Categorization of the pelvic limb standing posture in nine breeds of dogs

The objective of the study was to categorize objectively nine breeds of healthy dogs according to pelvic limb standing posture. A total of 135 dogs from different breeds were used and the standing angles of the hip, stifle, and tarsal joints, together with the percentages of the greater trochanter, patella and tuber calcanei heights, with respect to crista iliaca height, were used as discriminant variables for the categorization of pelvic limb posture. All included breeds were allocated to three groups of the standing pelvic limb posture. The best discriminant variables between the three groups were the percentage of patellar height, and the standing angles of the stifle and tarsal joints. German shepherds, Anatolian shepherds, golden retrievers, Rottweilers, Belgian Malinois and Dobermann pinschers were well separated between 89% and 100% success rate for the categorization. The minimal success rate was determined in Berner sennenhunds as the ratio of 75%. It was also determined that Dobermann pinschers had the straightest pelvic limbs, while German shepherds had the most angulated pelvic limbs. Further studies are required to document the impact of postural differences in active and passive structure diseases of the locomotor system of the pelvic limb among dog breeds.     

Gross osteology and radiology of the pelvic limb of the adult small East African goat

The aim of this study was to provide the detailed normal gross osteology and radiographic anatomy of the pelvic limb in adult small East African goats as a reference for clinical use, biomedical research and teaching. Radiography of the pelvic limb was performed in five adult small East African goats. Bone specimens of four skeletally mature small East African goats were used for gross osteological study. The ilial wing was wide. The ischiatic tuberosity was prominent and well developed. The acetabulum was rounded. The minor trochanter was located caudomedially, and the femoral trochlea was deep and narrow. The lateral and medial condyles of the femur were approximately of the same size. The tibial tuberosity was prominent, and the cochlea grooves were deep with a pronounced intermediate ridge. The trochlea of the talus was deep. The patella presented a prominent tuberosity on the cranial surface. The metatarsal sesamoid bone was seen in all animals. The observed gross osteology and radiographic anatomy of the pelvic limb of small East African goats was consistent with the presence of strong extensor muscles of the hip, stifle and tarsus for propulsion during terrestrial walking and trotting.     

Femoral and sciatic nerve blockade of the pelvic limb with and without obturator nerve block for tibial plateau levelling osteotomy surgery in dogs

ObjectiveTo determine the effect of blocking the obturator nerve in addition to performing femoral nerve and sciatic nerve blocks on intraoperative nociception in dogs undergoing unilateral tibial plateau levelling osteotomy (TPLO) surgery.Study designProspective, blinded, randomized, placebo-controlled, clinical comparison.AnimalsA total of 88 client-owned dogs undergoing unilateral TPLO surgery (100 procedures).MethodsDogs were randomly assigned to either group FSO (femoral, sciatic and obturator nerve blocks) [n = 50; ropivacaine 0.75% (0.75 mg kg^–1)] or group FSP (femoral, sciatic and placebo) [n = 50; ropivacaine 0.75% (0.75 mg kg^–1) femoral and sciatic nerve blocks plus saline solution 0.9% (0.1 mL kg^–1) as a placebo injection around the obturator nerve]. The anaesthetic protocol was standardized. Data collection included intraoperative cardiopulmonary variables and opioid consumption. Rescue analgesia consisted of an intravenous bolus of fentanyl (2 μg kg^–1) and was administered when a change in cardiopulmonary variables (20% increase in mean arterial pressure or heart rate) was attributed to a sympathetic stimulus. Data were analysed using generalized linear mixed models, cross tables and multivariable binary logistic regression. Results were expressed as adjusted odds ratios with 95% confidence intervals and Wald p values (α = 0.05).ResultsThere were no clinically relevant differences between groups in intraoperative cardiopulmonary variables and need for rescue analgesia. The requirement for rescue analgesia was significantly higher in dogs with a body weight >34 kg.Conclusions and clinical relevanceAnaesthesia of the obturator nerve in addition to the femoral and sciatic nerves was not associated with clinically significant differences in cardiopulmonary variables or a reduced need for rescue analgesia. Therefore, the clinical benefit of an additional obturator nerve block for intraoperative antinociception in dogs undergoing unilateral TPLO surgery using the described anaesthetic regimen is low.     

