Prevalence and risk factors for medical events following exercise at Australian Greyhound race meetings.

AIM: A prospective, observational study to determine the prevalence of post-exercise conditions at Australian Greyhound race meetings and to assess association with race performance and other environmental, race- and dog-related factors was undertaken. METHODS: A total of 4020 starters were observed (2813 Greyhounds, 1009 trainers, 536 races, 52 race meets, 48 race dates and 11 race tracks) following a race. The presence of diaphragmatic flutter (DF), ataxia, seizure, collapse or sudden death was recorded. Risk factors were screened by univariable logistic regression prior to multivariable backward stepwise model building. RESULTS: In this study, 962 starters (n = 768 dogs) had DF (23.9%), 16 starters were ataxic (0.4%) and there were no observed cases of collapse, seizure or sudden death. Race track location, increasing race distance, race grade based on increasing 1st place prize value, lower (earlier) race number at the meeting, age, a previous observation of DF at the last start, females, colour (white) and better finishing position were all associated with an increased risk of a Greyhound being observed with DF. However, when logistic regression assessing the random effect of dog was performed, the presence of previous DF was not significant. In this cohort, DF was common following strenuous exercise in Greyhounds and on its own does not appear to result in reduced performance or distress to the animal. CONCLUSION: The incidence of ataxia was low and collapse, seizure and sudden death were not observed. However, even though uncommon, ataxia has welfare concerns for racing Greyhounds that warrants further investigation.

Reference limits for urinary fractional excretion of electrolytes in adult non-racing Greyhound dogs.

OBJECTIVE: To determine reference limits for urinary fractional excretion of electrolytes in Greyhound dogs. METHODS: Urinary fractional excretion was calculated using a spot clearance method preceded by a 16 to 20 hour fast in 48 Greyhound dogs. Raw data analysed using the bootstrap estimate was used to calculate the reference limits. RESULTS: The observed range for urinary fractional excretion in Greyhound dogs was 0.0 to 0.77% for sodium, 0.9 to 14.7% for potassium, 0 to 0.66% for chloride, 0.03 to 0.22% for calcium and 0.4 to 20.1% for phosphate. Expressed as percentages, the suggested reference limits for fractional excretion in Greyhound dogs are as follows: sodium < or = 0.72, potassium < or = 12.2, chloride < or = 0.55, calcium < or = 0.13 and phosphate < or = 16.5. CLINICAL SIGNIFICANCE: Veterinary practitioners may use these reference limits for urinary electrolyte fractional excretion when investigating renal tubular disease in Greyhound dogs.

Primary hypoparathyroidism in dogs: a retrospective study of 17 cases.

OBJECTIVE: To evaluate the clinico-pathological findings, response to treatment and prevalence of complications in dogs with primary hypoparathyroidism. DESIGN: Retrospective study of 17 dogs presenting to the University of Melbourne Veterinary Clinical Centre and Murdoch University Veterinary Hospital over a 15 year period (1990 to 2004). Case records were evaluated for signalment, body weight, diet type, historical and clinical findings, serum total calcium, phosphate, albumin and parathyroid hormone concentrations, urinary fractional excretion ratios of calcium and phosphate, electrocardiogram (ECG) results, treatments administered, outcome and period of follow-up. RESULTS: The most common breeds identified were St Bernard (three dogs), Chihuahua (two dogs), German Shepherd (two dogs) and Jack Russell Terrier (two dogs). Three dogs were cross bred. Seizures, muscle tremors and fasciculations, stiff gait, tetany, muscle cramping, behavioural change and hyperventilation were the most common clinical signs. Vomiting, inappetence, diarrhoea, abdominal pain, hyperthermia, facial pruritus, ataxia, weakness, cataracts, and circling also occurred with less frequency. The mean duration of observed clinical signs preceding diagnosis was 33 days (median 13 days, range 1 to 173 days). All dogs had marked hypocalcaemia with normal or mildly increased serum albumin concentrations. Mean phosphate concentrations were significantly higher in inappetent dogs (P = 0.049). Mean serum calcium concentrations were significantly lower in dogs with cataracts compared to those without (P = 0.046). There were no other significant relationships between serum calcium or phosphate concentrations and the clinical presentation or outcome. No significant correlations were identified between the presence of a particular clinical sign and the duration of clinical signs. ECGs were obtained in four dogs and all exhibited QT interval prolongation due to a ST-segment prolongation. Sixteen of 17 dogs were treated successfully for hypocalcaemia and discharged from hospital. Acute management included parenteral calcium gluconate (10 dogs) and intravenous anticonvulsants (five dogs). Chronic therapy included oral vitamin D analogues and calcium supplementation. Treatment complications occurred in two dogs and included acute renal failure (one dog) and iatrogenic tissue necrosis following subcutaneous calcium administration (one dog). The mean follow-up period was 14.5 months (median 13 months, range 0 to 39 months). Twelve dogs were alive at the last follow up and two dogs were euthanased for unrelated reasons. The type of vitamin D analogue used was not associated with outcome. CONCLUSION: Primary hypoparathyroidism was an uncommon diagnosis in dogs. Saint Bernards, cross bred dogs, German Shepherd dogs and Terrier breeds were most commonly affected. Neurological signs were the most common presenting clinical signs, although alimentary signs may have been more common than previously reported. Dogs with primary hypoparathyroidism appeared to have a good prognosis following initiation of calcium supplementation and vitamin D therapy. Complications of treatment were uncommon and could be minimised with regular monitoring.

