Association in bitches between breed, size, neutering and docking, and acquired urinary incontinence due to incompetence of the urethral sphincter mechanism

Later-age neutering causes lower risk of early-onset urinary incontinence than early neutering-a VetCompass target trial emulation study

There is growing evidence supporting clinically important associations between age at neutering in bitches and subsequent urinary incontinence (UI), although much of this evidence to date is considered weak. Target trial emulation is an innovative approach in causal inference that has gained substantial attention in recent years, aiming to simulate a hypothetical randomised controlled trial by leveraging observational data. Using anonymised veterinary clinical data from the VetCompass Programme, this study applied the target trial emulation framework to determine whether later-age neutering (≥ 7 to ≤ 18 months) causes decreased odds of early-onset UI (diagnosed < 8.5 years) compared to early-age neutering (3 to < 7 months). The study included bitches in the VetCompass database born from January 1, 2010, to December 31, 2012, and neutered between 3 and 18 months old. Bitches were retrospectively confirmed from the electronic health records as neutered early or later. The primary outcome was a diagnosis of early-onset UI. Informed from a directed acyclic graph, data on the following covariates were extracted: breed, insurance status, co-morbidities and veterinary group. Inverse probability of treatment weighting was used to adjust for confounding, with inverse probability of censoring weighting accounting for censored bitches. The emulated trial included 612 early-age neutered bitches and 888 later-age neutered bitches. A pooled logistic regression outcome model identified bitches neutered later at 0.80 times the odds (95% CI 0.54 to 0.97) of early-onset UI compared with bitches neutered early. The findings show that later-age neutering causes reduced odds of early-onset UI diagnosis compared with early-age neutering. Decision-making on the age of neutering should be carefully considered, with preference given to delaying neutering until after 7 months of age unless other major reasons justify earlier surgery. The study is one of the first to demonstrate successful application of the target trial framework to veterinary observational data.

ACVIM consensus statement on diagnosis and management of urinary incontinence in dogs

Urinary incontinence (UI) is a disorder of micturition that can occur in dogs of any age, sex, and breed depending on the underlying cause and time of onset. Diagnosis and treatment for various causes of UI in dogs have been described by multiple comprehensive single author review articles, but large prospective clinical trials comparing treatment outcomes in veterinary medicine are lacking. The objectives of this consensus statement therefore are to provide guidelines on both recommended diagnostic testing and treatment for various causes of UI in dogs. Specifically, pathophysiology directly related to the canine urinary system will be reviewed and diagnostic and therapeutic challenges will be addressed. A panel of 12 experts in the field (8 small animal internists [L. Adams, J. Bartges, A. Berent, J. Byron, J. Foster, A. Kendall, S. Vaden, J. Westropp], 2 neurologists [J. Coates, N. Olby], 1 radiologist [G. Oetelaar], and 1 surgeon [C. Adin]) was formed to assess and summarize evidence in the peer-reviewed literature and to complement it with consensus recommendations using the Delphi method. Some statements were not voted on by all panelists. This consensus statement aims to provide guidance for management of both male and female dogs with underlying storage or voiding disorders resulting in UI.

Applying children's enuresis treatment with amitriptyline for canine post-spaying urinary incontinence: A pilot estriol-controlled randomized clinical trial

Urinary incontinence due to urethral sphincter mechanism incompetence (USMI) affects up to 20% of bitches that undergo spaying surgery. Amitriptyline is a tricyclic antidepressant whose urinary retention is a reported side effect. This study aimed to assess the efficacy and safety of amitriptyline when compared to estriol orally. Fifteen bitches with a clinical diagnosis of post-spaying UI were evaluated during 60 days in a non-blinded randomized clinical trial. All patients were enrolled after clinical evaluation consisting of anamnesis, physical examination, and complementary exams (complete blood count, biochemical parameters, urinalysis, and abdominal ultrasound). The amitriptyline (AMT) group consisted of 8 bitches, which received the initial dose of 1 mg/kg every 12 h, whereas the estriol (EST) group consisted of 7 bitches which were initially treated with 1 mg/animal every 24 h. Patients underwent clinical evaluation at 7 days, and then at 21 and 60 days of treatment to assess safety and efficacy, as well as adjustments of dose when necessary. A urinary incontinence scale was used to assess the level of incontinence and therapeutic response to treatment. During the period of the study, estriol was fully effective in 71% of cases and amitriptyline in 62%. Both drugs proved safe in the medical treatment of USMI, with adverse effects such as somnolence (AMT, n = 5/8) and male attraction (EST, n = 1/7). The results support the amitriptyline recommendation as a substitute for estriol in USMI treatment.

Understanding the effects of sustained supraphysiologic concentrations of luteinizing hormone in gonadectomized dogs: What we know and what we still need to learn

Removal of the gonads with surgical sterilization results in a loss of negative feedback to the hypothalamus and anterior pituitary. The sustained supraphysiologic luteinizing hormone (LH) concentrations in gonadectomized dogs can significantly alter organ function and even induce neoplastic changes. For example, gonad removal has a profound effect on thyroid function and is reported to be the most significant cause for the development of hypothyroidism in dogs. Thirty percent more gonadectomized dogs develop hypothyroidism compared with intact dogs. Within the canine thyroid, LH receptors are co-localized with thyroid stimulating hormone (TSH) receptors. Continuous LH receptor activation in gonadectomized dogs may interfere TSH receptor function by consuming second messengers involved in G-protein receptor cell signaling, preventing the action of TSH when it binds to its receptor in the thyroid, resulting in hypothyroidism. The incidence of anterior cruciate ligament ruptures is significantly increased following gonad removal independent of breed, sex, weight or body condition. Luteinizing hormone receptors are expressed in the cruciate ligament and continuous LH receptor activation may increase laxity in these ligaments, resulting in joint instability. Both male and female gonadectomized dogs are at a significantly increased risk for lymphoma and hemangiosarcoma. Luteinizing hormone receptors are also abundant in these tissues. Research in four canine hemangiosarcoma cell lines found that LH receptor activation induces cell proliferation. In addition, research in three canine T-cell lymphoma cell lines found that LH receptor activation induces cell proliferation, adhesion, and invasion as well as increases LH receptor expression. Research is needed to determine if LH reducing strategies using gonadotropin releasing hormone agonists will increase remission times in gonadectomized dogs with LH receptor-positive tumors. In conclusion, among the non-reproductive functions of gonads, suppression of LH secretion and resulting LH receptor overexpression appear necessary in maintaining endocrine, musculoskeletal, and anti-neoplastic health.