Comparison of clinical effects of epidural levobupivacaine morphine versus bupivacaine morphine in dogs undergoing elective pelvic limb surgery

Objective

To evaluate the efficacy, in terms of the amount of rescue analgesia required, and the clinical usefulness of epidural injection of morphine with bupivacaine or levobupivacaine for elective pelvic limb surgery in dogs during a 24-hour perioperative period.

Retrospective comparison of three locoregional techniques for pelvic limb surgery in dogs

ObjectiveTo retrospectively compare the efficacy and duration of effect of three commonly used locoregional blocks in dogs undergoing pelvic limb orthopaedic surgery.Study designRetrospective clinical study.AnimalsA total of 236 dogs that underwent pelvic limb surgery and were administered a locoregional technique.MethodsA total of 236 hospital records were reviewed and 230 included in statistical analysis. Dogs were grouped as following: electrostimulation-guided pre-iliac femoral and sciatic nerve block (group PFS, n = 70); ultrasound-guided saphenous and sciatic nerve block (group SS, n = 76); or lumbosacral epidural (group EPI, n = 84). In group EPI, bupivacaine 0.5% or ropivacaine 0.75% was used with morphine. Dogs were pain scored (short form of the Glasgow Composite Measure Pain Scale) hourly following recovery from anaesthesia. Analysed data included: time to first postoperative dose of methadone, pain score at that time, intraoperative rescue analgesia, intraoperative hypotension and ability to walk and urinate overnight. Separate analyses were performed including all pelvic limb surgeries and including only elective stifle surgeries. Kruskal–Wallis and Mann–Whitney tests were performed. A p value < 0.05 was considered significant. The median (range) is reported.ResultsFor all pelvic limb surgeries, the time to first postoperative methadone was 530 (110–1337), 440 (140–1030) and 466 (135–1094) minutes in groups EPI, PFS and SS, respectively, and was not significantly different. Postoperatively, 10/84, 15/70 and 12/76 dogs in groups EPI, PFS and SS, respectively, did not require methadone (nonsignificant). Significantly fewer dogs in group EPI (18%) required intraoperative rescue analgesia compared with group SS (38%), but not compared with PFS (30%). Significantly more dogs in group EPI had hypotension intraoperatively (30%) and urinary retention postoperatively (62%).Conclusions and clinical relevanceIntraoperative analgesia may be superior with EPI than SS for some surgeries of the pelvic limb, but not for stifle surgeries. All three techniques provided similar requirement for postoperative analgesia, but EPI caused higher incidence of intraoperative hypotension and postopertive urinary retention.     

Feasibility of computed tomography in awake dogs with traumatic pelvic fracture

In veterinary medicine, general anesthesia or sedation is generally required to immobilize patients during computed tomography (CT) scanning. This may not be suitable in all patients because of risks of anesthesia. We evaluated the feasibility of pelvic CT examination in 14 awake animals with pelvic trauma. Physical restraint was applied by wrapping the patient in a towel and then taping to the CT table or by directly taping the patient to the CT table. The effect of patient positioning, cooperation on the CT table, preparation time for scanning, scanning time, frequency of repeat scans, image quality, and complications related to physical restraint were evaluated. Fractures were recorded and compared between radiography and CT. Ten of 14 dogs were scanned in lateral recumbency and four in sternal recumbency. All patients were cooperative with the exception of one that moved slightly during the scan. Both physical restraint methods were adequate for CT scanning. Patient preparation took less than 5 min while the scan time was typically less than 1 min. No repeat scans were required in any patient. The transverse CT image quality was good (10/14) or fair (4/14) for interpretation. When comparing the CT images to radiographs, more pelvic fractures were identified with CT than with radiography and a few patients were overdiagnosed based on radiographs. No complications or additional injuries associated with physical restraint were noticed.     

