Electroejaculation does not impair sperm motility in the beagle dog: a comparative study of electroejaculation and collection by artificial vagina

Novel Low-Voltage Electro-Ejaculation Approach for Sperm Collection from Zoo Captive Lanyu Miniature Pigs (Sus barbatus sumatranus)

Semen collection can be achieved via hand penile massage or rectal stimulation using electro-ejaculation methods. Traditional electro-ejaculation procedure applied relatively high voltage of 3-15 volts with a maximum current of 900 mA. However, these manipulations often result in great stress and discomforts in animals. In this study, we showed low-voltage electro-ejaculation procedure using 2-3 volts with a maximum current of 500 mA can efficiently stimulated ejaculations in zoo captive lanyu miniature pigs with a high success rate of 81.3% (13/16). Besides normal semen properties (semen volume, pH, sperm concentration), we demonstrated that low-voltage electro-ejaculation caused less stress in the animals, and sperm cells obtained via low-voltage electro-ejaculation exhibit low abnormality (10.3%), high viability (84.3%), motility (75.7%), progressive motility (63.7%), and acrosome integrity (88%). However, cryopreservation protocol used in the current study requires further optimization, as sperm mitochondrial function was partially compromised during freezing procedures. Taken together, we demonstrated in this study that a low-voltage electro-ejaculation approach can be used to obtain quality sperm cells from zoo captive lanyu miniature pig with less physical stress during electro-ejaculation procedure.

Social rank does not affect sperm quality in male African wild dogs (Lycaon pictus)

Sperm banking and AI could benefit endangered African wild dog conservation. However, it is unclear whether their dominance hierarchy causes a decrease in reproductive and sperm quality parameters in subordinate males that typically do not breed. In this study, we investigated the effect of social rank on male reproductive parameters, including faecal androgen and glucocorticoid metabolite concentrations, prostate and testes volume, preputial gland size, semen collection success and sperm quality. Samples were obtained from captive males (prebreeding season: n=12 from four packs; breeding season: n=24 from seven packs) that were classified as alpha (dominant), beta or gamma (subordinates) based on the frequency of dominant versus submissive behaviours. In the prebreeding season, semen was successfully collected from all alpha but only half the subordinate males, with urine contamination (associated with lower rank) significantly reducing total and progressive motility, sperm motility index, normal sperm morphology and acrosome integrity. The breeding season was associated with a significant increase in faecal androgens, prostate and testis volume, as well as progressive motility and the total number of spermatozoa ejaculated. However, with the exception of prostate volume (mean±s.e.m: 12.5±4.5, 7.1±1.0 and 7.3±1.0cm3 in alpha, beta and gamma males respectively; P=0.035), all other reproductive and sperm quality parameters did not differ between males of each social rank. In conclusion, reproductive suppression of subordinate males appears to be behaviourally mediated, because males of all social ranks produce semen of similar quality, making them suitable candidates for sperm banking, particularly during the breeding season when sperm quality improves.

Effect of semen collection method on sperm motility of gray wolves (Canis lupus) and domestic dogs (C. l. familiaris)

Genetic management of Mexican gray wolves includes semen banking, but due to the small number of animals in the population and handling restrictions, improvements in semen collection and cryopreservation rely on results from studies of domestic dogs. Semen collection from wolves requires anesthesia and electroejaculation, which introduce potentially important variables into species comparisons, as dog semen is typically collected manually from conscious animals. To investigate possible effects of collection method on semen quality, we compared semen collection by the traditional manual method and by electroejaculation (EE) in a group of dogs (n = 5) to collection by EE only in wolves (n = 7). Samples were divided into two aliquots: neat or diluted in Tris/egg yolk extender, with motility evaluated at intervals up to 24 h. There were no differences (P > 0.10) in sperm motility in either neat or extended samples at 24 h from EE dogs and wolves, although motility of the wolf neat samples declined more rapidly (P < 0.05). However, there were differences (P < 0.01) between EE and manually collected dog semen in motility at 24 h, in both the neat and extended samples. Therefore, general motility patterns of dog and wolf semen collected by EE were similar, especially when diluted with a Tris/egg yolk extender, but sperm collected from dogs by EE did not maintain motility as long as manually collected samples, perhaps related to the longer exposure of EE samples to more prostate fluid.

Influence of extender, freezing rate, and thawing rate on post-thaw motility, viability and morphology of coyote (Canis latrans) spermatozoa

The objective of this study was to examine the post-thaw effects of three cryoprotective extenders (Tris-fructose-citric acid extender, Tris-glucose-citric acid extender, and lactose extender), three linear freezing rates (-1, -6, and -20 degrees C/min), and three thawing rates (37 degrees C water bath for 120s, 60 degrees C water bath for 30s, and 70 degrees C water bath for 8s) on coyote spermatozoa. After thawing, the findings supported that cryopreservation of coyote (Canis latrans) spermatozoa frozen at a moderate freezing rate (-6 degrees C/min), in either a Tris-fructose or Tris-glucose extender, and thawed at a slow rate (37 degrees C water bath for 120s) or moderate rate (60 degrees C water bath for 30s), resulted in a more vigorous post-thaw motility (range, 57.5-44.0%) and viability (range, 64-49.6%) with the least amount of morphological and acrosomal abnormalities.

