at mulesing such as the use of portable yards had little effect on the prevalence of arthritis.

Arthritis in lambs and sheep

In PracticeVolume 13, Issue 5 p. 204-207 Farm Animal Practice Arthritis in lambs and sheep Ken Angus, Ken AngusSearch for more papers by this author Ken Angus, Ken AngusSearch for more papers by this author First published: 01 September 1991 https://doi.org/10.1136/inpract.13.5.204Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume13, Issue5September 1991Pages 204-207 RelatedInformation