Intraoperative extracorporeal irradiation for limb sparing in 13 dogs

OBJECTIVE: To evaluate extracorporeal intraoperative radiation therapy (IORT) as a treatment method for limb and joint sparing in dogs with appendicular sarcomas in sites other than the distal aspect of the radius. STUDY DESIGN: Retrospective study. ANIMALS: Thirteen client-owned dogs. METHODS: The bone tumor database and medical records (1998-2002) were reviewed for dogs with primary appendicular bone tumors treated with IORT limb-sparing surgery and adjuvant chemotherapy. The segment of bone containing the tumor was isolated from adjacent soft tissue and an osteotomy performed distant to the tumor. The bone segment was exteriorized, irradiated (70 Gy single fraction), and then stabilized with internal fixation. Adjuvant chemotherapy was administered. Lameness was graded and local and distant tumor control was determined. Associations between intra- and postoperative variables with complications and Kaplan-Meier survival analysis for median disease-free interval and survival time were calculated. RESULTS: Limb function was good or excellent in 10 dogs (77%). Postoperative complications (9 dogs, 69%) included deep infection, fracture of the irradiated bone, and implant failure. Surgical failure was more likely if a single implant was used to stabilize the osteotomized bone and if deep infection developed postoperatively. In 3 dogs, tumors recurred locally within bone in the radiation field. The disease-free and overall success rates of extracorporeal IORT for limb and joint preservation were 46% and 54%, respectively. CONCLUSIONS: Extracorporeal IORT provides a novel alternative to traditional techniques for preservation of joint and limb function in dogs with primary appendicular sarcomas. A minimum of 2 implants and intramedullary bone cement should be used to stabilize the osteotomized bone to minimize postoperative complications. Extracorporeal IORT should be used with caution in dogs with tumors of the distal tibia because of a high complication rate. Dogs with tumors in areas of good soft-tissue coverage, such as the humerus and femur, may be good candidates for limb and joint-sparing surgery using extracorporeal IORT. CLINICAL RELEVANCE: Extracorporeal IORT is a surgical technique that can be used for limb and joint salvage in dogs with primary appendicular sarcomas in sites usually not amenable to traditional limb-sparing techniques.     

A longitudinal study on diarrhoea and vomiting in young dogs of four large breeds

Background

Prospective studies to document the occurrence of canine diarrhoea and vomiting are relatively scarce in dogs, and the majority of published studies are based on information from clinical records. This study investigates the incidence risk of diarrhoea and vomiting as well as potential risk factors.

Methods

A cohort study of 585 privately owned dogs of four breeds: Newfoundland, Labrador retriever, Leonberger, and Irish wolfhound. The owners maintained a continuous log regarding housing, exercise, nutrition, and health of their dogs. Episodes of diarrhoea and vomiting were recorded in a consecutive manner in a booklet. The owners completed the questionnaires and reported information at three, four, six, 12, 18, and 24/25 months of age, called observational ages.Associations with potential risk factors for diarrhoea and vomiting were investigated in separate generalized estimating equation analyses.

Results

The incidence of both diarrhoea and vomiting was influenced by breed. Both diarrhoea and vomiting were relatively common in young dogs, occurring most frequently during the first months of life. After three months of age, the odds of diarrhoea were significantly lower when compared to the observational period seven weeks to three months (OR ranging from 0.31 to 0.70 depending on the period). More males than females suffered from diarrhoea (OR = 1.42). The occurrence of diarrhoea was more common in dogs that also experienced episode(s) of vomiting during the study period (OR = 5.43) and vice versa (OR = 5.50). In the majority of dogs episodes of diarrhoea and vomiting did not occur at the same time. Dogs in urban areas had higher odds (OR = 1.88) of getting diarrhoea compared to dogs living in rural areas. The occurrence of both diarrhoea and vomiting demonstrated a seasonal variation with higher incidence during the summer months.

Conclusion

Both diarrhoea and vomiting occurred most frequently during the first months of life. The incidence of diarrhoea and vomiting was significantly different between breeds. Diarrhoea occurred more frequently in males and in dogs living in urban areas. Also, a positive association between the occurrence of diarrhoea and vomiting in the same dog was found.     

Intercalary bone grafts for joint and limb preservation in 17 dogs with high-grade malignant tumors of the diaphysis

