Chapter 4 Infertility in the Bitch

 

4.1 Infertility in the Bitch  

4.1.1 Definition

• A. Infertility in the bitch is defined as the inability to be bred by a male dog, conceive, or carry a pregnancy to term. Infertility may occur due to anatomic,physiologic, and behavioral problems and/or husbandry misunderstandings.
• B. Categories of Infertility based on definition
  • 1. Failure to conceive
  • 2. Failure to exhibit normal breeding behavior
  • 3. Unusual estrous cycles
  • 4. Other disturbances

4.1.2 Causes of increased incidence

• A. Line breeding/inbreeding
• B. Selection of difficult breeders as genetic stock
• C. Assistance of veterinarians (vaginal cytology, artificial insemination) in producing pregnancy in difficult breeders, ultimately resulting in breed or bloodline reproductive problems
• D. Increasing numbers of bitches with "silent" heats, low attractiveness to males dogs, inordinately short or long heats, problems with libido 

4.1.3 History

• A. Need very detailed information from client may require research by owner into the pedigree of the animal and questioning of the dog's previous owner, original breeder, and/or owners of the male to which the bitch has been bred
  • 1. Any history of infertility in the pedigree?
  • 2. How long does the estrous cycle last (from the first day the owner's notice that she is in heat until she is "out")? Bitches with short or exceedingly long cycles have decreased conception rates
  • 3. How long will she stand for the male animal to breed her?
    • a) Some bitches stand for the entire duration of their cycle--from proestrus until diestrus-- whereas others do not stand at all.
    • b) It is difficult to know when to breed these bitches, and many are bred either too early or too late in their cycle.
  • 4. How long is the interestrous interval, or how many cycles does she have per year?
    • a) More than two estrous periods per year may contribute to the development of cystic endometrial hyperplasia.
    • b) Long interestrous intervals suggest a hormonal problem.
  • 5. Concerning the bitch's previous breedings, it is important to question the owner as to his or her knowledge of canine reproduction
    • a) Some breeders know as much or more than their veterinarian, and when they say a bitch is infertile they can be relied upon.
    • b) Some "breeders," however, are obvious neophytes and understand little about producing pregnancy even in the normal bitch
  • 6. Is the male animal proved to be fertile? The most reliable proof is his current reproductive history. Has he recently sired litters?
  • 7. Has the bitch been bred to more than one male animal with no pregnancies? Occasionally a mating between a particular male animal and particular bitch does not result in a pregnancy, although neither he nor she is truly infertile.
  • 8. Did the breeding result in a tie? Did the owner actually see a breeding occur? Some owners believe that a breeding always results if a male and female dog are placed together, even without supervision.
  • 9. Was the bitch palpated (by a veterinarian) and determined to be pregnant? If so, she may be ovulating normally and fertilization may be occurring but implantation may be abnormal.
  • 10. Have there been any abortions, stillbirths, vaginal discharge, or other evidence of infection? Has a recent serologic test for Brucella canis been performed?
  • 11. Has the bitch produced previous litters? If she has never produced a litter, congenital infertility should be considered.
  • 12. Is there a history of an extra reproductive disease that might interfere with fertility?
    • a) Diabetes mellitus
    • b) Hyperadrenocorticism
    • c) Hypoadrenocoriticism
    • d) Hypothyroidism
    • e) Chronic cystitis
• B. Client can be provided with a written history questionnaire such as the one provided in this syllabus or you may design your own questionnaire.
• C. A good history is important in narrowing the diagnosis to which definition of infertility is occurring 

4.1.4 Physical examination

4.1.4.1 A general physical examination

should be performed on the bitch prior to examining the problem area (reproductive system). This is to look for signs that might support an endocrine disorder or other extrareproductive disease.

4.1.4.2 A reproductive examination

should also be performed, examining the following structures.

