Gonadectomy in immature dogs: effects on skeletal, physical, and behavioral development

In a 15-month study, the effects of prepubertal gonadectomy on skeletal growth, weight gain, food intake, body fat, secondary sex characteristics, and behavioral development were investigated in 32 mixed-breed dogs. Male and female pups from 5 litters were randomly allotted to 3 groups: group I, neuter at 7 weeks (n = 14); group II, neuter at 7 months (n = 8); and group III, sexually intact dogs (n = 10). Growth plate closure was delayed (group I vs group III; P less than 0.000001; group II vs group III, P less than 0.000001) in all neutered dogs, as compared with sexually intact dogs. Growth plate closure was delayed longer (group I vs group II, P less than 0.000045) in dogs neutered at 7 weeks old, compared with dogs neutered at 7 months old. The rate of growth was unaffected by gonadectomy, but the extended growth period resulted in greater final radial/ulnar length in all male dogs and bitches neutered at 7 weeks. Gonadectomy did not influence food intake, weight gain, or back-fat depth. Penile development was immature in the adult group-I males (mean +/- SEM diameter of pars glandis = 11.1 +/- 1.0 mm), compared with adult group-II (16.3 +/- 0.5 mm) and group-III (21.0 +/- 2.2 mm) males. Subjectively, the prepuce and os penis of the group-I males were immature, compared with those of group-II and group-III males. Vulvar development in group-I and group-II bitches was less mature than vulvar development in the sexually intact bitches. Of 7 behavioral characteristics assessed, only general activity and excitability rated differently among treatment groups. All neutered dogs were judged to be more active (group I, P less than 0.004) than sexually intact dogs. Group-I males were judged to be more excitable (P less than 0.02) than group-III males. It was concluded that with respect to skeletal, physical, and behavioral development, the effect of neutering pups at 7 weeks old was similar to that of neutering pups at 7 months old.     

Factors associated with aggression between pairs of domestic ferrets

OBJECTIVE: To identify factors (eg, familiarity, sex, neutering status, and time of year) associated with aggression between domestic ferrets and test a method for reducing aggression when introducing ferrets. DESIGN: Prospective trial. ANIMALS: 56 healthy domestic ferrets. PROCEDURE: To identify variables associated with aggression, pairs were placed in an enclosed area and observed. To test whether increasing familiarity would decrease aggression when introducing ferrets, pairs of ferrets were housed in separate cages next to each other or in separate rooms for 2 weeks prior to introduction. RESULTS: 49 of 82 pairs of strangers fought, but 31 cage mate pairs did not. Time of year had no apparent effect. Pairs consisting of 2 neutered females or 2 sexually intact males were significantly more likely to fight than were pairs consisting of a neutered female and a sexually intact male. Pairs caged next to each other for 2 weeks prior to introduction were no less likely to fight than were control pairs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that familiarity, sex, and neutering status are important determinants of aggression between ferrets. If unfamiliar neutered ferrets are introduced, then pairing 2 males or a male and female would likely result in the lowest levels of aggression. However, neutered females and sexually intact males are not indiscriminately aggressive, as a neutered female can be paired with a sexually intact male without resulting in aggression. Caging ferrets next to each other for 2 weeks does not decrease aggression when the ferrets are introduced.     

Epidemiologic, clinical, pathologic, and prognostic characteristics of splenic hemangiosarcoma and splenic hematoma in dogs: 217 cases (1985)

