Objective comparison of a sit to stand test to the walk test for the identification of unilateral lameness caused by cranial cruciate ligament disease in dogs.

OBJECTIVE: The purpose of this study was to evaluate a sit to stand test with the walk test for the identification of unilateral cranial cruciate ligament rupture in dogs. MATERIALS AND METHODS: Peak vertical force and vertical impulse were measured on a pressure-sensitive walkway, during a sit to stand test and walk test, and in 10 dogs with unilateral cranial cruciate ligament rupture and 18 non-lame dogs. Data collected were used to calculate symmetry indices (SI) of ipsilateral and contralateral hindlimbs (HL), diagonal limb pairs (DLP) and ipsilateral limb pairs (ILP). RESULTS: The symmetry indices of peak vertical force of HL during the walk test and sit to stand test were 100% and 90% sensitive for discriminating lame and non-lame dogs respectively. The symmetry indices of vertical impulse of HLs during the walk test and sit to stand test were 100% and 50% sensitive for discriminating lame and non-lame dogs respectively. Analysis of ipsilateral and diagonal limb pairs did not improve the discrimination in either test. The time taken to collect data from the sit to stand test data was shorter than for the walk test. CLINICAL SIGNIFICANCE: Whilst the sit to stand test required a shorter time for collection of data than the walk test, it did not accurately identify all dogs with lameness associated with CCLR, and thus has relatively limited clinical utility in its tested form.

Femoral condylar fractures in four continental giant breed rabbits.

Four male neutered continental giant rabbits aged between 10 and 30 months were presented with femoral condylar fractures, which developed without an observed traumatic injury. Stabilisation of the condylar fracture was achieved with screw fixation in all cases, which was supplemented with additional fixation in three cases. Complications consequent to the surgical intervention occurred in two cases: a femoral fracture and loss of fixation. Three rabbits were reported to have recovered normal limb function, and the rabbit that developed a femoral fracture as a consequence of its surgical intervention was treated with amputation.

Presentation, treatment and outcome of long-bone fractures in pet rabbits (Oryctolagus cuniculus).

OBJECTIVES: To describe the incidence, aetiology, characteristics, assessment, management and outcome of long-bone fractures in rabbits presenting to a single institution. MATERIALS AND METHODS: Medical records of pet rabbits diagnosed with long-bone fractures over a 12-year period were analysed. Patient signalment, fracture aetiology, fracture location, fracture description, time from fracture occurrence to veterinary presentation, fixation method, postoperative complications, clinical outcome and follow-up were recorded. RESULTS: Twenty-eight pet rabbits that sustained 30 fractures were included in the study [femoral (n=12), tibial (n=6), metacarpal/metatarsal/phalangeal (n=5), radial and ulnar (n=4) and tarsal (n=3)]. Twenty-one (75%) of the rabbits were less than 2 years of age, including seven (25%) under 6 months of age. Twenty-five fractures had no identifiable cause and five were traumatic. Only one fracture was open. Surgical stabilisation was performed in 22 fractures, four were non-surgically managed, two had the affected limb amputated, one underwent digital amputation and one was euthanased. Postoperative complications occurred in nine fractures [major (n=6), minor (n=3)]. The frequency of complications or attainment of a functional recovery was not notably different between the different methods of fixation. Overall, 24 rabbits recovered, two were euthanased and four underwent limb amputation. CLINICAL SIGNIFICANCE: Fractures in rabbits typically occur in young animals and they usually lack an obvious aetiology. The majority of the rabbits treated achieved a functional recovery, although the postoperative complication rate was high in fractures treated surgically (41%).

An in vitro study of the effect of the optimal irrigation solution conditions during canine articular surgery.

OBJECTIVES: To establish whether chondrocyte viability, matrix degradation and the induction of proteolytic gene expression in canine cartilage is independent of irrigation fluid osmolality and time following exposure to the irrigation fluid. METHODS: Canine cartilage explants were exposed to one of three different solution types i) Culture medium (270-280 mOsmol/kg) ii) NaCl 0.9% (302 mOsmol/kg) iii) NaCl 0.9% with sucrose (600 mOsmol/kg). Chondrocyte viability and selected proteolytic gene expression were measured at two time points; immediately following exposure and 24 h following exposure. The media samples at 24 h following exposure were assessed for sulphated glycosaminoglycan (sGAG) release. RESULTS: In all samples, no cell death was observed across the superficial or deeper layers of the cartilage. When adjusting for time, gene expression was not shown to be dependent on solution type. However for all solution types, Matrix Metalloproteinase 13 (MMP13) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5 (ADAMTS5) expression was significantly decreased in cartilage samples at 24 h post exposure comparatively to samples tested immediately post exposure. No significant differences were identified in the relative sGAG release between the solution types. CLINICAL SIGNIFCANCE: Arthroscopic solution irrigation of cartilage explants had no effect on cell viability or proteinase production. At present there is no indication to optimise irrigation fluid osmolarity, as conventional arthroscopic solution was not deleterious to healthy cartilage in this model.

