Clinical and spermatological findings in male dogs with acquired infertility: A retrospective analysis

Negative impact of benign prostatic hyperplasia on fertility in dogs-a mini-review

The aim of this article is to provide a comprehensive review of the negative impact of benign prostatic hyperplasia (BPH) on fertility in dogs. BPH is the most common disease of the prostate gland and one of the major causes of infertility in dogs, associated with impaired semen quality. Hormonal imbalance, oxidative stress, biochemical changes in prostatic fluid and haematospermia have been discussed as causes of reduced semen quality in dogs with BPH. Chronic prostatitis often occurs concurrently with BPH and has an additive negative effect on semen quality and fertility. In breeding dogs with infertility associated with BPH, treatment with the anti-androgen osaterone acetate or the 5α-reductase inhibitor finasteride is recommended to reduce prostate size and clinical symptoms and to restore fertility. Combined occurrence of BPH and chronic prostatitis requires simultaneous treatment of both conditions, including microbials with good penetration into the prostate. The use of antioxidants in the supportive treatment of BPH seems reasonable.

Impact of autologous platelet-rich plasma used for treatment of oligozoospermia in dogs on the quality of semen and testicular blood flow

Platelet-rich plasma (PRP) is widely used in regenerative medicine, and the current study aimed to investigate the effects of autologous PRP on semen characteristics, testicular blood flow, and testosterone levels in the treatment of oligozoospermia in dogs. Ten stray male dogs diagnosed with oligozoospermia were included in the study. The dogs were randomly assigned to two groups: Group I, the control group (n = 5), which received no treatment, and Group II, the PRP group (n = 5), which received a single intra-testicular injection of 0.5 mL of autologous PRP into each testicle. Testicular hemodynamics, hormonal and biochemical analysis and semen parameters were assessed for both groups and the examination was extended to 8 weeks. The results demonstrated that dogs treated with PRP showed significantly higher values of End Diastolic Velocity (EDV) and Peak Systolic Velocity (PSV) (P < 0.001) at the 6th to 8th weeks post-injection, compared to baseline (day 0) values. Conversely, the values of Resistance Index (RI) and Pulsatility Index (PI) showed a significant decrease (P < 0.001) in group II from week 2 to week 8. Additionally, PRP treatment led to significant increases in sperm concentration, motility percentage, and the proportion of live and normal spermatozoa (P < 0.001), with maximum values observed at 28 and 60 days post-treatment, compared to day 0. Moreover, serum testosterone and nitric oxide (NO) levels were significantly higher (P < 0.001) in group II and remained elevated through the 8th week following injection, compared to baseline values and group I. In conclusion, this study demonstrates that autologous PRP treatment effectively increases sperm concentration, motility, and normal spermatozoa, improves testicular blood flow, and elevates testosterone and NO levels. These findings suggest that PRP may be a promising therapeutic option for the treatment of oligozoospermia in dogs. Further studies are needed to confirm and expand upon these results.

A Systematic Review of Medical Treatments for Benign Prostatic Hyperplasia in Dogs: Evaluating Strategies for Reproductive Function Preservation

Benign prostatic hyperplasia (BPH) is a common condition in intact male dogs and a leading cause of subfertility. While surgical and chemical castration are effective treatments for BPH, managing this condition in breeding dogs is challenging due to the desire to preserve reproductive function. This study systematically reviews medical treatments for BPH that maintain breeding potential. Thus, a comprehensive literature search was conducted across four databases (CAB Direct, Scopus, PubMed, and Web of Science) to identify peer-reviewed studies published between 2000 and 2024, following PRISMA guidelines. Specific inclusion and exclusion criteria were applied, and a risk of bias assessment was performed using a modified Cochrane tool. A total of 35 studies were included, evaluating therapies such as finasteride, osaterone acetate, tamoxifen, and others, with outcomes including prostate size, sperm quality, hormonal levels, and tissue morphology. Evidence suggests that osaterone acetate and finasteride are acceptable treatments for BPH in breeding dogs, in spite of a still debatable effect on some sperm characteristics. Therapies like tamoxifen and acyline should be excluded due to their detrimental effects on reproductive function. Further research is required for apparently promising approaches concerning tadalafil, anastrazole, mepartricin, and U. fissa.