Data on age, sex, and breed were obtained from surgical pathologic records of 92 dogs with splenic hemangiosarcoma (SHS) and for 125 dogs with splenic hematoma (SHA) diagnosed in 1985 at the University of Pennsylvania School of Veterinary Medicine. Further information on body weight, clinical and surgical findings, and survival time was obtained for 59 dogs (64.1%) with SHS and 91 dogs (72.8%) with SHA. Splenic hemangiosarcoma was markedly more common in dogs 8 to 13 years old, and SHA was appreciably more common in dogs greater than or equal to 8 years old, compared with dogs 1 to 7 years old. Compared with sexually intact females, only spayed females were at significantly (odds ratio [or], 2.2; 95% confidence interval [CI], 1.2 to 4.1) increased risk for developing SHS; sex predisposition was not found for dogs with SHA. The German Shepherd Dog was the only breed with increased risk for development of either SHS (OR, 4.7; 95% CI, 2.7 to 7.8) or SHA (OR, 2.8; 95% CI, 1.7 to 4.9), compared with all other purebred dogs. Association of tumor type for 7 commonly reported clinical signs with observance of hemoperitoneum at surgery was determined; anorexia (P = 0.01), collapse (P = 0.01), and hemoperitoneum (P less than 0.001) were significantly more common in dogs with SHS. The median survival time for dogs with SHS was 19 days, compared with 338 days for dogs with SHA (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence of cranial cruciate ligament rupture in a population of dogs with lameness previously attributed to hip dysplasia: 369 cases (1994-2003)

OBJECTIVE: To determine the prevalence of cranial cruciate ligament rupture (CCLR) in dogs with lameness previously attributed to canine hip dysplasia (CHD). DESIGN: Retrospective study. ANIMALS: 369 client-owned dogs. PROCEDURES: Hospital medical records from 1994 to 2003 were reviewed for dogs in which the referring veterinarian had diagnosed hip dysplasia or hip pain. Dogs were designated as having hind limb lameness because of partial or complete CCLR or CHD. RESULTS: 8% of dogs were sexually intact females, 43% were spayed females, 14% were sexually intact males, and 35% were castrated males. Mean age was 3.8 years (range, 3 months to 15 years). The most common breeds were the Labrador Retriever (21%), German Shepherd Dog (13%), and Golden Retriever (11%). The prevalence of CCLR as the cause of hind limb lameness was 32% (95% confidence interval, 27.2% to 36.8%). The distribution of CCLR among hind limbs was left (29%), right (28%), and bilateral (43%). Of 119 dogs with CCLR, 94% had concurrent radiographic signs of CHD, 92% had stifle joint effusion, and 81% had a cranial drawer sign. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of the high prevalence of CCLR in dogs referred for lameness because of CHD, it is important to exclude other sources of stifle joint disease before making recommendations for treatment of CHD.     

Golden Retriever uveitis: 75 cases (1994-1999)

OBJECTIVE: To document the presenting ocular signs and the clinical course of Golden Retriever dogs with a progressive anterior uveitis, often associated with the histologic presence of iridociliary cysts. Animals studied Seventy-five Golden Retriever dogs (142 affected eyes) referred to a private practice referral ophthalmology clinic between 1994 and 1999. Procedures Complete ophthalmic evaluation with slit-lamp biomicroscopy, indirect ophthalmoscopy, applanation tonometry, and gonioscopy. Hematology, serum biochemical evaluations, and serologic titers for endemic infectious agents were also used in selected cases. RESULTS: The age range of affected dogs was 4.5-14.5 years, with a mean age of 8.6 +/- 2.1 years. The majority of the dogs (n = 66) were affected in both eyes at first presentation. The sex distribution included 4 intact males, 32 neutered males, and 39 spayed females. Hematology, serum biochemical evaluations, and serologic titers for endemic infectious agents failed to demonstrate any underlying disorder. The ophthalmic hallmark of this syndrome was the appearance of pigment on the anterior lens capsule, often in a radial orientation. This capsular pigment was seen both with and without associated uveal cysts. Although single to multiple iridociliary cysts were noted clinically in only 13.3% of the cases, cysts were common on histopathology of advanced glaucomatous, blind eyes. Fibrin was observed in the anterior chamber of 37% of the cases, and often was a precursor for glaucoma. Cataract formation (37%) and glaucoma (46%) were frequent sequelae to the uveitis. Posterior synechiae formation occurred in 50% of the cases. Histopathologic analysis of four enucleated eyes and the eviscerated specimens from 14 glaucomatous eyes demonstrated thin-walled iridociliary epithelial cysts in 3/4 and 12/14 cases, respectively. Microscopically, little to no uveal inflammatory infiltration was commonly noted. Conclusion The overall prognosis for this progressive uveitis in Golden Retriever dogs is guarded, with 46% of the eyes becoming blind due to glaucoma. Iridociliary cysts in Golden Retriever dogs may lead to the development of glaucoma in this breed.     

