Quality assurance of canine vaginal cytology: A preliminary study

An immersive simulation strategy to teach canine vaginal cytology: A multi-centre study

Vaginal cytology (VC) is an essential technique for monitoring the bitch's estrus cycle. Currently, animal-free teaching methodologies have not been investigated for VC. Hence, this study aimed to evaluate an immersive simulation with a VC model and augmented reality tools. Students (n = 219) from four universities were enrolled, having learning stations with models for practising VC that provided immediate feedback on the technique. Augmented reality tools comprised QR codes that endorsed students to short videos of owners' avatars reporting the clinical reproductive story of the simulated animals and slides with QR codes leading to microscopy slide navigation videos. Proestrus, estrus, diestrus, anestrus and vaginitis were identified in the learning stations. The students' perceptions were evaluated through questionnaires assessing satisfaction, motivation, confidence, impact on learning and diagnostic accuracy. Before the immersive simulation, students had no experience with VC, being afraid of doing a VC with a live dog. Almost all the students considered practicing VC as essential and 94% reported that repeating the procedure (>2 times) was the most important parameter for learning. The simulation activity lasted ≈3 h and significantly improved the confidence of students, being less afraid of doing a VC in a live animal. Slide navigation videos improved the diagnostic accuracy of the estrus cycle stage, and students diagnosed the estrus and vaginitis cases more accurately. The immersive simulation strategy allowed repeated practice in a safe, motivated and standardized environment, being appraised by students as an essential strategy for learning VC.

Ovarian and uterine changes during the oestrous cycle in female dogs

CONTEXT

An accurate staging of sexual cycle is essential for the optimum timing of medical interventions.

AIMS

Here, an updated insight into clinical, endocrinological and vagino-cytological parameters, and their correlation with histomorphology of ovarian and uterine tissue samples is presented.

METHODS

Samples from 39 dogs were collected at various stages of the oestrous cycle: pro-oestrus (n =8), oestrus (n =12), dioestrus (n =9) (luteal phase) and anoestrus (n =10), according to clinical observations. Final allocation of samples was done after histomorphological evaluation of all tissues. Peripheral oestradiol-17ß (E2) and progesterone (P4) concentrations were measured, P4 by both chemiluminescent immunoassay (CLIA) and radioimmunoassay (RIA).

KEY RESULTS

Differences were observed between determination of the stage of the oestrous cycle, either by clinical, endocrinological or histomorphological evaluation. Individuals considered to be in clinical and endocrinological oestrus, had entered the luteal phase according to histomorphology. P4 concentrations measured by two different assays differed, underlying the importance to understand that absolute P4 concentrations may deviate depending on the used assay. Comparison of E2 and P4 concentrations is suggested to be useful when defining the transition from early follicular phase to the time of ovulation.

CONCLUSIONS AND IMPLICATIONS

Based on parallel histomorphological observations, combined with clinical and endocrinological findings on the same individuals, the present study emphasises that an accurate classification of the stage of the cycle in female dogs based solely on clinical and endocrinological assessments can be difficult. The histomorphological findings presented herein provide new insights into the transitional phases between the different stages of the oestrous cycle in the dog.

Validation of a dry-slide immunoassay for progesterone analysis in canine plasma in a clinical setting

BACKGROUND

The identification of canine ovulation is critical for successful breeding. Progesterone measurements are useful for identifying ovulation. Progesterone assays are also quantitative and easily accessed, making them valuable in veterinary practice.

OBJECTIVES

We aimed to validate a dry-slide immunoassay (DSI) for use in dogs, including a method comparison with the chemiluminescence assay (CLIA) and mass spectrometry.

METHODS

Twenty-nine bitches were prospectively recruited. Accuracy, precision, interference, and stability were evaluated. Method comparison between DSI and CLIA and mass spectrometry was conducted, and bias was calculated.

RESULTS

Repeatability was 8.0%-10.8%, and within-laboratory imprecision was 8.8%-11.1% for four concentration levels. Recovery under dilution was 61%-100%, and the method was linear to a concentration of ~50 nmol/L. Recovery after the addition of a high progesterone sample was 76%-83%. Minor changes were seen in one hemolytic and two lipemic samples. Storage at room temperature for 12-24 hours resulted in concentrations that were 57%-96% of the initial concentrations. For samples frozen at -80°C, the concentrations were reduced 17%-27%. There was a significant difference between results from the DSI and CLIA, and a proportional bias was seen when DSI was compared with mass spectrometry, where CLIA correlated better than DSI.

