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Article #1 CE Acquired Infertility in Male Dogs with Normal Libido Cristina Gobello, DMV, DECAR Yanina Corrada, MV National University of La Plata, Argentina ABSTRACT: This article discusses the signalment, history, physical examination, and testing needed for diagnosis and treatment of a common complaint related to stud dog reproductive per- formance: acquired infertility with normal libido. Study of signalment ensures correct interpretation of the disorder according to the dog’s breed and age. Health and repro- ductive history records are essential. A complete physical evaluation of the genital tract including a functional ejaculation test should be performed. Causes of acquired infertility may be pretesticular, testicular, or posttesticular. Although many tests help achieve the correct diagnosis, the first test usually conducted is the spermogram, which permits identi- fication of patients as those with normal or abnormal semen. Persistent oligozoospermia or azoospermia can prompt use of a testicular biopsy. Treatment should be based on the spe- cific cause. Certain drug regimens have been proposed for use when no cause can be iden- tified, although they are based largely on human studies.The prognosis for a dog with sper- matozoa in the ejaculate depends on the site and extent of the insult and ultimately on the diagnosis and appropriate therapy. nfertility of male dogs has been less described initiated only after a definitive diagnosis has in the literature than its female counterpart. been achieved. Indiscriminate use of fertility IInfertility can be classified as congenital, if it drugs is usually ineffective, potentially danger- appears early in sexual life, or acquired, if it ous, and frequently confusing for the veterinar- appears after the animal has been fertile. The ian. This article aims to serve as a guide, via a presence or absence of normal libido also helps systematic approach, to diagnosis and treatment the clinician to categorize the infertility and to of this reproductive problem of the stud dog. reduce the number of possible causes. Three common complaints concerning male dog infer- SIGNALMENT tility are observed: failure to mate, absence of Evaluation of complete signalment of the libido, and failure to produce litters after normal affected dog ensures a correct interpretation of matings. In practice, the third complaint— the complaint on the basis of the stud dog’s acquired infertility with normal libido—is most breed and age.1 Certain breeds, such as beagles, often seen: a dog that has been siring litters stops are prone to autoimmune orchitis, which may be doing so despite a normal libido. These males associated with autoimmune thyroiditis.2 A nor- may also show reduced libido if they are not mal total sperm count should also be interpreted treated (primary testicular fail- in view of the body weight for each particular Email comments/questions to ure). A detailed evaluation of breed because a positive correlation between [email protected], the animal can lead to an etio- these two parameters has been noted.3 Also, fax 800-556-3288, or log on to logic diagnosis and appropriate advanced age has a negative influence on www.VetLearn.com treatment. Therapy should be fertility.4 COMPENDIUM 18 January 2004 Acquired Infertility in Male Dogs with Normal Libido CE 19 HISTORY ment progressive testicular atrophy. Softer testes have Clinicians should question the owner about any been correlated with abnormal spermatogenesis,7 and change in the dog’s management, housing, medications severe testicular degeneration eventually causes a re- and supplements, potential environmental toxins, con- duced testicular size. current training or competition, travel, and diet. Infor- Special attention should be paid to determining mation pertaining to the general health history (past whether disorders in related systems, such as urinary episodes of illness, hyperthermia, or fever) and previous tract infection and dermatologic problems suggestive of laboratory tests should be recorded. The relationship endocrine diseases, exist. between the timing of the management changes or health disorders and the appearance of infertility should Functional Evaluation be analyzed with care. Testicular infertility problems are Functional evaluation of the ejaculation process not expected to appear simultaneously with insults but should usually precede a stressful physical examination rather after at least one spermatic cycle (approximately and blood and urine sampling; it should be repeated on 62 days5), and they may take 6 months or longer to another day if results are abnormal. Semen may be col- improve. In contrast, epididymal insults may be evident lected either on a table or on the floor, with good foot- in the spermogram in