Anatomical and pathological characteristics of ribs in the Atlantic salmon (Salmo salar L.) and its relevance to soft tissue changes.

Studies on the anatomical and pathological characteristics of ribs in farmed Atlantic salmon (Salmo salar L.) are warranted due to their possible association with red and melanized focal changes (RFC and MFC) in the fillet, a major quality and animal welfare concern. In this work, we provide an anatomical description of ribs based on radiographical and histological analyses. We also address various pathological rib changes and their association to RFC and MFC. In total, 129 fish were investigated; captured wild (n = 10) and hatchery reared (n = 119) Atlantic salmon (3.5-6.1 kg). The fish were selected based on the macroscopic presence of RFC, MFC or no changes (controls). Radiographic results revealed costal abnormalities in all fish groups. By histological investigations of the variations herein, our results provide new insight into the anatomical characteristics including vascularization within the ribs; a potential site for haemorrhage following costal fractures. Costal fractures were detected by radiology in 40 of 129 samples (RFC: 38.4%, MFC: 47.2%, controls: 9.5 %). A statistically significant association was found between costal fractures and red (p = 0.007) and melanized changes (p = 0.000). However, red and melanized changes were also observed in samples with no costal fractures (n = 45), indicating that also other factors influence the development of RFC/MFC.

Perinatal exposure to a human relevant mixture of persistent organic pollutants: Effects on mammary gland development, ovarian folliculogenesis and liver in CD-1 mice.

The ability of persistent organic pollutants (POPs) with endocrine disrupting properties to interfere with the developing reproductive system is of increasing concern. POPs are transferred from dams to offspring and the high sensitivity of neonates to endocrine disturbances may be caused by underdeveloped systems of metabolism and excretion. The present study aimed to characterize the effect of in utero and lactational exposure to a human relevant mixture of POPs on the female mammary gland, ovarian folliculogenesis and liver function in CD-1 offspring mice. Dams were exposed to the mixture through the diet at Control, Low or High doses (representing 0x, 5000x and 100 000x human estimated daily intake levels, respectively) from weaning and throughout mating, gestation, and lactation. Perinatally exposed female offspring exhibited altered mammary gland development and a suppressed ovarian follicle maturation. Increased hepatic cytochrome P450 enzymatic activities indirectly indicated activation of nuclear receptors and potential generation of reactive products. Hepatocellular hypertrophy was observed from weaning until 30 weeks of age and could potentially lead to hepatotoxicity. Further studies should investigate the effects of human relevant mixtures of POPs on several hormones combined with female reproductive ability and liver function.

Granulomatous interstitial polymyositis and intramuscular neuritis in a dog.

BACKGROUND: Granulomatous myositis is a rare condition in both humans and dogs. In humans it is most frequently related to sarcoidosis, where a concurrent granulomatous neuritis has been reported occasionally. Simultaneous granulomatous myositis and neuritis have been diagnosed previously in dogs (unpublished observations), but have not been studied further. Additional investigations are therefore warranted to characterize this disorder. Here we present a detailed description of concurrent idiopathic granulomatous myositis and granulomatous neuritis in a dog with suspected immune-mediated aetiology. CASE PRESENTATION: The dog presented with dysphonia and paresis in the pelvic limbs and tail. In addition to muscle biopsies being taken for histopathology, magnetic resonance imaging, computed tomography and electrodiagnostics were performed. Muscle biopsies displayed granuloma formation with giant cells and epithelioid macrophages in muscle fibres and nerve branches. Microorganisms were not detected. Long-term treatment with glucocorticoids was clinically successful. Two years after the clinical signs started, the dog presented with signs of sepsis and died. Histopathologically, no granulomatous inflammation could be demonstrated in either muscles or nerves at that time. CONCLUSIONS: This case illustrates a granulomatous interstitial polymyositis and intramuscular neuritis that improved clinically and resolved histologically with glucocorticoid treatment. Idiopathic granulomatous myositis and neuritis should be considered as a differential diagnosis in dogs with clinical signs of neuromuscular disorders.

Medial humeral epicondylar lesions and discreet calcified structures in the canine elbow: radiographic description of 183 cases.

