Investigating uterine disease in the bitch: uterine cannulation for cytology, microbiology and hysteroscopy

The reproductive microbiome in dogs: Friend or foe?

The microbiome of the reproductive tract is an area of research in full development. Specifically, the microbiome may be involved in reproductive health, disease, and pregnancy outcomes, as has been shown in humans and animals, including dogs. The aim of the present review was to summarize current knowledge on the microbiome of the canine reproductive tract, to expose the controversial role that some bacterial agents may play in canine subfertility, and to highlight future research perspectives. This review discussed whether the use of antimicrobials in dogs is appropriate to increase reproductive performance and to treat subfertility without proper diagnosis, and the possible use of probiotics to modulate the reproductive canine microbiome. Finally, we indicate areas in which scientific knowledge is currently lacking, and could be promising directions for future research.

Uterine issues in infertile queens: nine cases

This prospective case series investigated potential uterine causes of infertility in queens. Purebred queens with infertility (failure to conceive, embryonic death, or failure to maintain pregnancy and produce viable kittens), but no other reproductive disorders were examined approximately 1-8 weeks before mating (Visit 1), 21 days after mating (Visit 2), and 45 days after mating (Visit 3) if pregnant at Visit 2. Investigations included vaginal cytology and bacteriology, urine bacteriology, and ultrasonography. At Visit 2 or 3, uterine biopsy or ovariohysterectomy was performed for histology. Of nine eligible queens, seven were non-pregnant by ultrasound at Visit 2 and two had lost pregnancies by Visit 3. Ovulation was confirmed by serum progesterone concentration in all queens. Ultrasonic appearance of the ovaries and uterus was compatible with a healthy status except for one queen with signs of cystic endometrial hyperplasia (CEH) and pyometra, a follicular cyst in another, and fetal resorptions in two queens. Six cats had histologic lesions of endometrial hyperplasia, including CEH (n=1). Only one cat had no histologic uterine lesions. Bacteria were cultured from vaginal samples in seven queens at Visit 1, (two were non-evaluable), and in five of seven queens sampled at Visit 2. Uterine cultures were negative except for the cat with pyometra. All urine cultures were negative. In summary, the most frequent pathology observed in these infertile queens was histologic endometrial hyperplasia, which can potentially inhibit embryo implantation and healthy placental development. This suggests that uterine disease might contribute substantially to infertility in purebred queens.

Use of Hysteroscopy for Diagnosing Causes of Infertility in Camelids

Hysteroscopy in alpacas and llamas allows for the identification of abnormalities on the surface or within the endometrium that cannot be identified with other methods. Hysteroscopy also allows for site-directed endometrial cytology, culture, and biopsy to achieve a definitive diagnosis. Even when no cause for infertility can be found, previously infertile females tend to become pregnant and maintain their pregnancies to term following the hysteroscopic procedure. This therapeutic effect may be a response to pre-hysteroscopy estrogen treatment, dilation of the uterine horns during hysteroscopy, and/or posttreatment uterine lavages. Complications following hysteroscopy have not been reported in camelids.

Videovaginoscopy of the canine vagina

Endoscopy enables a rapid and non-traumatic examination of the vaginal cavity of female dogs. Its implementation requires specific equipment as well as knowledge about the species-specific vaginal anatomy and the procedure. Vaginoscopy is the diagnostic tool of choice for several vaginal conditions and diseases such as congenital abnormalities, neoplasia or ectopic ureter. Furthermore, vaginal inspection may provide additional information in cases of vulvar discharge or infertility. Vaginoscopy is a superior tool compared to other methods in assisted reproduction. Changes of the vaginal mucosa during the oestrous cycle can be observed to determine the hormonal actions and the time of ovulations in addition to other routine examinations, such as progesterone assay and vaginal cytology. Finally, intrauterine insemination, which is recommended for insemination with frozen-thawed semen, can be performed endoscopically by transcervical catheterization.

Diagnostic and prognostic markers for uterine diseases in dogs

Common uterine diseases in female dogs include cystic endometrial hyperplasia (CEH), mucometra, hydrometra and pyometra. It is important in clinical practice to recognize pyometra because it is potentially life-threatening due to the systemic illness induced by bacterial infection of the uterus. In contrast, the uterine content is sterile in CEH and mucometra/hydrometra, and clinical signs are mostly mild or absent. Optimal treatment depends on the type of uterine disease and its severity, but diagnosis and prognosis determination may be challenging and the diseases difficult to separate clinically. Diagnostic findings or biomarkers that may aid in the differentiation of the diseases are valuable, especially when several bitches are admitted with a fluid-filled uterus during night-time, and it has to be decided which patient to operate on first. Additionally, some variables may indicate outcome as measured by mortality or morbidity. If the uterus is not enlarged or fluid-filled, detection of uterine disease can be even more difficult. In this study, clinically useful variables with possible diagnostic or prognostic value for uterine diseases in dogs are discussed.

