Infertility

From Dog
Testicular torsion in a dog with Sertoli cell tumor, causing infertility[1]
Enlarged clitoris seen at physical examination in an infertile hermaphrodite dog[2]
Diff-Quick stained smear showing a high proportion of defective spermatozoa and various degrees of tail coiling in an English Bulldog[3]
Cystic endometrial hyperplasia in a bitch, a leading cause of infertility[4]

Infertility is a relatively uncommon reproductive disease of dogs.

During neonatal and juvenile life, the canine uterus undergoes extensive structural and functional changes as well as uterine gland differentiation and enlargement. Gland development within the lining of the uterus begins at 1 wk of age, leading to budding from the luminal epithelium, and rapid proliferation of both luminal epithelial and stromal cells and within 3 weeks, epithelial glands are clearly identifiable with proliferation of luminal, glandular, and stromal cells. Similar glandular development occurs within the male testis, leading to rapid differentiation of the testicular tissues.

Exposure to ascending urinary or genital infections, dietary mycotoxins[5] and viruses in pups may result in permanent maldevelopment of reproductive organs, leading to adult infertility[6].

Infertility results in failure to conceive, failure to sustain pregnancy (miscarriage) or production of dead fetuses.

Although oxidative stress is a leading cause of canine azoospermia, supplementation of subfertile dogs with vitamin C and vitamin E does not significantly improve fertility rates[7].

Causes include:

- breed variability[8] - predisposition to azoospermia and teratozoospermia in the Beagle (testosterone-responsive azoospermia[9][10]) and English Bulldog[3]
- Trisomy-X[11] - persistent anestrus, anovulation, a slow rise in serum progesterone concentrations, 'split' heats, insufficient luteal phase or persistent estrus[12]
- Robertsonian translocation[13]
- Hermaphroditism
  • Systemic diseases
- Immune-mediated disease - lupus erythematosus, immune-mediated thyroiditis[14]
- Hypoadrenocorticism
- Leishmania spp[15]
- Hypothyroidism - predisposition in the Dogue de Bordeaux and Leonberger[16]
- Canine herpesvirus[17]
- Brucella spp[18]
- Mycotoxins - Fusarium spp
- Cannabis toxicity
  • Female reproductive disorders
- Hydrosalpynx
- Cystic endometrial hyperplasia
- Pyometra
- Uterine leiomyoma
- Papillary adenoma, papillary adenocarcinoma
- Ovarian cystadenoma
- Paraovarian cyst
- Ovarian carcinoma
- Dysgerminoma
- Granulosa cell tumor
- Mixed Müllerian tumor
- Leuteoma
- Teratoma
- Thecomas
  • Male reproductive disorders
- Cryptorchidism (bilateral)
- Prostatitis
- Epididymitis - Streptococcus canis
- Prostatitis[19]
- Prostatic adenocarcinoma
- Prostatic hyperplasia
- Prostatic squamous metaplasia
- Seminoma
- Sertoli cell tumor
- Testicular torsion[20]

When presented with a dog for infertility examination, a complete history, physical examination, testicular ultrasonography (testicular atrophy or testicular neoplasia)[21], ejaculate evaluation should be completed[22]. In dogs, fine-needle aspiration of testicular samples will help elucidate sperm motility and detect the presence of oligospermia or azoospermia[23]. Some sperm defects are considered to be genetic in origin when they appear in the semen and may not necessarily imply a disease state.

in male dogs with low sperm production, injections of testosterone or gonadotropin-releasing hormone analogue may assist in improving spermatogenesis[24].

Although cystic endometrial hyperplasia is a leading cause of infertility in bitches[25], many that present for infertility are reproductively normal and are able to conceive with appropriate intervention and breeding management[26].

In problematic bitches, parasite serology, use of vaginal cytologic evaluation, abdominal ultrasonography[27], resting hormone assays, hormone challenge testing and exploratory laparotomy with biopsy may be required to determine any underlying pathology.

In bitches, an estradiol concentration of > 20 pg/mL can be considered as normal ovarian activity. Some bitches have progesterone insufficiency[28], causing implantation failure, and consequently, progesterone should be measured when the bitch is showing signs of estrus or within 50 - 80 days after that with a level > 2 ng/mL indicative of functional corpora lutea. A hormone challenge test can be used if a progesterone level of < 2 ng/mL is found, or the animal is presumed to be in proestrus. Progesterone levels should increase to > 2 ng/mL by 1 wk following the injection of human chorionic gonadotropin or gonadotropin releasing hormone.

In bitches with hormone imbalances, successfully treatment can be achieved with gonadotrophin-releasing hormone analogue injections given at the time of proestrus[29]. In those bitches with shortened interestrus periods, suppression of one estrus with synthetic progestins (e.g. proligestone or megestrol acetate[30]) administered at recommended doses, allows fertile breedings on the subsequent cycle, producing litter sizes within the normal range.

Assisted reproductive techniques such as in vitro fertilization, embryo transfer, and cryopreservation of gametes are emerging as important methods of improving infertility in both sexes of dogs[31].