BACKGROUND: In this 4-year prospective observational study, all elbows in a dysplasia screening program including 14,073 dogs were studied using radiographs in two projections. Elbows were evaluated for the presence of medial humeral epicondylar lesions or discreet calcified structures and were described as they appeared. The age, breed, and sex of affected dogs were recorded. The prevalence for each lesion was calculated exclusively on breeds where the number of radiographed dogs exceeded 500. RESULTS: Medial humeral epicondylar lesions or medial discreet calcified structures were diagnosed in 183 dogs and 211 elbows. The prevalence of true Flexor enthesopathy (FE) in this Norwegian population of mainly young, large breed dogs was calculated to be approximately 1.4 per 1000 dogs and varied by breed. Also, the prevalence of the other lesions varied considerably by breed. The most common finding was discreet calcified structures, termed medial ossified structures (MOS) (0.7%). In elbows affected with fragmented medial epicondyles (FME) (0.07%) and especially FE (0.14%), the degree of periarticular new bone formation (PNBF) was increased when compared to unaffected elbows. In joints affected with MOSs or medial lucent lesions MLLs (0.25%), there was no difference in the presence or degree of PNBF compared to unaffected joints, even in older dogs. CONCLUSIONS: The prevalence of medial humeral epicondylar lesions and MOSs differs considerably among dog breeds. Elbow joints with FMEs and particularly FE had a highly increased presence and degree of PNBF compared to joints without these lesions. Elbow joints with MOSs or MLLs did not have an increased presence or degree of PNBF compared to joints without these lesions.

Vertebral column deformity with curved cross-stitch vertebrae in Norwegian seawater-farmed Atlantic salmon, Salmo salar L.

Pathological changes in the vertebral column of farmed Atlantic salmon in Norway have been reported since the 1990s. Based on the characteristic radiographic findings, we here present a vertebral column deformity named "curved cross-stitch vertebrae" that mainly affects the middle aspect of the vertebral column. Sixty fish, from the west/northwest coast of mid-Norway, were sampled at slaughter and examined by radiography, computed tomography (CT), necropsy, macrophotography, and histology. The vertebral deformities were radiographically graded as mild, moderate, or marked. The main differences between these grades of changes were defined by increased curving of the peripheries of endplates, reduced intervertebral spaces, and vertical displacement of the vertebrae. The curved rims of endplates were located peripheral to a continuous and approximately circular borderline. The CT studies revealed small, multifocal, hypo-attenuating, round to crescent-shaped areas in the notochord, compatible with the presence of gas. Additionally, histology revealed that the axial parts of endplates had circular zones with perforations, through which either notochordal tissue prolapsed into the vertebrae or vascularized fibrochondroid proliferations extended from the vertebrae into the notochord. Inflammation was present in many vertebral bodies. To the best of our knowledge, this is the first report of gas in the notochord of fish.

Primary bone cancer in Leonbergers may be associated with a higher bodyweight during adolescence.

Weight-bearing stress may be a risk factor for both human and canine primary bone cancer. A cohort of Leonbergers (LB) was followed from birth to death and the cause of death recorded. We hypothesised that dogs dying due to primary bone cancer would be larger; measured by bodyweight (BW) and the circumference of the distal radius and ulna (CDRU) than those of the same breed that died of other causes. Information obtained from breeders, owners and veterinary surgeons were questionnaire-based. The dogs were examined by a veterinary surgeon at pre-specified "observational ages" (3, 4, 6, 12, 18, and 24 m). Data were recorded, including BW and CDRU. The study population consisted of 196 LB, 9 of which died due to primary bone cancer (6 males, 3 females). Individual growth curves, showing BW and CDRU during the first 2 years of life, were made for these 9 dogs and compared to gender-specific mean values for LB that died from other causes. These curves showed that LB succumbing to primary bone cancer generally had a higher BW during the growth period than the remaining dogs, and that this difference appeared to be largest in the male LB. Male LB that developed primary bone cancer later in life also had a larger CDRU during most part of this period, as compared to those that did not develop this disease. Logistic regression showed a statistically significant effect of BW on the odds ratio of developing primary bone cancer at 12 m and 18 m and of CDRU at 18 m, and a Poisson regression verified consistency of these results. At these ages, an increase in BW of 1 kg yielded a nearly 20% higher risk of developing primary bone cancer, while a 1 cm larger CDRU was associated with a nearly 70% increased risk. These findings support that weight-bearing stress during the period of high proliferative activity in the long bones associated with growth may increase the risk of canine primary bone cancer.

