Weight loss outcomes are generally worse for dogs and cats with class II obesity, defined as > 40% overweight.

In pet dogs and cats, adiposity is most-often estimated clinically using a 9-category body condition score (BCS), with BCS 9 equating to ~ 40% overweight. Animals that are more overweight (> 40%) are seen in clinical practice but are not appropriately depicted by descriptions in the existing categories. To determine whether being > 40% overweight has clinical relevance, this study aimed to compare the outcomes of weight management in animals that were > 40% overweight with those < 40% overweight. Records of dogs and cats attending a specialist obesity care clinic, where adiposity is determined using dual-energy X-ray absorptiometry (DXA), were reviewed. Animals were assigned to two classes (class I ≤ 40% overweight: 118/398 [40%] dogs and 68/116 [59%] cats; class II, > 40% overweight: 180/398 [60%] dogs and 48/116 [41%] cats) based on DXA results, and weight loss outcomes were compared. Fewer class II dogs obesity completed weight management than class I dogs (P < 0.001), rate of weight loss was also slower (P = 0.012) and lean tissue loss greater (P < 0.001). Compared with class I, cats with class II obesity lost more weight (P = 0.048) albeit over a longer period (P = 0.043) leading to greater lean tissue loss (P = 0.004). Approximately half the pets presenting to a specialist clinic were have class II obesity (> 40% overweight), and some weight loss outcomes are worse for these animals.

"Just old age" - a qualitative investigation of owner and veterinary professional experiences of and attitudes to ageing in dogs in the UK.

OBJECTIVES: Many UK dogs live into old age, but owners may not recognise or report age-associated signs of disease which lead to negative welfare. This study investigated dog owner and veterinary professional experiences and attitudes towards ageing in dogs, how health care is offered, barriers to its delivery, and some best-practice solutions. MATERIALS AND METHODS: In-depth semi-structured interviews were conducted with 15 owners of 21 dogs (aged 8 to 17 years mean: 13) and 11 veterinary professional (eight veterinary surgeons, two nurses and one physiotherapist). Open-text responses from 61 dog owners were collected using an online survey. Transcripts and survey responses were inductively coded into themes. RESULTS: Four themes were constructed: "just old age", barriers to care, trust in veterinary surgeons, and tools to improve health care. Age-related changes were mostly perceived as "just old age" by dog owners. Many dogs were no longer vaccinated and did not attend check-ups unless owners identified a problem. The greatest barriers to health care were finances (dog owners), owner awareness, willingness to act and consultation time (veterinary professionals). Trust in veterinary professionals was more likely when dog owner experienced continuity, prioritisation of care, clear communication and an accessible, knowledgeable and empathic veterinary professional. Participants suggested that senior health care and communication between dog owners and veterinary professionals could be improved through questionnaires, and evidence-based online information. CLINICAL SIGNIFICANCE: Opportunities to educate owners on which clinical signs represent healthy or pathological ageing are being missed. Resources should be developed to guide on best-practice discussions in consultations, encourage more owners to recognise clinical signs and to seek and trust veterinary advice.

The effect of obesity and subsequent weight reduction on cardiac structure and function in dogs.