Semen collection in the dog

This review will discuss semen collection in the dog. Semen samples may be collected from male dogs for the purposes of artificial insemination, cryopreservation or diagnosis. The materials needed for semen collection depend on which method is used and the collector's level of expertise with this procedure. At minimum, two sterile centrifuge tubes or specimen cups can be used to collect semen as it is ejaculated (for the combined first and second fractions and for the third fraction). The most common method for semen collection in the dog is by digital stimulation. Under ideal conditions, this procedure is performed in the presence of an estrous bitch. Initially, the dog's penis is vigorously massaged through the prepuce at the level of the bulbus glandis (caudal-most aspect of the prepuce) until a partial erection develops (initial engorgement of the bulbus glandis). The prepuce is quickly retracted past the bulbus glandis and firm constant pressure is applied to the penis behind the bulbus glandis by squeezing the penis between index finger and thumb. Pelvic thrusting may occur following application of pressure behind the bulbus glandis during the development a "full" erection. The ejaculate is composed of three fractions: first (sperm-poor), second (sperm-rich) and third (prostatic fluid). In addition to digital stimulation of the penis, spermatozoa have been collected from dogs using electroejaculation and pharmacologic methods.

Endocrine profiles and semen quality in spinal cord injured men

PURPOSE

To evaluate the hypothalamic-pituitary-testis (HPT) axis, endocrine profiles and semen quality in men with spinal cord injury (SCI).

MATERIALS AND METHODS

Fifty-five men with SCI were studied. Serum levels of FSH, LH, testosterone, oestradiol and prolactin (PRL) were determined; the LH-releasing hormone (LHRH) stimulation test and a semen analysis were performed, and testicular volumes were measured. Thirty-six age-matched healthy male volunteers and 34 noninjured infertile men served as controls.

RESULTS

Eight SCI subjects had low basal LH, four had low basal FSH, and 16 had decreased basal serum levels of LH and FSH. Of subjects with lower serum levels of gonadotrophins (LH and/or FSH), nine had low serum testosterone and seven had hyperprolactinaemia. Serum levels of oestradiol were similar for all groups. There were increased LH and FSH responses to LHRH in SCI subjects compared to normal controls, but this difference was only statistically significant in SCI subjects with lower than normal serum levels of LH and/or FSH. There was no significant difference in testis volume between SCI subjects and controls. The mean semen volume in SCI subjects was lower than from controls, but the difference was not statistically significant. Sperm motility and percent normal sperm morphology were lower in SCI compared to normal controls but not to infertile control subjects. In total, 51% and 86% of SCI subjects had at least one hormonal or axis abnormality, respectively.

CONCLUSION

We conclude that hypogonadotropism in SCI subjects is likely to be secondary to altered neural or hormonal pathways between the hypothalamus and the pituitary gland, and that these endocrine abnormalities may be the mechanisms contributing to impairment of semen quality.

Canine model of infertility after spinal cord injury: time course of acute changes in semen quality and spermatogenesis

PURPOSE

We established a canine model of subfertility after spinal cord injury and examined the time course of acute changes in semen quality and spermatogenesis after spinal cord injury.

MATERIALS AND METHODS

Seven dogs underwent surgical T7 spinal cord injury. Six dogs were used as controls. Electroejaculation and testicular fine needle aspiration were performed at baseline and twice weekly for 3 weeks after spinal cord injury. Semen quality change was examined by standard semen analysis. Spermatogenesis was assessed by flow cytometry of testicular fine needle aspiration in all dogs as well as by testicular histology at study conclusion in 4 controls and 4 spinal cord injured dogs.

RESULTS

No significant changes in spinal cord injured dogs were noted before 3 weeks after injury. From baseline to 3 weeks after injury certain changes were evident in spinal cord injured dogs. Mean antegrade sperm motility decreased from 62.9% to 20.1% (p = 0.008), mean total sperm (antegrade plus retrograde total sperm) decreased from 423 to 294 x 106 which was not statistically significant, and the incidence of testicular haploid cells decreased from 75.6% to 48.3% (p = 0.028). No significant change in any parameter was present in control dogs. The mean number of mature spermatids per cross-sectional tubule on final testicular histology was significantly decreased in spinal cord injured dogs compared with controls (13.6 versus 43.9, p = 0.02).