Acquired myasthenia gravis associated with a non-invasive thymic carcinoma in a dog.

An 8 1/2-year-old neutered male Beagle was diagnosed with acquired myasthenia gravis associated with a non-invasive thymic carcinoma. The thymic mass was surgically excised and the dog was treated with pyridostigmine, prednisolone and azathioprine. Serial acetylcholine receptor antibody titres were increased initially but slowly declined to normal values over a period of 24 weeks. Improved exercise tolerance was seen following therapy, however, oesophageal dysfunction persisted. The dog was euthanased 26 weeks after initial presentation due to a complicating illness. A necropsy showed no regrowth or metastasis of the thymic carcinoma.

Sodium cloprostenol administered at a continuous low dosage induces polydipsia and suppresses luteal function in early dioestrous bitches.

The aim of this study was to determine whether sodium cloprostenol administered at a continuous low dosage induced luteolysis and polydipsia in early dioestrous bitches. Sodium cloprostenol was administered subcutaneously to greyhounds at doses of 4.04-5.19 microg/kg/day (treated group, n=5) or 0 microg/kg/day (control group, n=5) delivered by mini-osmotic pumps for 7 days. The treated bitches and two of the control bitches were in early dioestrus (Days 5-14, and 6 and 10, respectively) when the mini-osmotic pump was inserted (Day 0). Concentrations of plasmatic progesterone were measured in dioestrous bitches each day from Day -2 to 7, and then weekly until Day 90. Daily intake of water was ascertained in all bitches from Day -2 until Day 10, and their weight was measured on Days -2, 6 and 13. Biochemical analyses on plasma for concentrations of urea and glucose, and urinalyses were performed on all bitches before (Day -1), during (Day 4) and after treatment (Day 10). Concentrations of plasmatic progesterone declined dramatically and rapidly in treated bitches after Day 0 to <2.9 ng/ml but were not similarly affected in the dioestrous control bitches. However, in three of five treated bitches, concentrations of plasmatic progesterone increased to >1 ng/ml in the period from Day 10 to 90 indicating that luteolysis was incomplete. All treated bitches were polydipsic (intake of water >100 ml/kg/day) for 2-6 days during the period of treatment, and for 0-2 days immediately after treatment (Days 7 and 8). One control bitch was polydipsic on Days -2, -1 and 0. The treated bitches were also polyuric since they were hyposthenuric (<1.007, n=4) or isothenuric (1.010, n=1) on Day 4, their weight did not increase and no gastrointestinal or respiratory effects were observed. The control bitches were always hypersthenuric when measured during and after treatment (>1.021). Biochemical analyses of plasma and other data obtained from urinalyses did not reveal any differences between groups. This study indicated that sodium cloprostenol administered at a continuous low dosage induced polydipsia and suppressed luteal function in early dioestrous bitches.

Acute bronchopneumonia associated with Mycobacterium fortuitum infection in a dog.

Mycobacterium fortuitum was isolated in a sample of bronchial fluid collected by transtracheal aspiration from a 1-year-old Corgi dog with a productive cough of 10 days' duration and with radiographic and cytological features of acute suppurative bronchopneumonia. The dog responded favourably to intravenous gentamicin and cephalexin for three days and a six week course of oral ciprofloxacin. Saprophytic mycobacterial pneumonia should be considered in cases of severe pulmonary consolidation in young dogs.

An interobserver and intraobserver study of buccal mucosal bleeding time in Greyhounds.

