Comparison of radiography and computed tomography to evaluate fractures of the canine tarsus

Detection and accurate classification of traumatic tarsal fractures are important for identifying cases requiring surgical intervention. The aim of this prospective, experimental, methods comparison study was to directly compare the accuracy, sensitivity, and specificity of tarsal computed tomography (CT), ten‐view and two‐view digital radiographs for detecting traumatic fractures of the canine tarsus. The working hypothesis was that tarsal fractures would be detected with higher accuracy, sensitivity, and specificity using CT imaging compared to radiography, and a ten‐view would be superior to a two‐view radiographic study. Ten cadaver hind limbs of medium to large dogs received a CT scan and ten‐view radiographic study before and after induction of fractures with a hydraulic press. All bones included in the radiographic images were assessed for fractures by two observers and gross dissection was used as the gold standard. The two‐view radiographic study (dorsoplantar, lateromedial) was created from the ten‐view study and reviewed 2 years later. All limbs sustained fractures, the most common locations were the talus and calcaneus (n = 7). The sensitivity of CT was greater than ten‐view radiographic study (77% vs. 57%), while the specificity was similar (97% vs. 98%). The sensitivity and specificity of the ten‐view and two‐view radiograph studies were similar (57% vs. 55%; both 98%). Computed tomography images were reassessed postdissection to determine if failure to identify fractures resulted from observer error. Overall, CT was better than radiography for detecting fractures of the canine tarsus, however there was little improvement with ten‐view compared to two‐view radiographic studies.     

Examining the Microbial Degradation of Naphthenic Acids Using Stable Isotope Analysis of Carbon and Nitrogen

Naphthenic acids (NAs) are a complex group of naturally occurring oil sands constituents that constitute a significant portion of the dissolved organic carbon (DOC) pool available for microbial degradation in the process-related waste water associated with oil sands mine sites. One approach to understanding the biological fate of oil sands process-derived carbon and nitrogen in aquatic reclamation of the mine sites involves the use of stable isotope analyses. However, for stable isotope analyses to be useful in such field-based assessments, there is a need to determine how microbial degradation of a complex mixture of NAs might change the stable isotope values (δ ¹³C, δ ¹⁵N). In batch cultures and semi-continuous laboratory microcosms, utilization of a commercial mixture of NAs by oil sands-derived microbial cultures resulted in microbial biomass that was similar or slightly ¹³C enriched (1.4‰ to 3.0‰) relative to the DOC source, depending on the length of incubation. Utilization of a NA-containing extract of oil sands processed water resulted in greater ¹³C enrichment of microbial biomass (8.5‰) relative to the DOC source. Overall, the δ ¹³C of the DOC comprised of complex mixtures of NAs showed minimal change (?0.5‰ to ?0.1‰) during the incubation period whereas the δ ¹³C of the dissolved inorganic carbon (DIC) was more variable (?5.0‰ to +5.4‰). In tests where the concentration of available nitrogen was increased, the final biomass values were ¹⁵N enriched (3.8‰ to 8.4‰) relative to the initial biomass. The isotope trends established in this study should enhance our ability to interpret field-based data from sites with hydrocarbon contamination, particularly in terms of carbon source utilization and ¹⁵N enrichment.     

Effectiveness of a non-surgical alternative to the Mules operation in sheep

Objective To measure changes to the perineal bare area, local tissue reaction and healing responses of young sheep, following intradermal administration of cetrimide and polyvinylpyrrolidone (PVP), with and without ethanol, to the breech and tail. Method A needle‐less injector was used to deposit formulations containing 40 g/L cetrimide and 30 g/L PVP (group 2) or 20 g/L cetrimide, 30 g/L PVP and 15 g/L ethanol (group 3), within the dermis of the tail and the region surrounding the perineal bare breech area of groups (N = 8) of Merino weaner sheep. The dimensions of the perineal bare area (length, width and diagonal distances left and right) and tail width were recorded before and at intervals after treatment for 60 days. Observations of swelling and bruising and scab formation at the treatment sites were recorded for up to 35 days after treatment. Rectal temperatures were monitored for up to 35 days after treatment and bodyweight for up to 60 days after treatment. An untreated control group (group 1) was included. Results Comparison of day ‐3 and day 35 measurement data showed that both treated groups had significantly (P < 0.05) wider breech bare areas compared to the untreated controls and that group 2 sheep had significantly (P < 0.05) longer breech bare areas compared to group 3 sheep or to the untreated controls, which were not significantly different. At this time scabs were still firmly in place on many treated sheep. At day 35 there was no increase in tail bare area caused by either treatment. By day 60 there was no significant difference between the treated and control groups in either the breech or tail regions indicating that the changes present at day 35, were not permanent. Mean weight gain in the groups throughout the 60‐day interval was unaffected by treatment. Intradermal treatment was associated with a significant elevation in body temperature. This effect lasted for 3 days and was associated with signs of discomfort and depressed appearance in at least some of the treated sheep. Bruising was mild to severe in all treated sheep within two days of treatment but was not evident in any sheep by day 21. Mild to moderate swelling was also associated with treatment but was not uniform across sheep in the groups. The tail of one sheep was severely swollen for several days. Swelling remained obvious in most treated sheep until day 14 but was not present at day 21. Conclusion Under the conditions of this study intradermal injection of cetrimide had no permanent effect on bare area measurements on the breech or the amount of wool‐bearing skin on the tail. It also caused signs of discomfort and pain that raise welfare concerns.     

Impact of reader antenna polarisation, distance, inlay design, conveyor speed, tag location and orientation on the coupling of UHF RFID as applied to modified atmosphere packaged meat

Undetected RFID tags make the potential benefits of RFID unattainable. This study aimed to determine the most significant factors that affect RFID and particularly its application to the traceability of meat. Experimental parameters included five RFID tag inlays, two levels of conveyor speeds, five variations of beef sample and an empty container, 12 tags per test sample, three distances and two types of reader antenna polarisations. Tag detection rates were determined in three replicates per combination of test parameters. A GLM ANOVA was carried out on tag detection rate. In decreasing order of significance in terms of the effect on mean tag detection rate were distance, sample, inlay design, conveyor speed and reader antenna polarisation. Interaction of these factors also proved significant, in decreasing order of importance were reader antenna * inlay, sample type * distance, inlay * distance, sample type * inlay, sample type * reader antenna, distance * speed, sample type * speed and finally sample type * distance * speed. Linearly polarised antenna preformed better overall at detecting tags, with 63% mean detection rate compared with circularly polarised antenna with 57% mean detection rate. Varying the tag inlay resulted in mean detection rates of between 62% and 88%. Ideal transponder location on package was reader antenna polarisation dependent, but generally tags facing reader antennas exhibited better detection rate. Results revealed that the under side of the package was the most un-detectable transponder location, considering the placement of reader antennas on top, left and right sides of the sample. Conveyor speed also proved significant with a variation from 0.5 to 1.0 m/s resulting in an average detection rate ranging from 62% to 57%, respectively. Circularly polarised antennas are believed to perform better in cases of random tag orientation on products. It can be concluded that RFID systems implementation in the meat supply chain requires a holistic approach where distances, polarisations, inlay type, meat composition and conveyor speed need to be considered.