OBJECTIVE: To evaluate postoperative complications, limb function, and tumor control after intercalary resection and reconstruction for preservation of limb and joint function in dogs with high-grade malignant tumors of diaphyseal bone. STUDY DESIGN: Retrospective study. ANIMALS: Seventeen client-owned dogs. METHODS: The bone tumor database and medical records were reviewed (1986-2002) for dogs with diaphyseal tumors treated with intercalary resection and reconstruction with either an allograft or irradiated autograft. Clinical presentation, diagnostic findings, surgical management, and outcome were determined from medical records and telephone interviews with veterinarians and owners. Statistical analyses included chi2 to test associations between intra- and postoperative variables with complications, and Kaplan-Meier survival analysis for disease-free interval, metastasis-free interval (MFI), and median survival time. RESULTS: Intercalary limb-sparing surgery was performed in 17 dogs with diaphyseal tumors: osteosarcoma (OSA) (15), histiocytic sarcoma (1), and solitary metastasis from a pulmonary adenocarcinoma (1). One dog was excluded from further analysis when the spared limb was amputated 4 days postoperatively because of incomplete tumor resection. In 16 dogs, limb function was good to excellent. Complications occurred in 5 dogs (31.3%) and included superficial infection in 2 dogs (12.5%) and implant failure in 4 dogs (25%). All implant failures occurred in the ulna and there was a significant association between implant failure and non-cemented allografts (P=.042). Non-union of 1 or both osteotomies was diagnosed in 10 dogs (83.3%) and, despite lack of clinical signs in all cases, was significantly associated with the use of intracavitary locally released cisplatin (P=.046) and cemented intercalary grafts (P=.046). Local tumor recurrence was diagnosed in 1 dog (6.3%) and metastatic disease in 12 dogs (75.0%), including 10 dogs with OSA. The median MFI was 137 days. The local disease-free and overall limb-salvage rate was 94% and 100%, respectively. Overall median survival time was 393 days and the median survival time for dogs with OSA was 449 days. CONCLUSION: Intercalary limb-sparing surgery results in better postoperative limb function with fewer and less severe complications than historical reports of dogs treated with non-intercalary limb-sparing surgery. CLINICAL RELEVANCE: In dogs with diaphyseal tumors, intercalary limb-sparing surgery preserves normal joint function and results in good to excellent limb use with few complications and good local tumor control.     

Mid-to-caudal partial hemipelvectomy with limb preservation for ischial tumor in a dog

A 10-year-old spayed female Golden Retriever was referred for hindlimb lameness. A firm mass was palpated over the right caudal pelvis. Computed tomography revealed an osteolytic bone region and an associated periosteal reaction in the ischium, including the acetabulum. The histological diagnosis was sarcoma of unknown origin. A mid-to-caudal partial hemipelvectomy was performed to remove the mass. Femoral head and neck osteotomy was performed to allow hindlimb preservation. Following surgery, the dog regained satisfactory hindlimb use over time and was alive for 821 days with no recurrence or metastatic disease. This report indicates that mid-to-caudal partial hemipelvectomy with femoral head and neck osteotomy is technically feasible and allows for tumor control with preservation of the hindlimb and its function.     

RESEARCH PAPER: Ultrasound‐guided nerve blocks of the pelvic limb in dogs

ObjectivesTo evaluate the efficacy of ultrasound‐guidance in nerve blockade of the sciatic and saphenous nerves in dogs and to determine if this technique could allow lower anaesthetic doses to be used with predictable onset and duration of effect.Study designProspective randomized (for dose and leg) blinded experimental crossover trial with 10 day washout period.AnimalsSix healthy female Hound dogs aged 12.3 ± 0.5 (mean ± SD) months and weighing 18.7 ± 0.8 (mean ± SD) kg.MethodsAn ultrasound‐guided, perineural injection was used with saline at 0.2 mL kg^?1 (Sal) or bupivacaine 0.5% at 0.05 (low dose; LD), 0.1 (medium dose; MD), or 0.2 (high dose; HD) mL kg^?1, divided 2/3 at the sciatic nerve and 1/3 at the saphenous nerve. Blocks were performed using dexmedetomidine sedation with atipamezole reversal immediately after completion of the injections. Motor/proprioceptive and sensory functions were scored using a 0–8 and a 0–2 scale, respectively. Clinically relevant blocks were defined as a motor score ≥2 and sensory score ≥1. Nonparametric methods were used for statistical analysis.ResultsNo adverse effects were noted. There was a significant difference between the treatments with bupivacaine and the saline control, but not between the three bupivacaine treatments. Success rates of clinically relevant sciatic and saphenous blocks were both 67% (CI 95% 0.22–0.96). Onset and duration of the blocks were variable; 20–160 and 20–540 minutes, respectively.Conclusion and clinical relevanceNone of the bupivacaine doses was significantly superior, though there was a tendency for a better block with the high bupivacaine dose. Either the technique or the doses used need further modification before this method will be useful in clinical practice.     

