Janis P. Bridges

Corticosterone Responses of Grey‐Faced Petrels (Pterodroma macroptera gouldi) Are Higher during Incubation than during Other Breeding Stages

We report the results of the first field study examining seasonal changes in corticosterone responses of typically long‐lived birds of the order Procellariiformes. In particular, we examined whether grey‐faced petrels Pterodroma macroptera gouldi showed changes in circulating baseline corticosterone concentrations and corticosterone responses to a standardized handling protocol across the breeding season. Such changes have been associated with changes in body condition and variations in energy demands on adult birds through the breeding season. During early incubation, males were in significantly better condition than females that had just completed laying, whereas during late incubation, males were in significantly poorer condition than females. In spite of these differences, there was no significant difference in baseline corticosterone concentrations between sexes or among birds at different reproductive stages. However, we detected significant differences in corticosterone responses associated with a standardized handling protocol at different stages through the breeding season. Responses were significantly greater during incubation compared with the prelay period and late chick rearing. Body condition was weakly and negatively correlated with maximum and total integrated corticosterone level, indicating that some of the individual variability in stress corticosterone responses could be explained by variation in body condition. However, the largest stress response occurred during late incubation and was independent of sex, although males were in relatively poor condition and females in relatively good condition. This period coincided with the breeding stage in which energy constraints on individual adults were higher than at other periods of the reproductive cycle and birds may be physiologically primed for extended fasts.

The Efficacy and Safety of a Novel Lipophilic Formulation of Methimazole for the Once Daily Transdermal Treatment of Cats with Hyperthyroidism

BACKGROUND Previous studies on transdermal methimazole have used pluronic lecithin organogel as the vehicle. This might not be the most suitable vehicle for a lipophilic drug, such as methimazole. HYPOTHESIS/OBJECTIVES Once daily transdermal administration of a novel lipophilic formulation of methimazole is as safe and effective as oral carbimazole in treating hyperthyroidism in cats. ANIMALS Forty-five client-owned cats diagnosed with hyperthyroidism. METHODS Prospective study. Cats with newly diagnosed, untreated hyperthyroidism were treated with carbimazole (5 mg p.o., q12h) or methimazole (10 mg) applied to the inner pinnae q24h. Cats were examined after 0, 1, 4, 8, and 12 weeks of treatment. Clinical signs, body weight, systolic blood pressure, hematologic, serum biochemical and urine parameters, total serum thyroxine concentrations (TT4), and serum methimazole concentrations were recorded. RESULTS No significant differences between groups were detected at day 0. Both formulations were effective in treating hyperthyroidism. No significant differences were detected in thyroxine concentrations, body weight, blood pressure, heart rate, alkaline phosphatase, alanine aminotransferase, creatinine, urea, and urine specific gravity (USG) between groups. The serum methimazole concentrations correlated poorly with TT4-concentrations in both groups. CONCLUSIONS AND CLINICAL IMPORTANCE In this 12-week trial, once daily application of a novel formulation of transdermal methimazole applied to the pinnae was as effective and safe as twice daily oral carbimazole in the treatment of cats with hyperthyroidism. This novel formulation and transdermal application could have practical advantages to some pet owners.

Canine Soft Tissue Sarcoma Managed in First Opinion Practice: Outcome in 350 Cases

OBJECTIVE To determine outcome of dogs with a diagnosis of soft tissue sarcoma managed in first opinion practice. STUDY DESIGN Retrospective, case-controlled study ANIMALS Dogs (n = 350) with primary occurrence of a soft tissue sarcoma. METHODS A previously validated questionnaire was sent to all veterinarians requesting clinical information and ultimate outcome for all dogs. Histologic sections were reviewed by a single pathologist. RESULTS Most surgeries were unplanned, with only 15 (4%) dogs having a histologic and 59 (16.8%) dogs having a cytologic diagnosis before surgery. Median survival time for all dogs was not reached with 70% proportional survival at 5 years. Local recurrence developed in 73 (20.8%) cases. The extent of resection performed was not associated with improved survival (P = .2) or tumor recurrence (P = .8). Age <8 years (χ(2)  = 6.1; P = .01), tumors <5 cm in size (χ(2)  = 9.6; P = .002) and discrete tumors (χ(2)  = 16.6; P < .001) had improved survival outcomes. On multivariate analysis, a high tumor grade was significant for recurrence (HR 5.8; P < .001; 95% CI: 2.2-14.8). Evidence of a selection bias towards less aggressive tumors being managed in first opinion practice was confirmed. CONCLUSIONS Wide resection margins are not the primary determinant of outcome for all soft tissue sarcoma. Veterinarians need to better understand the biologic behavior of a suspected soft tissue sarcoma before treatment to allow surgical margins to be adjusted accordingly.