Adverse events diagnosed within three days of vaccine administration in dogs

OBJECTIVE: To determine incidence rates and potential risk factors for vaccine-associated adverse events (VAAEs) diagnosed within 3 days of administration in dogs. DESIGN: Retrospective cohort study. ANIMALS: 1,226,159 dogs vaccinated at 360 veterinary hospitals. PROCEDURE: Electronic records from January 1, 2002, through December 31, 2003, were searched for possible VAAEs (nonspecific vaccine reaction, allergic reaction, urticaria, or anaphylaxis) diagnosed within 3 days of vaccine administration. Information included age, weight, sex, neuter status, and breed. Specific clinical signs and treatments were reviewed in a random sample of 400 affected dogs. The association between potential risk factors and a VAAE was estimated by use of multivariate logistic regression. RESULTS: 4,678 adverse events (38.2/10,000 dogs vaccinated) were associated with administration of 3,439,576 doses of vaccine to 1,226,159 dogs. The VAAE rate decreased significantly as body weight increased. Risk was 27% to 38% greater for neutered versus sexually intact dogs and 35% to 64% greater for dogs approximately 1 to 3 years old versus 2 to 9 months old. The risk of a VAAE significantly increased as the number of vaccine doses administered per office visit increased; each additional vaccine significantly increased risk of an adverse event by 27% in dogs < or = 10 kg (22 lb) and 12% in dogs > 10 kg. CONCLUSIONS AND CLINICAL RELEVANCE: Young adult small-breed neutered dogs that received multiple vaccines per office visit were at greatest risk of a VAAE within 72 hours after vaccination. These factors should be considered in risk assessment and risk communication with clients regarding vaccination.     

Age, Tibial Plateau Angle, Sex, and Weight as Risk Factors for Contralateral Rupture of the Cranial Cruciate Ligament in Labradors

Objective— To compare rates of contralateral cranial cruciate ligament rupture (CCLR) in Labradors based on age and weight at initial rupture, sex, and tibial plateau angle (TPA) and to determine whether Labradors that rupture their initial cranial cruciate ligament (CCL) at an earlier age (<4 years) are more likely to rupture their contralateral side within a certain period of time. Study Design— Case series. Animals— Labradors (n=94) that had tibial plateau leveling osteotomy (TPLO). Methods— Two groups: no contralateral rupture (NR) and contralateral rupture (CR) were compared for significant (P<.05) differences in percentage of subsequent cruciate tears using a Wilcoxon's rank‐sum tests for continuous variables and Fisher's exact test for sex. Adjusted odds ratios for likelihood of subsequent cruciate tears (yes/no) were estimated using logistic regression. Associations of these characteristics with time to subsequent rupture were assessed using Kaplan–Meier survival analysis estimation. Predictors of presentation with bilateral ruptures (BR) versus single rupture were also evaluated using Wilcoxon's rank‐sum tests and a generalized Fisher's exact test. Results— Subsequent CCLR occurred in 45 dogs (48%), and BR on admission were identified in 10 dogs (10.6%). Comparing NR and CR dogs, there were no significant differences between age or weight at initial rupture, sex or TPA; however there were associations toward longer time to CR for dogs older than the median age and female dogs (intact and spayed). There were no significant differences in age, sex, weight, or TPA of dogs with bilateral CCL ruptures compared with initial unilateral ruptures; however, there was a trend toward dogs presenting at an older age and with lower TPA's in the BR group. Among the 84 NR/CR dogs, the median time to rupture of the contralateral CCL was 5.5 months (95% CI 5.2–5.7). Conclusions— Age and weight at initial rupture, sex, and TPA does not affect likelihood or rate of contralateral CCL rupture or presentation with bilateral CCL ruptures. Clinical Relevance— Approximately 50% of Labradors will rupture the contralateral CCL within 5.5 months of the initial rupture but age, weight, sex, and TPA cannot be used as predictive features.     

