Winter movement activity patterns of anadromous Arctic charr in two Labrador lakes

Anadromous Arctic charr, Salvelinus alpinus, feed in the marine environment for several months during the summer and migrate back to fresh water in late summer to spawn and/or overwinter. While overwintering, anadromous Arctic charr are generally believed to reduce or cease feeding, and they are poorly described in their winter movement activity. This study used telemetry data collected from two locations to describe overwintering movement activity, including interindividual variation. Movement activity declined markedly during the ice‐covered period, suggesting opportunistic maintenance feeding was used as an energy conservation strategy. Fall and spring movement was correlated with daylight hours, and ice break‐up had a significant effect on the timing of outmigration. Movement activity was negatively correlated with body length, with smaller individuals being more active than larger fish. Although general activity patterns were evident, there were significant differences among individuals, particularly during spring immediately prior to lake departure. Lake size and individual differences in metabolic rate may account for some of this variation.     

Influence of climate and abundance on migration timing of adult Atlantic salmon (Salmo salar) among rivers in Newfoundland and Labrador

Evidence mounts for the influence of climate variability on temporal trends in the phenology of many organisms including various species of fish. Accordingly, we examined variation in adult Atlantic salmon Salmo salar run timing in thirteen Newfoundland and Labrador rivers where returns were monitored at fishways or fish‐counting fences. Run timing varied significantly among rivers with the median date of return differing by up to 5 weeks. Duration of runs was generally short with most adults returning over a period of three to 5 weeks. A mixed model analysis incorporating a first‐order autoregressive error structure was used to generalise changes in run timing among all monitored rivers. Results indicated that the median date of return has advanced by almost 12 days over a 35‐year interval from 1978 to 2012, while several individual rivers have advanced by almost 21 days. The influence of climate on median timing was evident when the simultaneous effects of both climate and salmon abundance were controlled. We found earlier runs associated with overall warmer climate conditions on the Newfoundland and Labrador Shelf. Results contrast with those from the north‐east Atlantic where Atlantic salmon are returning later in some rivers coincident with warming climate conditions.     

Applying a kinetic method to an indirect ELISA measuring Ostertagia ostertagi antibodies in milk

Indirect enzyme-linked immunosorbent assays (ELISAs) are frequently run as endpoint ELISAs (e-ELISAs). However, kinetic ELISAs (k-ELISAs) have certain advantages over e-ELISAs. The objective of this study was to understand the relationship between e-ELISA and k-ELISA results. Specifically, to determine whether it was possible to run both k-ELISA and e-ELISA on the same plate and establish an appropriate time interval for k-ELISA measurements. A normalization method for k-ELISA slopes (slope ratio) is proposed. Using an indirect e-ELISA test measuring antibodies against Ostertagia ostertagi in milk from dairy cattle, we found that running a k-ELISA had no effect on optical density ratio results of an e-ELISA on the same plate, and that agreement was very strong at 10, 15, and 28 min, allowing for a reduction in the total processing time for ELISA tests.     

Intra- and interobserver assessments of intestinal wall thickness and segmentations from transverse sections of feline abdominal ultrasound images

Measurements of intestinal wall thicknesses from ultrasound imaging (US) are routinely used to support diagnoses of intestinal disorders in cats, however published studies describing observer agreement are currently lacking. The aim of this retrospective, observer agreement study was to quantify inter- and intraobserver repeatability and agreement in the measurement of intestinal wall layer thicknesses and the segmentation of transverse sections of small intestines in US images of 20 cats. Intestinal wall layer thickness measurements of the mucosa, submucosa, muscularis, serosa layer, and total thickness of these layers were performed on five cats with small cell epitheliotropic lymphoma, five with inflammatory bowel disease, and 10 with other conditions. Thickness measurements and the segmentation encompassing the serosa layer were obtained from five observers four times non-sequentially. The average standard deviation in thickness measurements (95% confidence interval) in the mucosa, submucosa, muscularis, serosa, and total thickness were 0.35 (0.07–0.95), 0.24 (0.07-0.52), 0.22 (0.06-0.49), 0.20 (0.05-0.49), and 0.57 (0.11-1.60) mm, respectively. The average intraclass correlation coefficients, which estimates the degree of consistency in thickness measurements and segmentation areas for each observer, ranged from 0.355 to 0.870 and 0.850 to 0.993, respectively. The interclass correlation coefficient, which estimates the degree of consistency when measuring a thickness or segmentation area over all observers ranged from 0.115 to 0.753, and 0.811 to 0.902, respectively. The overall average Dice Coefficient, which estimates the extent of overlap of the segmentations for all observers was 0.957 (0.933 to 0.972). Our results suggest segmentations of small intestines have a higher interobserver agreement than measurements of intestinal wall thicknesses.     

COMPUTED TOMOGRAPHIC FINDINGS IN 57 CATS WITH PRIMARY PULMONARY NEOPLASIA

Primary pulmonary neoplasia is relatively uncommon in cats and generally has a poor prognosis. In this multicenter, retrospective study of 57 cats with pulmonary neoplasia, the most frequent presenting signs were anorexia/inappetence (39%) and cough (37%). The pulmonary tumors were considered to be incidental findings in 9% cats. In computed tomographic (CT) images, primary pulmonary tumors appeared as a pulmonary mass in 55 (96%) cats and as a disseminated pulmonary lesion without a defined mass in two (4%) cats. Most pulmonary tumors were in the caudal lobes, with 28 (49%) in the right caudal lobe and 17 (30%) in the left caudal lobe. CT features associated with pulmonary tumors included mass in contact with visceral pleura (96%), irregular margins (83%), well‐defined borders (79%), bronchial compression (74%), gas‐containing cavities (63%), foci of mineral attenuation (56%), and bronchial invasion (19%). The mean (range) maximal dimension of the pulmonary masses was 3.5 cm (1.1–11.5 cm). Additional foci of pulmonary disease compatible with metastasis were observed in 53% cats. Pleural fluid was evident in 30% cats and pulmonary thrombosis in 12% cats. The histologic diagnoses were 47 (82%) adenocarcinomas, six (11%) tumors of bronchial origin, three (5%) adenosquamous cell carcinomas, and one (2%) squamous cell carcinoma. In this series, adenocarcinoma was the predominant tumor type, but shared many features with less common tumor types. No associations were identified between tumor type and CT features. Prevalence of suspected intrapulmonary metastasis was higher than in previous radiographic studies of cats with lung tumors.