Prevalence of Reproductive Disorders including Mammary Tumors and Associated Mortality in Female Dogs

Female dogs, especially intact or neutered lately, are at increased risk for reproductive disorders including mammary tumors (MTs). This retrospective study evaluated the prevalence of reproductive pathology and associated mortality in a cohort of female dogs presented at a single veterinary clinic. The medical records of female dogs born in 2000–2003 were reviewed. The study included 599 cases, of which 293 were followed up until death. Causes of death were analyzed according to the spaying status. Among the 599 female dogs, 306 were intact (51%), 50 (8%) had been spayed before 2 years of age (ES, early spaying), and 243 (41%) after 2 years (LS, late spaying). During their lifetime, 79 dogs (13.2%) developed pyometra, and 160 (26.7%) a mammary tumor. Among the 293 dogs with complete follow-up, 103 (35.1%) had at least one MT during their lifetime, of which 53 (51.5%) died of their mammary cancer. Spayed (ES + LS) female dogs had a 4-fold decreased risk of dying from mammary cancer (OR = 0.23, 95% CI 0.11–0.47, p < 0.0001) compared to intact females. In this low-sterilization rate population, MTs developed in 35.1% of female dogs over their lifetime and was the cause of death in half of them.

Long-term outcome of female dogs treated for intramural ectopic ureters with cystoscopic-guided laser ablation

OBJECTIVE

To report the complications and long-term outcome of female dogs with intramural ectopic ureter(s) (iEU) undergoing cystoscopic-guided laser ablation (CLA) and determine the effect of post-CLA neutering on urinary continence.

STUDY DESIGN

Retrospective clinical study.

ANIMALS OR SAMPLE POPULATION

Thirty-four client-owned dogs.

METHODS

Medical records of female dogs that had iEU-CLA were reviewed. A 10-point continence score was assigned before, immediately after, and at a minimum of 12 months postprocedure via owner telephone contact. Neutering status prior to and postprocedure was recorded.

RESULTS

Continence scores increased in all dogs after CLA (p < .0001, mean duration of follow-up: 63.9 ± 5.7 months) with an increase of the median score from 2 (preprocedure) to 10 (postprocedure). A urethral tear occurred in 2/34 dogs immediately after the procedure, successfully managed conservatively. Mild hematuria was present in 2/34, lasting less than 48 h. Postoperative urinary tract infections were documented in 6/34 dogs. Two dogs died of urinary-related issues at 1 and 5 months after CLA. Complete and near-complete urinary continence (scores 9 and 10/10) was achieved in 26/32 dogs including 3 dogs requiring medical (2) or surgical interventions (1). Post-CLA neutering did not affect continence scores (p = .44).

CONCLUSION

A large proportion of dogs regained and maintained full continence after CLA alone. Subsequent medical or surgical therapy allowed further improvements when needed. Post-CLA neutering did not negatively impact urinary continence score.

CLINICAL SIGNIFICANCE

The beneficial effect of iEU-CLA in female dogs is long standing and not affected by postprocedural neutering.

Prevalence and risk factors for urinary incontinence in bitches five years after ovariohysterectomy

ABSTRACT Ovariohysterectomy (OHE) is the most performed elective surgery in veterinary medicine. Although this procedure brings benefits both to the animal and public health, acquired urinary incontinence is a possible complication resultant from it. The aim of this study was to determine the prevalence of urinary incontinence and evaluate size, breed, and time of surgery as risk factors in a population of spayed female dogs in the Hospital de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul, in the year of 2013, through the use of a multiple-choice screening instrument. Identified estimated prevalence was 11.27% and main risk factors were as follows: large size (OR = 7.12 IC95% = 1.42 - 35.67), Rottweiler breed (OR = 8.92; IC95% = 5.25 - 15.15), Pit-bull breed (OR = 4.14; IC95% = 2.19 - 7.83), and Labrador breed (OR = 2.73; IC95% = 1.53 - 4.87). Time of surgery was not considered a risk factor for urinary incontinence in this population (OR = 1.45; IC95% = 0.86 - 2.40). Even though most owners reported a small impact on their relationship with the animal, urinary incontinence hazard should be addressed before spaying.

Desexing Dogs: A Review of the Current Literature

Background: Desexing dogs is promoted for population control, preventative healthcare, and behavior modification. Common methods are orchiectomy and ovariectomy/ovariohysterectomy. GnRH superagonist implants are available in some areas. Alternative methods like vasectomy and salpingectomy/hysterectomy are uncommon. The terminology used to describe desexing is inconsistent and contradictory, showing a need for the adaption of standardized terminology. Population Control: Surprisingly, empirical studies show no effects of desexing on population control in companion and shelter dogs despite desexing being consistently recommended in the literature. There is evidence for a population control effect in free-roaming dogs, where desexing also has benefits on zoonotic disease and bite risk. Population control in free-roaming dogs is mostly correlated with female, not male desexing. Health and Lifespan: Desexing affects numerous disease risks, but studies commonly neglect age at diagnosis and overall lifespan, age being by far the most important risk factor for most diseases. We argue that lifespan is a more important outcome than ultimate cause of death. A beneficial effect of desexing on lifespan is consistently demonstrated in females, while evidence for a beneficial effect in males is inconsistent. Studies are likely biased in desexing being a proxy for better care and desexed dogs having already lived to the age of desexing. Desexing reduces or eliminates common life-limiting diseases of the female reproductive system such as pyometra and mammary tumors, while no analogous effect exists in males. Disease risks increases across sexes and breeds include cruciate ligament rupture, various cancers, and obesity. Urinary incontinence risk is increased in females only. Various other disease risk changes show considerable variability between breeds and sexes. Behavioral Effects: Desexed males show reduced libido, roaming, conspecific mounting, and urinary marking frequency, as well as reduced male dog-directed aggression in a majority of males desexed for behavioral reasons. There is a detrimental effect on the risk and progression of age-related cognitive dysfunction. Desexed dogs may be less likely to cause bite injuries across sexes. The evidence for other effects such as human-directed aggression, human or object mounting, resource guarding, or shyness and anxiety is inconsistent and contradictory. There are few studies specific to females or individual breeds. Conclusions: The evidence for a beneficial effect of desexing is stronger in female than in male dogs; however, there is significant variation between breeds and sexes, and more research is needed to further elucidate these differences and to arrive at individualized evidence-based recommendations for clinical practice.

Associations between neutering and early-onset urinary incontinence in UK bitches under primary veterinary care

OBJECTIVES

To investigate association between neutering and early-onset urinary incontinence in bitches under primary veterinary care in the UK.

MATERIALS AND METHODS

A retrospective cohort study of bitches within VetCompass born between January 1, 2010 and December 31, 2012 that were followed until March 31, 2018. The clinical records were automatically searched and manually validated for incontinence cases. Incidence risk and rate over the study period were calculated. Cox regression modelling separately evaluated the hazard of urinary incontinence and association with neutering: (1) from the date of birth for all bitches, both neutered and entire; and, (2) from the date of neutering for the neutered subset. Other variables considered included breed, bodyweight and veterinary practice group.