Seroprevalence of Dirofilaria immitis, feline leukemia virus, and feline immunodeficiency virus infection among dogs and cats exported from the 2005 Gulf Coast hurricane disaster area

OBJECTIVE: To determine seroprevalence of dirofilariasis in dogs and seroprevalences of dirofilariasis, FeLV infection, and FIV infection in cats exported from the Gulf Coast region following the 2005 hurricanes. DESIGN: Seroprevalence survey. ANIMALS: 1,958 dogs and 1,289 cats exported from Louisiana, Mississippi, and Texas between August 20 and December 31, 2005. PROCEDURES: 141 animal welfare groups in 37 states and Alberta, Canada, reported results of serologic testing. Risk factors for infection, including age, sex, neuter status, breed, and state of rescue, were examined by means of univariate and multivariate logistic regression. RESULTS: Seroprevalence of dirofilariasis in dogs was 48.8%. Sexually intact dogs were 1.6 times as likely to have dirofilariasis as were neutered dogs, dogs in the ancient breed group were 2.2 times as likely and dogs in the guarding breed group were 1.7 times as likely to have dirofilariasis as were dogs in the herding breed group, and dogs from Mississippi were significantly less likely to have dirofilariasis than were dogs from Texas. Seroprevalences of dirofilariasis, FeLV infection, and FIV infection in cats were 4.0%, 2.6%, and 3.6%, respectively. Seroprevalence of FIV infection was significantly higher in adult cats than in juveniles and in males than in females. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that dogs and cats exported from the 2005 Gulf Coast hurricane disaster area had disease rates similar to those for animals in the region prior to the hurricanes.     

Pathologic changes in grossly normal menisci in dogs with rupture of the cranial cruciate ligament

OBJECTIVE: To determine whether histopathologic changes are detectable in grossly normal medial menisci from dogs with rupture of the cranial cruciate ligament (CCL). DESIGN: Case series. SAMPLE POPULATION: 40 medial menisci from dogs with rupture of the CCL and 20 medial menisci from control dogs without stifle joint disease. PROCEDURE: Data evaluated included age, duration of clinical signs, and whether rupture of the CCL was complete or incomplete. Three groups (n = 20/group) were also compared on the basis of 5 histologic criteria; group-1 menisci appeared grossly normal and were obtained from dogs with naturally occurring rupture of the CCL, group-2 menisci were grossly abnormal and were also obtained from dogs with naturally occurring CCL ruptures, and group-3 menisci were collected at postmortem from dogs without stifle joint disease that were of similar age and weight as dogs in groups 1 and 2. RESULTS: Group-2 menisci were significantly different from group-1 and -3 menisci in all histologic criteria. Group-1 menisci were significantly different from control menisci in only 1 of the 5 histologic criteria (cartilage differentiation). Dogs that were > or =3 years old had significantly more surface cellularity than did dogs that were < 3 years old. A significant difference was not detected between groups 1 and 2 with regard to completeness of rupture. CONCLUSIONS AND CLINICAL RELEVANCE: Histologic changes in meniscal cartilage correlate with gross appearance of the cartilage at time of surgery for rupture of the CCL. On the basis of minimal histologic changes, routine removal of grossly normal menisci does not appear to be warranted.     

