Normal and abnormal response to sperm deposition in female dogs: A review and new hypotheses for endometritis.

In mammalian species there are significant physiological responses of the female reproductive tract to the deposition of sperm. These are particularly notable in species where sperm are deposited directly into the uterus, and function both to facilitate sperm transport to the sperm reservoir, and to eliminate introduced contaminants. In the bitch, sperm are deposited into the vagina and are rapidly transported through the open cervix. Sperm are then distributed around the uterus by uterine contractions such that transportation to the tip of the uterine horns occurs within 1 min of the start of mating. The main sperm reservoir appears to be the distal part of the utero-tubal junction which forms a pre-uterine tube reservoir. Sperm remain attached here by their heads to uterine epithelium and remain viable. In non-capacitating conditions sperm slowly detach from this site and this seems important to replenish the uterine tube reservoir, where sperm may re-attach to the epithelium. Post-ovulatory signals trigger capacitation changes and subsequent hyperactivated motility that is associated with detachment of sperm from both reservoirs; thus facilitating fertilization. After mating, a physiological post-mating uterine inflammatory response occurs, evidenced by an influx of polymorphonuclear neutrophils, increased uterine contractions, an increased uterine artery blood flow and a decrease of the resistance index indicating a short-duration vasodilation. Disturbance of this tightly regulated system has the potential to impact fertility by a failure of elimination of the introduced contaminants (such that a clinically-significant post-breeding endometritis ensues) but also by impairing sperm transport.

Horse owners' knowledge, and opinions on recognising colic in the horse.

BACKGROUND: Colic is the most common emergency problem in the horse. An owner's ability to recognise colic and seek assistance is a critical first step in determining case outcome. OBJECTIVES: The aim of this study was to assess horse owners' knowledge and opinions on recognising colic. STUDY DESIGN: Cross-sectional study. METHODS: An online questionnaire was distributed to horse owners with open and closed questions on their knowledge of normal clinical parameters in the horse, confidence and approach to recognising colic (including assessment through case scenarios), and their demographics. Descriptive and chi squared statistical analyses were performed. RESULTS: There were 1564 participants. Many respondents either did not know or provided incorrect estimates for their horse's normal clinical parameters: only 45% (n = 693/1540) gave correct normal values for heart rate, 45% (n = 694/1541) for respiratory rate and 67% (n = 1028/1534) for rectal temperature. Knowledge of normal values was statistically associated with participants' educational qualifications (P<0.01). Owners said if they suspected their horse had colic they would assess faecal output (76%; n = 1131/1486), gastrointestinal sounds (75%; n = 1113/1486), respiratory rate (65%; n = 967/1486) and heart rate (54%; n = 797/1486). There was a lack of consensus on whether to call a vet for behavioural signs of colic, unless the signs were severe or persistent. The majority of participants (61%) were confident that they could recognise most types of colic. In the case scenarios, 49% were confident deciding that a surgical case had colic, but 9% were confident deciding an impaction case had colic. MAIN LIMITATIONS: Most respondents were UK based; risk of self-selection bias for owners with previous experience of colic. CONCLUSIONS: There was marked variation in horse owners' recognition and responses to colic, and significant gaps in knowledge. This highlights the need for the development of accessible educational resources to support owners' decision-making.

Development and validation of a new standardised data collection tool to aid in the diagnosis of canine skin allergies.

Canine atopic dermatitis (cAD) is a common hereditary clinical syndrome in domestic dogs with no definitive diagnostic tests, which causes marked morbidity and has a high economic impact internationally. We created a novel questionnaire for Labrador (LR) and Golden retriever (GR) owners to evaluate canine skin health with respect to clinical signs of cAD. 4,111 dogs had fully completed questionnaires (2,803 LR; 1,308 GR). 'Cases' (793) had a reported veterinary diagnosis of cAD, and 'controls' (1652) had no current or past clinical signs of cAD and were aged >3 years. Remaining dogs (1666) were initially categorised as 'Other'. Simulated annealing was used comparing 'Cases' and 'Others' to select a novel set of features able to classify a known case. Two feature sets are proposed, one for use on first evaluation and one for dogs with a history of skin problems. A sum for each list when applied to the whole population (including controls) was able to classify 'Cases' with a sensitivity of 89% to 94% and specificity of 71% to 69%, respectively, and identify potentially undiagnosed cases. Our findings demonstrate for the first time that owner questionnaire data can be reliably used to aid in the diagnostic process of cAD.