Two observers experienced with the buccal mucosal bleeding-time technique using a standardised device (Surgicutt) performed the test on 20 Greyhounds, to evaluate interobserver and intraobserver repeatability. The interobserver and intraobserver repeatability were both about 2 minutes. The results indicated that, for any two readings within a dog, the buccal mucosal bleeding time may differ by up to +/- 2 minutes. A single reading was accurate to within +/- 80 seconds. Sixty-one Greyhounds were used to establish a reference interval for the buccal mucosal bleeding time, and to assess the relationship between the buccal mucosal bleeding time and plasma von Willebrand factor concentration. The mean was 129.5 (SD 44.2) seconds. The reference interval was 53 to 235 seconds, which was slightly lower than non-greyhounds. No significant correlation (r=-0. 18, P=0.17) between the buccal mucosal bleeding time and plasma von Willebrand factor concentration was found in the 61 Greyhounds, where plasma von Willebrand factor concentration was in the range 29 to 160 Canine Units dL(-1).

Streptococcal meningoencephalitis in a dog.

A 5.5-year-old French bulldog was presented with acute neck pain and a short history of central vestibular syndrome. A marked neutrophilic pleocytosis and numerous gram-positive cocci were evident on cerebrospinal fluid (CSF) cytology. Streptococcus pneumoniae, a pathogen of humans, was isolated upon CSF microbiological culture. Treatment consisted of intravenous antibiotics, supportive care, and anticonvulsants for the generalized seizures which developed shortly after admission. The dog responded to therapy and two years later exhibited only a mild, residual head tilt. The pathogenesis and treatment of bacterial meningoencephalitis in dogs are reviewed.

The use of recombinant ovine IL-1beta and TNF-alpha as natural adjuvants and their physiological effects in vivo.

In the present study we have investigated the use of recombinant ovine IL-1beta and TNF-alpha both alone and in combination, as natural adjuvants in vaccination trials in sheep. Initial experiments were conducted to investigate the physiological effects of the cytokines in vivo and determine what dose could be administered without adverse pyrogenic effects. Even at the maximum dose tested (100 microg) the only significant physiological effect was a transient increase in body temperature of approximately 2 degrees C in sheep injected with TNF-alpha. Administration of either cytokine had profound effects on the levels of circulating leucocytes for up to 5 days postinjection. The incorporation of either IL-1beta or TNF-alpha in aqueous or Al(OH)3 vaccine formulations enhanced antibody responses to a recombinant antigen from the cestode parasite Taenia ovis. The addition of IL-1beta to aqueous vaccine formulations increased antibody responses 15-20-fold and in Al(OH)3 formulations by three to six fold. TNF-alpha stimulated 1.5 to six-fold and 2.5 to seven-fold increases in antibody levels in aqueous and Al(OH)3-based formulations, respectively, in a dose-dependent manner. The addition of either cytokine to Quil A or IFA vaccines did not enhance the antibody levels elicited. When 10 microg of both IL-1beta and TNF-alpha were incorporated in the aqueous or Al(OH)3 vaccine formulations, increases of 21-fold and 25-fold, respectively, were observed in antibody levels. The adjuvant activity of IL-1beta and TNF-alpha in combination in the Al(OH)3-based vaccine resulted in antibody levels commensurate with those obtained using Quil A or IFA.

Effect of desmopressin on plasma factor VIII and von Willebrand factor concentrations in Greyhounds.

OBJECTIVE: To determine the effect of 1-Deamino-8-D-arginine vasopressin on plasma concentrations of von Willebrand factor and factor VIII in Greyhound blood donors, and to compare the response of 1-Deamino-8-D-arginine vasopressin injection on plasma concentrations of von Willebrand factor between groups with different resting plasma concentrations of von Willebrand factor. ANIMALS: Fifteen Greyhound blood donors were used. Dogs were grouped into three categories depending on their von Willebrand factor concentrations. PROCEDURE: Desmopressin was administered subcutaneously at 1 microgram/kg [corrected] to all dogs. Plasma von Willebrand factor and factor VIII concentrations were measured before and 10, 20, 30, 45, 60, 90 and 120 min after desmopressin injection. RESULTS: The von Willebrand factor and factor VIII concentrations in all dogs increased significantly and remained higher than base-line throughout the 2 h period. CONCLUSION: Desmopressin is useful in increasing von Willebrand factor concentrations in Greyhound blood donors, including those with low resting concentrations.