RESULTS

Overall, 492 bitches were identified with early-onset urinary incontinence from a total of 72,971 included in the study period. Incidence risk was 0.68% (95% confidence intervals 0.62 to 0.74), while incidence rate increased with age. After accounting for confounding factors, increased hazard of early-onset urinary incontinence was identified in: (1) neutered bitches, with the effect increasing with age; and, (2) bitches neutered before 6 months, within the first 2 years following neutering. In both models, increased hazard was additionally associated with increasing bodyweight and breed.

CLINICAL SIGNIFICANCE

Neutering itself and early-age neutering (<6 months) are major risk factors for early-onset urinary incontinence. These results should be taken into account in making evidence-based recommendations on neutering and its timing.

Do prevalence rates and severity of acquired urinary incontinence differ between dogs spayed by laparoscopy or laparotomy? Comparing apples with apples with a matched-pair cohort study

OBJECTIVE

To compare the prevalence rates and severity of acquired urinary incontinence (AUI) between dogs spayed with laparoscopic and open laparotomy approaches.

STUDY DESIGN

Retrospective matched-pair cohort study.

ANIMALS

In total, 1285 privately owned dogs spayed >5 years previously were included in the study.

METHODS

Laparoscopically spayed dogs were matched with dogs spayed by traditional laparotomy. Matching variables were breed, bodyweight, age at spaying, time of spaying in relation to the onset of puberty, time interval since spaying, and age. In 400 matched-paired dogs, the outcome of AUI was assessed by using an owner questionnaire. A conditional logistic regression for matched pairs was performed on the data of 308 dogs.

RESULTS

Among 308 dogs, 30 and 29 dogs spayed by laparotomy and laparoscopy, respectively, were affected by AUI. The identified risk factors for AUI were age and time interval since spaying. The surgical approach (laparoscopy or laparotomy) was neither revealed as a risk factor nor did it influence the severity of AUI.

CONCLUSION

The risk of AUI after spaying is not influenced by the surgical approach, (laparoscopy or laparotomy). Nearly every fifth dog spayed by laparotomy or by laparoscopy was affected by AUI. A relatively longer time interval since spaying and increased age of the dog increased the risk for AUI.

CLINICAL SIGNIFICANCE

Owners of dogs with a predisposition for AUI must be counseled about this risk when they present their dogs for spaying, regardless of surgical approach chosen.

2019 AAHA Canine Life Stage Guidelines*

The guidelines are an update and extension of the AAHA Canine Life Stage Guidelines published in 2012. A noteworthy change from the earlier guidelines is the division of the dog’s lifespan into five stages (puppy, young adult, mature adult, senior, and end of life) instead of the previous six. This simplified grouping is consistent with how pet owners generally perceive their dog’s maturation and aging process and provides a readily understood basis for an evolving, lifelong healthcare strategy. The guidelines provide the following recommendations for managing 10 health-related factors at each of the first four canine life stages: lifestyle effect on the patient’s safety, zoonotic and human safety risk, behavior, nutrition, parasite control, vaccination, dental health, reproduction, breed-specific conditions, and a baseline diagnostic profile.

Prevalence of Spondylosis Deformans in Tailed Versus Tail-Docked Rottweilers

Tail docking is a routine procedure for rottweilers in the United States and Canada. A cross-sectional comparative study was conducted in tailed (n = 25) and docked (n = 39) rottweilers ≥5 yr old to compare prevalence and severity of spondylosis deformans in the lumbar spine between groups. The prevalence of spondylosis was 68.0% in tailed dogs and 76.9% in docked dogs, which was not significantly different (P = .563). Distribution of spondylosis severity did not significantly differ between tailed and docked dogs (P = .102). Logistic regression found moderate to severe spondylosis was associated with age and sex. Females were three times at greater risk than males (odds ratio 3.10, 95% confidence interval 1.060-9.08; P = .039). Risk increased 1.4 times for each additional year (odds ratio 1.43, 95% confidence interval 1.02-1.99, P = .036). Tail docking may not impact or only play a minor role in spondylosis deformans in rottweilers.

Spaying and urinary incontinence in bitches under UK primary veterinary care: a case-control study

Objectives

To evaluate associations between spaying and urinary incontinence in bitches under primary veterinary care in the UK.

Materials and Methods

A case–control study was nested within the study population of 333,910 bitches, which included all bitches within the VetCompass database with an electronic patient record in 2016 or in both 2015 and 2017. The electronic records were searched automatically for urinary incontinence cases, which were manually reviewed for inclusion. All non‐cases were included as controls. Additional demographic and clinical information was extracted on cases and controls.

Results

The study included 427 incident cases and 1708 controls that were presented between November 1, 2014 and October 31, 2017. Prior spaying was associated with increased odds of urinary incontinence (odds ratio: 3.01; 95% CIs: 2.23 to 4.05). Increased odds of urinary incontinence were additionally associated with increasing age and increasing bodyweight. Age at spay was not associated with urinary incontinence.

Clinical Significance

The findings support spaying as a major risk factor associated with urinary incontinence, but age at spay appears to be of less clinical importance. These results will help assist clinicians in making evidence‐based recommendations on spaying while taking other considerations for urinary incontinence into account.

Canine urethral sphincter pressure profile under incremental inflation of an artificial cuff: a cadaver study

OBJECTIVES

To determine whether artificial urethral sphincter filling volume is proportional to peak pressure exerted on the urethra.

MATERIALS AND METHODS

Urethral pressure profilometry was performed in five female, medium-sized, mixed-breed canine cadavers following artificial urethral sphincter placement. Maximum urethral pressure was recorded following sequential incremental inflation of 0.15 mL and compared to baseline pressure and between dogs using two-way analysis of variance.

RESULTS

Artificial urethral sphincter placement in cadavers was associated with an increase in urethral pressure, which was significantly correlated with inflation volume. The correlation was non-linear and demonstrated considerable individual variation. Maximum urethral pressures after artificial urethral sphincter placement exceeded those reported in conscious continent dogs within a narrow volume range, in which a 0.15 mL infusion more than doubled maximal urethral pressures.

CLINICAL SIGNIFICANCE

Rapid increases in urethral pressure from the artificial urethral sphincter over a small range of filling volumes (0.15 mL increments) might explain why some clinical cases can become suddenly dysuric following incremental inflations. We suggest that smaller increments of filling (0.05 to 0.1 mL) may achieve finer pressure control.

Urinary incontinence in male dogs under primary veterinary care in England: prevalence and risk factors

OBJECTIVE

To estimate prevalence and identify demographic risk factors for urinary incontinence in male dogs.

METHODS AND METHODS

The study population included all dogs within the VetCompass database from September 1, 2009 to July 7, 2013. Electronic patient records were searched for urinary incontinence cases; demographic and clinical information were extracted and analysed.

