Bayesian latent class models to determine diagnostic sensitivities and specificities of two point of care rapid tests (Selma plus, Dipslide) for the detection of Streptococcus uberis associated with mastitis in dairy cows

IntroductionDevelopment and validations of accurate mastitis diagnostics are crucial to make timely and evidence-based decisions on mastitis therapy in order to reduce its impact on productivity, animal welfare and practicing the prudent use of antimicrobials on dairy farms.MethodsThe objectives of this study were to assess the agreement between test results from reference laboratory and two point of care tests (Selma plus, Dipslide) and to estimate the test accuracies with Bayesian latent class models (BLCMs). In total of 509 single quarter milk samples from cows with mastitis were included in the study.ResultsAmong all analyzed mastitis pathogens, Streptococcus spp. was detected in up to one third of all analyzed samples and for Selma all Streptococcus samples were considered as Streptococcus uberis. The agreement (κ) when comparing two tests varied greatly depending on the bacteria, ranging from no agreement to good agreement (κ = negative to 0.86) depending on the prevalence of identified pathogens. Based on BLCMs to assess diagnostic test accuracies for the pathogen Streptococcus uberis, posterior sensitivities of 76, 71, and 64% for Selma plus, Dipslide and laboratory standard culture and specificities of 93%, 98% for Selma and Dipslide, respectively, were obtained.DiscussionThe two point of care rapid culture systems Dipslide and Selma plus plate can provide important preliminary pathogen identification for targeted mastitis therapy, especially when general information about growth and a rough classification of the bacteria into groups have an impact on treatment strategy. The two evaluated rapid culture systems, Dipslide and Selma plus plate, show good test accuracies for Streptococcus uberis at least at genus level. Therefore, using these tests may contribute to prudent use of antibiotics

The Resilient Dairy Genome Project - a general overview of methods and objectives related to feed efficiency and methane emissions.

The Resilient Dairy Genome Project (RDGP) is an international large-scale applied research project that aims to generate genomic tools to breed more resilient dairy cows. In this context, improving feed efficiency and reducing greenhouse gases from dairy is a high priority. The inclusion of traits related to feed efficiency (e.g., dry matter intake [DMI]) or greenhouse gases (e.g., methane emissions [CH4]) relies on available genotypes as well as high quality phenotypes. Currently, 7 countries, i.e., Australia [AUS], Canada [CAN], Denmark [DNK], Germany [DEU], Spain [ESP], Switzerland [CHE], and United States of America [USA] contribute with genotypes and phenotypes including DMI and CH4. However, combining data is challenging due to differences in recording protocols, measurement technology, genotyping, and animal management across sources. In this study, we provide an overview of how the RDGP partners address these issues to advance international collaboration to generate genomic tools for resilient dairy. Specifically, we describe the current state of the RDGP database, data collection protocols in each country, and the strategies used for managing the shared data. As of February 2022, the database contains 1,289,593 DMI records from 12,687 cows and 17,403 CH4 records from 3,093 cows and continues to grow as countries upload new data over the coming years. No strong genomic differentiation between the populations was identified in this study, which may be beneficial for eventual across-country genomic predictions. Moreover, our results reinforce the need to account for the heterogeneity in the DMI and CH4 phenotypes in genomic analysis

Lateral radioulnar subluxation in three cattle: clinical findings, treatment, and outcome