A survey of diseases of working farm dogs in New Zealand.

Abstract AIMS: To record the incidence of specific diseases affecting working farm dogs; identify any apparent breed predispositions; determine the most important causes of loss from death, euthanasia, or retirement of the dog; and identify potential interventions that could reduce the incidence of disease. METHODS: A national questionnaire-based cross-sectional study was conducted to identify the incidence of specific diseases, and circumstances of trauma affecting working farm dogs that presented to rural veterinary practices over a 12-month period, between April 2008 and April 2009. The practices were convenience-sampled on the basis of geography and size. RESULTS: Sixty-six practices were approached, and veterinarians from 30 practices agreed to participate, with representation from all major rural regions of New Zealand. Data were provided on 2,214 presentations, excluding revisits, of which 51% were for Huntaways and 39% Heading dogs. Trauma was identified as a cause of injury in 848 (38%) visits. Huntaways were apparently over-represented in cases of constipation, gastric dilatation-volvulus (GDV), theriogenological problems, laryngitis, hip dysplasia, and degenerative lumbosacral disease. In contrast, Heading dogs were over-represented among cases of multiple ligamentous injury of the stifle, disruption of the gastrocnemius or Achilles tendon, tarsal injuries, and hip luxation. Traumatic injury involved injury by stock (20%), automotive incidents (19%), transit across fence lines (16%), and dog bites (12%). Loss occurred following 10% of visits, of which trauma was known to be involved in 32%. The most important nontraumatic causes of loss were GDV, degenerative joint disease, mammary neoplasia and diseases involving the female reproductive tract, cardiac disease, and poisoning. CLINICAL RELEVANCE: Several important diseases appear amenable to intervention through nutrition, neutering, or behavioural modification, including constipation, GDV, theriogenological problems, dog-bite injuries, and laryngitis. Altering modes of transit across fence lines has the potential to reduce large numbers of serious orthopaedic injuries to working farm dogs.

Systemic effects of periodontal disease in cats

Background: Periodontal disease in cats is a local disease that may have systemic consequences that are affected by treatment. Objective: To test the hypotheses that systemic health indices would be correlated with the severity of periodontitis, and would improve with treatment. Animals and methods: Apparently otherwise healthy cats from an in-bred colony were randomly assigned to a treatment group (n = 30), or a control group (n = 18), which was left untreated for 3 months. Periodontal disease was scored at baseline in the treatment group according to calculus, gingivitis, and alveolar bone loss measured from dental radiographs. Blood, urine and saliva were collected from both groups before, and 16, 45, and 90 days after dental treatment. Assays included haematology, urinalysis, serum biochemistry, serum IgG, salivary IgA, lymphocyte subsets and proliferation, and plasma malonyldialdehyde (MDA). Correlations between the severity of periodontitis and assays at baseline were assessed, and the effect of treatment determined using linear mixed model methodology. Results: The severity of periodontitis was associated with age, bodyweight, total globulins (Globs), Alanine aminotransferase, and IgG, and negatively associated with albumin, haemoglobin, haematocrit, and Aspartate aminotransferase (AST). Treatment significantly reduced IgG, total Globs, AST, and eosinophils, and increased cholesterol. Other leucocyte assays and plasma MDA concentrations were not affected by the treatment. Cats ate dry food faster 1 week after, than they did 1 week before treatment. Conclusions and clinical relevance: Although the clinical significance of these findings are unknown, we conclude that periodontitis is not simply a localized disease, but also impacts on systemic health and wellbeing.

The prevalence of ocular lesions associated with hypertension in a population of geriatric cats in Auckland, New Zealand