RESULTS

Of 109,428 male dogs attending 119 clinics in England, there were an estimated 1027 dogs diagnosed with urinary incontinence, giving a prevalence of 0.94% (95% confidence interval: 0.88 to 1.00). Breeds with highest odds of incontinence in male dogs (compared with mixed breed dogs) included the bull mastiff (odds ratio: 17.21, 95% confidence interval: 6.65 to 44.56, case=5, non-case=314, P<0.001), Irish red setter (odds ratio: 12.79, 95% confidence interval: 4.83 to 33.84, case=5, non-case=142, P<0.001), fox terrier (odds ratio: 9.60, 95% confidence interval: 3.68 to 25.05, case=5, non-case=176, P < 0.001), bulldog (odds ratio: 5.72, 95% confidence interval: 2.24 to 14.59, case=5, non-case=929, P<0.001) and boxer (odds ratio: 3.65, 95% confidence interval: 1.84 to 7.25, case=10, non-case=1470, P<0.001). Increased odds of urinary incontinence were associated with greater age (age 9 to 12 years, odds ratio: 10.46, 95% confidence interval: 6.59 to 16.62, n=12,348, P<0.001) and being insured (odds ratio: 1.96, 95% confidence interval: 1.53 to 2.51, n=26,202, P<0.001). There was no association with castration or bodyweight using multi-variable analysis.

CLINICAL SIGNIFICANCE

The overall prevalence of urinary incontinence in male dogs is approximately 1%, which may be higher than expected given the sparsity of reports describing this problem. In contrast to bitches, neutering and bodyweight were not associated with greater odds of urinary incontinence, which is important when giving neutering advice.

Labrador retrievers under primary veterinary care in the UK: demography, mortality and disorders

BACKGROUND

Labrador retrievers are reportedly predisposed to many disorders but accurate prevalence information relating to the general population are lacking. This study aimed to describe demography, mortality and commonly recorded diseases in Labrador retrievers under UK veterinary care.

METHODS

The VetCompass™ programme collects electronic patient record data on dogs attending UK primary-care veterinary practices. Demographic analysis covered all33,320 Labrador retrievers in the VetCompass™ database under veterinary care during 2013 while disorder and mortality data were extracted from a random sample of 2074 (6.2%) of these dogs.

RESULTS

Of the Labrador retrievers with information available, 15,427 (46.4%) were female and 15,252 (53.6%) were male. Females were more likely to be neutered than males (59.7% versus 54.8%, P <  0.001). The overall mean adult bodyweight was 33.0 kg (SD 6.1). Adult males were heavier (35.2 kg, SD 5.9 kg) than adult females (30.4 kg, SD 5.2 kg) (P <  0.001). The median longevity of Labrador retrievers overall was 12.0 years (IQR 9.9-13.8, range 0.0-16.0). The most common recorded colours were black (44.6%), yellow (27.8%) and liver/chocolate (reported from hereon as chocolate) (23.8%). The median longevity of non-chocolate coloured dogs (n = 139, 12.1 years, IQR 10.2-13.9, range 0.0-16.0) was longer than for chocolate coloured animals (n = 34, 10.7 years, IQR 9.0-12.4, range 3.8-15.5) (P = 0.028).Of a random sample of 2074 (6.2%) Labrador retrievers under care in 2013 that had full disorder data extracted, 1277 (61.6%) had at least one disorder recorded. The total number of dogs who died at any date during the study was 176. The most prevalent disorders recorded were otitis externa (n = 215, prevalence 10.4%, 95% CI: 9.1-11.8), overweight/obesity (183, 8.8%, 95% CI: 7.6-10.1) and degenerative joint disease (115, 5.5%, 95% CI: 4.6-6.6). Overweight/obesity was not statistically significantly associated with neutering in females (8.3% of entire versus 12.5% of neutered, P = 0.065) but was associated with neutering in males (4.1% of entire versus 11.4% of neutered, P < 0.001). The prevalence of otitis externa in black dogs was 12.8%, in yellow dogs it was 17.0% but, in chocolate dogs, it rose to 23.4% (P < 0.001). Similarly, the prevalence of pyo-traumatic dermatitis in black dogs was 1.1%, in yellow dogs it was 1.6% but in chocolate dogs it rose to 4.0% (P = 0.011).

CONCLUSIONS

The current study assists prioritisation of health issues within Labrador retrievers. The most common disorders were overweight/obesity, otitis externa and degenerative joint disease. Males were significantly heavier females. These results can alert prospective owners to potential health issues and inform breed-specific wellness checks.

Long-Term Outcome of Female Dogs Treated with Static Hydraulic Urethral Sphincter for Urethral Sphincter Mechanism Incompetence

The purpose of the study was to report the postoperative outcome, complications, and long-term follow-up of the use of a static hydraulic urethral sphincter for the management of urethral sphincter mechanism incompetence in female dogs. Medical records were reviewed to extract information on long-term (&gt;365 days) outcome data. Telephone owner questionnaire was performed to assess postoperative urinary continence scores (scale 1–10, where 10 is complete continence) and the presence and frequency of complications. Twenty female dogs were included. Mean (±standard deviation) time to follow-up was 1,205.1 (±627.4) days. Median continence score/10 (range) was 3.5 (2–6) preoperatively, and 9.0 (7–10) at the last follow-up. Median continence score was significantly higher at all time points postoperatively compared with before surgery (P &lt; .001). Complete continence was achieved in 90% of bitches. Minor complications occurred in 13 bitches and included dysuria (8), bacterial cystitis (8), longer urination time (10), incisional seroma (5), urinary retention (3), hematuria (2), and pain when urinating (2). Major complications occurred in one dog (static hydraulic urethral sphincter removed 28 mo after placement). Continence scores were sustainably improved in the long-term. Complications were mostly minor. Urinary tract infections were the most common but resolved with conventional antibiotic treatment.

Urethral Sphincter Mechanism Incompetence in Dogs: An Update

Urethral sphincter mechanism incompetence (USMI) is the most common cause of acquired urinary incontinence in dogs. The pathogenesis of USMI is multifactorial and complex. Studies have shown variable results regarding the effects and timing of sterilization on the incidence of USMI. Diagnosis of USMI is often based on history, physical examination, and elimination of other differentials. Treatment options for USMI include medications, such as α-adrenergic agents and estrogen products, minimally-invasive urethral bulking procedures, surgical procedures (e.g., indwelling urethral occluders), or combination therapy. The overall prognosis for USMI is typically fair to good with long-term therapy.

Urethral Sphincter Mechanism Incompetence in 163 Neutered Female Dogs: Diagnosis, Treatment, and Relationship of Weight and Age at Neuter to Development of Disease

BACKGROUND

Urethral sphincter mechanism incompetence (USMI) is the most common cause of urinary incontinence in neutered bitches and is most common in dogs weighing >20 kg.

OBJECTIVES

To describe a population of neutered bitches with USMI and investigate their initial presentation, the relationship between weight and age at neuter, and treatment.