Pharmacokinetics of von Willebrand factor and factor VIII in canine von Willebrand disease and haemophilia A.

The pharmacokinetics of von Willebrand factor antigen (vWf:Ag) and factor VIII coagulant (FVIII:C) activity in dogs with von Willebrand Disease (vWD) and haemophilia A, respectively, were assessed after the administration of fresh frozen plasma (FFP) and cryoprecipitate. Loading doses necessary to attain target plasma concentrations of each factor were estimated to be 63 U kg-1 BW for FFP and 13 U kg-1 BW for cryoprecipitate to reach 35 U dl-1 vWf:Ag in vWD and 23 U kg-1 BW for FFP and 4 U kg-1 BW for cryoprecipitate to reach 30 U dl-1 FVIII:C in haemophilia A. The estimated volumes of FFP required to attain these target concentrations (49 ml kg-1 BW for vWD and 20 ml kg-1 BW for haemophilia A) are approximately 10-fold higher than the volumes of cryoprecipitate required (4 ml kg-1 BW for vWD and 2 ml kg-1 BW for haemophilia A). This indicates that cryoprecipitate is a more efficient and practical means of treating or preventing haemorrhage in these two haemostatic disorders.

Studies to detect carriers of haemophilia A in German shepherd dogs using diagnostic DNA polymorphisms in the human factor VIII gene.

The current study investigated whether the DNA polymorphisms in the human FVIII gene, that are used for the diagnosis of carriers of haemophilia A, were diagnostically useful in dogs. Genomic DNA from 20 German Shepherd dogs (13 females, three normal males and four haemophilic males) was tested using five restriction site polymorphisms [HindIII/F8 (exon 17-18), Taq I/ST14.1, BclI/ST14.1, BclI F8 (exon 17-18) and Bgl II/DX13]. The DNA probes (with the exception of DX13) all hybridized to the canine DNA at high stringency, indicating significant homology between the human and canine FVIII gene. A BclI polymorphism (13.5/13.5 + 12.8 kb) was detected with the ST14.1 probe.

von Willebrand's disease in Scottish Terriers in Australia.

Over a 5-year period (1988-92), von Willebrand factor antigen (vWf:Ag) assays were performed on plasma samples from 207 Scottish Terriers. Based on these tests, 47 dogs (23%) had vWf:Ag concentrations < 50 canine units (CU)/dL and were classified as heterozygous carriers of the von Willebrand's disease (vWD) gene, while 9 (4%) had concentrations below the sensitivity of the assays and were classified as homozygous. There was thus an overall prevalence of 27% for the vWD gene in the Scottish Terriers tested. The homozygous dogs (median age 0.6 years at diagnosis) consisted of 7 males and 2 females. Eight of these had haemorrhage attributable to the disease, mostly spontaneous and from the oral mucosa. Other signs included haemorrhage induced by trauma or surgery, easy bruising and epistaxis. Many haemorrhagic episodes were severe enough to warrant therapeutic intervention and there was a single fatality. Pedigree analysis, possible in 7 of the dogs, revealed that each was the progeny of a mating between dogs with vWf:Ag concentrations < 50 CU/dL, which supported an autosomal recessive mode of inheritance. A single heterozygous carrier suffered haemorrhage after surgery that, in contrast to the homozygotes, was mild and did not require therapy. The data indicate that vWD is a significant problem in Scottish Terriers in Australia. Accordingly, we recommend that steps be taken to reduce the prevalence of the disease and thereby the number of clinically affected dogs, such as the establishment of a national testing scheme to determine the vWD status of all breeding dogs.

Stability of von Willebrand factor and factor VIII in canine cryoprecipitate under various conditions of storage.

The stability of factor VIII and von Willebrand factor antigen in canine cryoprecipitate obtained from seven greyhound donors was determined after storage under various conditions, including twice freezing at -70 degrees C and thawing at 37 degrees C, slow thawing at 4 degrees C, refreezing the slowly thawed cryoprecipitate at -20 degrees C and thawing at 37 degrees C and maintaining the thawed cryoprecipitate at room temperature for 24 hours. The results indicated that factor VIII and von Willebrand factor antigen were effectively concentrated during the initial cryoprecipitation procedure. The cryoprecipitate which had been thawed and refrozen under the above conditions maintained factor VIII activities and concentrations of von Willebrand factor antigen similar to those in the original thawed cryoprecipitate. Furthermore, there was no significant loss of either of the coagulation factors in cryoprecipitate which was thawed in a warm water bath and stored for 24 hours at room temperature.