OBJECTIVE: To describe the clinical signs, conservative treatment, and short- and long-term outcomes of lateral radioulnar subluxation in cattle. ANIMALS: Three cattle with lateral radioulnar subluxation. STUDY DESIGN: Case series. METHODS: One 3-year-old Red Holstein cow, one 2-year-old Red Holstein cow, and one 9-month-old Holstein heifer were presented with acute, grade greater than 3 of 5, mixed lameness in one forelimb. Clinical, radiographic, and ultrasonographic examination results revealed radioulnar subluxation with lateral displacement in all cases. RESULTS: The subluxations were manually reduced under general anesthesia by simultaneous maximum flexion of the elbow and carpal joints, medial rotation of the forearm, and application of strong pressure to the radial head and olecranon. The short-term clinical outcome after stall rest was excellent in all three cases. Clinical and radiographic follow-up examinations were performed at varying intervals, with a final on-farm examination in all three cattle 12, 7, and 9 months after reduction. Osteoarthritic changes were visible in all three cases, mainly at the medial humeral trochlea, but lameness had completely resolved in all three animals. CONCLUSION: Conservative management of lateral radioulnar subluxation had an excellent clinical outcome in all three cattle. Follow-up radiographs revealed osseous proliferation mainly in the region of the medial trochlea of the humerus and subtle signs of osteoarthritic changes. CLINICAL SIGNIFICANCE: Lateral radio-ulnar subluxation is a rare but possibly underdiagnosed cause of lameness in cattle. It should be part of the differential diagnosis in cattle with elbow joint pain

Lateral radioulnar subluxation in three cattle: clinical findings, treatment, and outcome.

OBJECTIVE To describe the clinical signs, conservative treatment, and short- and long-term outcomes of lateral radioulnar subluxation in cattle. ANIMALS Three cattle with lateral radioulnar subluxation. STUDY DESIGN Case series. METHODS One 3-year-old Red Holstein cow, one 2-year-old Red Holstein cow, and one 9-month-old Holstein heifer were presented with acute, grade greater than 3 of 5, mixed lameness in one forelimb. Clinical, radiographic, and ultrasonographic examination results revealed radioulnar subluxation with lateral displacement in all cases. RESULTS The subluxations were manually reduced under general anesthesia by simultaneous maximum flexion of the elbow and carpal joints, medial rotation of the forearm, and application of strong pressure to the radial head and olecranon. The short-term clinical outcome after stall rest was excellent in all three cases. Clinical and radiographic follow-up examinations were performed at varying intervals, with a final on-farm examination in all three cattle 12, 7, and 9 months after reduction. Osteoarthritic changes were visible in all three cases, mainly at the medial humeral trochlea, but lameness had completely resolved in all three animals. CONCLUSION Conservative management of lateral radioulnar subluxation had an excellent clinical outcome in all three cattle. Follow-up radiographs revealed osseous proliferation mainly in the region of the medial trochlea of the humerus and subtle signs of osteoarthritic changes. CLINICAL SIGNIFICANCE Lateral radio-ulnar subluxation is a rare but possibly underdiagnosed cause of lameness in cattle. It should be part of the differential diagnosis in cattle with elbow joint pain

Pooling of interdigital swab samples for PCR detection of virulent Dichelobacter nodosus.

Virulent ovine foot rot is a contagious foot disease. Given the development and validation of a real-time PCR to detect Dichelobacter nodosus isolates that contain the virulence-associated protease genes aprV2 and aprB2, the diagnosis of foot rot has made considerable progress. We evaluated pooling methods to reduce the number of samples during a foot rot control program. Samples of individual feet were compared to a 4-feet sample of the same sheep. All further analyses based on 4-feet samples (pools-of-5 and pools-of-10 4-feet samples) were compared to samples of individual sheep, and a risk-based herd sampling was evaluated and compared to the whole flock. The sensitivity and specificity of the 4-feet samples for detection of aprV2-positive strains was 93.8% (CI: 87.6-97.5%) and 98.3% (CI: 96.5-99.3%), respectively. The sensitivity and specificity of the pools-of-10 was 86.7% (CI: 78.4-92.7%) and 100.0% (CI: 97.4-100%), respectively. Pools-of-5 were not significantly more sensitive than pools-of-10. The pooling of 4 individual foot samples into one 4-feet sample is an adequate method to reduce the number of samples of individual sheep. The sensitivity of pools-of-5 and pools-of-10 is too imprecise for a control program. Risk-based sampling allowed for a substantial reduction of samples to be tested, had a sensitivity of 95.8% (CI: 78.9-99.9%) and specificity of 100.0% (CI: 88.1-100.0%) when determining the foot rot flock status, and represents an adequate methodology to predict within-flock freedom from infection