ANIMALS

One hundred and sixty-three female dogs with USMI (UI) diagnosed between January 2009 and December 2012, and 193 continent neutered control (C) bitches.

METHODS

Retrospective data were collected from neutered female dogs with USMI and healthy, continent neutered females presented between January 2009 and December 2012.

RESULTS

Urinary incontinent dogs weighed more than C dogs (P = .003), and there was no difference in age at neuter. The relationship between weight at diagnosis and age at neuter was found to impact the hazard of USMI. A decrease in the hazard of USMI was found in dogs weighing >25 kg for every month delay of neuter in the first year. The hazard did not change for dogs <15 kg. Median time from neuter to development of incontinence was 3.73 years. Phenylpropanolamine was prescribed in 75.5%, diethylstilbestrol in 21.5%, and both in 3.1% of dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Neutering bitches expected to be >25 kg adult weight later in their first year may decrease the hazard of developing USMI, whereas age at neutering of bitches <25 kg may not impact continence. Heavier dogs have increased risk of USMI, and onset occurs within a few years of neuter.

Influence of ovariohysterectomy and deslorelin acetate on the spontaneous activity of the rabbit urinary bladder in vitro

Lower urinary tract symptoms are not only a serious health problem but also a substantial sociologic issue affecting human beings and companion animals. Estrogen deficiency is considered an etiologic factor of urinary incontinence in postmenopausal women and spayed female dogs. However, insufficient effectiveness of hormonal therapy has caused an intensive search for new therapeutic options. GnRH analogs have positive clinical effects in neutered female dogs suffering from incontinence, but the mechanism of action is not known. The aim of our study was to determine the effect of long-acting deslorelin acetate on the spontaneous activity of urinary bladder sections from a rabbit model of long-term estrogen deprivation. The study was conducted on 21 female New Zealand White rabbits divided into the following groups: control group, ovariohysterectomized (OHX) group, and ovariohysterectomized group given a deslorelin acetate implant. Urinary bladders were excised immediately after sacrifice, and the spontaneous activity of dorsal and ventral strips of the bladder body was examined in organ bath chambers. The amplitude and frequency of the spontaneous contractions were evaluated. Most of the sections developed spontaneous activity. Ovariohysterectomy caused a decrease in the amplitude of spontaneous contractions of the tissues obtained only from the dorsal part of the bladder body. After OHX, the frequency was higher compared with the control group in both parts of the bladder. Deslorelin acetate did not significantly affect the spontaneous contraction amplitude but caused a decrease in the frequency in the dorsal and ventral parts of the bladder. In conclusion, long-term changes in the levels of hormones and other regulatory substances associated with the reproductive system are related to altered spontaneous activity of the urinary bladder, which may impact the symptoms of urgency and incontinence appearing in women after menopause and in female animals after gonadectomy. However, long-acting deslorelin acetate partially reverses the effect of OHX on the spontaneous activity of the bladder. This process might underlie the positive effects of GnRH analogs in incontinent spayed female dogs.

Urinary incontinence in the bitch: an update

Urinary incontinence (UI), defined as the involuntary loss of urine during the filling phase of the bladder (Abrams et al. 2002), is a commonly seen problem in veterinary practice. Urinary sphincter mechanism incompetence (USMI) after spaying is the most common micturition disorder, and its medical treatment is normally successful, even though the underlying pathophysiological mechanism is not fully understood. Hormonal changes inducing structural and functional alterations in the bladder, as well as in the urethra composition, are discussed. To manage incontinent patients successfully, possible underlying abnormalities besides USMI should be ruled out. In the majority of cases, history, physical examination and simple tests including urinalysis and urine bacterial culture lead to a presumed aetiology. If USMI is the most likely cause, then the advantage of further diagnostic tests should be discussed with the owner before starting a trial therapy with alpha-adrenergic drugs. Potential side effects of this therapy have to be mentioned even though they rarely occur. It is important to thoroughly evaluate the success of the initial treatment. Its failure should lead to further diagnostic testing. Specialized clinical assessments may provide an aetiological diagnosis, and this could serve as a basis for discussing further treatment options. Surgical procedures, which may in rare cases cause irreversible side effects, may be instituted. If incontinence reoccurs after initial treatment was successfully performed, the diagnostic work-up including urinalysis should always be repeated. As results of urinalysis did not correlate well with results of bacterial culture, a urine culture is recommended (Comer and Ling 1981). Cystocentesis is the preferred method of urine collection (Bartges 2004). Equivocal results of quantitative cultures of urine samples obtained during midstream voiding or by catheterization require repeat collection by cystocentesis (Comer and Ling 1981).

Transobturator Vaginal Tape for Treatment of Urinary Incontinence in Spayed Bitches

This study investigated the long-term effectiveness and safety of a variant of the transobturator vaginal tape inside-out technique for acquired urinary incontinence. Twelve spayed female dogs were operated over a 2 yr period. No intraoperative complications were encountered. Transient dysuria was the most common postoperative complication (7 out of 12 dogs). On the 12th day postoperatively, incontinence was completely cured in 11 out of 12 dogs (92%). At the time of the second evaluation (median follow-up time was 21 mo), patients classified as “cured,” “greatly improved,” or “improved” were 25, 50, and 25% of the total, respectively. At the time of either the fourth evaluation or at the time of death (median follow-up time was 52 mo), 50% of the bitches (6 out of 12) had the same results as previously but the other 50% had leakage that reappeared sporadically. A fistula appeared on the path of the tape in two bitches at 28 and 32 mo postsurgically. The technique presented is effective and more cost effective than the standard technique and could constitute an attractive alternative; however, it could be associated with an immediate postoperative dysuria, delayed fistula formation, and a partial recurrence of clinical signs.

Survey of tail injuries sustained by working gundogs and terriers in Scotland

Working dog owners in Scotland were invited to take part in an internet survey regarding the 2010/2011 shooting season, which was designed to estimate the prevalence of tail injuries; assess the risk of tail injuries in docked and undocked working dogs; and identify risk factors for owner-reported tail injuries. Of 2860 working dogs, 13.5 per cent sustained at least one tail injury during the 2010/2011 shooting season. Undocked spaniels and hunt point retrievers (HPRs) were at greatest risk of tail injury with 56.6 per cent of undocked spaniels and 38.5 per cent of undocked HPRs sustaining at least one tail injury during the season. There was no statistically significant difference in the risk of tail injury in dogs with tails docked by one-third, half or shorter. To prevent one tail injury in one shooting season, between two and 18 spaniels or HPRs would need to be docked as puppies. The authors believe that this work provides the best available evidence on which to base a consultation for changes to the legislation on tail docking in working dogs in Scotland. Docking the tails of HPRs and spaniels by one-third would significantly decrease the risk of tail injury sustained while working in these breeds.