Incidence and impact of dog attacks on guide dogs in the UK: an update.

Data on dog attacks on Guide Dogs' stock were reviewed to investigate the characteristics of the attacks. An average of 11.2 attacks occurred each month. Nearly all of the attacks occurred in public areas, 68.4 per cent of victim dogs were qualified guide dogs and 55.5 per cent of victim dogs were working in harness when they were attacked. Guide Dogs' stock were injured in 43.2 per cent of attacks and veterinary costs for attacks were estimated at £34,514.30. Over 40 per cent of qualified guide dogs' working ability was affected and >20 per cent of qualified guide dogs required some time off from working after a dog attack. Twenty dogs were permanently withdrawn from the Guide Dogs' programme as a result of dog attacks, 13 of which were qualified and working with guide dog owners at the time of the withdrawal; this resulted in a financial cost of >£600,000 to the charity. More importantly perhaps, temporary and permanent withdrawals have a significant impact upon the mobility and independence of guide dog owners and in many cases significantly impacted their emotional well-being.

Using the incidence and impact of health conditions in guide dogs to investigate healthy ageing in working dogs.

This study aimed to use retirement data from working guide dogs to investigate healthy ageing in dogs and the demographic factors that influence ageing. Using a dataset of 7686 dogs spanning 20 years, dogs withdrawn for health reasons before they reached retirement were identified. Cases of retirement for old age, rather than for health reasons, were also recorded, as was the length of working life for all dogs. Specific health reasons were grouped into 14 different health categories. The influence of purebred or crossbreed, breed, and sex on the incidence of these health categories and the length of working life within each health category was considered. The majority (n = 6465/7686; 84%) of working guide dogs were able to function as guide dogs until they had worked for 8.5 years, when they retired. This working life might constitute a reference for the different breeds considered, with the exception of the German shepherd dog, which had a shorter working life. The most common reason for health withdrawals was musculoskeletal conditions (n = 387/1362; 28%), mostly arthritis. Skin conditions (mostly comprised of cases of atopic dermatitis) reduced working life most commonly (mean, approximately 5 years). Nervous sensory conditions (35% of which were cases of epilepsy) reduced working life by 3 years.

Veterinary practitioners' selection of diagnostic tests for the primary evaluation of colic in the horse.

The aim of this study was to survey veterinary practitioners' selection of diagnostic tests for horses with clinical signs of abdominal pain. A questionnaire was distributed to veterinary surgeons involved in the primary evaluation of horses with abdominal pain, including the respondent's demographics, selection of diagnostic tests and factors affecting decision-making. Data analysis included descriptive analysis, categorisation of free text and simple univariable correlations to explore the relationships between independent variables and the relative self-estimated frequency that diagnostic tests were performed. A total of 228 responses were analysed. Participants worked in mixed practice (55.7 per cent), first opinion equine (22.8 per cent), first and second opinion equine (17.9 per cent) and referral practice (3.1 per cent). The majority (48.2 per cent, 105/218) were very confident managing a colic case (confidence level 4/5). The most frequently used diagnostic tests were 'response to analgesia' (87.2±24.0 per cent cases), rectal examination (75.9±21.2 per cent) and nasogastric intubation (43.8±27.6 per cent). Approach varied between practitioners, and for all diagnostic tests with frequency of use ranging from 0 to 100 per cent of cases. 'Risk to personal safety' was the most common reason for not using rectal examination. Practitioner's opinion of their confidence level in managing a colic case was associated with how frequently they used different diagnostic tests. There was marked variation in practitioners' approaches, highlighting the need for further evidence to support decision-making.

Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015.