BACKGROUND: In people, the cardiovascular effects of obesity include systemic hypertension, cardiac remodelling and both systolic and diastolic dysfunction, whilst weight reduction can reverse myocardial remodelling and reduce risk of subsequent cardiovascular disease. To date, variable results are reported in studies of the effect of obesity and controlled weight reduction on cardiovascular morphology and function in dogs. This prospective study aimed to assess cardiac function, heart rate variability, cardiac biomarkers and body composition before and after weight reduction in pet dogs with obesity. Twenty-four client-owned dogs referred for weight management due to obesity were recruited. To assess the cardiac effects of obesity, body composition analysis (by dual energy X-ray absorptiometry, DEXA) and cardiovascular assessment (echocardiography, Doppler blood pressure, electrocardiography, cardiac biomarkers) were performed prior to weight management. Twelve dogs completed the study and reached target weight, receiving a further cardiovascular assessment and DEXA. A Wilcoxon-signed rank test was used to compare each variable pre- and post- weight reduction. RESULTS: Median (interquartile range) duration of weight loss was 224 days (124-245 days), percentage weight loss was 23% (18-31%) of starting weight. Median change in body fat mass was -50% (-44% to -55%; P = 0.004), whilst median change in lean mass was -7% (+ 1% to -18%, P = 0.083). Before weight reduction, diastolic dysfunction (evidence of impaired relaxation in all dogs), increased left ventricular wall thickness and mildly elevated systolic blood pressure (14/24 ≥ 160 mmHg, median 165 mmHg (140-183)) were common features in dogs with obesity. However, systolic left ventricular wall dimensions were the only variables that changed after weight reduction, with a decrease in both the systolic interventricular septum (P = 0.029) and systolic left ventricular free wall (P = 0.017). There was no evidence of decreased heart rate variability in dogs with obesity (P = 0.367), and no change in cardiac biomarker concentrations with weight reduction (N-terminal proBNP, P = 0.262; cardiac troponin I P = 0.657). CONCLUSIONS: Canine obesity results in diastolic dysfunction and left ventricular hypertrophy, the latter of which improves with significant weight and fat mass reduction. Further studies are required to clarify the clinical consequences of these findings.

Maintenance energy requirements in cats following controlled weight loss: An observational study.

There is a paucity of information regarding the phenomenon of weight regain after successful weight reduction in cats. This study aimed to estimate post-weight reduction maintenance energy requirements (MER) required to maintain stable weight in a group of pet cats. Nineteen cats that had successfully completed a controlled weight reduction programme were enrolled. For inclusion, at least 2 months of follow-up had to be available for review, and the maximum change in weight during maintenance was ±2%. Post-weight-reduction MER was estimated by determining dietary energy consumption from owner diary records. The Friedman test was used to compare bodyweight and energy intake at different stages of weight management. Simple and multiple linear regression were used to identify factors associated with post-weight-reduction MER. The median (interquartile range) duration of weight maintenance was 179 days (119-408 days) and, during this time, MER was 273 ± 56.7 kJ per kg0.67 ideal bodyweight (IBW) per day. Post-weight-reduction MER was greater than metabolisable energy intake at the end (233 ± 29.5 kJ IBW per kg0.67 per day; P < 0.001) but not the start (255 ± 38.6 kJ per kg0.67 IBW per day; P = 0.148) of the weight reduction period. Using simple and multiple linear regression, the only variable that was associated with post-weight reduction MER was the mean ME intake during weight reduction (r2 = 0.349, P = 0.008). Post-weight-reduction MER at the lower limits of MER recommendations for pet cats might predispose to weight regain during the weight maintenance phase.

An open-label randomised clinical trial to compare the efficacy of dietary caloric restriction and physical activity for weight loss in overweight pet dogs.

Canine obesity is usually managed with a combination of dietary caloric restriction and increasing physical activity, but no previous study has compared both of these strategies in a prospective randomised controlled trial. Thirteen overweight dogs (body condition score 6-9/9) were randomised to one of two interventions: dietary caloric restriction or physical activity. The dietary caloric restriction intervention comprised feeding a therapeutic weight loss diet, while the physical activity intervention comprised increasing the dog's current physical activity pattern by at least a third. The primary outcome measure was change in body weight, while secondary outcome measures included change in neck, thorax and abdominal circumference and change in physical activity measured by triaxial accelerometer. Bodyweight decreased significantly with the dietary caloric restriction (median -10% of starting body weight [SBW], 5 to -12%; P=0.028) but not with the physical activity intervention (-2% SBW, +3% to -6%; P=0.107). Abdominal circumference (dietary caloric restriction: median -12.0%; physical activity: median -7.8%, P=0.016) and thoracic circumference (dietary caloric restriction: median -7.5%, P=0.031; physical activity: median -3.6%, P=0.031) changed significantly in both groups. There was no change in activity levels within the dietary caloric restriction group, but vigorous activity increased significantly in the physical activity group (P=0.016). Dietary caloric restriction was more effective than physical activity for controlled weight loss in overweight pet dogs. Although advising owners to increase their dog's activity by a third led to a modest increase in measured vigorous physical activity, this was insufficient to promote weight loss on its own.