Abstract AIMS: To provide an estimate of the prevalence of ocular lesions associated with hypertension in geriatric cats in Auckland, New Zealand and to evaluate the importance of examination of the ocular fundi of cats over eight years of age. METHODS: A total of 105 cats ≥8 years of age were examined and clinical signs recorded. Blood was collected for the laboratory measurement of the concentrations of blood urea nitrogen (BUN), glucose and creatinine in serum, urine was collected for determination of urine specific gravity (USG), and blood pressure (BP) was measured using high definition oscillometry equipment. A cat was determined to have systemic hypertension with a systolic BP ≥160 mm Hg and a diastolic BP ≥100 mm Hg. Each animal had an ocular fundic examination using a retinal camera to diagnose ocular lesions associated with hypertension, including retinopathies, choroidopathies and optic neuropathies. RESULTS: Blood pressure was successfully recorded in 73 cats. Of these, 37 (51%) had no hypertensive ocular lesions and no underlying disease diagnosed, 24 (33%) had no hypertensive ocular lesions detected, but underlying disease such as chronic kidney disease, hyperthyroidism or diabetes mellitus was diagnosed, and 12 (16%) cats had evidence of hypertensive ocular lesions. Ten of the cats with hypertensive ocular lesions were hypertensive at the time of the first visit and two were normotensive. One additional cat had hypertensive ocular lesions, but it was not possible to obtain consistent BP readings in this animal. Chronic kidney disease was the most commonly diagnosed concurrent disease in cats with hypertensive ocular lesions (n=6). Mean systolic BP for cats with hypertensive ocular lesions (168.0 (SE 6.29) mm Hg) was higher than for those with no ocular lesions (144.7 (SE 3.11) mm Hg) or those with no lesions but with underlying disease (146.0 (SE 4.97) mm Hg) (p=0.001). CONCLUSIONS: Ocular fundic examination of cats over eight years of age allows identification of cats with hypertensive ocular lesions, often before the owner or veterinarian is aware the cat has a problem with its vision. This may result in diagnosis of systemic hypertension allowing early treatment and resolution of lesions. CLINICAL RELEVANCE: The current study demonstrates that ocular lesions resulting from hypertension occur frequently enough in cats in Auckland to support the recommendation for fundic examination in cats over eight years of age as part of the routine physical examination.

Reduction in the incidence of elbow dysplasia in four breeds of dog as measured by the New Zealand Veterinary Association scoring scheme.

Abstract AIM: To determine if there has been any reduction in the incidence of elbow dysplasia in four popular large-dog breeds as measured by the New Zealand Veterinary Association (NZVA) scoring scheme. METHODS: A retrospective analysis of the NZVA elbow dysplasia database was performed using records of all German Shepherd dogs, Labrador Retrievers, Golden Retrievers and Rottweilers that had undergone evaluation since the schemes inception in 1992. The data for each dog included date of birth, date of radiography, gender, grade of left and right elbow (0, 1, 2 or 3), and accredited or dysplastic status. Ordinal logistic regression was used to model the grade of the worst-affected elbow over time. The model included age at scoring and gender as additional variables. Given the known heritability of elbow dysplasia, the hypothesis was that if the NZVA scheme effectively identifies elbow dysplasia, and that dog breeders have been using the data responsibly, there should have been a trend towards a lower incidence of dogs graded dysplastic over time. RESULTS: In all four breeds, there was a significant trend towards lowergrades of the worst-affected elbow over time. For German Shepherd dogs the incidence of elbow dysplasia (worst elbowgrade not zero) fell from 75% to 47% between dogs born in 1991 vs those born in 2008. The corresponding figures were a drop from 86% to 68% for the Labrador Retriever, from 89% to 77% for Golden Retrievers, but only 98% to 95% for Rottweilers. In the Rottweiler and Golden Retriever, gender had a significant effect on the worst elbow grade. In the Golden Retriever, age at scoring also had a significant effect. CONCLUSIONS: There has been a significant reduction in the incidence of elbow dysplasia in four popular large-dog breeds as scored by the NZVA elbow dysplasia scoring scheme. The limitations of the study are the non-compulsory nature of the elbow dysplasia scheme, and the potential bias caused by dog breeders or veterinarians pre-screening potential submissions. The results therefore may not represent those of the overall population. CLINICAL RELEVANCE: The incidence of elbow dysplasia, as measured by the NZVA elbow dysplasia scheme, has reduced in the four breeds investigated since the schemes inception. The New Zealand Kennel Club (NZKC) and the veterinary profession can confidently support the NZVA scoring scheme, and should promote its use by dog breeders.

Blood metabolite responses to catecholamine injections in heifers of high or low genetic merit for milkfat production

Abstract Responses to acute intravenous injections of adrenalin and noradrenalin were examined in two groups of heifers (4 heifers/group) differing in predicted genetic merit by a mean of 33 breeding index units. A split-plot design was used in which the heifers were paired, one high breeding index and one low breeding index, for main plot comparisons between breeding index groups. Subplot treatments (four doses: 0, 0.25, 0.5, and 1 µg/kg bodyweight of noradrenalin; and four times of challenge: 1000 hand 1500 h on two consecutive days) were arranged in two 4 × 4 Latin Squares and applied to the four heifer pairs. The design was repeated on Days 3 and 4 using a second catecholamine, adrenalin. The concentrations of glucose and non-esterified fatty acids were measured in plasma collected at intervals (− 15, − 1, 5, 10, 15,20, 30, 45, 60, and 120 min) from treatment. Samples following the highest dose of each catecholamine were also analysed for insulin and 3-hydroxybutyrate. Glucose response to adrenalin in...