Housing- and exercise-related risk factors associated with the development of hip dysplasia as determined by radiographic evaluation in a prospective cohort of Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway.

OBJECTIVE: To identify housing- and exercise-related risk factors associated with the development of hip dysplasia (HD) as determined by radiographic evaluation in Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds in Norway. ANIMALS: 501 client-owned dogs from 103 litters. PROCEDURES: Dogs were assessed from birth until official radiographic screening for HD at 12 (Labrador Retriever [n = 133] and Irish Wolfhound [63]) or 18 (Newfoundland [125] and Leonberger [180]) months of age. Information regarding housing and exercise conditions during the preweaning and postweaning periods was obtained with questionnaires. Multivariable random effects logistic regression models were used to identify housing- and exercise-related risk factors associated with the development of radiographically detectable HD. RESULTS: Puppies walking on stairs from birth to 3 months of age had an increased risk of developing HD. Factors associated with a decreased risk of developing HD included off-leash exercise from birth to 3 months of age, birth during the spring and summer, and birth on a farm. Significant clustering of dogs with HD was detected within litters. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that puppies ≤ 3 months old should not be allowed access to stairs, but should be allowed outdoor exercise on soft ground in moderately rough terrain to decrease the risk for developing radiographically detectable HD. These findings could be used as practical recommendations for the prevention of HD in Newfoundlands, Labrador Retrievers, Leonbergers, and Irish Wolfhounds.

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.

Risk factors for hip-related clinical signs in a prospective cohort study of four large dog breeds in Norway.

We conducted a prospective cohort study including privately owned dogs from the breeds Newfondland (NF), Labrador Retriever (LR), Leonberger (LEO), and Irish Wolfhound (IW) followed from birth until age 9 yrs. We wanted to investigate whether radiological hip dysplasia status given at approximately age 12-18 mos and other factors during growth influenced development of clinical signs due to hip-joint disease necessitating veterinary consultation. Whether or not such signs occurred due to hip dysplasia or due to secondary or primary DJD could not be distinguished, and we therefore used the term "owner-reported veterinary-diagnosed hip-related clinical signs" ("the event"). The included dogs were followed from birth to the event or until a maximum of 9 yrs of age. Our objectives were to describe breed differences in time to incidence and to evaluate potential risk factors for the time to event. We used Kaplan-Meier curves to describe time to incidence, and potential risk factors were assessed by use of a Cox proportional-hazards model. We enrolled 494 dogs from 103 litters, and 46 dogs were reported as having had the event during the observation period. We observed a significant time-varying effect (TVE): LR and LEO developed clinical signs later in life than NF. If the radiological hip status was either mild, moderate, or severe the hazard of experiencing the event was significantly increased. Access to off-leash exercise at age 12 mos decreased the hazard of the event, and the hazard varied by litter. The findings supported the hypothesis that radiological hip status at screening and exercise conditions during growth influenced the time to incidence of the event and that there were breed differences in time to the event.

The effect of radiological hip dysplasia and breed on survival in a prospective cohort study of four large dog breeds followed over a 10 year period.

The aim of the study was to measure the effect of radiological hip and elbow dysplasia status and breed on overall survival in a cohort of four large dog breeds in Norway. Privately owned dogs of the Newfoundland (NF), Labrador Retriever (LR), Leonberger (LEO), and Irish Wolfhound (IW) breeds were followed prospectively from birth to 10 years of age. The age of death/euthanasia was registered. A total of 501 dogs from 103 litters were enrolled. Kaplan-Meier survival curves were used to describe breed differences in survival times. The effects of radiological hip and elbow dysplasia status as well as breed were assessed using a Cox proportional hazards model. The variables 'sex' and 'living region' were explored as potential confounders. Among LRs, 60.2% of the dogs were still alive at 10 years of age, and the corresponding figures for NFs, LEOs, and IWs were 28.8%, 16.11%, and 6.4%, respectively. Radiological hip dysplasia status and breed were found to influence overall survival. Two different time-varying effects were observed in that with the IW the hazard of death increased linearly through time, while the effect of severe radiological hip dysplasia decreased logarithmically with time. Location influenced the death hazard and dogs living in suburban areas or cities had longer mean time to death and a lower hazard compared to dogs living in the countryside. Radiological elbow dysplasia status was not found to have an effect on overall survival.

Causes of lower urinary tract disease in Norwegian cats.

