Validating a Time Series of Annual Grass Percent Cover in the Sagebrush Ecosystem

We mapped yearly (2000–2016) estimates of annual grass percent cover for much of the sagebrush ecosystem of the western United States using remotely sensed, climate, and geophysical data in regression-tree models. Annual grasses senesce and cure by early summer and then become beds of fine fuel that easily ignite and spread fire through rangeland systems. Our annual maps estimate the extent of these fuels and can serve as a tool to assist land managers and scientists in understanding the ecosystem’s response to weather variations, disturbances, and management. Validating the time series of annual maps is important for determining the usefulness of the data. To validate these maps, we compare Bureau of Land Management Assessment Inventory and Monitoring (AIM) data to mapped estimates and use a leave-one-out spatial assessment technique that is effective for validating maps that cover broad geographical extents. We hypothesize that the time series of annual maps exhibits high spatiotemporal variability because precipitation is highly variable in arid and semiarid environments where sagebrush is native, and invasive annual grasses respond to precipitation. The remotely sensed data that help drive our regression-tree model effectively measures annual grasses’ response to precipitation. The mean absolute error (MAE) rate varied depending on the validation data and technique used for comparison. The AIM plot data and our maps had substantial spatial incongruence, but despite this, the MAE rate for the assessment equaled 12.62%. The leave-one-out accuracy assessment had an MAE of 8.43%. We quantified bias, and bias was more substantial at higher percent cover. These annual maps can help management identify actions that may alleviate the current cycle of invasive grasses because it enables the assessment of the variability of annual grass ? percent cover distribution through space and time, as part of dynamic systems rather than static systems.     

Describing the within laboratory and between laboratory agreement of a serum ELISA in a national laboratory network

Results from laboratory assays for detection of animal disease are often assessed for repeatability (agreement within laboratory) and reproducibility (agreement between laboratories). This work aimed to understand the strengths and limitations of available methods for describing these quantities. Five major veterinary laboratories in Australia volunteered to participate in a designed evaluation based on repeat testing of twenty bovine sera. Sampling was stratified so that ten of the sera were negative to the virus neutralisation test (VNT) for antibody to bovine herpes virus 1 (BHV-1) and the remaining ten sera were VNT positive. Each serum was divided into 50 replicates and each laboratory assayed one replicate of each serum on a weekly basis using a commercial ELISA for BHV-1. Laboratories were blinded to the identity of sera. The data on sample to positive control ratio (S/P) for these 1000 individual assays were collated, sources of variance analysed using a random effects model, and reliability coefficients (ρ) obtained from the variance estimates as quantitative measures of within and between laboratory agreement. Coefficient of variation (CV) was calculated for combinations of sera and laboratory. CV was found to be higher for sera with the lowest mean S/P values (VNT -ve sera). For VNT -ve sera, agreement of S/P within laboratory was low to moderate (ρ: 0.01-0.27) and the agreement between all labs was low (ρ=0.02). Reliability coefficients for VNT +ve sera were very high for agreement within laboratories (ρ: 0.63-0.92) and moderate for agreement between laboratories (ρ=0.52). As well, simulation demonstrated that sero-prevalence has a dramatic affect on the reliability coefficient if sampling were to be irrespective of VNT status. We conclude that there are some limitations with the available approaches for assessing agreement within and between laboratories. Although reliability coefficients have some drawbacks they are an attractive way of reducing reliance on subjective assessment of agreement.     

Effects of oxypolygelatin and dextran 70 on hemostatic variables in dogs

Objective To evaluate and compare coagulation variables following the administration of oxypolygelatin and dextran 70 to clinically healthy dogs. Study design Randomized cross‐over experimental study. Animals A total of eight healthy adult female Beagles aged 2–4 years old and weighing 11.8 ± 2.7 kg. Methods The dogs received a 15‐minute intravenous (IV) infusion of 5 mL kg^?1 oxypolygelatin or 10 mL kg^?1 6% dextran 70. Before (PRE) and at 2, 5, and 24 hours after administration, packed cell volume (PCV), total solids concentration (TS), prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen concentration (FIB), platelet numbers (Plat), factor VIII coagulant activity (VIII:C), von Willebrand factor antigen concentration (vWf:Ag) and platelet function and buccal mucosal bleeding time (BMBT) were measured. Platelet function was assessed using aggregation and by measuring ATP release from aggregating platelets over 6 minutes, with 20, 10, and 5 µm ADP and 5 and 10 µg of collagen mL^?1 as platelet activation agonists. Results All baseline values were within our normal ranges, except for one dog that had low vWf:Ag PRE values prior to both dextran and oxypolygelatin administration. Following dextran and oxypolygelatin administration, the PCV and TP were significantly (p < 0.05) decreased. Plat, FIB, and vWf:Ag decreased, while BMBT and VIII:C increased following dextran administration. Dextran also caused a significant decrease in platelet aggregation in response to ADP. Oxypolygelatin caused a significant decrease in vWf:Ag, Plat, and FIB compared to PRE values. The total amount of ATP released, standardized to platelet number, did not vary significantly for either group at any sampling time from PRE values. No significant changes from PRE values were noted at any time in either group for PT or APTT. Conclusion At the doses administered, both dextran and oxypolygelatin can interfere with hemostatic variables in healthy dogs, but dextran's effect is more profound and prolonged when compared to oxypolygelatin. Clinical relevance Oxypolygelatin causes fewer hemostatic abnormalities when compared to dextran, making it a superior colloid for administration at the doses tested.     