• 1. external inspection of the vulva
  • a. size - should be similar to that of other bitches of her age and breed; a "juvenile" vulva may mean the following
    • i) A male dog may have difficulty penetrating her.
    • ii) Whelping may be difficult; the bitch may deliver a puppy to the area of the vulva but require an episiotomy at that point.
  • b. conformation - attention should be paid to the position of the vulva and swelling.
    • i) Some problems may be encountered in obese bitches due to a recessed vulva. These bitches may be prone to perivulvular dermatitis
    • ii) A swollen turgid vulva is an indication of proestrus
    • iii) A swollen flaccid vulva is an indication of estrus or approaching parturition
  • c. presence of a discharge (see tables on causes of vaginal discharge)
    • i) no discharge is present in anestrus or diestrus
    • ii) a bright red bloody discharge may indicate proestrus or estrus
    • iii) a greenish-black or dark bloody discharge may indicate separation of the placenta or postpartum lochia
    • iv) a reddish brown, yellowish or grayish thick creamy malodorous vaginal discharge may indicate an open cervix pyometra, metritis, or severe vaginitis
    • v) straw-colored vaginal discharge is sometimes seen in standing heat
    • vi) a clear mucoid discharge may precede parturition but otherwise usually is not worrisome
• 2. Palpation of the mammary glands for presence of mammary tumors, mastitis, inverted teats, and benign nodules
• 3. Palpation of the uterus - normally the uterus cannot be palpated unless the bitch is pregnant, it is immediately postpartum, or has an accumulation of material (pus, cystic endometrial hyperplasia with excessive secretion) in the uterus
• 4. Digital examination of the vagina (culture or cytology of the vagina should be performed prior to this if necessary) -a lubricated finger should be passed into the vaginal vault to assess
  • a. clitoral size and shape
  • b. presence of foreign bodies
  • c. presence of masses (e.g. transmissible venereal tumor)
  • d. presence of strictures or abnormal tissue bands
    • i) a persistent hymen may feel like a fibrous band across one side of the vagina or may completely encircle the vaginal opening
    • ii) history may indicate that male animals have had difficulty in penetration if the bitch has been bred.
• 5. Vaginoscopy - After digital examination vaginoscopy can be performed. Vaginoscopy should always be performed when the digital examination is abnormal.
  • a. an otoscope or vaginal speculum is of limited use because only a limited view of the vaginal vault is seen with this equipment.
  •  
  • b. a pediatric proctoscope may be used in all but the very smallest of miature breeds.
  •  
  • c. a complete vaginal examination is not possible without an endoscope or a proctoscope.
  • d. erythema, hemorrhages, discharge, ulcers or vesicles should be noted.
• 6. Rectal examination - a digital rectal examination should be performed
  • a. Check for a displaced, previously fractured pelvis, which might present an obstruction to whelping.
  • b. Palpate dorsally to evaluate the sublumbar lymph nodes. If they can be palpated, they are enlarged and may reflect a uterine infection or inflammation. 

4.2 Diagnosis

• A. Signalment
  • 1. Age of the bitch
    • a. young bitches - onset of first estrus
      • i) It may be late in the giant breeds--as late as 15-18 months.
      • ii) Small to medium breeds usually have their first heat at 6- 12 months.
      • iii) Dogs of some bloodlines consistently begin cycling at a later age.
      • iv) It is common for a bitch's first heat to be almost a "silent" heat.
      • v) The first heat may be a split heat
      • vi) The first estrous cycle is often anovulatory
    • b. bitches older than 4 years have a gradual decline in their reproductive performance
      • i) lengthening of the interestrous interval--may be > 12 months after 8 years
      • ii) high incidence of cystic endometrial hyperplasia
      • iii) decrease frequency of ovulation of ovarian follicles
      • iv) increase in pathologic conditions of the uterus
      • v) these conditions lead to
        • a decrease in the conception rate
        • a decrease in number of puppies whelped
        • a decrease in puppy viability
  • 2. Breed
    • a. Basenjis, wolf/dog crosses, and dingos cycle only once a year
    •  
    • b. Some bloodline of german shepherds cycle three to four times per year predisposing them to cystic endometrial hyperplasia
    •  
    • c. Some breeds of dogs, e.g. Shetland sheepdogs and golden retrievers are predisposed to the development of hypothyroidism
• B. Diagnostic testing
  • 1. General laboratory work-up
    • a. CBC
    • b. Biochemical profile (organ profile)
  • c. Urinalysis
  • 2. Serology for Brucella canis
  • 3. Thyroxine (T4) assay and/or thyroid-stimulating hormone (TSH) response test
  • 4. Other hormone assays
  • 5. Vaginal cytology (see diagram on diagnostic considerations for cytologic evaluation of purulent/septic vaginal discharge)
  • 6. Vaginal/cervical culture
  • 7. Endoscopic examination of the vagina and cervix
  • 8. Exploratory laparotomy (uterine aspiration or biopsy)
• C. Differential diagnosis (see algorithm)
  • 1. Brucella negative bitch with normal cycle
    • 1. Vaginal disorders (see diagram on vaginal obstructions in the bitch)
    • 2. Uterine disorders (read cystic endometrial hyperplasia/pyometra complex and subclinical metritis)
    • 3. Check fertility of male dog (see syllabus)
    • 4. Check on breeding management (see Canine Breeding Management Protocol)
  • 2. Brucella negative bitch with abnormal cycle
    • 1. Normal interestrous interval
      • a. Abnormally long or short heats
      • b. "Silent" heats
      • c. Split or "wolf" heats
      • d. Failure to stand for breeding
    • 2. Abnormal interestrous interval
      • a. Short interestrous interval
      • b. Long interestrous interval
      • c. Failure to cycle
      • d. If all else fails see protocol for induction of estrus in the bitch

