Treatment of chronic or recurrent proximal suspensory desmitis using radial pressure wave therapy in the horse

REASONS FOR PERFORMING STUDY: Proximal suspensory desmitis (PSD) is diagnosed with increasing frequency in horses and radial pressure wave therapy (RPWT) is a widely used therapy for painful orthopaedic conditions in man and dogs. There are, however, few published data as to the outcome of its use in PSD. OBJECTIVE: To evaluate the use of RPWT in the treatment of chronic or recurrent PSD in the horse, an injury which carries a poor prognosis for return to athletic function with conservative management alone. HYPOTHESIS: RPWT and controlled exercise improves the prognosis of chronic or recurrent PSD in the horse when compared to previously published results of controlled exercise alone. METHODS: The use of RPWT in the management of chronic or recurrent proximal suspensory desmitis (PSD) was evaluated in 65 horses. Diagnosis was based on response to local analgesia, ultrasonography and radiography. Horses were classified according to severity of ultrasonographic lesions, whether fore- or hindlimbs were affected, and duration of lameness prior to diagnosis. Horses were treated 3 times at 2-week intervals and followed a controlled exercise programme; they were reassessed clinically and ultrasonographically 10-12 weeks after diagnosis, when further exercise recommendations were made dependent upon the animal's progress. RESULTS: Forty-one percent of horses with hindlimb lameness and 53% with forelimb lameness were nonlame and returned to full work 6 months after diagnosis. The prognosis was significantly affected by the ultrasonographic grade at the time of diagnosis and by ultrasonographic evidence of resolution of the lesion in hindlimb cases. CONCLUSIONS: These findings, when compared to previously published results of treatment using controlled exercise alone, suggest that RPWT improves the prognosis for PSD in the hindlimb. POTENTIAL RELEVANCE: RPWT is a useful treatment modality for chronic or recurrent PSD when combined with controlled exercise. Further studies are required on the effect of RPWT employing histology and biomechanics in order to fully evaluate its use on equine tissues.     

Impact of dopamine or dobutamine infusions on cardiovascular variables after rapid blood loss and volume replacement during isoflurane-induced anesthesia in dogs

OBJECTIVE: To determine the cardiovascular effects of dopamine and dobutamine infusions during nor-movolemia, hypovolemia (HV) through blood loss of 10 mL/kg (HV(10)), further loss to 25 mL/kg (HV(25)), and volume replacement (VR) in isoflurane-anesthetized dogs. ANIMALS: 7 healthy young dogs. PROCEDURES: Dogs were anesthetized with isoflurane 2 times (3 weeks apart). Cardiovascular measurements were obtained for each volume state. The cardiac index (CI) determined by the lithium dilution technique was compared with CI assessed by the arterial pulse contour technique. At each volume state, random treatment with dobutamine or dopamine was assessed (CI by the arterial pulse contour technique). Ten-minute treatments with 3 and 6 microg of dobutamine/kg/min or 7 and 14 microg of dopamine/kg/min (low and high doses, respectively) were administered sequentially. Differences from baseline were determined for volume, drug, and dose effects. RESULTS: Significant proportional changes in blood pressure (BP), stroke index (SI), and CI were evident with changes in volume state. Systemic vascular resistance (SVR) decreased after VR. Dobutamine induced little change in BP; increased heart rate (HR), SI, and CI; and decreased SVR (high dose). Dopamine increased BP and SI, did not change CI, and increased SVR (high dose). The arterial pulse contour technique underestimated changes in CI associated with volume changes. CONCLUSIONS AND CLINICAL RELEVANCE: Isoflurane eliminates clinically obvious compensatory increases in HR during HV. Dopamine is suitable for temporary management of blood loss in isoflurane-anesthetized dogs. Dobutamine increased CI without an associated improvement in BP. The arterial pulse contour monitor should be recalibrated when volume status changes.     

Distal border fragments and shape of the navicular bone: radiological evaluation in lame horses and horses free from lameness

Reasons for performing study: The significance of distal border fragments of the navicular bone is not well understood. There are also no objective data about changes in thickness and proximal/distal extension of the palmar cortex of the navicular bone. Objectives: To describe the distribution of distal border fragments and their association with other radiological abnormalities of the navicular bone and describe the shape of the navicular bone in sound horses and horses with foot‐related lameness, including navicular pathology. Methods: Sound horses had radiographs acquired as part of a prepurchase examination. Lame horses had forelimb lameness abolished by palmar nerve blocks performed at the base of the proximal sesamoid bones. Diagnosis was assigned prospectively based on results of local analgesia and all imaging findings. The thickness of the palmar cortex of the navicular bone and size of proximal/distal extensions were measured objectively. Other radiological abnormalities were evaluated subjectively and each navicular bone graded. Results: Fifty‐five sound and 377 lame horses were included. All measurements were larger in lame compared with sound horses except the size of the distal extension of the palmar cortex. Fragments were observed in 3.6 and 8.7% of sound and lame horses respectively and in 24.1% of horses with a diagnosis of primary navicular pathology. There was an association between fragments and overall navicular bone grade, radiolucent areas at the angles of the distal border of the navicular bone and number and size of the synovial invaginations. Conclusions and potential relevance: The palmar cortex of the navicular bone was thicker in lame compared with sound horses. Distal border fragments were most frequent in horses with navicular pathology. Evaluation of changes in shape of the navicular bone may also be important for recognition of pathological abnormalities of the bone.     