Trauma resulting in hemarthrosis and long medial collateral ligament desmitis of the tarsocrural joint in a horse

A horse was initially diagnosed with hemarthrosis and desmitis of the long medial collateral ligament of the right tarsus and later developed prominent enthesiophytosis at the site of insertion of the ligament's deep portion. Hemarthrosis due to intra- or peri-articular pathology can cause recurrent lameness, even without evident external trauma.     

Detection of Mycobacterium avium ssp. paratuberculosis in ileocaecal lymph nodes collected from elderly slaughter cows using a semi-nested IS900 polymerase chain reaction

The aim of this study was to investigate the occurrence of subclinical Mycobacterium avium spp. paratuberculosis (MAP) infections at slaughter by testing ileocaecal lymph nodes with a semi-nested IS900 PCR. Tissue samples were available within the framework of a parallel study investigating BSE-susceptibility factors in members of BSE-cohorts in the German Federal State of Lower Saxony. Ileocaecal lymph nodes were collected over a 2-year sampling period from 99 slaughter cattle of a mean age of 6.5 years (5.5-7.5 years). A recently developed IS900 semi-nested polymerase chain reaction (snPCR) assay offering a sensitivity of 1 genome equivalent was used for the detection of MAP-DNA. Based on this snPCR, 17 out of the 99 samples gave positive results, indicating a MAP occurrence of 17.17% in the random sample. All PCR products were sequenced for screening of polymorphisms. Nucleotide homologies of 98.5-100% were found with respect to the MAP K10 reference sequence IS900 (GenBank: AE16958). PCR analysis of ileocaecal lymph nodes collected from slaughter cattle proved to be a suitable technique to determine MAP occurrence in the local cattle population.     

Evaluation of prognostic factors, survival rates, and treatment protocols for immune-mediated hemolytic anemia in dogs: 151 cases (1993-2002)

OBJECTIVE: To evaluate prognostic factors, survival, and treatment protocols for immune-mediated hemolytic anemia (IMHA) in dogs. DESIGN: Retrospective study. ANIMALS: 151 dogs with IMHA not associated with underlying infectious or neoplastic disease. PROCEDURE: lnformation recorded from review of medical records included signalment at the time of initial evaluation; vaccination history; 30-, 60-, and 365-day follow-up outcomes; laboratory data; results of imaging studies; and necropsy findings. Dogs were grouped according to the presence of spherocytes, autoagglutination, a regenerative erythrocyte response, and treatments received (azathioprine, azathioprine plus ultralow-dose aspirin, azathioprine plus mixed-molecular-weight heparin [mHEP], or azathioprine plus ultralow-dose aspirin plus mHEP) for comparisons. All dogs received glucocorticoids. RESULTS: Cocker Spaniels, Miniature Schnauzers, neutered dogs, and female dogs were overrepresented. Alterations in certain clinicopathologic variables were associated with increased mortality rate. Rates of survival following treatment with azathioprine, azathioprine plus ultralow-dose aspirin, azathioprine plus mHEP, and azathioprine plus ultralow-dose aspirin plus mHEP were 74%, 88%, 23%, and 70%, respectively, at hospital discharge; 57%, 82%, 17%, and 67%, respectively, at 30 days; and 45%, 69%, 17%, and 64%, respectively, at 1 year. In comparison, mean survival rates at discharge and at 30 days and 1 year after evaluation collated from 7 published reviews of canine IMHA were 57%, 58%, and 34%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with a combination of glucocorticoids, azathioprine, and ultralow-dose aspirin significantly improved short- and long-term survival in dogs with IMHA.