4.3 Infertility in the Male Dog

4.3.1 Definition:

In ability to breed or produce a successful pregnancy.

Characteristics of a fertile Male Dog

• 1. Capable of producing adequate number of normal spermatozoa in the testicles.
• 2. Have the ductal system capable of delivering spermatozoa.
• 3. Be capable of ejaculation
• 4. Have spermatozoa that can be "capacitated" in the female dog to penetrate the zona pellucida of the egg surface

4.3.2 Cause:

There are generally three causes of infertility in the male dog

A. Pregeminal causes - hypothalamic or pituitary lack of gonadotropin releasing hormone (GnRH), FSH, or LH.

B. Germinal causes - failure to respond to FSH or LH

C. Postgerminal causes - Blockage of the duct system 

4.3.3 History

A. In order to determine the cause of infertility in the male dog an adequate history must be taken

• 1. Is there infertility in the pedigree?
• 2. Has the dog ever produced any pregnancies?
• 3. Does the male dog appear to have a normal libido?
• 4. Did the owner ever see the breeding?
• 5. Did the breeder observe a tie?
• 6. What is the pedigree relation of this male and the bitches to which he has been bred?
• 7. How frequently is the male used for breeding?
• 8. Has the dog had any febrile illness within the last 2 months?
• 9. Has the dog had any symptoms of dysuria, pollakiuria or hematuria?
• 10. Has the male dog been tested for brucellosis recently?
• 11. Where is the dog housed?
• 12. Is the dog being heavily campaigned on the show circuit? When was he last sent out with a professional handler?
• 13. Is the male dog receiving medication of any kind?
• 14. Is there a history of extrareproducitve endocrine disease?
• 15. Have the bitches he has bred been proved to be fertile? Have they had previous litters?
• 16. To the owner's knowledge, has the dog ever had any orchitis epididymitis, scrotal swelling etc. ?
• 17. Has the previous laboratory testing of semen been done? What were the results?
  • a. How many semen evaluations have been performed over what interval of time?
  • b. Semen evaluations need not be performed more often than once every 60-70 days in the dog.
  • c. If an aspermic dog began normal spermatogenesis today, those spermatozoa would not be ejaculated for approximately 2 months.
• 18. Does the owner/breeder have a good knowledge of canine reproductive physiology? In other words, are the bitches being bred at adequate and appropriate intervals to achieve conception?

4.3.4 Physical Examination

• A. General physical examination
• B. Reproductive examination
  • 1. Scrotum - the scrotum should be visually evaluated and palpated.
    • a. The scrotum is checked for evidence of trauma or adhesions to the testes.
    • b. Nodules in the scrotum might suggest malignancy.
      • i. Mast cell tumors, squamous cell carcinomas melanomas
      • ii. Tumors of the scrotum may extend to the adjacent testicle.
  • 2. Testicles - the testes should be palpated and evaluated
    • a. Both testes should be present in the scrotal sac.
      • i. Testicular descent should be complete by 3 weeks in the dog.
      • ii. Bilaterally cryptochid dogs are infertile.
    • b. Testicles should be evaluated for size and consistency.
      • i. Hard nodules within the testes are suggestive of neoplasia.
      • ii. Small soft testicles are found in senile atrophy.
      • iii. The testes are usually swollen and firm with acute orchitis.
      • iv. The testes are usually atrophied and firm with chronic orchitis.
  • 3. Spermatic cords should be traced by palpation from the caudal testis to the inguinal ring.
  • 4. Prostate - the prostate should be evaluated by rectal palpation of the gland.
    • a. enlargement may indicate either benign hypertrophy or inflammation.
    • b. the urinary tract should be evaluated and prostatic wash performed with enlargement.
  • 5. Penis - the penis should be extruded as completely as possible from the sheath and examined for traumatic lesions, tumors, inflammation, etc. 