References

  1. Quartuccio M et al (2012) Sertoli cell tumors associated with feminizing syndrome and spermatic cord torsion in two cryptorchid dogs. J Vet Sci 13(2):207-209
  2. Silversides DW et al (2011) Disorder of sex development (XX male, SRY negative) in a French bulldog. Can Vet J 52(6):670-672
  3. 3.0 3.1 Rota A et al (2008) Severe tail defects in the spermatozoa ejaculated by an English bulldog. J Vet Med Sci 70(1):123-125
  4. Penn Veterinary Medicine
  5. Golinski PK & Nowak T (2004) Dietary origin of mycotoxins with estrogenic potential and possible health implications to female dogs. Pol J Vet Sci 7(4):337-341
  6. Cooke PS et al (2012) Uterine gland development begins postnatally and is accompanied by estrogen and progesterone receptor expression in the dog. Theriogenology 78(8):1787-1795
  7. Lopes-Santiago BV et al (2012) Evaluation of sperm DNA peroxidation in fertile and subfertile dogs. Reprod Domest Anim 47(6):208-209
  8. Lange-Consiglio A et al (2010) Morphometric characteristics and chromatin integrity of spermatozoa in three Italian dog breeds. J Small Anim Pract 51(12):624-627
  9. Kawakami E et al (2009) Changes in plasma testosterone level and semen quality after frequent injections of GnRH analogue in a Beagle dog with azoospermia. J Vet Med Sci 71(10):1373-1375
  10. Kawakami E et al (2007) Changes in the plasma testosterone level and testicular superoxide dismutase activity of 5 azoospermic beagles after GnRH analogue injections. J Vet Med Sci 69(5):561-562
  11. O'Connor CL et al (2011) Trisomy-X with estrous cycle anomalies in two female dogs. Theriogenology 76(2):374-380
  12. Meyers-Wallen VN (2007) Unusual and abnormal canine estrous cycles. Theriogenology 9:1205–1210
  13. Switonski M et al (2003) Robertsonian translocation (8;14) in an infertile bitch (Canis familiaris). J Appl Genet 44(4):525-527
  14. Olson PN et al (1992) Clinical and laboratory findings associated with actual or suspected azoospermia in dogs: 18 cases (1979-1990). J Am Vet Med Assoc 201(3):478-482
  15. Mir F et al (2012) Subclinical leishmaniasis associated with infertility and chronic prostatitis in a dog. J Small Anim Pract 53(7):419-422
  16. Segalini V et al (2009) Thyroid function and infertility in the dog: a survey in five breeds. Reprod Domest Anim 44(2):211-213
  17. Dahlbom M et al (2009) Seroprevalence of canine herpesvirus-1 and Brucella canis in Finnish breeding kennels with and without reproductive problems. Reprod Domest Anim 44(1):128-131
  18. López G et al (2009) A serological and bacteriological survey of dogs to detect Brucella infection in Lomas de Zamora, Buenos Aires province. Rev Argent Microbiol 41(2):97-101
  19. Memon MA et al (2007) Common causes of male dog infertility. Theriogenology 68(3):322-328
  20. Visser AJ & Heyns CF (2003) Testicular function after torsion of the spermatic cord. BJU Int 92(3):200-203
  21. Davidson AP & Baker TW (2009) Reproductive ultrasound of the dog and tom. Top Companion Anim Med 24(2):64-70
  22. Lopate C et al (2012) The problem stud dog. Vet Clin North Am Small Anim Pract 42(3):469-488
  23. Romagnoli S et al (2009) Clinical use of testicular fine needle aspiration cytology in oligozoospermic and azoospermic dogs. Reprod Domest Anim 44(2):329-333
  24. Kawakami E et al (2005) Changes in plasma testosterone levels and semen quality after 3 injections of a GnRH analogue in 3 dogs with spermatogenic dysfunction. J Vet Med Sci 67(12):1249-1252
  25. Fontaine E et al (2009) Diagnosis of endometritis in the bitch: a new approach. Reprod Domest Anim 44(2):196-199
  26. Wilborn RR & Maxwell HS (2012) Clinical approaches to infertility in the bitch. Vet Clin North Am Small Anim Pract 42(3):457-468
  27. Davidson AP & Baker TW (2009) Reproductive ultrasound of the bitch and queen. Top Companion Anim Med 24(2):55-63
  28. Rube A et al (2007) Progesterone insufficiency in bitches in early and late dioestrus. Vet Rec 160(15):524-525
  29. Tsumagari S et al (2006) Successful pregnancy following gonadotrophin-releasing hormone analogue treatment in a previously infertile bitch. J Small Anim Pract 47(4):213-215
  30. Wanke MM et al (2006) Progestin treatment for infertility in bitches with short interestrus interval. Theriogenology 66(6-7):1579-1582
  31. Abe Y et al (2011) Cryopreservation of canine embryos. Biol Reprod 84(2):363-368