Use of ambulatory electrocardiography for detection of ventricular premature complexes in healthy dogs

OBJECTIVE: To evaluate the use of 24-hour ambulatory electrocardiography (AECG) for the detection of ventricular premature complexes (VPC) in healthy dogs. DESIGN: Case series. ANIMALS: 50 healthy mature dogs. PROCEDURE: A 24-hour AECG was performed on each dog and evaluated for the presence of VPC. RESULTS: Fifty dogs weighing between 18.2 to 40.9 kg (40 and 90 lb) representing 13 breeds were evaluated; there were 4 sexually intact females, 21 spayed females, 4 sexually intact males, and 21 castrated males. Ages ranged from 1 to 12 years. Thirty-four dogs had no VPC; 16 dogs had between 1 and 24 VPC. The grade of arrhythmia ranged from 1 to 4, with 4 dogs having an arrhythmia with a grade > 1. Significant differences were not detected between the group of dogs with VPC and those without VPC with regard to sex, age, and minimum, maximum, or mean heart rate. CONCLUSIONS AND CLINICAL RELEVANCE: We conclude that healthy mature dogs have infrequent VPC, as detected by use of 24-hour AECG. The presence of numerous or sequential VPC may be suggestive of cardiac or systemic disease and may indicate the need for thorough clinical evaluation.     

Evaluation of risk factors for degenerative joint disease associated with hip dysplasia in German Shepherd Dogs, Golden Retrievers, Labrador Retrievers, and Rottweilers.

OBJECTIVE: To determine whether age, breed, sex, weight, or distraction index (DI) was associated with the risk that dogs of 4 common breeds (German Shepherd Dog, Golden Retriever, Labrador Retriever, Rottweiler) would have radiographic evidence of degenerative joint disease (DJD) associated with hip dysplasia. DESIGN: Cross-sectional prevalence study. ANIMALS: 15,742 dogs. PROCEDURE: Hips of dogs were evaluated radiographically by use of the ventrodorsal hip-extended view, the compression v ew, and the distraction view. The ventrodorsal hip-extended view was examined to determine whether dogs had DJD. For each breed, a multiple logistic regression model incorporating age, sex, weight, and DI was created. For each breed, disease-susceptibility curves were produced, using all dogs, regardless of age, and dogs grouped on the basis of age. RESULTS: Weight and DI were significant risk factors for DJD in all breeds. For German Shepherd Dogs, the risk of having DJD was 4.95 times the risk for dogs of the other 3 breeds combined. In all breeds, the probability of having DJD increased with age. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the probability of having hip DJD increased with hip joint laxity as measured by use of DI. This association was breed-specific, indicating that breed-specific information on disease susceptibility should be incorporated when making breeding decisions and when deciding on possible surgical treatment of hip dysplasia.     

Evaluation of serum 17-hydroxyprogesterone concentration after administration of ACTH in dogs with hyperadrenocorticism

OBJECTIVE: To evaluate serum 17-hydroxyprogesterone (17-OHP) concentration measurement after administration of ACTH for use in the diagnosis of hyperadrenocorticism in dogs. DESIGN: Prospective study. ANIMALS: 110 dogs. PROCEDURE: Serum 17-OHP concentrations were measured before and after ACTH stimulation in 53 healthy dogs to establish reference values for this study. Affected dogs had pituitary-dependent (n = 40) or adrenal tumor-associated (12) hyperadrenocorticism or potentially had atypical hyperadrenocorticism (5; diagnosis confirmed in 1 dog). In affected dogs, frequency interval and borderline and abnormal serum 17-OHP concentrations after ACTH stimulation were determined. Serum cortisol concentrations were assessed via low-dose dexamethasone suppression and ACTH stimulation tests. RESULTS: In healthy dogs, serum 17-OHP concentration frequency intervals were grouped by sex and reproductive status (defined as < 95th percentile). Frequency intervals of serum 17-OHP concentrations after ACTH stimulation were < 77, < 2.0, < 3.2, and < 3.4 ng/mL (< 23.3, < 6.1, < 9.7, and < 10.3 nmol/L) for sexually intact and neutered females and sexually intact and neutered males, respectively. In 53 dogs with confirmed hyperadrenocorticism, serum cortisol concentrations after ACTH stimulation and 8 hours after administration of dexamethasone and serum 17-OHP concentrations after ACTH stimulation were considered borderline or abnormal in 79%, 93%, and 69% of dogs, respectively. Two of 5 dogs considered to have atypical hyperadrenocorticism had abnormal serum 17-OHP concentrations after ACTH stimulation. CONCLUSIONS AND CLINICAL RELEVANCE: Serum 17-OHP concentration measurement after ACTH stimulation may be useful in the diagnosis of hyperadrenocorticism in dogs when other test results are equivocal.     