CONCLUSIONS

In the canine model tested the dogs readily survived spinal cord injury, electroejaculation was effective for obtaining ejaculate and fine needle aspiration allowed serial examination of spermatogenesis. Three weeks after spinal cord injury but not before 3 weeks sperm motility and spermatogenesis were significantly decreased. However, at the same point this decrease in spermatogenesis was not yet reflected in the total ejaculated sperm count.

Characterization of semen collected from beagles and captive Japanese black bears (Ursus thibetanus japonicus)

This study characterized semen collected from the Japanese black bear, Ursus thibetanus aponicus, to provide information on semen cryopreservation for artificial breeding. Preliminary studies using a beagle dog as the model species showed that sperm concentration and total sperm count were lower in semen collected by electroejaculation than in semen collected by digital manipulation, but that sperm motility, viability and morphology were similar. Characterization of semen obtained from Japanese black bears by electroejaculation under general anesthesia revealed that semen volume and total number of spermatozoa collected were lower; but that sperm concentration, motility, viability and morphology were equivalent to those reported in other ursids. When semen was collected via a catheter inserted into the urethra during the stimulation for ejaculation, the sperm concentration, total sperm count and motility were relatively higher than when semen was collected directly in a test tube. Specific normal semen characteristics (mean +/- SEM) were pH, 7.6 +/- 0.0; volume, 0.212 +/- 0.038 mL; sperm concentration, 361 +/- 100 x 10(6)/mL; total sperm count, 84.0 +/- 32.2 x 106; +++ motility, 30 +/- 5%; motility, 77 +/- 3%; viability 77 +/- 2%; and abnormal morphology, 11+/- 2%. These results suggest that semen can be collected from Japanese black bears by electroejaculation.

Evaluation of the "Hamilton Thorn computer-based automated system" for dog semen analysis

An objective evaluation of semen is warranted to assess the canine male fertility and to select appropriate techniques and extenders for semen preservation. With conventional microscopic evaluation, the subjectivity of the analysis makes any comparison of results difficult. In the present study, we validated the Hamilton Thorn computer-aided semen analyzer (HTR-IVOS10 analyzer) for objective assessment of canine semen. A description of fertile canine motility parameters using this analyzer is reported. Semen analysis at 38 degreesC is found to be more optimal and accurate than 30 degreesC. The Makler chamber was preferred to the Cell-vu, which induced a decrease of all semen motility parameters. The repeatability of the measures was good with intra-and inter-assay coefficients of variation below 10% and 20%, respectively, for most of measured parameters. An overestimation of semen concentration, increasing with dilution of semen, was observed when HTR-IVOS10 results were compared with the classical manual Makler cell evaluation. A significant decrease in semen motility parameters was recorded when high semen dilutions were used. Generated from the analysis of 42 mature fertile male beagle dogs, a description of semen motility parameters using the CASA system is presented to serve as reference when comparing Beagle ejaculates both in clinical and experimental studies.

Seminal vesicle aspiration in spinal cord injured men: insight into poor sperm quality

PURPOSE

In men with spinal cord injury poor quality semen is seen when performing electroejaculation and penile vibratory stimulation. We determined whether sperm stasis within the seminal vesicles is a potential cause of this problem.

MATERIALS AND METHODS

Seminal vesicle aspiration was performed immediately before electroejaculation or penile vibratory stimulation in men with aspermia secondary to spinal cord injury. Sperm count and quality of seminal vesicle aspiration and subsequent ejaculation were compared with historical ejaculated counts, ultrasound findings and patient characteristics.

RESULTS

Mean total number of right plus left seminal vesicle sperm plus or minus standard deviation was 511 +/- 960 x 10(6). Mean total number of sperm obtained by seminal vesicle plus electroejaculation or penile vibratory stimulation was 918 +/- 1,261 x 10(6). Average motility and viability of the seminal vesicle aspirated sperm were 1.3 and 3.2%, respectively. Average motility of the ejaculated sperm was 26.4% after seminal vesicle aspiration versus 16.3% in previous ejaculation induction procedures performed in the same patients. Seminal vesicle aspirated sperm represented 66% of the total number of sperm obtained during the session and was equal to 49% of the sperm obtained at previous electroejaculation or penile vibratory stimulation sessions. The period of abstinence correlated only with ejaculate count (simple regression p = 0.009). No other clinical characteristics had any effect on sperm count or quality.

CONCLUSIONS

Large numbers of poor quality sperm are present within the seminal vesicles of spinal cord injured men and these sperm comprise a large portion of the specimens collected by electroejaculation or penile vibratory stimulation. This phenomenon is independent of the period of abstinence, implicating disordered storage of sperm due to spinal cord injury rather than infrequent ejaculation. The large number of senescent sperm within the seminal vesicles appears to be a primary cause of poor sperm quality in spinal cord injured men.