Chemical castration in dogs using calcium chloride: effects on testicular hemodynamics and semen characteristic and serum levels of testosterone

Dog overpopulation and stray dogs are global issues that are detrimental to public health and animal welfare. Thus, the goal of the current study was to provide alternatives for surgical castration. Therefore, calcium chloride was employed in this study, which might be an option for castration. Ten dogs were divided into two groups of five: a calcium chloride-treated group and a control group. The treated group received a single bilateral intratesticular injection of 1 ml of sterile saline containing calcium chloride dihydrate (CaCl2•2 H2O) at a dose of 20 mg/kg per testicle. While the control group was treated with 1 ml of sterile saline solution, Semen and blood collection, as well as Doppler ultrasonography, were routinely carried out every week on days 0, 7, 14, 21, and 28 in order to evaluate the impact of the injection on semen parameters and testicular blood flow. The testicular volume and echogenicity in the CaCl2-treated group were significantly (P < 0.001) lower in weeks 2 through 4 than in the control group. Furthermore, in canine semen, CaCl2 dramatically decreased the amount, motility, and viability of sperm. When compared to vehicle-control animals, azoospermia was seen 2 weeks after the injection and persisted for the end of the study. The testes of all dogs were surgically removed at 30 days post-injection, and testes were put in 10% neutral buffered formalin for tissue processing. When compared to the control group, the average weight of testes in the chemical groups was dramatically reduced. Significant decreases in spermatogenic processes, necrosis, and degeneration of seminiferous tubules packed with necrotic debris, and fibrosed interstitial tissue, necrosed and calcified Sertoli, and Leydig cells were seen 30 days after CaCl2 injection. There was a significant decrease in testosterone levels compared to day 0 before CaCl2 injection and the control group. From weeks 1 through 4, there was a substantial decrease in both peak systolic velocity (PSV) and end-diastolic velocity (EDV) values (P < 0.001) following a single intratesticular injection of CaCl2. The resistance index (RI) and pulsatility index (PI) showed the opposite tendency. Based on the histopathological and semen evaluations in this investigation, the study concludes that a single intratesticular injection of CaCl2 appears to be a practical and generally applicable approach for chemical sterilization of dogs.

Anti-Müllerian hormone as a diagnostic marker for testicular degeneration in dogs: insights from cryptorchid models

Introduction

The increasing prevalence of infertility in male dogs in clinical practice mirrors current trends seen in human medicine. Acquired infertility is notably more common in dogs compared to congenital causes, with conditions such as testicular degeneration leading to irreversible loss of fertility. Current diagnostic methods for testicular degeneration, such as histopathological and cytological examinations, rely on testicular biopsy or fine needle aspiration, making them less feasible for routine use. Anti-Müllerian hormone (AMH), produced by Sertoli cells, has emerged as a potential alternative biomarker for testicular health, which can be measured in serum. This study evaluates AMH as a potential marker for testicular degeneration, using cryptorchid dogs as models for impaired fertility and altered testicular histology.

Methods

The relationship between serum AMH levels and AMH tissue expression with impaired spermatogenesis and altered histology was investigated. Serum AMH levels were determined in intact, cryptorchid, and castrated individuals using an immuno-enzymatic ELISA kit and compared between subgroups based on testicular location. Tissue AMH immuno-expression was differentially quantified in two regions of interest (ROIs), the interstitial space and the seminiferous tubule, in both descended and retained gonads. Furthermore, testicles were analyzed using histomorphometric analysis in seminiferous tubules, while spermatogenesis was evaluated using the Johnsen score.

Results

Serum AMH levels were positively correlated with AMH expression assessed in both interstitial space (ρ = 0.494, p ≤ 0.01) and seminiferous tubules (ρ = 0.610, p ≤ 0.001). Conversely, serum AMH levels showed a negative correlation with the seminiferous tubule area (ρ = -0.435, p ≤ 0.05). Smaller seminiferous tubule areas were linked to increased AMH reactivity in both seminiferous tubules (ρ = -0.774, p ≤ 0.001) and interstitial space (ρ = -0.725, p ≤ 0.001). Additionally, lower Johnsen scores were associated with higher serum AMH levels (ρ = -0.537, p ≤ 0.01) and elevated AMH expression in both seminiferous tubules (ρ = -0.756, p ≤ 0.001) and interstitial space (ρ = -0.679, p ≤ 0.001).

Discussion

Our results suggest that higher serum levels and tissue expression of AMH are linked to smaller seminiferous tubules and poorer Johnsen scores, reflecting degenerative changes and Sertoli cell dysfunction in retained testicles. Given the similarities in the mechanisms that increase AMH levels in both cryptorchid and non-cryptorchid testicles affected by testicular degeneration, this study recommends using AMH as a marker for diagnosing testicular degeneration in dogs.