Comparison of tibial plateau angles in small and large breed dogs

Cranial cruciate ligament (CCL) disease can affect dogs of all sizes. The literature describing tibial plateau angle (TPA) in small breed dogs is limited. A retrospective study was conducted in unselected dogs presented for stifle or tibial examination to compare TPA in small breed dogs (n = 146 dogs, 185 stifles) versus large breed dogs (n = 200 dogs, 265 stifles). Small breed dogs had a mean TPA 3.1° ± 0.6° higher than large breed dogs. There were higher TPAs in spayed females and castrated males for all dogs compared with intact males (3.6° ± 1.0° and 2.7° ± 1.0°, respectively). Dogs with unilateral and bilateral CCL disease had higher TPAs compared to dogs with intact CCLs (2.0° ± 0.7° and 2.5° ± 0.8°, respectively). Tibial morphology differs between large and small breed dogs; however, the significance of the impact of TPA on CCL disease in small breed dogs is unknown.     

Nitric oxide metabolite production in the cranial cruciate ligament, synovial membrane, and articular cartilage of dogs with cranial cruciate ligament rupture

OBJECTIVE: To measure concentrations of nitric oxide metabolites (nitrite-nitrate [NOt]) in cartilage, synovial membrane, and cranial cruciate ligament (CCL) in dogs and evaluate associations with osteoarthritis in dogs with CCL rupture. ANIMALS: 46 dogs with CCL rupture and 54 control dogs without joint disease. PROCEDURE: Tissue specimens for histologic examination and explant culture were harvested during surgery in the CCL group or immediately after euthanasia in the control group; NOt concentrations were measured in supernatant of explant cultures and compared among dogs with various degrees of osteoarthritis and between dogs with and without CCL rupture. RESULTS: Osteoarthritic cartilage had significantly higher NOt concentration (1,171.6 nmol/g) than did healthy cartilage (491.0 nmol/g); NOt concentration was associated with severity of macroscopic and microscopic lesions. Synovial membrane NOt concentration did not differ between dogs with and without CCL rupture. Ruptured CCL produced less NOt than did intact ligaments. In control dogs, NOt concentrations were similar for intact ligaments (568.1 nmol/g) and articular cartilage (491.0 nmol/g). Synthesis of NOt was inhibited substantially by coincubation with inhibitors. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that NOt in canine joint tissues originates from the inducible nitric oxide synthase pathway. Nitric oxide metabolite production in cartilage was greater in dogs with osteoarthritis than in healthy dogs and was associated with lesion severity, suggesting that nitric oxide inhibitors may be considered as a treatment for osteoarthritis. The CCL produces substantial concentrations of NOt; the importance of this finding is unknown.     