REASONS FOR PERFORMING STUDY: Colic is the most common equine emergency problem, and one of the main causes of equid deaths. The horse owners' ability to recognise colic is a critical first step in determining case outcome. OBJECTIVES: To assess equine owners' knowledge and recognition of colic. STUDY DESIGN: Online questionnaire of horse owners. METHODS: An online survey was designed to evaluate owners' approach to colic in the horse. The survey included questions on owner demographics, their recognition of colic (including owner's opinions of their ability to recognise colic, their approach, and their recognition of colic using case vignettes), and their knowledge of normal ranges for clinical parameters. Descriptive and chi squared statistical analysis was performed. RESULTS: The survey was completed by 1061 UK respondents. Six per cent of owners thought they could recognise all types of colic, 61% said they could recognise most cases and 30% said they could recognise some but not all cases. Owners said they would assess faecal output (73% of respondents), gastrointestinal sounds (69%), respiratory rate (62%) and heart rate (50%) in horses with suspected colic. One fifth (22%) of owners would call a vet immediately without assessing any parameters. Many respondents either did not know, or provided incorrect estimates of normal values for clinical parameters: 30.4% were 'unsure' of the normal heart rate and 35.5% gave heart rate values which were outside reference ranges; only 24.5% gave appropriate values for normal respiratory rates and only 31% gave normal temperature values. There was no statistical significance between participants' age, educational qualifications, or their experience with horses and their knowledge of normal clinical parameters. CONCLUSIONS: Owners varied in their approach and ability to recognise colic, and many had significant gaps in their knowledge of normal parameters. Educational materials and/or training to assist owners could help address these issues. Ethical animal research: The study did not involve animal research. The study was reviewed and approved by the Ethics Committee, School of Veterinary Medicine and Science, University of Nottingham. The questionnaire was conducted in accordance with the 1998 Data Protection Act, and the British Educational Research Association's Revised Ethical Guidelines for Educational Research (2004). SOURCE OF FUNDING: Adelle Bowden's studentship is funded by the School of Veterinary Medicine and Science, University of Nottingham. Competing interests: None declared.

Use of contrast-enhanced ultrasonography in chronic pathologic canine testes.

Contrast-enhanced ultrasound with sulphur hexafluoride microbubbles was performed in seven healthy dogs without a history of reproductive pathology and with histologically confirmed normal testes and in 42 dogs with chronic scrotal anomalies. All dogs underwent orchiectomy and histological examination. Enhancement patterns and perfusion parameters (peak intensity and regional blood flow) of testes of healthy dogs and testes with chronic lesions were compared. Fourteen non-pathologic and 60 pathologic testes were considered. Forty testes were neoplastic (24 interstitial cell tumours, 9 seminomas, 7 Sertoli cell tumours), 20 were non-neoplastic (16 testicular degenerations, 2 chronic orchitis, 1 testicular atrophy, 1 interstitial cell hyperplasia). In healthy dogs, the contrast medium flow had a rapid homogeneous wash-in and wash-out, with a short peak phase. With contrast ultrasound, testes that were inhomogeneous with a hyperenhancing pattern were associated with neoplasia (sensitivity: 87.5%, specificity: 100%). Lesions with persistent inner vessels and a hypo-to-isoechoic background were significantly associated with seminomas (sensitivity: 77.8%, specificity: 100%). Testes with non-neoplastic lesions were characterized by a scant/moderate homogeneous enhancement. Perfusion parameters were higher in neoplastic lesions. Contrast ultrasound was a feasible diagnostic tool in the assessment of testicular lesions, with hyperenhancement being an important feature in the diagnosis of malignancy.

Uterine fluid from bitches with mating-induced endometritis reduces the attachment of spermatozoa to the uterine epithelium.