Potential role of oxidative stress in pathogenesis of benign prostatic hyperplasia in male dogs

The pathogenesis of benign prostatic hyperplasia (BPH) in dogs is still not fully understood. Some studies suggest that oxidative stress may have a potential role in the pathogenesis of BPH in dogs. Age-related hormonal changes may activate a chronic inflammatory response in the prostate. This causes the generation of reactive oxygen species (ROS) and results in oxidative stress. Excessive production of ROS results in DNA damage and hyperplastic transformation of prostatic cells. The use of antioxidants for improvement of treatment outcomes for canine PBH has been discussed. Further research is needed on the importance of oxidative stress in the development of BPH in dogs and the usefulness of antioxidants in the supportive treatment of this condition.

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.

Influence of dietary supplementation with Lepidium meyenii (Maca) on sperm quality in dogs

Maca is a traditional Andean crop used as a nutraceutical for the fertility-enhancing properties that are linked with antioxidant activity. The aim of this study was to evaluate, for the first time, the potential beneficial effects of oral Maca (Lepidium meyenii or Lepidium peruvianum) supplementation in improving reproductive performance in male dogs. Forty-eight male dogs of different breeds were enrolled in the study, fed the same maintenance diet, and exposed to the same environmental conditions. The subjects were divided into four groups of 12 dogs each: Subfertile treatment group, Subfertile control group, Normofertile treatment group, and Normofertile control group. The dogs in the treatment groups received Lepidium meyenii in their diet in a capsule formulation [75 mg/kg Maca extract 10:1, thickening agent (hydroxypropyl methylcellulose), ground rice], while the control groups received placebo capsule (starch). For each subject included in the study, the spermiogram was analyzed at three time points of the sperm cycle: at day 0 (T0), day 31 (T31), and day 62 (T62). Dietary supplementation with Maca in subfertile subjects resulted in a significant increase in ejaculate volume and total sperm count compared to the control group. This increase was also observed in normofertile subjects in the treatment group. In addition, total and progressive motility as well as sperm morphology were significantly improved in the groups treated with Maca compared to the control groups. The results thus highlight, for the first time, the potential efficacy of supplementation with 75 mg/kg of Maca extract daily in improving semen quality in dogs.

Diagnostic tests in canine andrology - What do they really tell us about fertility?

Dog breeders often require breeding soundness evaluations which include andrological examinations of the genital organs, hormone measurements, and semen analyses. During the past decades, a considerable number of research results have been published, allowing diagnoses of specific andrological conditions and fertility assessment. For specific examinations, however, no standard procedures have been defined and for some parameters different reference ranges have been published. Therefore, examination results from different facilities are difficult to compare and profound conclusions regarding health and fertility of a male dog are not always possible. Conventional semen examination, however, is still useful in identifying deviations or no deviations from normality, especially if confounding factors are taken into account and if the exam is repeated in case of inconclusive findings. A standardization of examination procedures and reference ranges would help to harmonize the exchange of examination results and interpretation of the findings.

Oxidative stress biomarkers in dogs with benign prostatic hyperplasia

BACKGROUND

The aim of this study was to evaluate total antioxidant capacity (TAC) and biomarkers of lipid and protein peroxidation in the blood serum of dogs with benign prostatic hyperplasia (BPH). The study was conducted on 36 intact male dogs of various breeds. The dogs were assigned to two groups: BPH group (n = 18) and non-affected group (n = 18). Blood samples were collected from the cephalic vein. The antioxidant status of the serum was assessed using TAC. The levels of bityrosine, formylkynurenine and SH-groups were used as protein peroxidation biomarkers and the level of radical cations of N,N-diethyl-paraphenylene diamine (RC-DEPPD) was used as a marker for lipid peroxidation. TAC and the concentrations of SH-groups and RC-DEPPD in the serum were determined spectrophotometrically, the concentrations of bityrosine and formylokynurenine, were determined using spectrofluorimetric methods.

RESULTS

The mean value of TAC in the serum was significantly lower (P = 0.01) in BPH dogs than in non-affected dogs (3.10 ± 0.56 vs 4.20 ± 1.60 μmol/g protein). Mean levels of protein and lipid oxidation biomarkers showed a trend towards oxidative imbalance, but there were no statistically significant differences between dogs with BPH and controls (P > 0.05).

CONCLUSION

In conclusion, significantly lower serum TAC in dogs with BPH compared to non-affected dogs suggests a potential involvement of oxidative stress in the pathogenesis of BPH in dogs. More studies are needed to clarify the role of oxidative stress in the development of BPH in dogs.