Localization of cathepsin K and tartrate-resistant acid phosphatase in synovium and cranial cruciate ligament in dogs with cruciate disease

OBJECTIVE: To localize cathepsin K and tartrate-resistant acid phosphatase (TRAP) in synovium and cranial cruciate ligament (CCL) of dogs with cruciate disease. ANIMALS: Dogs (n=15) with cruciate disease and ruptured CCL, and 12 dogs with intact CCL. METHODS: Synovium and CCL were examined histologically and cells containing cathepsin K or TRAP were identified immunohistochemically and histochemically, respectively. RESULTS: Increased cellular localization of cathepsin K and TRAP was detected in synovium and ruptured CCL in dogs with cruciate disease, when compared with tissues from dogs with intact CCL. Inflammation of synovium with TRAP+ macrophage-like cells was seen in 73% of dogs with CCL disease, but was not seen in dogs with intact CCL. The presence of cathepsin K and TRAP protein in synovium and CCL tissues was significantly correlated in dogs with CCL rupture. CONCLUSION: Inflammation of the epiligament of ruptured CCL with cathepsin K+ and TRAP+ macrophage-like cells forms part of a similar, more generalized chronic inflammatory change within the periarticular tissues of the stifle of a large proportion of dogs with CCL rupture. CLINICAL RELEVANCE: Production of matrix-degrading enzymes by the synovium may induce progressive pathologic rupture of the CCL. Therefore, these collagenolytic pathways may offer a novel target for medical therapy of joint inflammation in canine patients with cruciate disease.     

Use of a microtiter Coombs' test for study of age, gender, and breed distributions in immunohemolytic anemia of the dog

Sixteen of 17 dogs with immunohemolytic anemia had a microtiter Coombs' test titer greater than or equal to 1:64. Performance of the test as a hemagglutination assay apparently increased the sensitivity of the test. Three of the dogs with immunohemolytic anemia were sexually intact females, 11 were spayed females, and 3 were sexually intact males. When age and gender were considered together, females were 4.3 times more likely to have immunohemolytic anemia than were males (P less than 0.05). When corrected for population age distribution, spayed females were not predisposed to the problem.     

Adiposity and adiponectin in dogs: investigation of causes of discrepant results between two studies

Although one study showed lower adiponectin concentrations in obese dogs, other recent studies indicate that adiponectin might not be decreased in obese dogs, raising the possibility that the physiology of adiponectin is different in dogs than in humans. The aim of this study was to investigate possible causes of the discrepancy between the two largest studies to date that assessed the association between adiposity and adiponectin concentration in dogs, including the validity of the assay, laboratory error, and the effects of breed, sex, and neuter status on the relationship between adiposity and adiponectin concentrations. Adiponectin concentrations measured with a previously validated adiponectin ELISA were compared with those estimated by Western blotting analysis of reduced and denatured plasma samples. The possibility of laboratory error and the effect of EDTA anticoagulant and aprotinin were tested. Adiponectin concentration was measured by ELISA in 20 lean dogs (10 male and 10 female, 5 neutered in each sex). There was close correlation between adiponectin concentrations measured by ELISA and those estimated by Western blotting analysis (r = 0.90; P < 0.001). There was no substantial effect of EDTA, aprotinin, or laboratory error on the results. There was confounding by neuter status of the relationship between adiposity and adiponectin concentrations, but adiponectin concentrations were not significantly lower in male than in female lean dogs (females, 36 mg/L; males, 26 mg/L; P > 0.20) and were not significantly lower in intact than in neutered lean male dogs (intact, 28 mg/L; neutered, 23 mg/L; P = 0.49). We conclude that the adiponectin ELISA previously validated for use in dogs appears to be suitable for determination of canine adiponectin concentrations and that testosterone does not appear to have a strong effect on plasma adiponectin concentrations in dogs. Obesity might decrease adiponectin concentrations in intact but not in neutered dogs.     

Effect of gonadectomy on subsequent development of age-related cognitive impairment in dogs.