CONCLUSIONS

Precision and accuracy were acceptable. A proportional bias was seen between DSI and CLIA. A small amount of interference was seen with hemolysis and lipemia. Progesterone concentrations were decreased in samples stored at room temperature and -80°C. The results support the use of the DSI for ovulation timing but not for artificial insemination with frozen semen since progesterone concentrations might exceed the assay's linearity and precision limits.

Oestrus status does not alter breeding suitability assessments regarding medial patellar luxation in female small breed dogs: A blinded multi-observer study

Study aims were to evaluate if medial patellar luxation clinical grades changed with oestrus status, and to determine interobserver agreement for different classification methods for grading patellar luxation. Intact female dogs were recruited for grading by 3 independent observers on 2 occasions (pro-oestrus/oestrus and dioestrus/anoestrus) using a published grading system. Observers were blinded to oestrus status. Oestrus status was confirmed by vaginal cytology. Observer agreement was determined using Fleiss' multirater kappa on the original grading scores, simplification to the Norwegian Kennel Club system, and further simplification to a binary suitable/not-suitable for breeding system. The exact McNemar's test was used to assess the effect of oestrus on classification. Of 70 dogs recruited, 53 underwent paired observations. Interobserver agreement was considered moderate to very good for the study sub-groups, with overall kappa values of 0.68 (95% CI 0.63-0.72), 0.79 (0.73-0.84) and 0.92 (0.85-0.99), and percentage agreements of 65%, 81% and 94%, for the original, simplified and binary classifications. Oestrus status did not have a significant effect on classification of breeding suitability. Clinicians and owners should not be concerned about the timing of patellar luxation grading in relation to oestrus. Experienced observers show good or very good agreement using the Norwegian Kennel Club and binary categorisations.

Canine Vaginal Cytology: A Revised Definition of Exfoliated Vaginal Cells

Vaginal cytology is an important examination method in the context of gynecological disorders and cycle staging in the bitch. While collection and preparation of samples are easy, the evaluation appears to be challenging. Inconsistent definitions of cell attributes such as size, cornification and the appearance of the nucleus have been published. The aim of the project was to develop a tutorial for vaginal cell determination. To get a deeper insight into the use of cytology in practice, an online survey was distributed to veterinarians interested in small animal reproduction. Participants were asked to define eight cells and answer questions. The agreement of the 16 participants, working in eight different countries, determining the cells was poor (κ = 0.412). Eleven respondents stated that vaginal cytology has a low reliability. Nevertheless, 13 participants use this tool regularly. The tutorial was developed as a flowchart based on the survey results, scientific literature and own measurements. It guides the user systematically through the evaluation of specific cell characteristics. An evaluation of the results of five raters with difference experience levels led to a high agreement (κ = 0.858). Vaginal cytology is a useful diagnostic tool, but it seems helpful to standardize the determination of cell types.

Factors influencing English Bulldog bitch fertility after surgical uterine deposition of fresh semen

The aim of this study was to evaluate the effect of body weight, oxytocin deposition in the uterus at artificial insemination (AI), vaginal cytology, serum progesterone (P₄) concentration at AI, semen volume and total sperm cells per AI on whelping rate and litter size of English Bulldogs bitches following intrauterine surgical semen deposition. Seventy-eight English Bulldog bitches were artificially inseminated via semen infusion (number of sperm cells inseminated 300-2500 × 10⁶) at the uterine body with fresh semen without extender and under general anesthesia. Whelping rate was greater (P < 0.05) in bitches with >23 kg than bitches with <23 kg (83.9 vs 63.8%). Whelping rate was greater (P < 0.01) in bitches with >75% vaginal cornified epithelium at AI (85.1%) than animals with <75% cornified epithelium (51.6%). Whelping rates were influenced (P < 0.01) by the semen volume at AI (54.3% vs 86.1% for bitches receiving <4 mL or >4 mL of semen). Litter size was larger (P < 0.05) in bitches >23 kg than lighter animals (3.72 ± 1.79 and 2.30 ± 1.46 pups per litter, respectively). Litter size was not influenced by sperm concentration, semen volume, vaginal cytology, serum P₄ concentration and infusion of oxytocin in the uterus at AI (P > 0.1). The results of this study indicate that increasing body weight of English Bulldog bitches is related to higher whelping rates and larger litter size. Also, >75% of superficial cornified vaginal cells (squamous) at AI and >4 mL semen volume maximize whelping rates in this breed of dogs.