The Financial Costs, Behaviour and Psychology of Obesity: A One Health Analysis.

People who are overweight or have obesity are estimated to comprise 30% of the global population and up to 59% of companion dogs and cats are estimated to be above their optimal body weight. The prevalence of human and companion obesity is increasing. The direct and indirect costs of obesity and associated comorbidities are significant for human and veterinary healthcare. There are numerous similarities between obesity in people and companion animals, likely related to the shared environmental and lifestyle elements of this multifactorial disease. While the study of human obesity is relatively robust, research conducted in pets is generally limited to small studies, studies with cross-sectional designs or reports that have yet to be replicated. Greater understanding of human obesity may elucidate some of the factors driving the more recent rise in pet obesity. In particular, there are overlapping features of obesity in children and pets that are, in part, related to dependency on their 'parents' for care and feeding. When feeding is used in a coercive and controlling fashion, it may lead to undesirable feeding behaviour and increase the risk for obesity. A 'responsive parenting' intervention teaches parents to respond appropriately to hunger-satiety cues and to recognize and respond to others' distress. Such interventions may impact on childhood overweight and obesity and have the potential to be adapted for use with companion animals. Social behaviour towards people with obesity or owners of pets with obesity is often driven by beliefs about the cause of the obesity. Educating healthcare professionals and the public about the multifactorial nature of this complex disease process is a fundamental step in reducing the bias and stigma associated with obesity. Children living in low-income households have particularly high rates of obesity and as household income falls, rates of obesity also rise in pets and their owners. There are risk regulators (i.e. dynamic components of interconnected systems that influence obesity-related behaviours) and internal factors (i.e. biological determinants of obesity) that may influence the development of both childhood and pet obesity, and poverty may intersect with these variables to exacerbate obesity in low-income environments. This review discusses the costs, behaviours and psychology related to obesity in people and pets, and also proposes potential techniques that can be considered for prevention and treatment of this disease in pets. A 'One Health' approach to obesity suggests that an understanding of human obesity may elucidate some of the factors driving the more recent rise in pet obesity.

Gastric carcinoma in canines and humans, a review.

Gastric carcinoma (GC) is the most common neoplasm in the stomach of dogs. Although incidence in the general population is reported to be low, breed-specific GC has a high incidence. Median age at presentation ranges from 8 to approximately 10 years. The disease is mostly located in the lesser curvature and antropyloric region of the stomach. Unfortunately, diagnosis is usually made when the disease is at an advanced stage and, therefore, prognosis is poor. Due to similarities in clinical presentation, diagnosis, histology and prognosis, canine GC may serve as a valuable model for human GC. Extensive pedigrees of canine gastric carcinoma cases could reveal insights for human gastric carcinoma. Putative species differences include the role of Helicobacter in pathogenesis, the wide array of genetic data and screening available for humans, and treatment protocols that are available for human GC.

The association between dog ownership or dog walking and fitness or weight status in childhood.

BACKGROUND: Health benefits of dog walking are established in adults: dog owners are on average more physically active, and those walking their dogs regularly have lower weight status than those who do not. However, there has been little research on children. OBJECTIVES: This study aimed to examine the association between dog ownership or dog walking and childhood fitness or weight status. METHODS: A survey of pet ownership and involvement in dog walking was combined with fitness and weight status measurements of 1021 9 to 10-year-old children in the Liverpool SportsLinx study. RESULTS: We found little evidence to support that children who live with, or walk with, dogs are any fitter or less likely to be obese than those who do not. CONCLUSIONS: This is an important finding, as it suggests that the activity that children currently do with dogs is not sufficient enough to impact weight status or fitness.

Pyloric localisation in 57 dogs of breeds susceptible to gastric dilatation-volvulus in the UK using computed tomography.