OBJECTIVE: To determine whether gonadectomy predisposes dogs to development of age-related behavioral changes linked to cognitive impairment. DESIGN: Cohort study. ANIMALS: 29 sexually intact male dogs, 63 spayed female dogs, and 47 castrated male dogs 11 to 14 years old. PROCEDURE: Information on possible impairments in 4 behavioral categories linked to cognitive impairment (orientation in the home and yard, social interactions, house training, and sleep-wake cycle) was obtained from owners of the dogs by use of a structured telephone interview format. A second interview was performed 12 to 18 months after the initial interview, and differences in responses were evaluated. RESULTS: Sexually intact male dogs were significantly less likely than neutered dogs to progress from mild impairment (i.e., impairment in 1 category) to severe impairment (i.e., impairment in > or = 2 categories) during the time between the first and second interviews. This difference was not attributable to differences in ages of the dogs, duration of follow-up, or the owners' perceptions of the dogs' overall health. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the presence of circulating testosterone in aging sexually intact male dogs may slow the progression of cognitive impairment, at least among dogs that already have signs of mild impairment. Estrogens would be expected to have a similar protective role in sexually intact female dogs; unfortunately, too few sexually intact female dogs were available for inclusion in the study to test this hypothesis. There may be a need to evaluate possible methods for counteracting the effects of loss of sex hormones in gonadectomized dogs.     

Influence of signalment on developing cranial cruciate rupture in dogs in the UK

Objectives : To investigate risk factors associated with cranial cruciate ligament rupture in dogs. Methods : Retrospective case‐control study: medical records of a first‐opinion veterinary practice were searched for dogs diagnosed with cranial cruciate ligament rupture (1995 to 2007). For each case, six unaffected dogs were randomly selected from all dogs presenting that day for comparison. Multi‐variable binary logistic regression was performed to assess the association of variables on likelihood of cruciate rupture. Results : Frequency of cranial cruciate ligament rupture was 1·19% [95% confidence interval (CI) 1·02 to 1.36%]. West Highland white terriers (n=17), Yorkshire terriers (n=14) and Rottweilers (n=11) were at significantly increased risk of cranial cruciate ligament rupture (P≤0·002). Rottweilers were at five times greater risk compared with other pure breeds (OR 5·12, 95% CI 2·281 to 11·494, P<0·001), obesity quadrupled the risk of cranial cruciate ligament rupture (OR 3·756, 95% CI 1·659 to 8·502, P=0·001) and females were twice as likely to suffer cranial cruciate ligament failure compared to males (OR 2·054, 95% CI 1·467 to 2·877, P<0·001). Dogs less than two years old were statistically less likely to sustain cranial cruciate ligament rupture than dogs older than eight years (OR 0·246, 95% CI 0·127 to 0·477, P<0·001). There was no significant difference in median weights (in kilograms) of neutered dogs, compared to their entire counterparts in either the case group (P=0·994) or in the control group (P=0·630). There was also no significant difference in body condition (‐underweight/normal weight/overweight/obese) of neutered versus entire dogs among the cases (P=0·243), or the controls (P=0·211). Clinical Significance : Cranial cruciate ligament rupture is more likely in Rottweilers and in female dogs, older dogs and obese dogs. Following multi‐variable analysis, it was established that neutering was not associated with increased risk of cranial cruciate ligament rupture.     

Growth dynamics of the canine proximal tibial physis

Objective: To determine growth of the proximal tibial physis in the Labrador Retriever, a breed of dog at risk for rupture of the cranial cruciate ligament (CCL). Animals: Male Labrador Retriever dogs (n=6). Methods: Tantalum markers (0.5 mm diameter) were implanted in the right proximal tibial epiphysis and metaphysis of each dog at 16 weeks of age. Lateral and craniocaudal radiographic projections of the tibia were made monthly and longitudinal growth was assessed from radiographs; a growth curve was generated from the data. Data from dogs that had undergone proximal tibial epiphysiodesis (PTE) was compared with the growth curve to demonstrate if the growth curve accurately predicted changes in the growth associated with this procedure. Results: Growth rate of individual dogs decreased slowly and non‐linearly over the 1st year of age. Growth from the proximal tibial physis is described. Conclusions: Growth of individual dogs described here follows the model of saltation and stasis. The growth curve generated predicted the change in tibial plateau angle (TPA) for two Labrador Retrievers that had PTE (±1°).