Radiographic and ultrasonographic diagnosis of stenosing tenosynovitis of the abductor pollicis longus muscle in dogs

Stenosing tenosynovitis of the abductor pollicis longus muscle causes chronic front limb lameness in dogs. The lesion, similar to de Quervain's tenosynovitis in people, is caused by repetitive movements of the carpus. Thirty dogs with front limb lameness, painful carpal flexion, and a firm soft tissue swelling medial to the carpus were examined prospectively. Seven dogs had bilateral abductor pollicis longus tenosynovitis. Radiographs of the carpus were characterized by a deeper radiolucent medial radial sulcus and bony proliferations medial and slightly cranial to the distal radius, resulting in stenosis of the tendon sheath and subsequent tendinitis. Ultrasonographic examination of the firm soft tissue swelling medial to the carpus was characterized by an irregular hypoechoic abductor pollicis longus tendon or tendinitis in 22 of 37 dogs. Nineteen of 37 abductor pollicis longus tendon sheaths were fluid-filled and all tendon sheaths were thickened, more hyperechoic, with small hyperechoic mineralizations embedded in the connective tissue of the abductor pollicis longus tendon sheath in 25 dogs. Enthesopathy of the abductor pollicis longus tendon was identified in seven dogs. While radiographs of stenosing tenosynovitis of the abductor pollicis longus are helpful in visualizing the deep radial sulcus and osteophytes medial to the distal radius, ultrasonography is useful to distinguish between lesions of the tendon or tendon sheath and to determine thickness and fluid content of the abductor pollicis longus tendon sheath.     

Comparison of epidural versus intrathecal anaesthesia in dogs undergoing pelvic limb orthopaedic surgery

ObjectiveTo compare the procedural failure rate (PFR), intraoperative rescue analgesia (iRA) probability and postoperative duration of motor block after epidural and intrathecal anaesthesia in dogs undergoing pelvic limb orthopaedic surgery.Study designProspective, randomized clinical trial.AnimalsNinety-two client-owned dogs.MethodsDogs were assigned randomly to receive either lumbosacral epidural anaesthesia (EA) (bupivacaine 0.5% and morphine 1%) or intrathecal anaesthesia with the same drugs in a hyperbaric solution (HIA). Inaccurate positioning of the needle, assessed by radiographic imaging, and lack of cerebral spinal fluid outflow were considered procedural failures (PFs) of EA and HIA, respectively. Fentanyl (1 μg kg⁻¹ IV) was provided for intraoperative rescue analgesia, when either the heart rate or the mean arterial pressure increased by 30% above the pre-stimulation value. Its use was recorded as a sign of intraoperative analgesic failure. The motor block resolution was evaluated postoperatively. Variables were compared using Fisher's exact test, the Mann–Whitney U test and the Kaplan–Meier ‘survival’ analysis as relevant.ResultsThe PFRs in the EA and HIA groups were 15/47 (32%) and 3/45 (7%), respectively (p = 0.003). Differences in iRA were analysed in 26 and 30 subjects in the EA and HIA groups respectively, using Kaplan–Meier survival analysis. The iRA probability within the first 80 minutes of needle injection (NI) was higher in the EA group (p = 0.045). The incidence of dogs walking within 3 hours of NI was significantly higher in the HIA group (8/20, 40%) than in the EA group (0/17) (p = 0.004).Conclusions and clinical relevanceHIA was found to have lower PF, lower intraoperative analgesic failure and faster motor block resolution. In this study HIA was shown to provide some advantages over EA in dogs undergoing commonly performed pelvic limb orthopaedic surgery in a day-hospital regime.     

八种肉用犬的繁殖性能研究

本文通过对狼犬、鞑子犬、青龙犬、大丹犬、英卡犬、沙皮犬、藏鳌、拿波伦犬等8个品种192只犬繁殖性能研究。发现这八种犬的发情季节多集中在3月份和10～11月份，发情持续时间一般为14d，交配最佳时间为11d。配种次数与窝产仔数间不存在相关。     

Efficacy and cost-effectiveness of transdermal fentanyl patches for the relief of post-operative pain in dogs after anterior cruciate ligament and pelvic limb repair

