These notes form part of the Dogs NSW Member Education Breed Seminars, held on DOGS NSW grounds - Dr. Ciaran Galvin MVB (UCD IRELAND)
COMMON QUESTIONS WHICH YOU MAY OR MAY NOT KNOW THE ANSWERS TO?
My dog is not getting bitches pregnant. What can I do?
Infertility may be due to problems with the bitch or the male. Causes of infertility described in male dogs include inability to breed and poor semen quality. Causes of inability to breed include poor libido and pain, as may be seen in dogs with prostate disease. Causes of poor semen quality include pre- testicular causes, such as systemic disease including hypothyroidism and immotile cilia syndrome; testicular causes including testicular atrophy, testicular neoplasia, and brucellosis; and post- testicular causes including spermatocele and retrograde ejaculation.
Clinical signs Poor libido is manifested by a male dog expressing no interest in mounting an estrous bitch. Pain may be evidenced in the same way or may be seen as mounting followed by quick dismount or even crying out as the dog ejaculates. Prostate disease may be evidenced by dripping of bloody ﬂuid from the prepuce unassociated with urination, hematuria, hemospermia (blood in the ejaculate), presence of ribbon- shaped faeces, or pain when ejaculating . Immotile cilia syndrome, also termed ciliary dyskinesia, includes lack of motility in the respiratory tract and so is usually evidenced by chronic respiratory disease. Hypothyroid dogs may or may not exhibit classic signs of bilaterally symmetrical alopecia and lethargy. Testicular atrophy is self - evident and may also be seen as a component of testicular neoplasia, especially if the contralateral testis is enlarged.
Diagnosis Poor libido may be due to pain or may be behavioural in origin. Sources of pain include the caudal spine, rear limbs, and prostate. Arthritis or other causes of bone pain are visible radiographically. Deﬁnitive diagnosis of immotile cilia syndrome requires electron microscopy of immotile spermatozoa or cells retrieved from the respiratory tract.
Behavioural causes include frequent disciplining when having shown mounting behaviour in the past, or recollection of pain when collected or bred in the past.
Poor semen quality may be deﬁned as aspermia (lack of an ejaculate), azoospermia (ejaculation of seminal ﬂuid containing no spermatozoa), oligozoospermia (ejaculation of an abnormally low number of spermatozoa), teratozoospermia (ejaculation of an abnormally low percentage of normally shaped spermatozoa), or asthenozoospermia (ejaculation of abnormally low percentage of progressively motile spermatozoa). These abnormalities often occur together.
Aspermia is often due to pain. Sources of pain include the caudal spine, rear limbs, and prostate. Azoospermia may be due to pain or apprehension, such that the dog does not provide a complete ejaculate, may be indicative of lack of spermatogenesis, or may be due to obstruction of the ductus deferens preventing movement of spermatozoa from the epididymis through the urethra. Alkaline phosphatase (ALP) is secreted into seminal ﬂuid from the epididymes and testes. Measurement of ALP in seminal ﬂuid can be used to assess if a complete ejaculate was provided. If concentration of ALP in azoospermic seminal ﬂuid is greater than 5000 IU/l, a complete ejaculate was obtained and the dog is not making spermatozoa. If concentration is lower than 5000 I U/l, a complete ejaculate was not obtained. Semen collection should be attempted again with all distractions removed and diagnostics performed as above to identify sources of pain. Blockages along the spermatic cord, such as spermatocele, may be identiﬁed by a skilled ultrasonographer. Oligozoospermia may be due to incomplete ejaculation, retrograde ejaculation, or reproductive tract disease.
Some reports suggest that dogs with hypothyroidism may have abnormally low sperm numbers; hypothyroidism is best diagnosed by demonstration of abnormally low free thyroxine and abnormally high thyroid stimulating hormone. Retrograde ejaculation is diagnosed by collection of a urine sample by cystocentesis immediately after ejaculation and demonstration of a greater number of spermatozoa in the urine than in the seminal ﬂuid.
Testicular changes that may be evident on palpation include increase in testicular size, most often due to neoplasia, and decreased testicular size, most often due to atrophy. The three common types of testicular neoplasia are seminoma, interstitial (Leydig) cell tumor, and Sertoli cell tumor, which may secrete estrogen and be associated with bilaterally symmetrical alopecia, attraction of male dogs, gynecomastia, and atrophy of the contralateral testis. Metastasis is uncommon with all three tumor types. Some testicular tumors are not palpable and are best identiﬁed by ultrasound. Testicular atrophy may occur secondary to testicular neoplasia in the atrophied or contralateral testis, elevated body temperature due to fever or heat stroke, or direct increase in scrotal temperature, as may occur with trauma or frostbite. Oligozoospermia may be a manifestation of prostate disease or brucellosis . Teratozoospermia and asthenozoospermia often occur together and are usually due to the same causes as oligozoospermia. Asthenozoospermia in the presence of a large number of normally shaped spermatozoa may be indicative of contaminated equipment; another semen sample should be collected using clean equipment and meticulous care should be taken not to expose the semen to soap or other toxic substances.
Treatment Poor libido due to pain should be treated by management of the underlying cause, if possible. Undeﬁned causes of poor libido may be treated by administration of gonadotropin releasing hormone (1 to 2 μ g/kg intramuscularly 60 minutes before semen collection or breeding). Castration cures most cases of testicular neoplasia. Retrograde ejaculation may be treated with sympathomimetic agents, which promote closure of the bladder neck during ejaculation. Examples include phenylpropanolamine (3 m g/kg per os twice daily) and pseudoephedrine hydrochloride (3 to 5 mg/kg per os three times daily or 3 and 1 hours before semen collection or attempted breeding).
This article appeared (with permission) in DOGS NSW magazine, May 2018 edition.