4.3.5 Diagnosis

• A. Signalment
  • 1. Age
    • a. Ejaculates from medium sized dogs do not contain normal spermatozoa until they are 1 year of age.
    • b. Large breeds continue to show abnormal spermatozoa until they are 15-18 months old.
    • c. The American Kennel Club refuses to register litters sired by male dogs older than 12 years. However senile changes in large breeds begin at 6 years of age.
• B. Breed - Male dogs of some breeds characteristically have difficulty naturally breeding due to their conformation
• C. Diagnostic testing
  • 1. CBC, Biochemical profile
  • 2. Brucella canis serology
  • 3. Urinalysis and urine culture if indicated
  • 4. T4 evaluation and/or TSH response test
  • 5. FSH, LH and testosterone evaluation
    • a. Elevated FSH and aspermia means primary germinal hypoplasia.
    • b. Low FSH, LH, and testosterone and aspermia may indicate a pregerminal lesion.
    • c. Normal FSH, LH, and testosterone levels with aspermia are suggestive of a postgerminal obstructive defect, retrograde ejaculation or transitory arrest of spermatogenesis.
  • 6. Semen evaluation
  • 7. Testicular aspiration or biopsy
• D. Differential diagnosis
  • 1. Congenital infertility
    • a. Endocrine problems
      • i. Panhypopituitarism - congenitally low or absent FSH and LH
      • ii. Hypothyroidism - associated with depressed gonadotropic function, lowered steroid synthesis rates, and hence deficient spermatogenic function
    • b. Chromosomal abnormalities
      • i. Klinefelter's syndrome - doubling of the usual number of chromosomes (79XXY)
      • ii. Kartagener's syndrome - produces defects in the ciliated cells in the body and defects in spermatozoal motility is also noted
    • c. Anatomic defects
      • i. Bilateral cryptochidism
      • ii. Persistent penile frenulum
      • iii. Shortened os penis
      • iv. Segmental aplasia of the ductus deferens or epididymis
      • v. "Sertoli cell only syndrome" - no evidence of spermatogonia in the testicle 
    • d. Retrograde ejaculation - failure of closure of the internal bladder sphincter. Semen flows by gravity into the bladder. Sympathomimetic agents have been tried to close the internal sphincter to achieve antegrade ejaculation
  • 2. Acquired infertility
    • a. Endocrine abnormality
      • i. Tumors of the hypothalamus or adenohypophysis
      • ii. Hypothyroidism
      • iii. Hyperadrenocorticism
      • iv. Hypoadrenocorticism
    • b. Metabolic diseases
      • i. Chronic uremia - impaired Leydig cell function
      • ii. Chronic liver disease - testicular atrophy
    • c. Stress - methods not clearly defined
    • d. Febrile illness - chronic warming of the scrotal sac to 104 degrees Fahrenheit for 5 days
    • e. Environmental alterations
      • i. Excessive kenneling
      • ii. Psychological changes
      • iii. High ambient temperatures
    • f. Infection
      • i. Brucellosis
      • ii. Prostatic infection may predispose to urethritis, epididymitis, or orchitis
    • g. Acquired anatomic defects
      • i. obstruction of the ejaculatory ducts due to epididymitis
      • ii. fracture of os penis or phimosis
    • h. Overuse ?
    • i. Testicular neoplasia
    • j. Prior hormonal treatment
    • k. Testicular torsion
    • l. Retrograde ejaculation
    • m. Immune-mediated infertility
    • n. Drug induced infertility - alkylating agents, antimetabolites, nitrofurantoin, cimetidien, and azulfidine are agents that can cause temporary or permanent infertility. Semen banks may be used.
    • o. Obesity - leads to alteration in serum estradiol and testosterone levels 

4.3.6 Treatment

• A. Fertility is restored in only a small percentage of cases.
• B. Definitive diagnosis of male fertility is difficult so treatment is usually empirical.
• C. A complete work-up is necessary prior to treatment any with hormonal agents.
• D. Due to the development and transport of spermatozoa takes about 75 days therapy should be given for 2-3 months before expecting any improvement.