The outcome of combined urethropexy and colposuspension for management of bitches with urinary incontinence associated with urethral sphincter mechanism incompetence

OBJECTIVE

To report 1) a combined technique of urethropexy and colposuspension; 2) intra- and postoperative complications; and 3) medium term outcome.

STUDY DESIGN

Retrospective case series.

ANIMALS

Female dogs (n = 30) with urinary incontinence associated with urethral sphincter mechanism incompetence (USMI) unresponsive to medical management.

METHODS

Through a ventral median celiotomy, the bladder was positioned abdominally to permit the urethra to be anchored with single interrupted polypropylene sutures to the prepubic tendon and linea alba. The vagina was freed from the vesicovaginal and rectovaginal attachments and advanced cranially by traction before attachment to the prepubic tendon with polypropylene mattress sutures. Bitches were re-examined 2 weeks postoperatively; medium term outcome (>6 months) was evaluated by telephone interview of owners.

RESULTS

At a median follow up of 39.5 months, 21 bitches (70%) were considered to have an "excellent" medium term outcome with complete resolution of their urinary signs; 8 (26.6%) had a "good" outcome, and 3 (10%) had mild transient dysuria postoperatively.

CONCLUSION

Combined urethropexy and colposuspension resulted in complete resolution of urinary incontinence in 70% of bitches with USMI and was not associated with major complications.

Transobturator vaginal tape inside out for treatment of urethral sphincter mechanism incompetence in female dogs: cadaveric study and preliminary study in continent female dogs

OBJECTIVES

(1) To describe a surgical technique adapted from the "transobturator vaginal tape inside-out" (TVT-O) used in women and to define the trajectory of the tape on canine cadavers, and (2) to determine the urodynamic and morphological effects of the TVT-O in continent bitches.

STUDY DESIGN

Cadaveric and experimental in vivo study.

ANIMALS

Fresh female canine cadavers (n=12) and spayed female Beagle dogs (2).

METHODS

(1) TVT-O was inserted in 12 cadavers. Dissection was performed and distances between the tape and neighboring structures were recorded. (2) TVT-O was inserted in 2 continent female Beagle dogs. Urethral pressure profilometry and vaginourethrograms were performed preoperatively, immediately after surgery, and 2, 4, and 6 months postoperatively. Histopathology was performed 6 months after surgery.

RESULTS

(1) TVT-O tape was consistently located in a perineal space before entering the obturator foramina and was located at a safe distance from major neurovascular structures including the femoral vessels and obturator nerve. (2) TVT-O was performed without any surgical or postoperative complications in 2 continent bitches. Histopathologic examination of the tissues surrounding the tape revealed a mild fibroblastic proliferation with a mild to minimal lymphoplasmacytic inflammatory infiltration.

CONCLUSIONS

TVT-O is a feasible and accurate procedure that can be performed in continent bitches with a low risk of complications.

Transobturator vaginal tape inside out for treatment of urethral sphincter mechanism incompetence: preliminary results in 7 female dogs

OBJECTIVES

To evaluate the clinical efficacy of the transobturator vaginal tape inside-out (TVT-O) in incontinent female dogs affected with urethral sphincter mechanism incompetence (USMI) and to determine its urodynamic and morphologic effects.

STUDY DESIGN

Case series.

ANIMALS

Incontinent spayed female dogs (n=7).

METHODS

TVT-O tape was inserted in 7 incontinent female dogs diagnosed with USMI. Urethral pressure profilometry (UPP) and vaginourethrograms were performed preoperatively, and 1 and 3 months postoperatively. Clinical efficacy of the technique was evaluated and complications reported. Follow-up information was evaluated by a telephone questionnaire.

RESULTS

All dogs were continent immediately after the procedure. Incontinence recurred 2 months after surgery in 1 dog and was treated by phenylpropanolamine administration. At mean follow-up time of 11.3 months, 6 of 7 dogs were continent. An iatrogenic urethral tear occurred intraoperatively in 1 dog. No postoperative complications were encountered. The postoperative UPPs showed significantly increased maximal urethral closure pressure and integrated pressure. Postoperative vaginourethrograms were unremarkable. The surgical procedure did not modify the location of the urinary bladder neck in dogs with a "pelvic urinary bladder" preoperatively.

CONCLUSIONS

TVT-O was efficient in maintaining short term continence in 6 of 7 dogs affected with USMI.

Acquired urinary incontinence in the bitch: update and perspectives from human medicine. Part 2: The urethral component, pathophysiology and medical treatment

Various pathologies can affect the bladder and/or urethral contractility causing signs of urinary incontinence. In this second part of a three-part review, the pathophysiology of impaired urethral contractility (including urethral hyper- and hypotonicity) in the bitch and in women is discussed. Urethral sphincter mechanism incompetence (USMI) is the most common form of acquired urinary incontinence in bitches and is characterized by a decreased urethral tone. The pathophysiology and current recommended medical treatment options for USMI and cases of modified urethral tonicity due to a neurological disorder or functional outlet obstruction are discussed. Treatment options in human medicine in cases of impaired urethral contractility are described.

Therapeutic efficacy of botulinum toxin in the treatment of urinary incontinence in female dogs

Urinary incontinence in animals poses a growing therapeutic problem. Satisfactory results in the treatment of incontinence are not reported despite the wide availability of pharmaceuticals addressing the problem. The growing number of side effects and the need for sustained pharmacotherapy have prompted a search for new treatment methods. The experiment described in this study was performed on 11 bitches with clinical symptoms of urinary incontinence. The dogs underwent cystoscopy during which botulinum toxin solution was injected into the wall of the urinary bladder (50-100 botulinum toxin units were given per animal in 10 injections), causing changes in its innervation. Positive therapeutic effects lasting for 5 months in average were noted in 70% of the treated animals.

The association between acquired urinary sphincter mechanism incompetence in bitches and early spaying: a case-control study

A case-control study was conducted between December 2005 and August 2006 in London (1) to estimate the strength of association between early ovariohysterectomy (spaying) and urinary incontinence (sphincter mechanism incompetence), (2) to identify other risk factors for incontinence, and (3) to assess any implications of incontinence on the owner-pet relationship. Cases were defined as bitches that developed incontinence after spaying and were treated, and the controls comprised continent spayed bitches. Questionnaires from 202 cases were compared to 168 controls, and analysed using multivariable logistic regression. No significant association between early spaying and incontinence was detected although there was a tendency that early spayed bitches were less likely to be incontinent. Docked bitches were 3.8 times more likely to be incontinent than undocked bitches; bitches weighing over 10 kg were 3.7 times more likely to be incontinent than smaller dogs; and older bitches were more likely to be incontinent (OR=3.1-23.8) than younger animals. Some owners were found to have a negative attitude towards incontinence.