Persistence of free fluid in the uterine lumen of bitches with endometrial hyperplasia appears to be diagnostic for mating-induced endometritis and is associated with reduced chances of pregnancy. This study investigated the possibility that reduced fertility might be associated with an effect of uterine fluid on sperm. Uterine lavage fluid was collected pre- and post-insemination from normal bitches without ultrasonographically-detectable luminal fluid (n=4), and previously non-pregnant bitches with endometrial hyperplasia and luminal fluid (n=4). Concentrations of polymorphonuclear neutrophils (PMNs) were measured and the effect of the fluid on the attachment of spermatozoa to the uterine epithelium was studied using medium (M) 199 as a control. To elucidate whether any effect was accounted for by the presence of PMNs, attachment was also measured in M199 with PMNs added at the concentration found in lavage fluid. Pre-insemination lavage fluid from both groups contained low concentrations of PMNs which increased post-insemination; the increase was larger for bitches with uterine fluid. Compared with M199 controls, lavage fluid reduced the attachment of spermatozoa; fluid from bitches with endometrial hyperplasia and uterine fluid had a greater effect than normal bitches, and post-insemination fluid had a greater effect than pre-insemination fluid. Spermatozoal attachment was reduced by a similar magnitude for M199 with added PMNs, although post-insemination fluid from bitches with endometrial hyperplasia reduced attachment more than M199 with added PMNs. Poor fertility in bitches with uterine luminal fluid might be partially associated with impaired attachment of spermatozoa to uterine epithelium, mediated principally, but not solely, by PMN influx into the uterine lumen.

Uterine artery blood flow characteristics assessed during oestrus and the early luteal phase of pregnant and non-pregnant bitches.

The aim of this study was to measure uterine artery blood velocity daily using Doppler ultrasonography in 10 young and 10 older clinically normal bitches throughout oestrus. Typical arterial waveforms identified in young bitches were characterised by a systolic peak and subsequent flow throughout diastole, whereas in older bitches, flow was sometimes absent in diastole. For 3 days immediately prior to ovulation, at the time of declining plasma oestrogen and increasing progesterone concentrations, resistance index (RI) increased, principally associated with decreased diastolic velocity; in some bitches there was absent late diastolic flow during this time. In older bitches, the waveform appearance was more variable, with absent late and early diastolic flow observed in some cases. Mean RI was higher throughout oestrus for older bitches compared with young bitches, although both groups had a similar 3-day duration increase before ovulation. Nine of the young bitches and five of the older bitches became pregnant; litter size was smaller for the older bitches. Non-pregnant bitches: (1) were significantly older; (2) had fewer waveforms with continuous diastolic flow 2 days before ovulation; (3) had lower end diastolic velocity, higher RI and fewer waveforms with continuous diastolic flow 2 days after ovulation, and (4) had lower plasma progesterone concentrations 5 days after ovulation. These are the first detailed observations of uterine artery blood velocity and waveform appearance throughout oestrus in bitches, and this is the first description of a link between impaired diastolic flow and reduced fertility. Assessment of uterine artery velocity could be useful to promote understanding of physiological mechanisms and could also become an important tool to assess potential infertility.

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.

Epithelial surface changes and spermatozoa storage in the reproductive tract of the bitch.

Spermatozoa are known to bind to the epithelial cells lining the uterine tube in various species, but information in canids is conflicting and sparse. The first aim of this study was to measure the epithelial surface outline (ESO) of different regions of the canine uterine tube in the four stages of the oestrous cycle as an indicator of a changing potential reservoir for spermatozoa. The second aim was to identify the site of sperm storage in the bitch after natural mating. Reproductive tracts were collected from bitches undergoing routine ovariohysterectomy. Histological analysis showed that, when corrected for uterine tube size, the ESO of pro-oestrus (P<0.005) and oestrus (P<0.05) tubes were larger than anoestrus, but not metoestrus, tubes. The second study examined reproductive tracts from 12 Beagle bitches at 6, 12, 24 and 48h after mating. Light and electron microscopy revealed large numbers of spermatozoa in the proximal regions of the uterus and particularly the distal utero-tubal junction (UTJ), with few present in the proximal UTJ or uterine tubes. Spermatozoa were bound by their heads to microvilli on the epithelial surface of the uterine lumen and to ciliated cells in the distal UTJ. This is the first report to measure and document differences in potential epithelial attachment sites of the uterine tubes at different stages of the oestrous cycle and to provide compelling evidence that the main spermatozoal storage site in the reproductive tract of the bitch is the distal UTJ.

