A forensic investigation into the etiology of bat mortality at a wind farm: barotrauma or traumatic injury?

Migrating bats have increased mortality near moving turbine blades at wind farms. The authors evaluated competing hypotheses of barotrauma and traumatic injury to determine the cause. They first examined the utility of lungs from salvaged bat carcasses for histopathologic diagnosis of barotrauma and studied laboratory mice as a model system. Postmortem time, environmental temperature, and freezing of carcasses all affected the development of vascular congestion, hemorrhage, and edema. These common tissue artifacts mimicked the diagnostic criteria of pulmonary barotrauma; therefore, lung tissues from salvaged bats should not be used for barotrauma diagnosis. The authors next compared wind farm (WF) bats to building collision (BC) bats collected near downtown Chicago buildings. WF bats had an increased incidence in fracture cases and specific bone fractures and had more external lacerations than BC bats. WF bats had additional features of traumatic injury, including diaphragmatic hernia, subcutaneous hemorrhage, and bone marrow emboli. In summary, 73% (190 of 262) of WF bats had lesions consistent with traumatic injury. The authors then examined for ruptured tympana, a sensitive marker of barotrauma in humans. BC bats had only 1 case (2%, 1 of 42), but this was attributed to concurrent cranial fractures, whereas WF bats had a 20% (16 of 81) incidence. When cases with concurrent traumatic injury were excluded, this yielded a small fraction (6%, 5 of 81) of WF bats with lesions possibly consistent with barotrauma etiology. Forensic pathology examination of the data strongly suggests that traumatic injury is the major cause of bat mortality at wind farms and, at best, barotrauma is a minor etiology.     

Evaluation of cognitive learning, memory, psychomotor, immunologic, and retinal functions in healthy puppies fed foods fortified with docosahexaenoic acid-rich fish oil from 8 to 52 weeks of age

Objective-To assess effects of foods fortified with docosahexaenoic acid (DHA)-rich fish oil on cognitive, memory, psychomotor, immunologic, and retinal function and other measures of development in healthy puppies. Design-Evaluation study. Animals-48 Beagle puppies. Procedures-Puppies were assigned to 3 groups after weaning (n = 16/group) and received 1 of 3 foods (low-DHA, moderate-DHA, or high-DHA food) as their sole source of nutrition until 1 year of age. Visual discrimination learning and memory tasks, psychomotor performance tasks, and physiologic tests including blood and serum analysis, electroretinography, and dual-energy x-ray absorptiometry were performed at various time points. Anti-rabies virus antibody titers were evaluated 1, 2, 4, and 8 weeks after vaccination at 16 weeks of age. Results-Foods had similar proximate analysis results but varied in concentration of DHA from fish oil; the high-DHA food also contained higher concentrations of vitamin E, taurine, choline, and l-carnitine than did other foods. The high-DHA group had significantly better results for reversal task learning, visual contrast discrimination, and early psychomotor performance in side-to-side navigation through an obstacle-containing maze than did the moderate-DHA and low-DHA groups. The high-DHA group had significantly higher anti-rabies antibody titers 1 and 2 weeks after vaccination than did other groups. Peak b-wave amplitudes during scotopic electroretinography were positively correlated with serum DHA concentrations at all evaluated time points. Conclusions and Clinical Relevance-Dietary fortification with fish oils rich in DHA and possibly other nutrients implicated in neurocognitive development following weaning improved cognitive, memory, psychomotor, immunologic, and retinal functions in growing dogs.     