Prevalence and effect of uterine luminal free fluid on pregnancy and litter size in bitches

Free fluid within the uterine lumen has been identified ultrasonographically as a transient finding in normal bitches in the period immediately after mating, and delayed clearance of the fluid has been documented in bitches with endometrial hyperplasia. This study used B-mode ultrasonography to investigate the prevalence of free fluid in the uterine lumen in normal bitches (n = 53) and bitches with endometrial hyperplasia (n = 10) on Days -7, 0, +5, and +14 in relation to estimated ovulation. For normal bitches without endometrial hyperplasia, 47 (86.6%) bitches become pregnant, whereas for bitches with endometrial hyperplasia, 3 (30%) become pregnant. In both the groups, the presence of uterine fluid on Days -7 and 0 was not associated with the probability of a bitch becoming pregnant, whereas the presence of uterine fluid on either Day +5 or +14 was significantly associated with a reduced likelihood of pregnancy. In pregnant bitches, uterine luminal fluid present on Day 0 was associated with a smaller litter size. This is the first study to establish the prevalence and effect of uterine luminal free fluid in bitches. We postulate that as the uterine luminal free fluid may be detected in normal bitches before mating and has no effect on the pregnancy rate or litter size in either group, this fluid is "physiological." However, it seems that the later in estrus the uterine fluid is present, the more likely it is to have an adverse effect on fertility. In some cases, this is manifest as a reduced litter size, while, importantly, the presence of fluid 5 to 14 days after ovulation is strongly associated with an absence of pregnancy, both in bitches with and without endometrial hyperplasia. We propose that ultrasonographic detection of uterine luminal free fluid after mating may be a useful prognostic indicator for pregnancy outcome, which may allow the targeting of treatments specifically to a population of animals that presumably develop mating-induced endometritis.

Endometrial cytology and computerized morphometric analysis of epithelial nuclei: a useful tool for reproductive diagnosis in the bitch

New diagnostic approaches are required to recognize early canine hypofertility or infertility. We suggest that the identification of different cytologic types, cellular aspects, and nuclear features of the endometrial epithelial cells may be suitable for this purpose. This study was performed on the bitch (Canis familiaris) during the physiologic reproductive cycle and in uterine diseases. We also applied computerized cytomorphometry to evaluate nuclear area, perimeter, diameter, density, aspect, and roundness of endometrial epithelial cells in healthy dogs (N=35) at different stages of the reproductive cycle (before puberty, during proestrus, estrus, diestrus, and anestrus) and in bitches affected by uterine disorders (N=10). The stage of the estrous cycle was determined by vaginal cytology and progesterone evaluation and also confirmed by clinical and histologic observations. Samples for endometrial cytology were collected in vivo by uterine flushing with transcervical uterine cannulation. After uterine sampling, each dog underwent OHE or uterine stump revision. Cytologic analyses were compared with histologic examinations to verify the uterine condition. The uterine cellular population was represented by endometrial epithelial cells, erythrocytes, neutrophils, lymphocytes, eosinophils, macrophages, plasma cells, and cervical or incidental vaginal cells. Bacteria and amorphous material were observed. The proportion of different cells and nuclear features in the cytologic samples varied throughout the stages of the reproductive cycle and between normal and pathologic uterine conditions. The computer-assisted nuclear morphometry, performed in cytologic specimens by means of the six nuclear parameters chosen to evaluate the endometrial epithelial cell population, proved to be useful for determining the stage of the reproductive cycle. Furthermore, this system was demonstrated to be a valid support to diagnose and distinguish uterine disorders.

Canine and feline pregnancy loss due to viral and non-infectious causes: a review

Among the causes for pregnancy loss, viruses and non-infectious factors are among the most important. In both dogs and cats, research and clinical evidence provide proof that there is an increasing incidence of pregnancy loss associated with infectious diseases like herpesvirus, as well as the presence of toxicants or chemicals in the animal's diet and environment. Endocrine causes must be taken into consideration when dealing with pregnancy loss. This review will cover the most recent knowledge regarding viral and non-infectious of pregnancy losses in the dog and cat.

Mucometra, cystic endometrial hyperplasia, and pyometra in the bitch: advances in treatment and assessment of future reproductive success

Pyometra is a common reproductive disorder which affects nearly one fourth of all female dogs before they reach 10 y of age. An association between pyometra and the most common uterine disease of the bitch, cystic endometrial hyperplasia, has been established, as the latter allows commensal bacteria originating from the vagina to proliferate in the uterus at the end of estrus. The progressive degenerative process in the development of cystic endometrial hyperplasia is usually proposed as the initiating lesion for pyometra in bitches; this is mediated by progesterone and potentially aggravated by estrogens. However, a separate process caused by local uterine irritation to trophoblastic reaction and bacterial proliferation has been recently proposed as an alternate mechanism leading to the development of pyometra. Pyometra is clinically distinct in pathogenesis, signs, treatment and prognosis from postpartum metritis or mucometra. Treatment of pyometra has historically involved ovariohysterectomy, however, during the last 10 y, numerous effective treatments have been proposed to treat both open and closed cervix pyometra with good success and future fertility. Among the treatments available, the use of repeated low doses of prostaglandins alone or in association with either dopamine agonists or progesterone-receptor antagonists has been demonstrated to be a viable alternative for valuable breeding dogs.