OBJECTIVE: Describe the location of the pylorus using CT in dog breeds susceptible to gastric dilatation-volvulus in the UK. METHODS: Descriptive anatomical study. Abdominal CT scans of 57 client-owned dogs were reviewed to assess pyloric position relative to the 9th, 10th, 11th and 13th ribs and 2 and 3 cm caudal to the 13th rib at the 8, 9 and 10 o'clock positions. The angle of the pylorus from the centre of the abdominal cavity relative to the sagittal plane was also determined. RESULTS: In 88 per cent of cases, the pylorus was located in the right cranioventral abdomen with 63 per cent positioned at the 9-10 o'clock position. The overall distance between the pylorus and right abdominal wall (RAW) at the 13th rib 10 o'clock position was equivalent to 29 per cent of ventral abdominal length, significantly greater than the median overall distance of ∼14 per cent of ventral abdominal length between the pylorus and RAW at the 9th or 10th rib 10 o'clock position (P<0.0001). CLINICAL SIGNIFICANCE: Common gastropexy locations may result in considerable displacement of the pylorus relative to its natural anatomic location. Further case-control studies are required to assess the clinical significance of this finding.

Clinical leishmaniasis in dogs living in the UK.

OBJECTIVES: To investigate the prevalence of leishmaniasis in dogs in the UK and to describe clinical presentation, clinicopathological abnormalities, therapeutic protocols and outcome in this non-endemic country. MATERIALS AND METHODS: Medical records of dogs diagnosed with leishmaniasis at seven referral centres in the UK were retrospectively reviewed. RESULTS: The prevalence was between 0·007 and 0·04% with a higher number of cases in southern England. All dogs had a history of travel to or from an endemic country. Lethargy, dermatological disease, decreased appetite and lameness were the most common reasons for presentation. Allopurinol was used alone for treatment in the majority of cases. CLINICAL SIGNIFICANCE: Although rare, leishmaniasis should be considered in dogs in the UK if they have compatible clinical signs and history of travel to or from endemic areas.

Cohort Study of the Success of Controlled Weight Loss Programs for Obese Dogs.

BACKGROUND: Most weight loss studies in obese dogs assess rate and percentage of weight loss in the first 2-3 months, rather than the likelihood of successfully reaching target weight. OBJECTIVE: To determine outcome of controlled weight loss programs for obese dogs, and to determine the factors associated with successful completion. ANIMALS: 143 obese dogs undergoing a controlled weight loss program. METHODS: This was a cohort study of obese dogs attending a referral weight management clinic. Dogs were studied during their period of weight loss, and cases classified according to outcome as "completed" (reached target weight), "euthanized" (was euthanized before reaching target weight), or "stopped prematurely" (program stopped early for other reasons). Factors associated with successful completion were assessed using simple and multiple logistic regression. RESULTS: 87/143 dogs (61%) completed their weight loss program, 11 [8%] died or were euthanized, and the remaining 45 [32%] stopped prematurely. Reasons for dogs stopping prematurely included inability to contact owner, refusal to comply with weight management advice, or development of another illness. Successful weight loss was positively associated with a faster rate (P < .001), a longer duration (P < .001), and feeding a dried weight management diet (P = .010), but negatively associated with starting body fat (P < .001), and use of dirlotapide (P = .0046). CONCLUSIONS AND CLINICAL RELEVANCE: Just over half of all obese dogs on a controlled weight loss program reach their target weight. Future studies should better clarify reasons for success in individual cases, and also the role of factors such as activity and behavioral modification.

Best in show but not best shape: a photographic assessment of show dog body condition.

Previous studies suggest that owners often wrongly perceive overweight dogs to be in normal condition. The body shape of dogs attending shows might influence owners' perceptions, with online images of overweight show winners having a negative effect. This was an observational in silico study of canine body condition. 14 obese-prone breeds and 14 matched non-obese-probe breeds were first selected, and one operator then used an online search engine to identify 40 images, per breed, of dogs that had appeared at a major national UK show (Crufts). After images were anonymised and coded, a second observer subjectively assessed body condition, in a single sitting, using a previously validated method. Of 1120 photographs initially identified, 960 were suitable for assessing body condition, with all unsuitable images being from longhaired breeds. None of the dogs (0 per cent) were underweight, 708 (74 per cent) were in ideal condition and 252 (26 per cent) were overweight. Pugs, basset hounds and Labrador retrievers were most likely to be overweight, while standard poodles, Rhodesian ridgebacks, Hungarian vizslas and Dobermanns were least likely to be overweight. Given the proportion of show dogs from some breeds that are overweight, breed standards should be redefined to be consistent with a dog in optimal body condition.