Canine ovulation timing: A survey on methodology and an assessment on reliability of vaginal cytology

Ovulation timing in bitches is a routine procedure in small animal practice around the world. It is most frequently used for supporting breeding management, high-risk pregnancy monitoring and determination of the time of parturition. To learn more about how and for what reasons veterinarians interested in small animal reproduction perform canine ovulation timing, an online survey was conducted in 2017. The link to the survey was distributed via the mailing list cafereprod-l@list.cornell.edu and the website, the Twitter account and the Facebook page of EVSSAR. All respondents recommended using quantitative progesterone measurement for ovulation timing alone or in combination with other diagnostic tests. Vaginal cytology was also a commonly used technique. The 63 respondents followed different protocols for sampling and staining vaginal epithelial cells. Interestingly, 50 respondents used vaginal cytology routinely, but only two consider it as a very reliable and another nine as a somewhat reliable test if used alone. In a second project, delegates attending the EVSSAR congress held in Vienna, Austria, in June 2017 had the opportunity to examine seven stained vaginal smear slides under optical microscopy in a blinded approach. The results showed a marked heterogeneity in the identification of vaginal cells and assessment of the time in relation to ovulation. This heterogeneity supports the opinion of survey participants that vaginal cytology alone is not a valid tool for determining the day of ovulation. Results of both projects suggest that there is no standard procedure for the examination of vaginal smears in dogs. It is not recommended to determine the optimal time for mating based on the examination of a single vaginal smear only. According to some comments of survey participants, it is more useful to assess vaginal samples repeatedly and to use the findings to determine when to start progesterone measurement.

Blood periovulatory progesterone quantification using different techniques in the dog

Blood progesterone concentration is used in several procedures related to the reproduction in the bitch, such as ovulation monitoring, estimating time of parturition, or hypo-luteoidism management. Several techniques are available to evaluate blood progesterone concentration, such as the radioimmunoassay (RIA), the chemiluminescent immunoassay (CLIA), and the enzyme-linked immunosorbent assay (ELISA). The aim of this study was to compare the blood progesterone concentration using these three methods during the periovulatory period of 23 bitches. Vaginal cytology was used to classify cytologic estrus (CE) and cytologic diestrus (CD), and blood samples were collected once during proestrus and every other day between CE and CD. The samples were retrospectively classified in the different phases of the estrus based on CD. Pregnancy rate and gestational length were also recorded. A significant increase of the circulating progesterone during the progression of the estrus was recorded, and there were significant differences in the values when using the different methods, with lesser, intermediate, and greatest values with use of the RIA, CLIA, and ELISA, respectively. There was a high correlation (Pearson's correlation coefficient = 0.978) and substantial strength-of-agreement (Lin's concordance correlation coefficient = 0.966) between values obtained when using CLIA and RIA, while there was a high correlation (Pearson's correlation coefficient = 0.955) but poor strength-of-agreement (Lin's concordance correlation coefficient = 0.866) with use of the ELISA and RIA. The data reported in this study provide evidence that the method used for measuring the blood progesterone concentration during the periovulatory phase of the bitch significantly affected the progesterone values.

Monitoramento do ciclo estral de cutias (Dasyprocta leporina Lichtenstein, 1823) através de citologia esfoliativa vaginal e ultrassonografia