The bitch uterine response to semen deposition and its modification by male accessory gland secretions.

Little is known about the response of the bitch's reproductive tract to semen deposition. In this study, an influx of polymorphonuclear neutrophils (PMNs) into the uterus was detected after artificial insemination, but there was normal fertility. Doppler ultrasonography showed that insemination induced an increase in uterine artery blood velocity and a decrease in the resistance index of short duration, indicating vasodilation. Semen that was extended in fluid from the sperm rich fraction of the ejaculate (seminal plasma, SP), or third fraction of the ejaculate (prostatic fluid, PF), produced a similar magnitude of effect but of longer duration. It was hypothesised that vasodilation following insemination was largely induced by SP and PF which, together with PMN influx, was part of a normal uterine response. Physiological concentrations of PMNs in vitro reduced the ability of spermatozoa to attach to uterine epithelium, most likely as a result of spermatozoa becoming attached to PMNs. However, both SP and PF increased attachment of spermatozoa to the uterine epithelium by reducing sperm attachment to PMNs, and potentially by an additional mechanism that did not involve inhibition of sperm binding to PMNs. These are the first canine studies to document an apparent physiological response by the uterus to semen, associated with uterine artery vasodilation and PMN influx. Moreover, these investigations are the first to demonstrate that canine SF and PF are part of the mechanism for increasing uterine perfusion and that both fluids have a modulatory effect on PMN-induced inhibition of spermatozoal attachment to uterine epithelium, most likely mediated by reduced sperm attachment to PMNs.

Periovulatory changes in the endoscopic appearance of the reproductive tract and teasing behavior in the bitch.

A variety of diagnostic techniques have been applied to address the problem of determining optimal mating time in the bitch, although some have not been objectively investigated. Nine healthy bitches were examined daily using routine clinical methods as part of their normal breeding management with the aim of establishing which method was most useful. Accordingly, measurement of the degree of vulval swelling, endoscopic measurement of the vaginal mucosal color and appearance, and objective evaluation of behavior of the bitch were related to the time of ovulation (calculated when progesterone reached 5 ng/mL; Day 0) and the duration of the fertilization period (Day 2 to Day 5) determined by measurement of plasma progesterone concentration and assessment of vaginal cytology. There was a surprisingly large individual variation in measurements of vulval swelling, such that although trends were apparent this technique was not precise enough to establish the optimal mating time. However, measuring color saturation and vaginal mucosal fold width was successful. A consistent change in the mucosal color saturation was observed that related to the beginning (Day -5) and duration of the fertile period although there was no difference in measurement of color saturation between Day -5 and Day 2 (P = 0.31), and Day 2 and Day 5 (P = 0.43). The vaginal mucosal folds were smaller in width at the beginning of the fertilization period (Day 2) than at the beginning of the fertile period (Day -5) (P = 0.008), and all bitches had a consistent appearance of mucosal contours on Day 3. Assessment of sexual behavior was not considered precise enough to enable determination of the optimal time for mating because of the large amount of individual variation in behavioral scores. There was no difference in female behavior scores between Day -5 and Day 2 (P = 0.29), or between Day 2 and Day 5 (P = 0.06). Using objective techniques this study has quantified changes in the color and fold width of the vaginal mucosa that have previously only been subjectively reported. These changes can be used to identify the fertilization period and it is possible, with future refining of the technique, that endoscopic examination could replace vaginal cytology to be used in conjunction with plasma progesterone concentration when examining bitches to determine the optimal time to breed.

Delayed uterine fluid clearance and reduced uterine perfusion in bitches with endometrial hyperplasia and clinical management with postmating antibiotic.

