Cohort‐specific variation in juvenile coho salmon habitat use

In this study, we examined summer and fall freshwater rearing habitat use by juvenile coho salmon (Oncorhynchus kisutch) in the quickly urbanising Big Lake drainage in south‐central Alaska. Habitat use was assessed by regressing fish count data against habitat survey information across thirty study sites using generalised linear mixed models. Habitat associations were examined by age‐0 and age‐1+ cohorts separately, providing an opportunity to compare habitat use across different juvenile coho salmon life stages during freshwater rearing. Regression results indicated that the age‐0 cohorts were strongly associated with shallow, wide stream reaches with in‐stream vegetation, whereas age‐1+ cohorts were associated with deeper stream reaches. Furthermore, associations between fork length and habitat characteristics suggest cohort‐specific habitat use patterns are distinct from those attributable to fish size. Habitat use information generated from this study is being used to guide optimal fish passage restoration planning in the Big Lake drainage. Evidence for habitat use partitioning by age cohort during freshwater juvenile rearing indicates that pooling age cohorts into a single “juvenile” stage for the purposes of watershed management may mask important habitat use dynamics.     

Multiple watershed alterations influence fish community structure in Great Plains prairie streams

Stream fish distributions are commonly linked to environmental disturbances affecting terrestrial landscapes. In Great Plains prairie streams, the independent and interactive effects of watershed impoundments and land cover changes remain poorly understood despite their prevalence and assumed contribution to declining stream fish diversity. We used structural equation models and fish community samples from third‐order streams in the Kansas River and Arkansas River basins of Kansas, USA to test the simultaneous effects of geographic location, terrestrial landscape alteration, watershed impoundments and local habitat on species richness for stream‐associated and impoundment‐associated habitat guilds. Watershed impoundment density increased from west to east in both basins, while per cent altered terrestrial landscape (urbanisation + row‐crop agriculture) averaged ~50% in the west, declined throughout the Flint Hills ecoregion and increased (Kansas River basin ~80%) or decreased (Arkansas River basin ~30%) to the east. Geographic location had the strongest effect on richness for both guilds across basins, supporting known zoogeography patterns. In addition to location, impoundment species richness was positively correlated with local habitat in both basins; whereas stream‐species richness was negatively correlated with landscape alterations (Kansas River basin) or landscape alterations and watershed impoundments (Arkansas River basin). These findings suggest that convergences in the relative proportions of impoundment and stream species (i.e., community structure) in the eastern extent of both basins are related to positive effects of increased habitat opportunities for impoundment species and negative effects caused by landscape alterations (Kansas River basin) or landscape alterations plus watershed impoundments (Arkansas River basin) for stream species.     

Identification of mutations in the COL4A5 collagen gene in Alport syndrome

X-linked Alport syndrome is a hereditary glomerulonephritis in which progressive loss of kidney function is often accompanied by progressive loss of hearing. Ultrastructural defects in glomerular basement membranes (GBM) of Alport syndrome patients implicate an altered structural protein as the cause of nephritis. The product of COL4A5, the alpha 5(IV) collagen chain, is a specific component of GBM within the kidney, and the gene maps to the same X chromosomal region as does Alport syndrome. Three structural aberrations were found in COL4A5, in intragenic deletion, a Pst I site variant, and an uncharacterized abnormality, which appear to cause nephritis and deafness, with allele-specific severity, in three Alport syndrome kindreds in Utah.     

Blood lead concentrations in rabbits

Blood lead concentrations in 68 healthy rabbits from laboratory (n = 15), meat production (n = 45), and home environments (n = 8) were determined. The median blood lead concentration of this heterogeneous population was 8 micrograms/dl (range = 2 to 27 micrograms/dl).     

A modified ventral fixation for surgical management of atlantoaxial subluxation in 19 dogs

OBJECTIVE: To describe a modified ventral stabilization technique for surgical management of atlantoaxial subluxation in dogs and to evaluate the outcome. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Nineteen client-owned dogs. METHODS: Medical records of 19 dogs with a radiographic diagnosis of atlantoaxial subluxation surgically managed by a modified ventral fixation technique (cortical screws, Kirschner wires, polymethylmethacrylate) were reviewed. Data on pre- and post-operative neurologic status, surgical technique, and complications were retrieved. Follow-up evaluation was performed at approximately 1 month. Telephone interview of the owner was used for long-term assessment (median follow-up for 17 surviving dogs was 10.5 months). RESULTS: Adequate reduction and stabilization was achieved in all dogs based on radiographic assessment immediately after surgery. Improved neurologic outcome occurred in 16 dogs at 1 month and in 15 dogs at follow-up; 2 dogs died of post-operative complications within 24 hours of surgery. One dog was euthanatized at the owners' request because of recurrent neck pain associated with implant failure after 1 month. Two dogs required surgery to remove broken and migrated implants, but further stabilization was not necessary. CONCLUSIONS: Adequate stabilization and improved neurologic outcome was achieved in most dogs. However, on account of the small size of the study and the variable neurologic signs of the dogs on admission, the surgical technique described could not be compared to those previously reported. CLINICAL RELEVANCE: The surgical technique described is an effective means of surgical treatment for atlantoaxial subluxation.     

Effects of a higher incubation temperature between embryonic day 9 and 12 on growth and meat quality characteristics of turkeys

1. The study investigated the influence of manipulating incubation temperature for a short period on the post-hatch development up to week 16 in male and female BUT Big 6 turkeys.