Longevity of Mycobacterium bovis in brushtail possum (Trichosurus vulpecula) carcasses,and contact rates between possums and carcasses

Abstract

AIM: To determine, for a variety of environmental conditions, how long Mycobacterium bovis might remain viable inside the carcass of a brushtail possum (Trichosurus vulpecula) that died of bovine tuberculosis (Tb), and to measure the rate of contact between free-ranging possums and possum carcasses.

METHODS: Lesions of M. bovis were simulated by inoculating excised spleens weighing 0.5–1 g with 0.2 mL liquid culture containing approximately 5 x 10⁷ cfu M. bovis/mL. Simulated lesions were inserted into possum carcasses (n=48) at the peripheral lymph nodes. Carcasses were placed in the field at two sites (a tussock grassland and a podocarp-broadleaved forest site) and in two seasons (summer and winter) for up to 62 days. Survival rates of M. bovis were estimated by sampling the simulated lesions over time, and culturing the recovered lesion to determine if any viable M. bovis bacteria were present.

The time taken for a free-ranging possum to first encounter a dead possum in its home range was estimated by live-trapping possums and fitting them with proximity loggers (n=13). A ‘contact’ was recorded if these possums came within 40–50 cm of proximity loggers fitted to possum carcasses.

RESULTS: There were strong seasonal and site effects in the survival rate of M. bovis in possum carcasses. In the grassland habitat, no viable bacilli were cultured from any carcass after 3 days in summer, whereas in winter all samples were culture-positive for the first 20 days, and some were still positive after 27 days. The survival rates for forest habitat were intermediate between the results for grassland, and there were no culture-positive carcasses after 9 days in summer or 27 days in winter.

In summer, infected carcasses (n=6) were first encountered by possums a mean 1.9 (range 0.4–6.7) days after placement.

CONCLUSIONS: Possum carcasses were contacted by free-ranging possums within the period that viable M. bovis were shown to survive in a carcass. The risk of such infection is likely to be most significant in winter or in areas with microhabitats where the survival of M. bovis is high. However, the generally low survival rate of M. bovis in possum carcasses and the low frequency of possum-to-carcass contacts indicate this route of transmission alone could not maintain Tb in a possum population.     

Re: Advances in animal welfare in New Zealand

Extract

The review article which appeared in the Jubilee Issue of the New Zealand Veterinary Journal (Stafford et al 2002) provided a good summary of recent research into the animal suffering associated with normal farming practices and pest control. In many cases, such research has been helpful in making improvements to animal welfare regulations, and the knowledge gained may prove even more useful in making further beneficial changes during the current submission round on codes of ethical conduct.     

Nasal infection with Scedosporium apiospermum in a dog

CASE HISTORY: A 2-year-old female Siberian Husky was presented with a 6-month history of sneezing and mucous discharge from the right nostril.

CLINICAL FINDINGS: Reduced airflow through the right nostril was evident. Radiographs showed subtle loss of detail of turbinates within the right nasal chamber. Rhinoscopy revealed swollen and erythematous turbinates and a white mass within the caudal aspect of the right nasal cavity. Histopathologically, there was a heavy mixed inflammatory infiltrate in the submus- cosa of the right turbinate, and the presence of fungal hyphae and spores in the white mass. A heavy growth of Scedosporium apiospermum was cultured from the mass.

DIAGNOSIS: Chronic rhinitis of the right nasal cavity and infection with S. apiospermum.

CLINICAL RELEVANCE: This is the first reported case of S. apiospermum isolated from the nasal cavity of a dog in New Zealand. Fungal culture is necessary to differentiate this fungus from Aspergillus spp.     

Successful treatment of a pancreatic pseudocyst by omentalisation in a dog

CASE HISTORY A 3-year-old male Labrador retriever was presented with a history of dietary indiscretion followed by vomiting and abdominal pain.

CLINICAL FINDINGS AND TREATMENT: Abdominal ultrasonography revealed the presence of a fluid-filled cystic structure in the region of the pancreas. Flocculent, dark fluid was drained from the cystic structure during exploratory celiotomy prior to resection of the lateral cystic wall. Omentum was sutured into the cystic cavity to provide drainage and enhance immune response. A jejunostomy feeding tube was placed. Post-surgical care consisted of antibiotic therapy. The dog was clinically normal at 1 and 7 months post-operatively and the pancreas appeared normal on final ultrasonographic examination.

CLINICAL RELEVANCE: This case describes the use of omentum to provide physiological drainage of a pancreatic pseudocyst. This surgical technique may help clinicians manage patients with this condition in the future.     

Pancreatic cyst in a cat

CASE HISTORY: A 5-year-old neutered male Cornish Rex cat was presented for evaluation with a history of vomiting over the previous 5 days.

CLINICAL FINDINGS: An abdominal mass was palpated, which was shown to be cystic by ultrasound examination. Exploratory surgery revealed this to be associated with the pancreas and it was duly resected. Histopathology was performed on the cystic mass.

DIAGNOSIS: Pancreatic cyst with associated chronic active infl ammation.

CLINICAL RELEVANCE: This is the first report of a true pancreatic cyst in a cat.