Feeding obese dogs during weight loss is on average cost-neutral.

OBJECTIVES: The cost of feeding a purpose-formulated weight loss diet may deter owners of obese dogs from proceeding with a weight loss programme. The current study aimed to compare average food costs during weight loss with those before weight loss. MATERIALS AND METHODS: Average daily food costs, for before and during weight loss, were calculated in 22 obese dogs that had successfully completed weight management. RESULTS: The median food cost before weight loss was £0 · 52/day (£0 · 24-3 · 31/day), for main meal only, and £0 · 64/day (£0 · 26-3 · 31/day) for main meal and additional food (table scraps and treats). The median food cost during weight loss was £0 · 90/day (£0 · 26-1 · 36/day), and no additional food was given. The average daily feeding costs during weight loss did not differ from pre-weight-loss costs, either with (P = 0 · 425) or without (P = 0 · 222) the additional food included. CLINICAL SIGNIFICANCE: Knowledge that average diet costs do not significantly differ from food costs prior to weight loss may help veterinarians to persuade owners to enrol obese dogs in a weight management programme.

Hypothalamic-anterior pituitary hormone deficiencies following traumatic brain injury in dogs.

Traumatic brain injury is an important cause of hypopituitarism in human beings, but limited information exists in the veterinary literature regarding this condition. The primary study objective was to investigate whether hypothalamic-anterior pituitary axis dysfunction exists following traumatic brain injury in 17 client owned dogs. In this retrospective, observational, open, cohort study, information about dogs presented to four separate referral centres between April 2008 and October 2013 was reviewed. Cases were included if they had suffered from non-fatal traumatic brain injury, resulting in neurological dysfunction, and follow-up evaluation included measurement of the serum concentration of insulin-like growth factor 1 (IGF-1), endogenous adrenocorticotrophic hormone (ACTH), basal cortisol, thyroid-stimulating hormone, total thyroxine (TT4) and, if appropriate, free thyroxine. Decreased IGF-1 concentration was the most common abnormality detected (7/17, 41 per cent; median 132 ng/ml, range <15-536), followed by a decreased TT4 concentration (4/17, 23 per cent; median 19, range 4-49). Basal cortisol concentration was less than 20 nmol/l in two cases (2/17, 12 per cent; median 65, range <20-1735), with concurrently undetectable ACTH (<5 pg/ml). This study demonstrates that dogs with a history of traumatic brain injury can develop endocrine abnormalities indicative of hypothalamic-anterior pituitary dysfunction.

A novel zoometric index for assessing body composition in adult rabbits.

Obesity is an emerging problem in domesticated rabbits, and an easy-to-use measure of adipose tissue mass is needed. The current study aimed to develop a zoometric ratio, capable of estimating body condition in rabbits. Body weight (BW), body condition score (BCS), and zoometric measures (distal forelimb length, DFL; vertebral length, VL were measured in 150 pet rabbits. Zoometric formulae were created, combining BW with a zoometric measure, and these were tested for their ability to predict adipose tissue mass judged by BCS. Seventy-five (50 per cent) of the rabbits were in ideal condition (BCS 2.5-3.5), 52 (35 per cent) were overweight (BCS>3.5), and 23 (15 per cent) were underweight (BCS<2.5). Median (range) DFL and VL measurements were 12.1 (8.8-16.4 cm) and 34.0 (26.5-50.5 cm), respectively. In rabbits of medium breed size, the BW/DFL ratio was most strongly associated with BCS (Kendall's τ 0.80, P<0.001). Using BW/DFL limits for optimum body condition (eg, minimum 0.16; maximum 0.21), all underweight and overweight rabbits were correctly classified, while only 2/61 (3 per cent) rabbits with an optimum BCS were incorrectly classified as overweight. This study provides preliminary evidence that the BW/DFL might be a useful indirect measure of adipose tissue mass in rabbits of medium breed size.