Spaying-related urinary incontinence and oestrogen therapy in the bitch

Some aspects of spaying-related urinary incontinence in the bitch still remain incompletely clarified. Therefore, the aims of the present study were to evaluate the prevalence of the disease among spayed dogs, to detect differences in risk related to the type of surgery, to describe the characteristics of incontinent bitches, to assess the influence of age at surgery on the onset of incontinence occurrence, and to assess the effectiveness and long-term side effects of oestrogen therapy in affected bitches. Among 750 bitches submitted to ovariectomy or ovariohysterectomy, those showing spaying-related urinary incontinence were evaluated. Oestrogen replacement therapy consisted of administering an effective dose followed by an individual maintenance dose. The results showed that the disease occurred in 5% of neutered bitches, the type of surgery did not affect the disease occurrence, affected bitches frequently represented large or giant breeds or large-size mongrels, the body weight of the affected bitches at surgery was often > 20 kg, the disease seems to be associated with tail docking, the age at surgery influences the onset ofincontinence, with earlier occurrence in older bitches, and that a strong co-operation between owners and veterinarians is necessary to achieve successful response to oestrogen replacement therapy. Long-term administration seems to be unrelated to oestrogenic side effects.

Differences in the expression of luteinizing hormone and follicle-stimulating hormone receptors in the lower urinary tract between intact and gonadectomised male and female dogs

Receptors for LH (LHR) and FSH (FSHR) are expressed in the canine lower urinary tract (LUT). As gonadectomy results in an increase in plasma LH and FSH, the objective of this study was to determine whether there are any differences in the expression of LHR and FSHR in the LUT between intact and gonadectomised dogs. Four regions of the LUT, i.e. body and neck of the bladder as well as proximal and distal urethra, were collected from 20 healthy dogs (5 intact males, 5 intact anoestrous females, 4 castrated males and 6 spayed females). The mRNA and protein expression of receptors was determined by in situ hybridization and immunohistochemistry, respectively, and assessed semi-quantitatively incorporating both the distribution and the intensity of specific staining. Expression of LHR and FSHR was present in all tissue layers (epithelium, sub-epithelial stroma and muscle) of each region with different levels of the expression. Overall mRNA and protein expression for both LHR and FSHR was significantly (P<0.001) lower in gonadectomised dogs. Intact dogs had more (P<0.05) LHR and FSHR mRNA and protein in all tissue layers of the four regions, except for LHR mRNA expression in the sub-epithelial stroma where no differences were observed between the two statuses. Decreases in LHR and FSHR mRNA and protein in gonadectomised dogs appeared to be more consistent in spayed bitches compared to castrated males. Lower expression of LHR and FSHR observed in gonadectomised dogs may adversely affect the normal canine LUT function.

Immunohistochemical study of the pre- and postnatal innervation of the dog lower urinary tract: morphological aspects at the basis of the consolidation of the micturition reflex

Immunohistochemical studies were performed on male and female bladder and urethra collected from 4 adults dogs and 10 foetal specimens with crown-rump length from 53 to 155 mm (medium-sized breeds, presumptive 38 days of gestation to term). A panel of antisera was tested, including PGP 9.5 to describe the general intramural innervation, ChAT and TH to depict the cholinergic and nor-adrenergic components and NOS1, CGRP, SP, NPY, VIP, SOM, GAL, 5-HT to investigate the possible nitrergic, peptidergic and aminergic ones. A rich cholinergic innervation was present in adult bladder and urethra, along with a lesser number of adrenergic nerves and a small number of nitrergic ones. Either bladder or urethra received numerous CGRP-, SP-, NPY-, VIP-containing nerve fibres which were distributed throughout the muscle layers. All over the lower urinary tract strong to weak ChAT-, CGRP-, SP- and NPY-immunoreactivity was detected in intramural ganglia, in peripheral nerve bundles and around blood vessels. 5-HT-immunoreactive endocrine cells were present in the urethral epithelium. Early foetal organs were supplied only by cholinergic nerve fibres. Few NOS-, CGRP- and SP-ergic components appeared at the end of pregnancy. It can be guessed that sensory mediators such as CGRP and SP increase in postnatal ages while other neuropeptides, such as NPY and VIP, appear only after birth, as the urinary reflex consolidates.

Urodynamic parameters and plasma LH/FSH in spayed Beagle bitches before and 8 weeks after GnRH depot analogue treatment

The pathophysiology of urinary incontinence due to spaying remains unknown. Incontinent bitches can be treated successfully with depot preparations of GnRH-analogues and there are differences in plasma gonadotropin levels between continent and incontinent spayed bitches. It is therefore assumed that the supraordinated hormones, GnRH, FSH, and/or LH, have an effect on the urodynamic parameters. In this study, the potential influence of these hormones on the lower urinary tract was investigated by measuring urethral pressure profiles and cystometry. Simultaneously, plasma concentrations in 10 spayed Beagle bitches were determined 5 weeks prior to and 8 weeks after treatment with the GnRH analogue leuprolide. Within 1 week of GnRH analogue administration, plasma FSH and LH levels decreased from 72.5 and 7.7 to 7.75 and 0.72ng/mL, respectively. These plasma gonadotropin levels correspond with those of intact bitches during anoestrus. Urethral pressure profiles indicated that the treatment had no significant effect on maximum urethral closure pressure, functional and total length of the urethra, or area of the closure pressure curve. The data obtained by cystometry regarding mean bladder threshold volume showed a significant increase from 109 to 172mL. The improvement in bladder function after the application of GnRH-application is presumably a direct effect of the GnRH as a relationship between the plasma gonadotropin levels and the urodynamic parameters could not demonstrated.

Luteinizing hormone and follicle-stimulating hormone receptors and their transcribed genes (mRNA) are present in the lower urinary tract of intact male and female dogs

In dogs, one of the side effects of neutering is the development of urinary incontinence. The relationship between neutering and urinary incontinence caused by acquired urethral sphincter mechanism incompetence (USMI) has been reported. Recently, GnRH analogue treatment that suppresses elevated plasma gonadotrophin concentrations post-spaying has been successfully used in incontinent bitches. These data and the fact that non-gonadal tissues may contain receptors for LH (LHR) and FSH (FSHR) suggest that there might be a functional relationship between gonadotrophins and the lower urinary tract in dogs. This study aimed to investigate the presence of LHR and FSHR in the lower urinary tract of intact male and female dogs. Four regions of the lower urinary tract, i.e. (i) body of the bladder, (ii) neck of the bladder, (iii) proximal urethra and (iv) distal urethra were collected from 10 healthy dogs (5 males and 5 anoestrous females). In situ hybridization and immunohistochemistry were performed to characterise the presence of receptor mRNA and receptor protein. Staining was rated semi-quantitatively, incorporating both the distribution and intensity of specific staining. The distribution of receptor expression in different tissue layers (epithelium, subepithelial stroma and muscle) in each region was statistically analyzed. Luteinizing hormone receptor and FSHR mRNA and protein were present in all four regions and in three tissue layers of males and females. Irrespective of region and layer, female dogs expressed significantly higher expression for LHR mRNA (P<0.001), LHR protein (P<0.05) and FSHR protein (P<0.001). The expression of LHR and FSHR mRNA and protein was not uniform and depended on region, tissue layer and gender. The expression of LHR mRNA was higher in the bladder, compared to the urethra (P<0.05). The FSHR mRNA significantly increased from the bladder to the urethra. Protein expression for LHR and FSHR was highest in the proximal urethra (P<0.05). The overall expression for LHR and FSHR at both mRNA and protein levels was highest in the epithelium, intermediate to low in the subepithelial stroma and muscle. A significant interaction between region and tissue layer showed that mRNA and protein expression for LHR and FSHR decreased from the bladder to the urethra in the epithelium and subepithelial stroma. In contrast, it gradually increased from the bladder to the urethra in the muscle. In conclusion, the present study showed that both mRNA and protein for LHR and FSHR were expressed in the canine lower urinary tract, and the expression levels varied between genders and among regions and tissue layers. The presence of these receptors suggests that gonadotrophins have a role in the physiology and/or pathology of the lower urinary tract function in the dog.