In many species a transient uterine inflammatory response follows mating and is proposed to remove excess spermatozoa, bacteria, and other contaminants from the uterus. Similar events have been documented in the bitch involving increased uterine contractions, polymorphonuclear neutrophil influx and uterine artery vasodilation. Some healthy bitches with endometrial hyperplasia have increased numbers of uterine luminal polymorphonuclear neutrophils after mating and reduced fertility; it is purported that this represents a presumed postmating endometritis. This study used B-mode and Doppler ultrasonography at the time of mating to measure uterine contractions, clearance of ejaculated fluid, and uterine artery velocity in normal bitches and those with endometrial hyperplasia. Mating resulted in an increase in the number of uterine contractions, although fewer mating-induced contractions were noted in bitches with endometrial hyperplasia. Interestingly, uterine fluid cleared significantly more slowly after mating from the bitches with endometrial hyperplasia than the normal bitches (P = 0.01). In a further study, Doppler ultrasonography showed that in normal bitches there was a significant increase in uterine artery blood velocity (P = 0.04) and a decrease in the resistance index after mating (P = 0.04), indicating vasodilation. In bitches with endometrial hyperplasia the baseline resistance index was significantly higher than normal bitches (P = 0.05), and furthermore, although there was a significant decrease in resistance index after mating, in the bitches with endometrial hyperplasia this was of a smaller magnitude that in normal bitches. These findings indicate lower baseline uterine perfusion, and a blunted vasodilation response to mating in bitches with endometrial hyperplasia. Short-duration postmating administration of systemic antibiotic increased pregnancy rates in bitches with endometrial hyperplasia (P < 0.01). Litter sizes in bitches with endometrial hyperplasia were lower than those of normal bitches both before and after treatment with postmating antibiotic (P = 0.04 and < 0.01, respectively). Mating-induced endometritis in bitches with endometrial hyperplasia appears to affect fertility by reducing the uterine vasodilatory response to mating and delaying clearance of uterine fluid as a result of decreased uterine contractions but the effect can be ameliorated in part by the postmating administration of antibiotic.

Perturbed sperm-epithelial interaction in bitches with mating-induced endometritis.

In several species there is a transient uterine inflammatory response after mating that is purported to clear excess and dead spermatozoa, bacteria and other contaminants from the uterus. In particular individuals this inflammatory response is substantial, resulting in an acute mating-induced endometritis, causing infertility. In this study, the influx of polymorphonuclear neutrophils (PMNs) into the uterine lumen of bitches was investigated after artificial insemination with fresh semen. In normal bitches, an influx of PMNs was detected, followed by high pregnancy rates and normal litter size, and may be a physiological inflammatory response. In bitches with endometrial hyperplasia, there was a larger influx of PMNs and pregnancy rates and litter size were reduced, although the effect was partly ameliorated by the post-mating administration of antibiotics. It is postulated that in bitches with endometrial hyperplasia, post-mating endometritis develops with the potential to affect reproduction adversely. In vitro studies demonstrated a reduced ability of spermatozoa to attach to the uterine epithelium of bitches with endometrial hyperplasia. Moreover, PMNs in the co-culture system inhibited spermatozoal attachment to normal and hyperplastic uterine epithelium, especially hyperplastic epithelium. It was concluded that decreased spermatozoal attachment to uterine epithelium mediates a reduction in fertility of bitches with endometrial hyperplasia. This is the first study to detail an apparent physiological uterine inflammatory response to spermatozoa and its perturbation in bitches with endometrial disease, and the first to recognise the clinical significance and potential aetiology of mating-induced endometritis.

The effect of cryopreservation on the capacitation status and epithelial cell attachment capability of dog spermatozoa.