Advanced Small Animal Reproductive Techniques

Small animal reproductive techniques have become quite advanced in recent years. Techniques described in this paper include transcervical catheterization for the purpose of insemination and intrauterine diagnostics (e.g., cytology, culture, and/or biopsy), and semen cryopreservation that allows international shipping of valuable semen and preservation of reproductive capacity. The use of uterine and fetal monitoring devices that enable intervention and mediation of dystocia is also described.

Transcervical insemination techniques in the bitch

The benefits of using endoscopic TCI for frozen semen come from being able to achieve the same or better results without the need and risks of general anesthesia and surgery. The ability to do all fresh and chilled inseminations this way will certainly improve conception rates without the owner having to make a decision about exposing their bitch to the risks of anesthesia and surgery. The other potential uses open up a whole new field for canine theriogenology. Above all, the client response to the technique is overwhelmingly positive. At times the learning process will be discouraging, but the end result is worth the effort. The endoscope should not be treated as something special for frozen semen insemination but should be used at every opportunity in order to develop experience and expertise in all situations.

Radiographic contrast medium for uterine insemination in the bitch, and its effect upon the quality and fertility of fresh dog semen

Four ejaculates were collected from each of 6 adult male beagle dogs. The second fraction was divided into 3 aliquants which were then diluted with physiological saline, an isoosmolar solution of sodium/meglumine diatroate, and an iso-osmolar solution of iohexol. The diluted samples were incubated at 39 degrees C and evaluated at 0, 60, 90, 120, 240 and 360 min after dilution. A variety of assessments was made, including, spermatozoal motility, spermatozoal morphology, and acrosorne status. The practicality of using 1.0 ml of iso-osmolar contrast medium combined with radiographic examination was evaluated as a method of confirming accurate placement of a transcervical uterine catheter by injecting contrast after positioning the catheter in 4 beagle bitches. The effect of the procedure on fertility was assessed using 5 greyhound bitches which were inseminated with fresh semen and in which pregnancy was monitored using diagnostic B-mode ultrasound imaging. There was no significant difference between physiological saline and the sodium/meglumine diatroate solution upon semen quality, while the iohexol solution produced a significant reduction in spermatozoal motility and morphology. No adverse clinical effects were observed when contrast medium was administered into the uterus to either group of bitches. A subjective assessment of radiographic quality showed that the sodium/meglumine diatroate solution, which contained twice the iodine concentration of the iohexol solution, produced significantly greater radiopacity and was radiographically more useful than the iohexol solution. The sodium/meglurnine diatroate solution had no adverse effect upon the fertility of dog semen, and all bitches that were inseminated with this technique conceived and maintained the pregnancy to term. Litter size was considered to be normal for the breed. Small volumes of an iso-osmolar solution of sodium/meglumine diatroate may be useful for ensuring correct placement of transcervical catheters prior to artificial insemination in the bitch.

Uterine, cervical and vaginal microflora of the normal bitch throughout the reproductive cycle

Samples for microbiological culture were collected from the uterus of bitches using transcervical uterine cannulation (31 samples, 23 bitches) and from the uterus, cervix and vagina post mortem (19 bitches) at all stages of the reproductive cycle. Samples were cultured for aerobic and anaerobic bacteria and for aerobic mycoplasmas. Bacteria were always found in the uterus during pro-oestrus and oestrus (12 positive in 12 cultures) and rarely at other stages of the reproductive cycle: during anoestrus (one in 14) and other stages (none in 24). When microorganisms were detected at three sites post mortem, those found in the cervix and vagina were always of the same species as those found in the uterus. In six out of 13 instances, microorganisms were found in the cervix or vagina when none were found in the uterus. The mean number of isolates, number of bacteria seen in uterine cytology and bacterial growth were greater (P < 0.005) during oestrus and pro-oestrus than at other stages. Bacteria isolated from the uterus, in order of frequency, were Escherichia coli, Haemophilus species, alpha-haemolytic streptococci, Corynebacterium species, Streptococcus canis, Alcaligenes faecalis, Bacteroides species, Pasteurella species and Proteus mirabilis. No mycoplasmas were cultured from the samples. This study indicates that the uterus of the normal bitch has a uterine microflora during pro-oestrus and oestrus that is similar to that of the vagina and cervix.