Browsing by Author "Owen R"

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    Prevalence of cardiomyopathy and cardiac mortality in a colony of non-purebred cats in New Zealand.
    (Taylor and Francis Group, 2024-09-29) Seo J; Owen R; Hunt H; Luis Fuentes V; Connolly DJ; Munday JS
    Aims To evaluate the prevalence of subclinical cardiomyopathy and cardiac mortality in a research colony of non-purebred cats, established as a model of the wider cat population in New Zealand. Methods All apparently healthy, compliant, non-pregnant, non-neonatal cats in the colony at the Centre for Feline Nutrition (Massey University, Palmerston North, NZ) underwent physical examination and echocardiography using a 4.4–6.2-MHz probe by a board-certified veterinary cardiologist. Cardiac phenotype was classified following current guidelines. Hypertrophic cardiomyopathy (HCM) phenotype was defined as an end-diastolic left ventricular wall thickness ≥ 6 mm. Colony mortality data from February 2012 to February 2022 was reviewed to determine cardiac mortality. Results Cats (n = 132; 65 females and 67 males) included in the study had a median age of 4.1 (IQR 3.0–8.0) years. Thirty-two (24%) cats had a heart murmur, and three (2%) cats had an arrhythmia. Echocardiography revealed heart disease in 24 (18.2%) cats, including 23 with an HCM phenotype and one with a restrictive cardiomyopathy phenotype. Of the cats with the HCM phenotype, 3/23 had systemic hypertension or hyperthyroidism or both, and these cats were excluded from the final diagnosis of HCM (20/132; 15.2 (95% CI = 9.5–22.4)%). Between 2012 and 2022, 168 colony cats died, with 132 undergoing post-mortem examination. Heart disease was considered the cause of death in 7/132 (5.3%; 95% CI = 2.2–10.6%) cats; five had HCM, one a congenital heart defect, and one myocarditis. The overall prevalence of death related to HCM in the colony during this period was 3.8% (95% CI = 1.2–8.6%). Three cats with HCM and the cat with a congenital heart defect died unexpectedly without prior clinical signs, while congestive heart failure was observed prior to death in two cats with HCM and the cat with myocarditis. Additionally, 30/132 (22.7%) cats had cardiac abnormalities but died for non-cardiac reasons. Conclusions Subclinical cardiomyopathy, specifically HCM, was common in cats in the colony. Given that the colony originated as a convenience selection of non-purebred cats in New Zealand, the true prevalence of HCM in the wider New Zealand population is likely to fall within the 95% CI (9.5–22%). The proportion of deaths of colony cats due to HCM was lower (3.8%) supporting the conclusion that subclinical cardiomyopathy may not progress to clinical disease causing death. Clinical relevance Veterinarians should be aware of the high prevalence of subclinical HCM when treating cats. Abbreviations CAM: Systolic anterior motion of the chordae tendineae; CFN: Centre for Feline Nutrition; HCM: Hypertrophic cardiomyopathy; LA/Ao: Left atrial to aortic ratio; LV FS: Left ventricular fractional shortening; LVIDd: Left ventricular internal diameters in end-diastole; LVIDs: Left ventricular internal diameter in end-systole; LVWT: Max Maximum left ventricular wall thickness; SAM: Systolic anterior motion of the mitral valve; 2D: Two-dimensional
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    Survey of Handlers of 158 Police Dogs in New Zealand: Functional Assessment and Canine Orthopedic Index.
    (Frontiers Media S.A., 2019-04-16) Baltzer WI; Owen R; Bridges J; Levine D
    Objectives: To determine the functional assessment (FA) of fitness and Canine Orthopedic Index (COI) scores of 158 police dogs. The hypothesis was the dogs would have excellent fitness and no evidence of orthopedic disease regardless of age as reported by the handlers. Study Design: Observational, prospective study. Sample Population: Handlers of dogs >1 year of age in active duty or breeding/active duty. Methods: COI and FA questionnaires were completed via e-mail. Fisher's Exact test for count data assessed scores by age group (<2 years, 2–5 years, >5 years); Wilcoxon Signed-rank test correlated COI parameters (stiffness, function, gait, quality of life) to FA. Results: The dogs were 3.2 ± 2.4 (mean ± standard deviation) years-old, 96% were German Shepherds and 111 were male. 32% of dogs could hold the “Hup” position for no longer than 4 s and 8% frequently had difficulty with this task. Difficulty jumping into vehicles occurred in 1/3 of the dogs. Overall FA was impaired in 20% (score >8), abnormal in 15% (score = 5–7), and reduced (score = 1–4) in 36% of dogs. Only 29% had normal function (FA score = 0) and these were significantly younger (2.8 ± 1.7 years, p < 0.05) than impaired dogs (6.6 ± 2.2 years). COI stiffness score was abnormal in 37% (3.3 ± 2.2) and gait was abnormal in 41% (5.4 ± 4.0). Quality of life (QOL) was excellent in 69% of dogs. Stiffness for the <2 year-old group was 0.2 ± 0.8, for the 2–5 year-old group was 1.1 ± 2.0 and for the >5 year-old group was 3.2 ± 2.4. Gait score for the <2 year group was 0.8 ± 2.2, and for the 2–5 year group was 1.9 ± 3.2 and for the >5 year group was 6.0 ± 4.3. Quality of life was close to excellent for the <2 year-olds (0.3 ± 1.1) and 2–5 year-olds (0.8 ± 2.0) but the >5 year-olds scored higher (3.0 ± 2.5). Only the COI gait score correlated with the FA score (p = 0.30). Conclusions and Clinical Relevance: Police dogs were reported by handlers to have good to excellent QOL, however, increasing age was associated with declining FA and COI scores.