Gait in ducks (Anas platyrhynchos) and chickens (Gallus gallus) - similarities in adaptation to high growth rate.

Genetic selection for increased growth rate and muscle mass in broiler chickens has been accompanied by mobility issues and poor gait. There are concerns that the Pekin duck, which is on a similar selection trajectory (for production traits) to the broiler chicken, may encounter gait problems in the future. In order to understand how gait has been altered by selection, the walking ability of divergent lines of high- and low-growth chickens and ducks was objectively measured using a pressure platform, which recorded various components of their gait. In both species, lines which had been selected for large breast muscle mass moved at a slower velocity and with a greater step width than their lighter conspecifics. These high-growth lines also spent more time supported by two feet in order to improve balance when compared with their lighter, low-growth conspecifics. We demonstrate that chicken and duck lines which have been subjected to intense selection for high growth rates and meat yields have adapted their gait in similar ways. A greater understanding of which components of gait have been altered in selected lines with impaired walking ability may lead to more effective breeding strategies to improve gait in poultry.

Cumulative incidence and risk factors for limber tail in the Dogslife labrador retriever cohort.

Limber tail is a condition that typically affects larger working breeds causing tail limpness and pain, resolving without veterinary intervention. It is poorly understood and the disease burden has not been well characterised. Data collected from owners of the Dogslife cohort of Labrador Retrievers have been used to describe incidents and a case-control study was undertaken to elucidate risk factors with 38 cases and 86 controls. The cumulative incidence of unexplained tail limpness was 9.7 per cent. Swimming is not a necessary precursor for limber tail, but it is a risk factor (OR=4.7) and working dogs were more susceptible than non-working dogs (OR=5.1). Higher latitudes were shown to be a risk factor for developing the condition and the case dogs were more related to each other than might be expected by chance. This suggests that dogs may have an underlying genetic predisposition to developing the condition. This study is the first, large-scale investigation of limber tail and the findings reveal an unexpectedly high illness burden. Anecdotally, accepted risk factors have been confirmed and the extent of their impact has been quantified. Identifying latitude and a potential underlying genetic predisposition suggests avenues for future work on this painful and distressing condition.

Dogslife: A cohort study of Labrador Retrievers in the UK.

Studies of animals that visit primary and secondary veterinary centres dominate companion animal epidemiology. Dogslife is a research initiative that collects data directly from owners about the health and lifestyle of Kennel Club (KC) registered Labrador Retrievers (LR) in the UK. The ultimate aim is to seek associations between canine lifestyle and health. A selection of data from Dogslife regarding the height, weight and lifestyle of 4307 LR up to four years of age is reported here. The majority of the dogs were household pets, living with at least one other pet, in families or households with more than one adult. The dogs typically ate diets of dried food and daily meal frequency decreased as the dogs aged. Working dogs spent more time exercising than pets, and dogs in Wales and Scotland were exercised more than their counterparts in England. Dogs in households with children spent less time exercising than dogs in other types of households. There was considerable variation in height and weight measurements indicative of a highly heterogeneous population. The average male height at the shoulders was 2-3cm taller than the UK breed standard. Dog weights continued to increase between one and four years of age. Those with chocolate coloured coats were heavier than their yellow and black counterparts. Greater dog weight was also associated with dogs whose owners reported restricting their dog's exercise due to where they lived. These findings highlight the utility of wide public engagement in the collation of phenotypic measures, providing a unique insight into the physical development and lifestyle of a cohort of LRs. In combination with concurrently collected data on the health of the cohort, phenotypic data from the Dogslife Project will contribute to understanding the relationship between dog lifestyle and health.

Bilateral calcaneal stress fractures in two cats.