A novel treatment for dynamic laryngeal collapse associated with poll flexion: the modified checkrein

Reasons for performing the study: Dynamic laryngeal collapse (DLC) associated with poll flexion is a performance limiting dynamic upper airway disorder commonly diagnosed in Coldblooded trotters. An inspiratory obstruction occurs when affected horses are driven with tension on the reins, inducing poll flexion. To date, surgical treatment and conservative management have failed to improve racing performance in affected horses. Objectives: To test the efficacy of an external device, the modified checkrein, in limiting poll flexion, diminishing laryngeal collapse and improving airway mechanics when horses are driven on a treadmill with tension on the reins and test the hypothesis that the modified checkrein will limit poll flexion thereby improving endoscopic appearance of the larynx and reduce airway obstruction in harness racehorses affected with DLC. Methods: Fourteen Norwegian Coldblooded trotter (NCT) racehorses previously diagnosed with DLC associated with poll flexion exercised on a high‐speed treadmill at speeds that resulted in heart rate >200 beats/min. Upper airway videoendoscopy recordings, tracheal pressures and video recordings of the head and neck position were collected while horses exercised with the conventional checkrein on Day 1 and the modified checkrein on Day 2. Results: The modified checkrein successfully limited poll flexion as measured by no change in head position parameters between phases of no rein tension and phases of rein tension. Endoscopic scores were significantly improved (arytenoids cartilage collapse P<0.0001; vocal fold collapse P<0.0001) and tracheal peak inspiratory pressures were significantly less negative (P = 0.0162) when horses were fitted with the modified checkrein compared to the conventional checkrein. Conclusions and potential relevance: The modified checkrein successfully limited poll flexion and also prevented upper airway obstruction in NCT horses affected with DLC associated with poll flexion. The modified checkrein seems promising in offering a method of conservative management in harness racehorses affected with this disorder.     

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

Genetic parameters of piglet survival traits and birth weight were estimated on the first generation data of a selection experiment aimed at improving piglet survival using a multiple trait linear and threshold model. Data on 5293 piglets for survival at birth, at day one after birth and during the entire nursing period, as well as individual birth weight and litter size, were recorded in an outdoor production system. Genetic effects of piglet survival traits and birth weight were estimated based on threshold and Gaussian models, respectively, using a Bayesian approach. The statistical model included as fixed effects selection group, parity, gender, fostering, gestation length and month of farrowing and, alternatively, an adjustment for litter size. Direct genetic effects (i.e. the piglet's genetic potential) for piglet survival and birth weight were estimated separately, whereas maternal genetic and environmental effects could only be estimated for the given data structure in a combined litter effect. Posterior means of heritabilities for direct genetic effects of survival at birth, at first day after birth and the entire nursing period, as well as birth weight, were 0.08, 0.07, 0.08 and 0.20, respectively. Genetic correlations among survival traits were in the range of 0.29 to 0.40 and indicate that these traits were mainly attributable to different genetic effects. Genetic correlations between direct effects of survival traits and birth weight ranged between 0.18 and 0.23 and were reduced when weights of stillborn piglets were omitted in the analysis or the traits were adjusted for litter size. The magnitudes of direct genetic effects of survival traits are substantially higher than estimates in the literature, which may indicate that these traits have a higher genetic influence under outdoor conditions. The use of birth weight in the multiple trait estimation provided important information for the estimation of survival traits due to its favourable genetic correlations with survival, its high heritability and its high information content as a continuously measured trait.     

Control charts applied to simulated sow herd datasets

Statistical control charts were used to detect process change in pig production. Two charts were tested to detect small deviations in production processes: the cumulative sum (CUSUM) control chart and the exponentially weighted moving average (EWMA) control chart. A Monte-Carlo simulation was used for developing an optimal design of the EWMA and the CUSUM charts. The traits piglets born in total and the return to oestrus rate were considered. Over a given time period, small shifts were purposely implemented to test the performance of the charts. The average time to signal (ATS) and false positive rate (FPR) were taken as classification parameters to evaluate the performance of the charts. All shifts in the number of piglets born in total were detected with CUSUM and EWMA control charts. The trait piglets born in total showed an ATS ranging from 1.3 (FPR = 33.5%) to 6.8 weeks (FPR = 1.2%) using the CUSUM chart. The EWMA chart presented an ATS which ranged between 2.0 (FPR = 14.9%) and 6.3 (FPR = 1.9%) weeks. The application of the CUSUM to the return to oestrus rate resulted in an ATS of 2.6 (FPR =  38.3%) to 15.6 weeks (FPR = 3.0%) and the EWMA chart produced a signal between 4.1 (FPR = 14.5%) and 16.4 weeks (FPR = 1.4%). Both charts appear to be useful tools for tracking commercial swine farm processes and detecting emerging change in process performance.     