Oxygenation and ventilation characteristics in obese sedated dogs before and after weight loss: a clinical trial.

This prospective clinical study examined the effect of obesity and subsequent weight loss on oxygenation and ventilation during deep sedation in pet dogs. Data from nine dogs completing a formalised weight loss programme were evaluated. Dual-energy X-ray absorptiometry (DEXA) was used to quantify body fat mass prior to and after weight loss. Dogs were deeply sedated and positioned in dorsal recumbency. Sedation was scored using a semi-objective scheme. As part of the monitoring of sedation, arterial oxygen partial pressure (PaO2) and arterial carbon dioxide partial pressure (PaCO2) were measured after 10 min in dorsal recumbency. Oxygen saturation of haemoglobin (SpO2) was monitored continuously using pulse oximetry, starting oxygen supplementation where indicated (SpO2<90%) via a face mask. Morphometric measurements were taken from DEXA images and compared before and after weight loss. Several oxygen indices were calculated and correlated with body fat variables evaluated by DEXA. All body fat variables improved significantly after weight loss. PaO2 increased from 27.9±19.2 kPa to 34.8±24.4 kPa, while FiO2 decreased from 0.74±0.31 to 0.66±0.35. Morphometric measurements improved significantly after weight loss. PaO2/FiO2 (inspired oxygen fraction) and Pa/AO2 (ratio of PaO2 to alveolar PO2) also improved significantly, but there was no change in f-shunt and PaCO2 after weight loss. On multiple linear regression analysis, all oxygen indices were negatively associated with thoracic fat percentage. In conclusion, obesity decreases oxygenation in dogs during deep sedation. Oxygenation status improves with successful weight loss, but ventilation is not influenced by obesity.

Maintenance energy requirements in miniature colony dogs.

There are numerous reports of maintenance energy requirements (MER) in dogs, but little information is available about energy requirements of miniature dog breeds. In this prospective, observational, cohort study, we aimed to determine MER in dogs from a number of miniature breeds and to determine which factors were associated with it. Forty-two dogs participated in the study. MER was calculated by determining daily energy intake (EI) during a period of 196 days (28-359 days) when body weight did not change significantly (e.g. ±2% in 12 weeks). Estimated median MER was 473 kJ/kg(0.75) /day (285-766 kJ/kg(0.75) /day), that is, median 113 kcal/kg(0.75) /day (68-183 kcal/kg(0.75) /day). In the obese dogs that lost weight, median MER after weight loss was completed was 360 kJ/kg(0.75) /day (285-515 kJ/kg(0.75) /day), that is, 86 kcal/kg(0.75) /day, (68-123 kcal/kg(0.75) /day). Simple linear regression analysis suggested that three breeds (e.g. Chihuahua, p = 0.002; Yorkshire terrier, p = 0.039; dachshund, p = 0.035) had an effect on MER. In addition to breed, simple linear regression revealed that neuter status (p = 0.079) and having previously been overweight (p = 0.002) were also of significance. However, with multiple linear regression analysis, only previous overweight status (MER less in dogs previously overweight p = 0.008) and breed (MER greater in Yorkshire terriers [p = 0.029] and less in Chihuahuas [p = 0.089]) remained in the final model. This study is the first to estimate MER in dogs of miniature breeds. Although further information from pet dogs is now needed, the current work will be useful for setting energy and nutrient requirement in such dogs for the future.

Canine breed predispositions for marked hypocobalaminaemia or decreased folate concentration assessed by a laboratory survey.