2. Eggs were incubated at a control temperature of 37·5°C and 55% RH until d 18 when transferred to a hatcher at 37·5°C and 85% RH. For a 4 d period between embryonic day 9 (ED 9) and 12, eggs were incubated at 38·5°C and 55% RH (HT).

3. Birds were slaughtered at 16 weeks of age to analyse meat quality parameters of the Musculus pectoralis superficialis (MPS).

4. Across both incubation treatments, the turkey males had significantly higher live and breast weights, but lower breast yields than the females. The sex of the animals only influenced the yellowness of the MPS with lower values in the males.

5. Temperature manipulation resulted in significantly decreased live weights of HT birds compared with the control animals across all ages in both sexes. No impact of incubation treatment on meat quality characteristics was found.

6. The results indicate a negative effect of higher incubation temperature on the post-hatch growth, possibly by influencing the mechanisms that regulate the hypertrophic growth of the muscle fibres.     

Gingival overgrowth in dogs associated with clinically relevant cyclosporine blood levels: observations in a canine renal transplantation model

Objective— To investigate the development of gingival hyperplasia in dogs after renal transplantation and administration of microemulsified cyclosporine A (MCsA).
Study Design— Experimental study.
Animals— Healthy adult mongrel dogs (n=5).
Methods— As part of study on renal transplantation, dogs administered MCsA (20 mg/kg/day), azathioprine, and prednisolone to prevent graft rejection were monitored for development of gingival changes. Prednisolone was discontinued after 3 months. MCsA dose was adjusted to maintain whole blood trough concentration of 400–700 ng/mL. Gingival change was evaluated by weekly examination and photodocumentation, and gingival biopsy for histopathology was performed at 28 weeks.
Results— One dog was lost because of acute graft rejection. Gingival hyperplasia developed in 3 of 4 dogs. The earliest gingival changes occurred in the interdental papillae at 20 weeks after transplantation. On histopathology, the underlying connective tissue was thickened and contained increase numbers of fibroblasts and inflammatory infiltrates.
Conclusions— Long-term immunosuppression with an MCsA-based treatment likely induces substantial gingival hyperplasia when therapeutic, immunosuppressive blood levels of MCsA were maintained for 32 weeks.
Clinical Relevance— MCsA is used for immune-mediated diseases and preventing rejection after transplant in dogs. MCsA blood levels, and gingival hyperplasia should be monitored by routine examination of the interdental papilla in dogs administered MCsA for long periods.     

Oviposition preference,larval distribution and impact of the swede midge, <Emphasis Type="Italic">Contarinia nasturtii</Emphasis>, on growth and yield of canola

The swede midge (Contarinia nasturtii) has become a significant economic pest of canola (Brassica napus L.) in Ontario and an emergent pest in the Prairie provinces. Determining yield impacts of swede midge damage and the growth stage(s) at which canola is most vulnerable or attractive to swede midge will contribute to the development of pest management recommendations throughout the growth of the crop. In four experiments, canola plants were exposed to specific densities of adult swede midge and measures of oviposition, damage and yield were collected. There was a significant positive relationship between female density and total oviposition per plant with a very high capacity for larval numbers on canola; up to ~ 4000. Given a choice of four growth stages, approximately 85% of oviposition occurred on seven-leaf and early bud canola. Given no choice, the high total oviposition on 3-leaf and flowering stages suggests that swede midge will oviposit on less favorable canola growth stages, if no others are present. Damage sustained on primary racemes remained relatively constant over time. However, damage ratings on secondary and tertiary racemes decreased over time in the highest treatment densities, suggesting compensation by the plant. All yield measures, except seed weight per pod, significantly decreased with increasing female density on primary and/or secondary racemes. A density of ~ 0.6 females per plant resulted in 10% reductions in the number of pods and seed weight produced on primary racemes. These results support recommendations for insecticide applications at, or just prior to, the early bud stage.     

Psoas compartment and sacral plexus block via electrostimulation for pelvic limb amputation in dogs

Objective

To assess the efficacy of psoas compartment and sacral plexus block for pelvic limb amputation in dogs.

Estimating total body water content in suckling and lactating llamas (<Emphasis Type="Italic">Lama glama</Emphasis>) by isotope dilution

Total body water (TBW) in 17 suckling and six lactating llamas was estimated from isotope dilution at three different post natum and lactation stages using both ¹⁸O and deuterium oxide (D₂O). In total, 69 TBW measurements were undertaken. While TBW in lactating dams, expressed in kilogram, remained stable during the three measurement periods (91.8 ± 15.0 kg), the body water fraction (TBW expressed in percent of body mass) increased slightly (P = 0.042) from 62.9% to 65.8%. In contrast, TBW (kilogram) in suckling llamas increased significantly (P < 0.001) with age and decreased slightly when expressed as a percentage of body mass (P = 0.016). Relating TBW to body mass across all animals yielded a highly significant regression equation (TBW in kilogram = 2.633 + 0.623 body mass in kilogram, P < 0.001, n = 69) explaining 99.5% of the variation. The water fraction instead decreased in a curve linear fashion with increasing body mass (TBW in percent of body mass = 88.23 body mass in kilogram^−0.064, P < 0.001, R ² = 0.460). The present results on TBW can serve as reference values for suckling and lactating llamas, e.g., for the evaluation of fluid losses during disease. Additionally, the established regression equations can be used to predict TBW from body mass, providing that the body masses fall inside the range of masses used to derive the equations.