Evaluation of the urodynamic and hemodynamic effects of orally administered phenylpropanolamine and ephedrine in female dogs

OBJECTIVE

To compare the urodynamic and hemodynamic effects of different dosages of phenylpropanolamine and ephedrine and determine effective dosages in increasing urethral resistance in female dogs.

ANIMALS

20 sexually intact female Beagles.

PROCEDURE

Dogs were allocated into 4 groups and received phenylpropanolamine once, twice, or 3 times daily, or ephedrine twice daily, for 14 days. On days 0, 7, and 14, urethral pressure profiles were performed while dogs were anesthetized with propofol. Variables recorded included maximum urethral pressure, maximum urethral closure pressure, integrated pressure, functional profile length, anatomic profile length, plateau distance, distance before maximum urethral pressure, and maximum meatus pressure. Arterial and central venous pressures were measured before anesthetic induction and 10 and 35 minutes after induction.

RESULTS

Administration of phenylpropanolamine once daily or ephedrine twice daily significantly increased maximum urethral pressure and maximum urethral closure pressure. Values for integrated pressure were significantly increased after 14 days of once-daily administration of phenylpropanolamine. Variables did not change significantly from day 7 to day 14. Diastolic and mean arterial blood pressures increased significantly during the treatment periods, and arterial pressure decreased during propofol infusion.

CONCLUSIONS AND CLINICAL RELEVANCE

Oral administration of phenylpropanolamine once daily or ephedrine twice daily increased urethral resistance in clinically normal dogs and may be recommended for management of urethral sphincter mechanism incompetence. Treatment efficacy may be assessed after 1 week. Dogs with concurrent cardiovascular disease should be monitored for blood pressure while receiving alpha-adrenergic agents because of the effects on diastolic and mean arterial pressure.

Immunohistochemical localization and quantitative assessment of GnRH-, FSH-, and LH-receptor mRNA Expression in canine skin: a powerful tool to study the pathogenesis of side effects after spaying

It has been proposed that gonadotropins and/or gonadotropin releasing hormone (GnRH) could be involved in the pathophysiology of the side effects after spaying in bitches, such as urinary incontinence and an increased production of a woolly undercoat. In order to provide tools to investigate the role of these hormones in dogs we developed immunohistochemical techniques and real-time RT-PCR to study whether GnRH-, LH-, and FSH-receptors exist in canine skin and urinary bladder. Tissue samples from the skin of the flank region and the ventral midline of the urinary bladder from euthanised dogs were examined. We were able to quantify mRNA expression of GnRH-, FSH-, and LH-receptors in canine skin and bladder biopsies with a high primer efficacy. Immunohistochemical studies showed that GnRH-, FSH-, and LH-receptors are expressed in vessel walls, the epidermis, the hair follicle and in sebaceous and sweat glands in canine skin and in transitional epithelium, and smooth muscle tissue in the urinary bladder. Our data provide the fundamentals to examine the distribution of FSH-, LH-, and GnRH-receptors in canine skin and urinary bladder and to assess gene activity at the transcriptional level by real-time RT-PCR.

Urodynamic and morphologic changes in the lower portion of the urogenital tract after administration of estriol alone and in combination with phenylpropanolamine in sexually intact and spayed female dogs

OBJECTIVE

To compare the urodynamic and morphologic effects of the administration of estriol alone and in combination with phenylpropanolamine on the lower portion of the urogenital tract in female dogs.

ANIMALS

3 sexually intact and 3 spayed female Beagles without urinary incontinence.

PROCEDURE

Dogs received estriol (2 mg, PO) once daily for 7 days followed by estriol (2 mg, PO) and phenylpropanolamine (1.5 mg/kg, PO) once daily for 7 days. Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed before treatment (day 0) and at days 7 and 14. The maximum urethral pressure (MUP) and closure pressure (MUCP), urethral functional and anatomic profile lengths, integrated pressure (IP), plateau, distance before MUP, maximum meatus pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured.

RESULTS

Before treatment, no urodynamic differences were observed between the 2 groups; however, vaginal length and width were significantly shorter in spayed dogs. Compared with day 0 values, estriol treatment significantly increased MUP, MUCP, and IP values at day 7, but at day 14, this effect decreased despite phenylpropanolamine administration. No morphologic changes from baseline were detected after either treatment in any dog.

CONCLUSIONS AND CLINICAL RELEVANCE

Data suggest that estriol mainly acts on the urethral sphincter mechanism by increasing urethral resistance in sexually intact and spayed female dogs without urinary incontinence. Administration of estriol and phenylpropanolamine did not increase the urethral resistance more than estriol alone. The urodynamic effects of estriol in female dogs with urinary incontinence remain to be elucidated.

Making a Rational Choice Between Ovariectomy and Ovariohysterectomy in the Dog: A Discussion of the Benefits of Either Technique

OBJECTIVE

To determine if ovariectomy (OVE) is a safe alternative to ovariohysterectomy (OVH) for canine gonadectomy.

STUDY DESIGN

Literature review.

METHODS

An on-line bibliographic search in MEDLINE and PubMed was performed in December 2004, covering the period 1969-2004. Relevant studies were compared and evaluated with regard to study design, surgical technique, and both short-term and long-term follow-up.

CONCLUSIONS

OVH is technically more complicated, time consuming, and is probably associated with greater morbidity (larger incision, more intraoperative trauma, increased discomfort) compared with OVE. No significant differences between techniques were observed for incidence of long-term urogenital problems, including endometritis/pyometra and urinary incontinence, making OVE the preferred method of gonadectomy in the healthy bitch.

CLINICAL RELEVANCE

Canine OVE can replace OVH as the procedure of choice for routine neutering of healthy female dogs.