Effect of drugs on fertility in male dogs: A review

The aim of this literature review is to present and discuss the available data on the effects of drugs on male dog fertility. Apart from hormones and antihormonal agents, there is still only little information available regarding the effect of other drugs on sexual function and fertility in male dogs. A negative impact on fertility in male dogs has been reported for vincristine, cyclophosphamide, tetracycline and ketoconazole. However, preclinical safety studies of drugs for human use indicated that spermatogenesis in dogs may be sensitive to a wide variety of drugs. Thus, in cases of reduced fertility or infertility in male dogs, medical treatment should always be considered. In most cases, the effects of drugs on sexual function and spermatogenesis are reversible after the discontinuation of the drug. Further studies on the effects of drugs on male dog fertility are needed.

Chronic Immune-Mediated Orchitis Is the Major Cause of Acquired Non-obstructive Azoospermia in Dogs

Azoospermia, the lack of spermatozoa in the ejaculate, is the most common finding in infertile but otherwise healthy male dogs and represents an increasing reproductive health issue in men, too. The diagnosis can be further classified as non-obstructive azoospermia and obstructive azoospermia due to an obstruction of the deferent ducts. Although non-obstructive azoospermia comprises more than half of azoospermic cases in men and is a common cause of infertility in the male dog, knowledge of the underlying etiology and pathophysiology is still strongly limited, and much uncertainty exists about the true incidence and possible treatment options. Therefore, this study aims to investigate and characterize infertile canine patients in detail by combining results of andrological examinations (clinical parameters, semen analysis, bacterial examination of semen, and Brucella canis serology), endocrine analysis (luteinizing hormone, testosterone, estradiol-17ß, and thyroid function), analysis of the alkaline phosphatase in seminal plasma, and histological assessment of testicular biopsies of 10 azoospermic dogs. Our results not only verify non-obstructive etiology for 9/10 cases of canine azoospermia but also further identified significant histopathological changes of the testicular tissue with severely disrupted spermatogenesis, including fibrotic remodeling, vacuolization, Sertoli-cell-only syndrome, tubular shadows, and an increase of the interstitial and vascular area. In addition, three dogs showed local and six dogs generalized immune-cell infiltration, indicating chronic immune-mediated orchitis. Only in one case (no. 1) that no immune cells were found, and obstructive azoospermia was suspected due to low alkaline phosphatase activity. Furthermore, the detection of anti-thyroideal antibodies in two dogs indicates an autoimmune thyroid disease and a correlation between the occurrence of thyroidal disorders and azoospermia. Our results confirm previous findings and contribute additional evidence suggesting that chronic immune-mediated orchitis is the major cause of infertility in dogs. Further studies should focus on uncovering underlying inflammatory processes behind spermatogenic failure in these cases and identify possible treatment options to (re-)initialize spermatogenesis.

Reversible infertility in male dog following prolonged treatment of Malassezia dermatitis with ketoconazole

BACKGROUND

Ketoconazole, an antifungal agent, adversely affects spermatogenesis in rodents, but knowledge on adverse effects of prolonged administration of ketoconazole on the fertility of male dogs is lacking. A case of reversible infertility with azoospermia in a male American Staffordshire terrier treated with ketoconazole is reported here.

CASE PRESENTATION

A seven-year old male American Staffordshire terrier treated for 3 months with ketoconazole for a persistent Malassezia dermatitis displayed reduced libido and mating of 3 bitches had been unsuccessful. The dog was presented at the clinic 40 days after the treatment had been stopped. At first presentation, low libido and complete absence of sperm in the ejaculate (azoospermia) associated with low testosterone level were found. Repeated examinations revealed that sperm quality and testosterone level had restored 100 days after ketoconazole had been withdrawn. Thereafter, the dog successfully mated 2 bitches.

CONCLUSION

The treatment with ketoconazole for 3 months may have led to reversible infertility characterized by azoospermia. Therefore, owners of stud dogs should be informed of this risk prior to initiating such treatment and in case of infertility, previous treatment with ketoconazole should be considered as a possible cause.

Effect of supplementation with the reduced form of coenzyme Q10 on semen quality and antioxidant status in dogs with poor semen quality: Three case studies

Oxidative stress owing to an imbalance between reactive oxygen species and antioxidants, such as coenzyme Q10 (CoQ10), is a major contributor to male infertility. We investigated the effects of the reduced form of CoQ10 (ubiquinol) supplementation on semen quality in dogs with poor semen quality. Three dogs received 100 mg of ubiquinol orally once daily for 12 weeks. Semen quality, serum testosterone, and seminal plasma superoxide dismutase (SOD) activity were examined at 2-week intervals from 2 weeks before ubiquinol supplementation to 4 weeks after the treatment. Ubiquinol improved sperm motility, reduced morphologically abnormal sperm, and increased seminal plasma SOD activity; however, it had no effect on testosterone level, semen volume, and sperm number. Ubiquinol supplementation could be used as a non-endocrine therapy for infertile dogs.