A study was made on causes of lower urinary tract disease in cats, and to investigate whether demographic data and factors related to husbandry might influence the occurrence of a particular diagnosis. The study was a prospective, descriptive, and analytical study of primary cases of feline lower urinary tract disease (FLUTD) in Norway. Only cats sampled by cystocentesis were included in the present study. Of the 119 cats included, 28.6% were diagnosed with obstructive FLUTD. The majority of cats were diagnosed with feline idiopathic cystitis (FIC) (55.5%). Urethral plugs were the second most common diagnosis (21.0%), whereas bacterial cystitis and urolithiasis each were diagnosed in 11.8%. Nearly one-third (28.6%) of the cats diagnosed with urolithiasis had significant bacteriuria. Thus, significant bacteriuria was diagnosed in a total of 15.1% of the cats. There were no significant differences in the urine specific gravity, pH and amount of epithelial cells in the urine sediment in the different aetiological categories of FLUTD. There was a higher amount of red blood cells in the urine sediment in cats diagnosed with urethral plugs and urolithiasis, whereas cats with bacterial cystitis and urolithiasis had a higher amount of white blood cells in their sediment. Regarding demographic data and factors related to husbandry, cats diagnosed with FLUTD were more often males and kept strictly indoors, when compared with a 'reference population'.

A prospective study on canine hip dysplasia and growth in a cohort of four large breeds in Norway (1998-2001).

The study-objective was to measure the effect of weight and growth related parameters on the risk of development of Canine Hip Dysplasia (CHD). The hypothesis was that heavy and fast growing dogs of large sized breeds were at increased risk of development of CHD compared to lighter and slower growing dogs. A prospective cohort study was conducted among dogs of four large breeds: Newfoundland (NF), Leonberger (LEO), Labrador retriever (LR), and Irish wolfhound (IW). The dogs were privately owned with individualized nutrition and environment, and they were followed from birth and throughout the growth period until the official screening for CHD was performed. The study sample consisted of 501 dogs from 103 litters, with the breed distribution 125 NF, 180 LEO, 133 LR, and 63 IW. Because the dogs were clustered in litters a multivariable random effects logistic regression model was used to assess statistically significant growth-related risk factors for CHD. The estimated incidence risk of CHD was 36% in NF, 25% in LEO, 20% in LR, and 10% in IW. Based upon the final multilevel model it appears that the odds of CHD among both LR and IW (odds ratio (OR) 0.22) are about one-fifth of the odds for NF. The odds for LEO (OR 0.60) are not significantly different from NF. There appeared to be an inverse relationship between body weight at 3 months of age and odds of CHD, with an OR of 0.89 (P=0.044). The degree of clustering at the litter-level was high (22.6%) and highly significant (P<0.001). Findings failed to support the hypothesis that heavy and fast growing dogs from four large sized breeds were at increased risk for development of CHD. There might be other unmeasured environmental risk factors for CHD in this cohort of dogs, although the contribution of the genetic variance to the litter-level clustering also needs further investigation.

A new type of radiographic bone remodeling in the distal radial and ulnar metaphysis in 54 Newfoundland dogs.

In this longitudinal observational study, 118 growing Newfoundland dogs were followed with sequential radiographic examination of the right front limb, which were scheduled at ages 3, 4, 6, 12, 18, and 24 months to record evidence of skeletal changes. All affected dogs had evidence of changes at 6 months and dogs included in this study had radiographic examination at 6 months and at least two other scheduled examinations that included either 4 or 12 months. The dogs were privately owned and had individualized nutrition and environment with no maintenance protocol required by the project leaders. Irregularities in bone remodeling in the distal radius and ulna were seen in radiographs of 54 of 118 (45.8%) dogs. These irregularities differ from changes previously described in the Newfoundland dog. The reported irregularities were seen as islands of reduced opacity outlined by thickened, radiopaque osseous trabeculae, which were aligned with the axis of stress. All the 54 dogs with irregularities during some phase of development consistently had changes at 6 months of age. Reorganization of the changes in the bone was slow, and residual changes were visible at 18-24 months of age in many cases. The significance of these findings may lie in their potential for misinterpretation if they had been discovered in the presence of clinical signs such as any lameness or growth arrest. Radiographic appearance indicates disturbances in the bone maturation. The etiopathogenesis is unclear. Nutritional, environmental and genetic factors have to be studied.