Two cats that developed bilateral calcaneal stress fractures are reported. One cat developed lameness associated with incomplete fractures at the base of both calcanei, both of which progressed to acute, complete fractures 2 months later. The second cat presented with acute complete calcaneal fracture, with evidence of remodelling of the contralateral calcaneus, which subsequently fractured two years later. The calcaneal fractures were successfully stabilised with lateral bone plates in each case. Stress fractures were suspected because of the bilateral nature, the simple and similar configuration, the consistent location of the fractures, the absence of other signs of trauma in both cases and the suspected insidious onset of the lameness. The feline calcaneus is susceptible to stress fracture, and cats presenting with calcaneal fractures without evidence of trauma should be evaluated for concurrent skeletal pathology.

Unilateral synostosis of the zygo-maticotemporal suture associated with mandibular coronoid process impingement in a dog.

A 13-month-old dog was investigated for the complaint of open-mouth locked jaw. There were not any previous episodes of trauma witnessed. Computed tomographic evaluation revealed unilateral zygomatico-temporal synostosis and associated craniofacial asymmetry, with impingement of the mandibular coronoid process resulting in unilateral temporomandibular joint subluxation. Closed reduction of the subluxation was not maintained. Partial zygomatico-temporal suturectomy resulted in resolution of the clinical signs. To the author's knowledge, isolated zygomaticotemporal syno-stosis with associated temporomandibular subluxation has not been reported in the dog.

Clinical assessments of increased sensory sensitivity in dogs with cranial cruciate ligament rupture.

Dogs with chronic pain have a compromised quality of life. Repeatable and accurate sensory assessments form a means by which the hypersensitivity likely to reflect chronic pain may be quantified. These assessments can be applied to individuals to identify those that may benefit from improved analgesic relief. In this study four sensory assessments were evaluated in dogs presenting with a naturally occurring chronic painful condition (cranial cruciate ligament rupture, CCLR) and were compared with healthy control animals of similar age and weight. Inter-digital von Frey filament and thermal sensitivity tests revealed that the affected hind limb of dogs with CCLR was significantly more sensitive than the opposing limb. Static weight bearing and gait parameter scores were also reduced in the affected hind limb compared to the opposing hind limb of dogs with CCLR; no such differences were found between the hind limbs of healthy (control) dogs. The quantitative sensory tests permitted the differentiation of limbs affected by CCLR from healthy limbs. Dogs presenting with CCLR demonstrate objectively quantitative sensory sensitivities, which may require additional consideration in case management.

Canine tissue-specific expression of multiple small leucine rich proteoglycans.

Small leucine rich proteoglycans (SLRPs) are important constituents of extracellular matrix (ECM) and contribute to the production, organization and remodelling of collagen and elastin through complex biological systems. The relative expression and distribution of SLRPs in a variety of different mammalian tissues is poorly characterized. The aim of this study was to map the expression of seven SLRPs (biglycan, versican, prolargin, fibromodulin, osteoglycin, decorin and lumican) in seven tissues (bone, cartilage, cruciate ligament, skin, ventricular myocardium, mitral valve and cornea) in young adult dogs using a combination of quantitative real-time PCR, immunohistochemistry and protein immunoblotting. Clear and consistent patterns of SLRP expression and distribution were identified for the seven tissues examined, with the greatest SLRP expression in cartilage, skin, cornea and mitral valve, and the least expression in myocardium. In general, lumican and prolargin had the greatest expression across the seven tissues whilst osteoglycin was the least abundantly expressed SLRP. These data provide a SLRP profile for different canine tissues which can inform future studies of SLRP expression in development and disease.

Linear-circular external skeletal fixation of intra-condylar humeral fractures with supracondylar comminution in four cats.

OBJECTIVES: Intra-condylar humeral fracture with supracondylar comminution in cats is rare, and the stabilisation for such fractures is challenging. The purpose of our study was to describe the use of a hybrid external skeletal fixator, and to report the complications and outcomes of this surgical technique. METHODS: A retrospective review was performed of clinical, radiographic and surgical records of all cats with intra-condylar humeral fractures and non-reconstructable supracondylar comminution stabilized by linear- circular external skeletal fixator in two institutions between January 2005 and March 2010. RESULTS: Four cats met the inclusion criteria of the study. All cases achieved fracture union and clinical outcome was considered excellent at the time of the final assessment (11 - 24 weeks). CLINICAL SIGNIFICANCE: This study demonstrates that a linear-circular fixator system can be used successfully in the management of intra-con dylar humeral fractures with non-reconstructable supracondylar comminution in cats.