A comparison of anaesthetic recoveries in cats following induction with either alfaxalone or ketamine and diazepam.

AIM: To determine if cats anaesthetised with alfaxalone have different recoveries to cats anaesthetised with a combination of ketamine and diazepam. METHODS: Anaesthesia for ovariohysterectomy was induced in cats with either alfaxalone (n=23) or a combination of ketamine and diazepam (n=22). All cats were premedicated with combinations of acepromazine and morphine. Recoveries were scored using a categorical grading scheme applied to 18 parameters over 60 minutes following extubation. The parameters scored covered movement, sensitivity to touch, sound and light, body position, sneezing and vocalisation. One person scored all recoveries and they were blinded to the induction drug used. Scores were compared between drugs at different times using the Kruskal–Wallis rank sum test. RESULTS: Recovery scores were not normally distributed. Analysis of the data using the Kruskal-Wallis rank sum test revealed that cats induced with alfaxalone showed an increase in recovery scores at 5 minutes for pawing at the head (p=0.001). No parameters differed significantly at 10 and 20 minutes. For cats anaesthetised with ketamine and diazepam there was an increase at 30 minutes in pacing, jerky sudden movements, unsettledness and increased sensitivity to touch at the surgical site and on the head (p≤0.01). At 60 minutes cats anaesthetised with ketamine and diazepam still showed an increase in unsettledness compared to those cats anaesthetised with alfaxalone (p=0.005). CONCLUSIONS: The results suggest that recoveries of cats following alfaxalone induction are significantly different to recoveries after induction with ketamine and diazepam. Overall, cats induced with ketamine and diazepam had more active and unsettled recoveries than alfaxalone over the 60-minute period observed. CLINICAL RELEVANCE: Cats recovering from alfaxalone anaesthesia have more settled recoveries than cats recovering from ketamine and diazepam anaesthesia. If a quiet settled recovery is desired following a surgical procedure, alfaxalone is likely to be a better choice than ketamine and diazepam.

Trends in the phenotypic hip status of selected breeds of dog as measured by the New Zealand Veterinary Association Hip Dysplasia scheme (1990–2008)

Abstract AIM: To determine whether there has been improvement in the phenotypic hip dysplasia status in four susceptible dog breeds as measured by the New Zealand Veterinary Association (NZVA) Canine Hip Dysplasia (CHD) scheme. METHODS: A retrospective analysis of the NZVA CHD database was performed using records of all German Shepherd dogs, Labrador Retrievers, Golden Retrievers and Rottweilers that had undergone evaluation for hip dysplasia between 1990 and 2008. The effect of date of birth on the total hip score was analysed using linear regression, including the covariates of age and gender. When a significant effect of date of birth on total score was noted, ordinal logistic regression was performed to determine the probability of different grades of the Norberg angle and subluxation scores by year of birth; these categories being most indicative of laxity of the coxofemoral joint. Given the known heritability of hip phenotype, determined using radiological measurements, the hypothesis was that if sufficient selection pressure has been applied there would have been a trend towards a lower total score over time. RESULTS: For Labrador Retrievers (n=1,451), Golden Retrievers (n=896) and Rottweilers (n=313), there was no effect of date of birth on total score over the period of the study (p>0.1). For German Shepherd dogs (n=1,087), there was a significant trend to a lower total score over time (p=0.0003). However the actual size of the effect was small. Ordinal logistic regression on the Norberg angle and subluxation scores for German Shepherd dogs demonstrated a significant lowering of grade in both of these measures of hip laxity. CONCLUSIONS: This study failed to show significant improvement in the phenotypic hip status of three out of the four most populous large-dog breeds in the NZVA CHD database. Even in the German Shepherd dog, the trend towards a lower total score did not represent a substantial change. Lack of evidence of phenotypic improvement may be due to insufficient selection pressure over the course of the study, selective usage of the scheme (and thus a biased sample), or deficiencies within the NZVA CHD scoring method itself. CLINICAL RELEVANCE: Greater improvement might be possible if use of the scheme (or an equivalent) is made a compulsory requirement for registration of pedigree breeding stock, if greater selection pressure is applied and/or if pedigree data are included to enable estimations of breeding value.