Effect of Tibial Plateau Leveling Osteotomy on Femorotibial Contact Mechanics and Stifle Kinematics

Objective— To evaluate the effects of tibial plateau leveling osteotomy (TPLO) on femorotibial contact mechanics and 3-dimensional (3D) kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs.
Study Design— In vitro biomechanical study.
Animals— Unpaired pelvic limbs from 8 dogs, weighing 28–35 kg.
Methods— Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135°. Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TPLO-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test ( P <.05) was used for statistical comparison.
Results— Significant disturbances to all measured contact mechanical variables were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and increased internal tibial rotation in the CrCL-deficient stifle. No significant differences in 3D femorotibial alignment were observed between normal and TPLO-treated stifles; however, femorotibial contact area remained significantly smaller and peak contact pressures in both medial and lateral stifle compartments were positioned more caudally on the tibial plateau, when compared with normal.
Conclusion— Whereas TPLO eliminates craniocaudal stifle instability during simulated weight bearing, the procedure fails to concurrently restore femorotibial contact mechanics to normal.
Clinical Relevance— Progression of stifle osteoarthritis in dogs treated with TPLO may be partly the result of abnormal stifle contact mechanics induced by altering the orientation of the proximal tibial articulating surface.     

INTEROBSERVER AGREEMENT ON THE ASSESSABILITY OF STANDARD VENTRODORSAL HIP-EXTENDED RADIOGRAPHS AND ITS EFFECT ON AGREEMENT IN THE DIAGNOSIS OF CANINE HIP DYSPLASIA AND ON ROUTINE FCI SCORING

Insufficient agreement on scoring hip quality might be caused by differences in the assessability of a radiograph (exposure, contrast, positioning, and diagnostic quality). We studied the agreement in assessability of standard ventrodorsal hip-extended radiographs by experienced (nine) and inexperienced (21) observers, using the standard subjective method of quality control, currently applied in screening programs. The effect of assessability on the agreement of scoring hip quality [dysplastic vs. nondysplastic and the final Federation Cinologique International (FCI) score] was also investigated. There was a significant difference ( P <0.0001) in agreement on assessability between the experienced and inexperienced observers. In 68% of evaluations, experienced observers stated that the radiograph was assessable. Inexperienced observers evaluated the radiographs as being assessable in only 46.5% of evaluations. Increased interobserver agreement on assessability of a radiograph did not increase the overall interobserver agreement in the diagnosis of hip dysplasia, nor did it result in consistent scoring of the hip status from that radiograph, despite a significant ( P <0.05) increase in agreement of FCI scoring with an increasing agreement on assessability at a one to five ratio in the experienced group. The inconsistent evaluation of radiographic quality, as well as the inconsistent evaluation of the hip quality, caused differences in diagnosing hip dysplasia and FCI scoring in the same dog ranging from excellent hips to moderate hip dysplasia. Therefore, the credibility of the FCI screening method for canine hip dysplasia, using the standard hip-extended radiographic view, as currently applied in most European countries, is questionable.     