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    Ultrasonographically derived caudal vena cava parameters acquired in a standing position and lateral recumbency in healthy, lightly sedated cats: a pilot study.
    (2022-10) Hultman TM; Boysen SR; Owen R; Yozova ID
    OBJECTIVES: The aim of this study was to determine the feasibility of ultrasonographically measuring the caudal vena cava (CVC) at the subxiphoid view of healthy, lightly sedated cats in a standing position and lateral recumbency. METHODS: This was a prospective, observational, experimental single-centre study. Twenty healthy research-purposed cats were enrolled. Two trained operators scanned each cat in two positions - standing and lateral recumbency - in a randomised order. CVC diameter was measured at the narrowest diameter during inspiration and at the widest diameter during expiration, at two anatomical locations along the CVC - where the CVC crosses the diaphragm (base) and 2 mm caudal to the diaphragm. The CVC collapsibility index (CVC-CI) was calculated for each site. Normalcy was assessed with a Shapiro-Wilk test. A one-way ANOVA with post-hoc Tukey's test was used to compare inspiratory with expiratory values within and between groups. A paired t-test compared the CVC-CI between groups (P ⩽0.05 indicated statistical significance). Spearman's correlation and Bland-Altman analysis assessed inter-operator variability. RESULTS: All ultrasonographic data passed normalcy and were reported as mean ± SD. When compared with each other, inspiratory and expiratory values were statistically different for position, location and operator (all P <0.0001). There was no statistically significant difference between lateral recumbency or standing position for inspiratory, expiratory and CVC-CI values. Inter-operator variability was substantial, with operator 2 consistently obtaining smaller measurements than operator 1. The mean CVC-CI in lateral recumbency at the base was 24% for operator 1 and 37% for operator 2. For the same site in standing position, CVC-CI was 27% and 41% for operators 1 and 2, respectively. CONCLUSIONS AND RELEVANCE: This pilot study demonstrates that it is possible to ultrasonographically measure the CVC diameter in both lateral recumbency and a standing position in healthy, lightly sedated cats. However, measurements obtained are operator dependent with variability between individuals. Further studies are needed to determine if ultrasonographic CVC assessment will prove helpful in estimating intravascular volume status in cats.
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    X-linked myotubular myopathy associated with an MTM1 variant in a Maine coon cat
    (Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine, 2022-09-26) Kopke MA; Shelton GD; Lyons LA; Wall MJ; Pemberton S; Gedye KR; Owen R; Guo LT; Buckley RM; Valencia JA; 99 Lives Consortium; Jones BR
    OBJECTIVE: Describe the clinical course and diagnostic and genetic findings in a cat with X-linked myotubular myopathy. CASE SUMMARY: A 7-month-old male Maine coon was evaluated for progressively worsening gait abnormalities and generalized weakness. Neurolocalization was to the neuromuscular system. Genetic testing for spinal muscular atrophy (LIX1) was negative. Given the progressive nature and suspected poor long-term prognosis, the owners elected euthanasia. Histopathology of skeletal muscle obtained post-mortem disclosed numerous rounded atrophic or hypotrophic fibers with internal nuclei or central basophilic staining. Using oxidative reactions mediated by cytochrome C oxidase and succinic dehydrogenase, scattered myofibers were observed to have central dark staining structures and a "ring-like" appearance. Given the cat's age and clinical history, a congenital myopathy was considered most likely, with the central nuclei and "ring-like" changes consistent with either centronuclear or myotubular myopathy. Whole genome sequencing identified an underlying missense variant in myotubularin 1 (MTM1), a known candidate gene for X-linked myotubular myopathy. NEW OR UNIQUE INFORMATION PROVIDED: This case is the first report of X-linked myotubular myopathy in a cat with an MTM1 missense mutation. Maine coon cat breeders may consider screening for this variant to prevent production of affected cats and to eradicate the variant from the breeding population.