Freezing and cooling of spermatozoa during cryopreservation for artificial insemination causes ultrastructural changes in the acrosome and plasma membrane which reduces longevity and fertility. Cryopreservation-induced capacitation-like changes and reduced ability of spermatozoa to bind to the cells of the reproductive tract of the bitch may contribute to the reduced fertility of cryopreserved spermatozoa. Previous studies in the dog have investigated the effects of extending and cooling spermatozoa on the plasma membrane but often only after freeze-thawing and not in conjunction with an assessment of their ability to bind to uterine tube epithelial explants. This study investigated the effect of each stage of the cryopreservation process on capacitation and attachment to the reproductive tract of the bitch. The capacitation status of spermatozoa was studied over time after cryopreservation using a chlortetracycline and Hoechst 33258 stain. The ability of spermatozoa to bind to uterine tube epithelial explants was studied using Hoechst 33342 stain. Extending, cooling and freeze-thawing promoted capacitation and decreased the spermatozoal binding ability. The effect of each stage appeared to be cumulative with the freeze-thawing stage being the most dramatic. The results suggested that the cumulative effect of each stage of the cryopreservation process results in the promotion of capacitation before spermatozoa have reached the site of fertilisation, and therefore spermatozoa have reduced ability to attach to epithelial cells. These effects are contributory factors to the reduced fertility of cryopreserved spermatozoa.

Stimulation of mating-induced uterine contractions in the bitch and their modification and enhancement of fertility by prostatic fluid.

Little is known about the response of the bitch's reproductive tract to mating or of the role of male accessory gland secretions in the female. In this clinical study, the component stimuli causing mating-induced uterine contractions were investigated in 64 bitches. Basal uterine contractions were present during oestrus and a significant increase in the frequency of contractions was observed during natural mating. Neither teasing with a male nor stimulation of the vagina or cervix by vaginal or transcervical insemination (TCI) caused an increase in the frequency of uterine contractions. Increased contractions were however present after both vaginal and transcervical insemination when the vestibule was distended, and dorsal wall of the vaginal was manually stimulated. Interestingly, this increase in uterine contractions was partially ameliorated when prostatic fluid was used as a flushing component following transcervical insemination. Two further studies performed with 72 bitches of which 18 were each inseminated transcervically with fresh or frozen semen flushed into the uterus with either saline or prostatic fluid demonstrated that prostatic fluid significantly increased the pregnancy rate and litter size of both groups. There are important mechanisms regulating the transport and elimination of sperm from the bitch's reproductive tract. Whilst physical aspects of coitus are undoubtedly involved in initiating uterine contractions, prostatic fluid appears to have an important role in modulating uterine contractions and fertility.

B-mode and contrast-enhanced ultrasonographic findings in canine prostatic disorders.

Ultrasound is a common imaging technique used for examination of the dog's prostate gland that has proven to be successful for diagnosis of many clinical conditions. Whilst B-mode ultrasound is useful for assessment of the prostate gland, there appears to be substantial variation in the appearance of some pathological conditions, although individual experienced ultrasonographers often have a high aptitude for making a correct diagnosis. Here, we report the normal volume and appearance of the canine prostate gland with B-mode ultrasound and use thematic analysis to identify the categories described by experienced ultrasonographers when reporting both normal and abnormal findings. Four thematic categories were identified: background echotexture, parenchymal stippling, generalized appearance and focal changes. We found that a relatively narrow variety of thematic variables (descriptors) were used for reporting of prostatic pathology within these thematic categories. There was also poor association between these descriptors and the underlying pathology, with the only unique descriptors being 'cysts' for benign prostatic hyperplasia and 'parenchymal mineralization' for adenocarcinoma. In comparison with the limitations of B-mode ultrasound, we document the value of measurement of vascular perfusion kinetics using contrast-enhanced ultrasound and demonstrate how perfusion kinetics differ between benign and malignant prostatic disease.

Fertility and whelping complications in bitches following correction of vaginal abnormalities.

The fertility and whelping complications of normal bitches and of bitches that had had surgery to correct a vaginal abnormality of varying severities were compared retrospectively. Reproductive performance and whelping statistics were compared between 37 bitches that had been diagnosed with a vaginal abnormality and 37 age- and breed-matched bitches with no history of vaginal abnormalities. There were no significant differences in reproductive performance between the affected and control bitches. When analysed by the severity of the abnormality, pregnancy rates were significantly lower for the group of bitches with the most severe abnormalities compared with the group of bitches that had mild vaginal abnormalities. Furthermore, the bitches that had severe abnormalities were significantly more likely to require a caesarean section than those with mild abnormalities.