less than 14 days.5 ing being essential. The male must be comfortable and One of the most common complaints related to stud dog reproductive performance is acquired infertility with normal libido. A complete reproductive history with special atten- secure to maintain good libido. Use of a teaser bitch tion to frequency of sexual use, breeding practices of the allows collection of a better quality sample. The most kennel, and previous reproductive problems is also frequently used method is manual stimulation: The pre- extremely important. As a guideline, a male dog having puce is gently massaged with one hand, and as the penis a whelping rate of 75% or less with apparently normal becomes partially erect the sheath is pulled behind the bitches with adequate breeding management is worthy bulbus glandis. With a gloved hand, the bulb is encir- of infertility investigation. Similarly, a male that recently cled with gentle, constant pressure. Functional abnor- failed to impregnate three bitches in succession should malities of ejaculation include aspermia, retrograde ejac- also be investigated.6 Confirmation that previous litters ulation, and incomplete ejaculation. were produced by the dog is needed. Aspermia (failure to ejaculate) may be due to sexual immaturity, drug therapy, psychologic factors, idiopathic PHYSICAL AND FUNCTIONAL causes, or secondary neuropathy. This result should be EXAMINATION confirmed by several attempts at semen collection, with Physical Evaluation careful attention to providing a favorable environment. A complete physical evaluation of the genital tract, The use of a teaser bitch, frozen vaginal discharge from including scrotum, testes, prostate gland, epididymides, an estrual bitch, or synthetic pheromones (e.g., methyl penis, and prepuce, should be performed. The scrotal p-hydroxybenzoate, Aldrich Chemical) will help rule skin should be examined for dermatitis and lesions such out inadequate sexual stimulation. as wounds or scars. The testis should feel resilient and of Retrograde ejaculation of semen into the urinary bladder normal consistency; any irregularity, either hard or soft, is a rare condition, and its etiology is not completely under- indicates an insult. The prostate should be felt symmet- stood. Diagnosis requires collection of urine before and rically in the pelvic canal; it should be movable and have after mating or ejaculation; more spermatozoa will be an even consistency. Serial total scrotal circumference present in the second sample. Retrograde ejaculation is measurements (total scrotal width, measured with clinically manifested as aspermia, oligozoospermia, or calipers) should always be taken because they can docu- azoospermia (the specific type depending on the grade). January 2004 COMPENDIUM 20 CE Acquired Infertility in Male Dogs with Normal Libido Causes of Acquired Infertility Alkaline phosphatase with Normal Libido Pretesticular >5,000 IU/L <5,000 IU/L Incorrect breeding management, functional alterations (e.g., incomplete ejaculation), systemic illness Testicular origin Bilateral obstruction distal to the tail of Testicular the epididymis (due to Toxins, medications, elevated scrotal temperature, granuloma, spermatocele, trauma, aging, irradiation, infectious agents (Brucella or neoplasia) canis; Escherichia coli; Proteus vulgaris; Streptococcus, Incomplete ejaculation Staphylococcus, and Mycoplasma spp; canine distemper virus), immunologic and neoplastic disorders Figure 1. Interpretation of the alkaline phosphatase Posttesticular value in azoospermic cases. Bilateral duct obstruction caused by granuloma, spermatocele, or neoplasia; retrograde ejaculation Some Agents Reported to Alter Reproductive Function11,12 acquired infertility with normal libido (see box on p. 21). Selection of the appropriate methods depends on Methyltestosterone presenting signs. Invasive, risky, or expensive methods Estrogens are usually proposed only after cheaper, safer ones have Betamethasone, prednisolone GnRH agonists and antagonists proved unsatisfactory. Ketoconazole Cimetidine Spermogram Antineoplastic agents The first evaluation usually performed in all cases is Glucocorticoids, anabolic steroids the spermogram, which permits identification of patients as those with normal semen and those with abnormal semen (Figure 2). Semen evaluation is neces- Apprehensive dogs may ejaculate incompletely (only sary to determine the severity of the problem and to set the first fraction is ejaculated) if they are in uncomfort- priorities for further diagnostic testing. Diagnosis of able surroundings or are not stimulated by an estrous dogs with normal semen may be benefited by the use of bitch. Diagnosis of incomplete ejaculation can be made spermatozoa functional tests and electron microscopic

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