Breed and sex risk factors for canine babesiosis in South Africa.

BACKGROUND: In South Africa, canine babesiosis typically is an acute disease in susceptible individuals and is a major cause of morbidity and mortality. Despite the importance of the disease, there have been no large studies that have examined the influence of breed and sex on disease susceptibility. HYPOTHESIS: Toy breeds have a lower risk of babesiosis than working dogs. ANIMALS: A total of 1,222 dogs diagnosed with canine babesiosis and 11,484 noninfected dogs presented to the Onderstepoort Veterinary Academic Hospital's small animal outpatient clinic between 2004 and 2010. METHODS: Retrospective study. RESULTS: Intact male, neutered male, and neutered female dogs had a significantly higher odds of being diagnosed with canine babesiosis compared to intact female dogs. Five of the 6 Toy breeds had significantly lower odds of being diagnosed with canine babesiosis than did the reference breed, Labrador Retrievers. In contrast, none of the 8 working dog breeds had significantly lower odds compared to the reference breed. CONCLUSIONS AND CLINICAL IMPORTANCE: Intact male, neutered male, and neutered female dogs were at increased risk of canine babesiosis compared to intact female dogs. Several dog breeds, notably Toy breeds, had a lower risk of babesiosis in a hospital population of dogs in South Africa. The mechanism or mechanisms by which Toy breeds are protected from developing canine babesiosis may be related to genetic background or environmental exposure and deserves further study.

Risk of canine cranial cruciate ligament rupture is not associated with the major histocompatibility complex.

OBJECTIVES: To investigate the association of the major histocompatability (MHC) class II allele haplotype frequencies with the diagnosis of cranial cruciate ligament (CCL) rupture in two breeds of dog. METHODS: DNA samples from populations of Labrador Retrievers and Golden Retrievers with CCL rupture and general populations of the same breeds were characterised for three DLA class II loci (DRB1*, DQA1* and DQB1*) alleles using sequence-based typing or reference strand-mediated conformation analysis. RESULTS: Although distinct differences in haplotype types, frequencies and homozygozity were observed between the two breeds, no disease specific association could be identified for the development of the CCL rupture within either population. CLINICAL SIGNIFICANCE: The risk for developing CCL rupture was not associated with DLA haplotype group(s) in Labrador Retrievers or Golden Retrievers, thus the hypothesis that there is an autoimmune basis to CCL rupture was not supported.

Assessment of the functionality of genome-wide canine SNP arrays and implications for canine disease association studies.

Domestic dogs share a wide range of important disease conditions with humans, including cancers, diabetes and epilepsy. Many of these conditions have similar or identical underlying pathologies to their human counterparts and thus dogs represent physiologically relevant natural models of human disorders. Comparative genomic approaches whereby disease genes can be identified in dog diseases and then mapped onto the human genome are now recognized as a valid method and are increasing in popularity. The majority of dog breeds have been created over the past few hundred years and, as a consequence, the dog genome is characterized by extensive linkage disequilibrium (LD), extending usually from hundreds of kilobases to several megabases within a breed, rather than tens of kilobases observed in the human genome. Genome-wide canine SNP arrays have been developed, and increasing success of using these arrays to map disease loci in dogs is emerging. No equivalent of the human HapMap currently exists for different canine breeds, and the LD structure for such breeds is far less understood than for humans. This study is a dedicated large-scale assessment of the functionalities (LD and SNP tagging performance) of canine genome-wide SNP arrays in multiple domestic dog breeds. We have used genotype data from 18 breeds as well as wolves and coyotes genotyped by the Illumina 22K canine SNP array and Affymetrix 50K canine SNP array. As expected, high tagging performance was observed with most of the breeds using both Illumina and Affymetrix arrays when multi-marker tagging was applied. In contrast, however, large differences in population structure, LD coverage and pairwise tagging performance were found between breeds, suggesting that study designs should be carefully assessed for individual breeds before undertaking genome-wide association studies (GWAS).

Management of laterally displaced proximal tibial physeal fractures in three dogs.

Fractures of the proximal tibial physis are uncommon in dogs, and are rarely associated with marked instability and lateral displacement of the proximal tibial epiphysis. Three dogs with proximal tibial physeal fractures demonstrating marked instability and lateral displacement were treated with two different principles of fixation. Healing of the physeal fracture was achieved with rigid internal fixation in one case, and with adaptational osteosynthesis supplemented with a temporary transarticular external skeletal fixator in two cases. Duration of surgery and technical difficulty was reduced using a modified adaptational osteosynthesis approach, suggesting that surgical treatment of these uncommon and challenging fractures may be more appropriately achieved by this technique.