OBJECTIVES: To determine whether transdermal fentanyl patches provided cost-effective post-operative analgesia in dogs with pelvic limb injuries. STUDY DESIGN: Prospective, randomized, blinded clinical trial. ANIMALS: Twenty-four dogs undergoing repair of ruptured cranial cruciate ligaments or pelvic limb fractures. METHODS: Dogs were randomly assigned to one of two groups: those receiving transdermal fentanyl patches (group F) and those receiving injectable morphine for control of post-operative pain (group M). Patients in both treatment groups were monitored for adequacy of analgesia and alterations in physiological variables. Plasma fentanyl concentrations were measured in Group F. Rescue morphine was given if a dog was deemed uncomfortable. The time of first rescue morphine, the total amount, and number of doses of morphine administered over 72 hours was quantified and compared for each group. RESULTS: There was no significant treatment effect on any of the parameters, except for serum cortisol concentration, which was significantly lower overall in group F (p = 0.01). Pain scores peaked at 6 hours post-extubation and were higher than baseline from 2 to 20 hours post-extubation. Cortisol concentrations were the highest at time 0 (extubation) and were significantly higher than baseline until 2 hours post-extubation. Pain scores correlated with fentanyl plasma concentrations (p = 0.0001 and p = 0.01, respectively), but the correlation was low (r = 0.26 and r = 0.16, respectively). No correlation was found between serum cortisol concentrations and pain scores in either group. Fentanyl cost and total cost for pain management were considerably higher for group F. CONCLUSIONS: Fentanyl patches did not provide better analgesia or a reduced requirement for rescue opioid compared with intramuscular morphine. CLINICAL RELEVANCE: When considering overall costs to the client for comparable analgesic intervention, fentanyl patches increased rather than decreased cost during the first 24 hours post-operatively.     

Effect of left vs. right recumbency on the vertebral heart score in normal dogs

The effect of right vs. left recumbency on computation of the vertebral heart score (VHS) was assessed in 63 healthy dogs. The VHS was significantly higher in right lateral recumbency (9.8 +/- 0.6 vs. 9.5 +/- 0.8; P < 0.0004). Gender and dog size did not significantly influence VHS values while there was m oredifference between left and right side measurements when considering the type of thorax (P = 0.055).     

Sciatic nerve block in dogs: description and evaluation of a modified ultrasound-guided parasacral approach

Objective

To develop a modified ultrasound-guided parasacral approach to the sciatic nerve and compare the effects of a volume of 0.2 mL kg^–1 of 0.5% levobupivacaine with an equivalent volume of 0.9% saline injected near the sciatic nerve.

Expression of relaxin receptor LRG7, canine relaxin, and relaxin-like factor in the pelvic diaphragm musculature of dogs with and without perineal hernia

OBJECTIVES: To compare the expression of canine relaxin, relaxin-like factor (RLF), and relaxin receptors within the muscles of the pelvic diaphragm of dogs with perineal hernia (PH) and clinically normal dogs. STUDY DESIGN: In vivo comparative study. ANIMALS: Fifteen client-owned intact male dogs with PH were studied. Four mature intact male dogs with no evidence of perineal pathology served as controls. METHODS: Biopsy samples from the levator ani, coccygeus, and internal obturator muscles were obtained. RNA samples were reverse transcribed and analyzed by real-time PCR for the expression of canine relaxin receptor LRG7, relaxin, and RLF. RESULTS: Significantly higher expression levels of canine relaxin receptors occurred in the musculature of the pelvic diaphragm and internal obturator muscle in dogs with PH compared with normal dogs. Expression of canine RLF revealed no significant difference between dogs with PH and controls. The difference in the expression of canine relaxin between groups was not statistically significant. CONCLUSIONS: Relaxin receptor up-regulation occurs in the coccygeus, levator ani, and internal obturator muscles of dogs with PH. CLINICAL RELEVANCE: The higher expression of relaxin receptors within the muscles of the pelvic diaphragm in dogs with PH suggests that relaxin might play a role in the pathogenesis of PH. Atrophy of these muscles, which predisposes to PH, may be attributable to increased relaxin activity.     

Identification of mutations in HSF4 in dogs of three different breeds with hereditary cataracts

Cataracts are a leading cause of blindness in both dogs and humans. Mutations in several genes have been associated with inherited forms of human cataract, but no mutations have been identified as the cause of any form of canine inherited cataract. We have used a candidate gene approach to investigate 20 genes, known to be associated with cataract in humans, for their potential association with the development of hereditary cataract (HC) in dogs. We have identified mutations in the HSF4 gene in Staffordshire Bull Terriers, Boston Terriers and Australian Shepherds affected by HC. Interestingly, different mutations in this single gene may be causing a recessive form of cataract in Staffordshire Bull Terriers and Boston Terriers and a dominant cataract in Australian Shepherds. Identification of the mutations that cause HC in these three breeds provides a method of controlling the disease within populations at risk using a simple diagnostic test, and also establishes cataract in these breeds as models for their human counterparts.