A RETROSPECTIVE ANALYSIS OF 140 DOGS WITH ORAL MELANOMA TREATED WITH EXTERNAL BEAM RADIATION

Despite the early notion that canine oral malignant melanoma is radioresistant, recent data suggest that external beam radiotherapy is effective in local tumor control. However, optimal fractionation schedules have not been established. The high rate of regional and distant metastasis is another problem that has hindered long-term control. The role of chemotherapy in the management of canine oral melanoma has also not been determined. In this study, data from 140 dogs irradiated at North Carolina State University were evaluated with the following objectives: (1) to compare the efficacy of three radiation therapy protocols (36 Gy, 9 Gy x 4 fractions; 30 Gy, 10 Gy x 3 fractions; or >45 Gy, 2-4 Gy x 12-19 fractions) for the treatment of dogs with oral malignant melanoma, (2) to identify any host or tumor factors influencing prognosis, and (3) to determine the impact of systemic chemotherapy on treatment outcome. Information regarding response to therapy, disease progression, and survival were determined from the medical records or from information obtained by telephone or mail survey. Relationships between host, tumor, and treatment variables and outcome measures (response, time to first event, and survival) were evaluated using Fisher's exact test (response) and the Cox regression model (time to first event and survival). The median time to first event for the 140 dogs was 5.0 months (95% C.I., 4-6 months) and the median survival was 7.0 months (95% C.I., 6-9 months). In the univariate analysis, the following variables were associated with increased time to first event and survival: (1) rostral tumor sublocation; (2) lack of bone lysis observed on skull imaging, and (3) microscopic tumor burden. In a multivariate analysis of 111 dogs with complete data for these variables, tumor sublocation, bone lysis, and tumor volume were identified as joint predictors of time to first event (p < .001, p < .001, and p = .04, respectively) and survival (p < .001, p < .001, and p = .05, respectively). There were no differences in response, time to first event and survival between the three radiation therapy protocols used. Systemic chemotherapy had no impact on the development of metastatic disease, time to first event, or survival, although the dosages used in this study were suboptimal. External beam radiation therapy is effective in local disease control of canine oral malignant melanoma; however, the optimal fractionation scheme has yet to be determined. The high metastatic rate observed with this disease and the inefficacy of systemic chemotherapy indicate that further investigation into novel therapies is warranted.     

Evaluation of age of dam effects on maternal performance of multilactation daughters from high- and low-milk EPD sires at three locations in the southern United States

Angus bulls (n = 16) selected for either high- or low-milk EPD but similar growth EPD were mated within location at random to Angus cows. Daughters were bred to calve at 2 yr of age and annually until 6 yr of age. Milk yield was measured four times during lactation with a portable milking machine to estimate 12-h milk yield. Milk was collected for analysis of the percentage of fat and protein. A mixed model procedure was used to analyze the weaning weight, milk yield, and milk component data. The model for weaning weight included location, genetic line of sire, gender of calf, and age of dam. Calf age at weaning was used as a covariate. The model for the milk yield and components included location, genetic line of sire, gender of calf, period, and age of dam. Random effects for all models included sire of dam nested within line, sire of calf, and year. Genetic line was a significant source of variation for milk yield (P < 0.01) and weaning weight (P < 0.01) but not for percentage of fat or protein. Location was significant for milk yield (P < 0.01), fat (P < 0.01), protein (P < 0.01), and weaning weight (P < 0.01). The interaction of line with location was not significant except for percentage of protein (P < 0.01). Age of dam was significant for milk yield (P < 0.01), weaning weight (P < 0.01), and percentage of protein (P < 0.01), but not for percentage of fat (P = 0.29). Line difference for mean weaning weight was 18.1 kg, which is similar to the difference between lines for milk EPD (19 kg). Weaning weights from high-milk EPD line daughters were heavier (P < 0.01) than low-milk EPD line daughters at each age of dam evaluated. Cows nursed by males had higher milk yields (4.33 kg/12 h) than cows nursed by heifers (4.0 kg/12 h). The difference in yields for gender was significant for 2-, 3-, and 5-yr-old cows, but not for 4- (P < 0.052) and 6-yr old (P < 0.15) cows. Correlation coefficients between weaning weight and weaning EPD, milk EPD, and total maternal EPD were greater than zero (P < 0.01) (0.76, 0.65, and 0.89, respectively). Daughters of sires with high-milk EPD produced more milk at each age and weaned heavier calves than daughters of sires with low-milk EPD. These results confirm the value of milk EPD for improvement of weaning weights in beef cattle and also validate age of dam effects on milk yield and the associated effects on weaning weights.