Complications following tarsal arthrodesis using bone plate fixation in dogs.

OBJECTIVES: To report the complications encountered following tarsal arthrodesis surgery with bone plate fixation and describe the previously unreported complication of plantar necrosis. METHODS: Medical records of 40 dogs that had been treated by tarsal arthrodesis with bone plate fixation were reviewed to determine the major and minor complications and the associated risk factors. RESULTS: The major complication rate was 32.5 per cent and the minor complication rate was 42.5 per cent. Pantarsal arthrodeses had a higher major complication rate than partial tarsal arthrodeses. Plantar necrosis was the most common major complication and occurred in 15 per cent of cases. Plantar necrosis occurred more frequently when a bone plate was applied to the medial aspect of the hock, and only occurred in cases where tarsometatarsal joint arthrodesis was performed. CLINICAL SIGNIFICANCE: Plantar necrosis is a catastrophic complication that may be associated with injury to the dorsal pedal artery or perforating metatarsal artery. Application of a bone plate to the medial aspect of the hock should be performed with care during tarsal arthrodesis, particularly where the tarsometatarsal joint is debrided of cartilage. Strict attention to surgical technique and proper postoperative coaptation is critical to reduce the potential for complications with tarsal arthrodesis.

Gene expression profiling of normal and ruptured canine anterior cruciate ligaments.

OBJECTIVE: To identify genes which may be involved in the development of anterior cruciate ligament (ACL) laxity and rupture in a naturally occurring canine osteoarthritis (OA) model. DESIGN: Three groups of dog were studied: (1) dogs with ACL rupture; (2) dogs with intact ACLs from a breed predisposed to ACL rupture; (3) dogs with intact ACLs from a breed at very low risk of rupture. The transcriptomes of the ACLs from each group were compared using a whole genome microarray and quantitative reverse transcriptase polymerase chain reaction. Differential gene expression in ruptured canine ACLs was compared with that published in the literature for ruptured human ACLs. RESULTS: No significant differences were identified between the gene expression profiles of normal ACLs of a breed predisposed to ACL rupture when compared to a breed relatively resistant to ACL rupture. A general pattern of increased protease and extracellular structural matrix gene expression was identified in the ruptured ACLs when compared to intact ACLs. The gene expression profiles of ruptured canine ACLs demonstrate similar patterns to those previously reported for ruptured human ACLs. CONCLUSIONS: A transcriptomic basis to breed specific risk for the development of canine ACL rupture was not identified. Although changes in matrix associated gene expression in the ruptured ACL are similar between humans and dogs, the molecular events which may predispose to ACL laxity and rupture were not defined.

Stabilisation of medial shoulder instability by imbrication of the subscapularis muscle tendon of insertion.

OBJECTIVES: To evaluate the efficacy of subscapularis muscle tendon of insertion imbrication as a treatment for medial shoulder instability. METHODS: Medial shoulder instability was diagnosed in five dogs. Initial management with medical or arthroscopic treatment failed to fully resolve lameness in four of the cases. Each case was treated by subscapularis muscle tendon of insertion imbrication. An anatomical model of medial shoulder instability was used to assess the effect of subscapularis muscle tendon of insertion imbrication on the angle of abduction of the shoulder. RESULTS: In clinical study, subscapularis muscle tendon of insertion imbrication was performed in five cases. Lameness resolved fully in three cases and partially in two cases. In cadaver study, transection of either the subscapularis muscle tendon of insertion or the subscapularis muscle tendon of insertion and medial glenohumeral ligament significantly increased the angle of abduction. Imbrication of the subscapularis muscle tendon of insertion significantly reduced the angle of abduction. No significant differences were noted between the angle of abduction of normal shoulder and the shoulder with medial shoulder instability treated by subscapularis muscle tendon of insertion imbrication. CLINICAL SIGNIFICANCE: Subscapularis muscle tendon of insertion imbrication is a moderately effective procedure for the management of medial shoulder instability unresponsive to medical and/or arthroscopic management. The angle of abduction of the shoulder was returned to normal in model of medial shoulder instability, following subscapularis muscle tendon of insertion. Subscapularis muscle tendon of insertion imbrication provides a relatively simple method of treating medial shoulder instability in dogs.