O objetivo deste estudo foi monitorar o ciclo estral em cutias (Dasyprocta leporina) criadas em cativeiro no semiárido brasileiro. Durante 70 dias, cinco cutias foram diariamente submetidas a citologia esfoliativa vaginal, e o monitoramento ultrassonográfico ovariano foi realizado a cada três dias. Um total de 8 ciclos estrais foi completamente monitorado, com duração de 28,2±0,7 dias, variando de 24 a 31 dias. Pela citologia esfoliativa vaginal, houve uma predominância de células superficiais nas fases de proestro e estro (P<0,05), seguida da predominância de células intermediárias no metaestro (P<0,05) e de células parabasais no diestro (P<0,05). Por ultrassonografia, não houve diferenças na morfologia ovariana durante as diferentes fases do ciclo estral (P>0,05). Os folículos foram identificados durante as fases estrogênicas (proestro e estro), com diâmetro médio de 1±0,5mm. Em apenas 12,5% das fases luteais, corpos lúteos medindo 1,4±0,9mm foram identificados. Conclui-se que a associação da citologia vaginal e da ultrassonografia ovariana constitui uma alternativa viável para o monitoramento de ciclos estrais e identificação das fases estrogênicas em cutias da espécie Dasyprocta leporina

Vaginal impedometry for detection of optimal breeding time in bitches

OBJECTIVE

To compare the efficacy of canine vaginal impedometry in identifying the preovulatory luteinizing hormone (LH) peak to that of currently used methods (serum progesterone concentration measurement, vaginal cytologic evaluation, and vaginoscopy).

DESIGN

Prospective study.

ANIMALS

12 sexually intact female dogs.

PROCEDURES

12 mature postpubertal Beagle (n = 3), Beagle-cross (2), and hound-cross (7) bitches ranging from 7.5 to 27.5 kg (16.5 to 60.6 lb) were enrolled in the study. After the onset of spontaneous proestrus, determined on the basis of appearance of serosanguineous vaginal discharge, serum progesterone assays, vaginoscopy, vaginal cytologic evaluation, and vaginal impedometry were performed daily until approximately 4 days after peak LH concentration (day 0) as measured by radioimmunoassay. Vaginal impedometry was compared against serum progesterone concentration measurement, vaginal cytologic evaluation, and vaginoscopy as a method for accurately identifying the LH peak and therefore the optimal breeding time. Ten of 12 bitches were bred with subsequent assessment of embryos.

RESULTS

Vaginal impedometry accurately predicted the preovulatory LH peak in 5 of 11 bitches. One bitch was removed from the study because data were not collected. Of the remaining 11 bitches, 6 had their LH peak on the day serum progesterone concentration first exceeded 2 ng/mL. Crenulation scores reached 1 (mean, 1.3; 95% confidence interval, 0.8 to 1.7) on day 0 as expected; however, these scores were not significantly different from those on days -1 or 1. Vaginal epithelial cell populations did not change noticeably on day 0. Nine of the 10 bitches that were bred produced viable embryos.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that daily use of vaginal impedometry in bitches was unreliable as a method for monitoring periovulatory events. All techniques evaluated (ie vaginal impedometry, serum progesterone concentration assays, vaginoscopy and vaginal cytologic evaluation) frequently produced inaccurate results when used individually. Multiple methods should be used to identify optimal breeding time in dogs.

Periovulatory time in the bitch: what's new to know?: Comparison between ovarian histology and clinical features

The ability to recognize specific events happening in the ovaries during periovulatory time allows optimal management of canine reproduction. The objective of this study was to assess the efficacy of vaginal cytology and blood progesterone (P4) assay to identify accurately the changes occurring at the ovarian structures, mainly during the fertile period. Tertiary follicles, corpora hemorrhagica (CHs) and corpora lutea (CLs) from forty healthy bitches undergoing ovariohysterectomy were evaluated by histo-morphometry based on their aspect, number and size. The tertiary follicles distribution (small, medium and large) was statistically different (P<0.002) among all the stages of the reproductive cycle, except for small follicles (<2mm), which were always observed from proestrus to anestrus. Very large follicles (>4mm) were predominant (P=0.008) around ovulation when P4 mean level was 6.1±1.7ng/mL. The early postovulatory estrous period was characterized by CHs (P<0.002) and P4 level of 16.7±5.9ng/mL. The end of the fertile period - start of diestrus - coincided with the development of CLs (P=0.001) associated with a P4 mean level of 73.9±9.9ng/mL. The small (P<0.001) and medium (P<0.05) follicle diameters were positively correlated with the bitch size. The number of follicles larger than 4mm was significantly lower in bitches younger than 4 years (P<0.02). This study provides insight into some critical steps in the canine reproductive processes in the periovulatory phase and the end of the fertile period, essential to plan breeding programs.