Canine reproductive ultrasound examination for predicting future sperm quality.

The reproductive potential of male animals is commonly evaluated using a breeding soundness examination incorporating B-mode ultrasound examination of the testes and recently Doppler ultrasound examination of the testicular arteries. These techniques may detect testicular normality or pathology, and while some measured parameters are associated with semen quality at the time of ultrasound examination, few studies have investigated the relationship with future semen quality. We hypothesized that B-mode and Doppler ultrasound measurements would correlate with future semen quality. Within two studies, we investigated the relationship between ultrasound measured testicular volume, testicular echogenicity, testicular homogeneity, subjective assessment of the testicular parenchyma, testicular artery resistance index, and pulsatility index with subsequent semen quality. Fifty-five normal fertile dogs of which 29 had stable semen quality and 26 had a subsequent decline in semen quality were examined during a 6-month period commencing 62 days after the ultrasound examination. Statistical analysis showed that no ultrasound parameters were predictive of future total sperm output or percentage live normal sperm. However, mean testicular echogenicity was positively related to future sperm motility (t = 2.202, p = .039). We conclude that quantitative ultrasound assessment of the appearance of the testicular parenchyma has potential for the evaluation of future semen quality in dogs.

Current knowledge on the transport and fate of spermatozoa in the reproductive tract of the bitch.

Canine sperm transport, distribution, storage and detachment is a complex, dynamic and highly regulated process. Transport of sperm within the bitch's reproductive tract is rapid and is influenced by the method of semen deposition (natural mating or artificial insemination) and by the timing of breeding in relation to the day of ovulation. The fertile lifespan of spermatozoa in the reproductive tract of the bitch is considerably longer than in most other domestic species, and the main sperm reservoirs appear to be the uterine crypts and the distal part of the uterotubal junction, where spermatozoa attach by their heads to uterine epithelium. While several in vitro studies demonstrated prolonged motility and viability of canine spermatozoa after coincubation with uterine tube explants, spermatozoal storage has not been documented in the canine uterine tube isthmus or ampulla in vivo. Several factors, including exposure to progesterone, solubilized zona pellucida proteins and post-ovulation uterine tube fluid, appear to trigger membrane events resulting in capacitation-like changes with subsequent motility pattern changes (transitional and hyperactivated) that are associated with sperm detachment. After mating or insemination, a normal low-magnitude post-mating uterine inflammatory response occurs, evidenced by an influx of polymorphonuclear neutrophils (PMNs), increased uterine contractions and an increased uterine artery blood flow. Recently, it was also shown that normal dogs with cystic endometrial hyperplasia develop a more significant endometritis, show fewer mating-induced uterine contractions, a decreased ability of spermatozoa to bind to uterine explants in vitro and a slower uterine clearance after mating.

Assessment of vascular perfusion kinetics using contrast-enhanced ultrasound for the diagnosis of prostatic disease in dogs.

Vascular perfusion was assessed in 10 dogs without prostatic abnormalities and 26 dogs with prostatic disease using contrast-enhanced ultrasound. The time to reach peak contrast intensity (TTP) and peak perfusion intensity (PPI) were measured, and histological biopsies were collected from each dog. Biopsies confirmed normal prostate (n = 10), benign prostatic hyperplasia (n = 11), mixed benign pathology (n = 9), prostatitis (n = 1), prostatic malignancy [adenocarcinoma (n = 4); leiomyosarcoma (n = 1)]. In normal dogs, mean PPI was 16.8% ± 5.8 SD, and mean TTP was 33.6 ± 6.4 s. Benign conditions overall were not statistically different from normal dogs (p > 0.05); for benign prostatic hyperplasia, mean PPI was 16.9 ± 3.8%, and mean TTP was 26.2 ± 5.8 s; for mixed benign pathology mean PPI was 14.8 ± 7.8%, and mean TTP was 31.9 ± 9.7 s; for prostatitis, PPI was 14.2%, and TTP was 25.9 s. The malignant conditions overall had perfusion values that differed from the normal dogs (p < 0.05), although evaluation of the data for individual malignancies did not demonstrate a consistent trend; for adenocarcinomas, the PPI was numerically higher with a mean of 23.7 ± 1.9%, and the mean TTP was 26.9 ± 4.8 s, whilst for the dog with leiomyosarcoma values were numerically lower with a PPI of 14.1% and TTP of 41.3 s. Contrast-enhanced ultrasound appears to offer some ability to document differences in perfusion that may differentiate between malignant and benign lesions, although studies with larger numbers of animals are required to confirm this contention.