OBJECTIVE: The aim of this study was to determine canine breed predispositions for decreased serum folate or markedly decreased cobalamin concentrations. METHODS: Retrospective analysis of samples from dogs that had serum folate and cobalamin concentrations measured, from 1990 to 2002 at the Comparative Gastroenterology Laboratory of Liverpool, were enrolled. A total of 13,069 samples were analysed. Those with trypsin-like immunoreactivity < 5·0 lg/L were excluded, and only breeds with at least 30 individuals tested were further analyzed. Breed predisposition was determined by calculating odds ratios and 95% confidence intervals for hypocobalaminaemia or decreased folate concentration. Significance was tested with a two-sided Fisher's exact test, and the level of statistical significance was set at P<0·05. RESULTS: A total of 9960 dogs fulfilled the inclusion criteria. Forty breeds contained at least 30 individuals. Predispositions for hypocobalaminaemia were identified in shar peis, Staffordshire bull terriers, German shepherd dogs and mixed breeds. Predispositions for decreased folate concentration were found in golden retrievers and boxers. CLINICAL SIGNIFICANCE: Predisposition for marked hypocobalaminaemia and decreased folate concentration differed between breeds. The shar peis had a markedly increased odds ratio for hypocobalaminaemia, as previously reported in North America, but other at-risk breeds were also identified.

Ex vivo evaluation of the biomechanical effect of varying monocortical screw numbers on a plate-rod canine femoral gap model.

OBJECTIVE: To compare the biomechanical behaviour of plate-rod constructs with varying numbers of monocortical screws applied to an ex vivo canine femoral-gap ostectomy model. SAMPLE POPULATION: Twenty Greyhound dog cadaveric femurs. METHODS: Bone mineral density (BMD) was assessed with dual x-ray absorptiometry. Bones were assigned to four groups. Bones had a 12-hole 3.5 mm locking compression plate with one bicortical non-locking cortical screw in the most proximal and distal plate holes and an intramedullary Steinmann pin applied across a 20 mm mid-diaphyseal ostectomy. Additionally, one to four monocortical non-locking cortical screws were then placed (Groups 1-4 respectively) in the proximal and distal fragments. Stiffness and axial collapse were determined before and after cyclic axial loading (6000 cycles at 20%, 40%, and 60% of mean bodyweight [total: 18000 cycles]). Constructs subsequently underwent an additional 45000 cycles at 60% of bodyweight (total: 63000 cycles). Loading to failure was then performed and ultimate load and mode of failure recorded. RESULTS: The BMD did not differ significantly between groups. Construct stiffness for group 1 was significantly less than group 4 (p = 0.008). Stiffness showed a linear increase with an increasing number of monocortical screws (p = 0.001). All constructs survived fatigue loading. Load-to-failure was not significantly different between groups. Mean load- to-failure of all groups was >1350N. CLINICAL RELEVANCE: Ex vivo canine large-breed femurs showed adequate stability biomechanically and gradually increasing stiffness with increasing monocortical screw numbers.

Relevance of sodium/glucose cotransporter-1 (SGLT1) to diabetes mellitus and obesity in dogs.

Glucose transport across the enterocyte brush border membrane by sodium/glucose cotransporter-1 (SGLT1, coded by Slc5a1) is the rate-limiting step for intestinal glucose transport. The relevance of SGLT1 expression in predisposition to diabetes mellitus and to obesity was investigated in dogs. Cultured Caco-2/TC7 cells were shown to express SGLT1 in vitro. A 2-kbp fragment of the Slc5a1 5' flanking region was cloned from canine genomic DNA, ligated into reporter gene plasmids, and shown to drive reporter gene expression in these cells above control (P < 0.001). To determine the effect of the 3 known SNPs in this region on promoter function, new promoter/reporter constructs (all permutations of these 3 SNPs) were created by site-directed mutagenesis. No significant differences in promoter function were seen, suggesting that these SNPs do not have a significant effect on the constitutive transcription of SGLT1 mRNA in dogs. A search for novel SNPs in this region in dogs was made in 2 breeds predisposed to diabetes mellitus (Samoyed and cairn terrier), 2 breeds that rarely develop diabetes (boxer and German shepherd), and 2 breeds predisposed to obesity (Labrador retriever and cocker spaniel). The Slc5a1 5' flanking region was amplified from 10 healthy individuals of each of these breeds by high-fidelity PCR with the use of breed-labeled primers and sequenced by pyrosequencing. The sequence of the Slc5a1 5' flanking region in all individuals of all breeds tested was identical. On this evidence, variations in Slc5a1 promoter sequence between dogs do not influence the pathogenesis of diabetes mellitus or obesity in these breeds.