| Infertility in the Dog part 2 |
| Some have suggested that intrauterine, rather than intra-vaginal, insemination might also be helpful. Given that, natural service is likely preferable to vaginal AI in this circumstance. Decreased volume almost always represents poor collection technique, but it has also been associated with retrograde ejaculation and with prostatic disease. Decreased volume could result in a decrease in the total number of sperm in the ejaculate. Normally some sperm flow retrograde into the urinary bladder. What constitutes an abnormal number of sperm in the bladder has not been defined, but certainly it is expected that more sperm will be discharged antegrade, through the urethra, than retrograde into the urinary bladder. Retrograde ejaculation is confirmed by examining urine for the presence of sperm, before and after ejaculation. Treatment with cx-adrenergic medication to increase uretharal sphincter pressure has been recommended. Dogs with abnnormal semen should be evaluated for prostatic disease as described above. Azoospermia may be the result of failure to produce sperm, failure to ejaculate sperm, or failure to collect the sperm-rich fraction of the ejaculate. To exlude the possiblility of incomplete ejaculation or failure to collect the sperm-rich fraction, alkaline phosphtase activity in the seminal fluid is determined. Alkaline phosphatase is produced in the canine epididymis. Fluid originating from the epididymis is expected to contain sperm and high concentrations of alkaline phosphatase, usually >5000IU/L. Azoospermia with high seminal flluid alkaline phosphatase indictes spermatogenic failure, or bilateral obstruction of flow from the testes to the epididymes. There are congenital and acquired causes of failure to produce sperm. The ultimate diagnosis may require a testicular biopsy. However, non-invasive testing should first be completed. For congenital causes, evaluation of the hypothalamic-pituitary-gonadal axis, and karyotyping could be considered. Blood in the semen most commonly originates from the prostate or from the suface of the penis during semen collection. The later can quickly be excluded by ispection of the penis as soon as the blood is noticed. Typically, when the penis is traumatized during semen collection, the blood is bright in color. Blood originating from the prostate is typically reddish-brown in color. This discoloration is present in all fractions of the ejaculate. Prepucial, urethral, bladder, or gonadal lesions are possible, but less likely, causes of hemospermia. White blood cells are commonly found in canine semen. Often they are from prepucial contamination. It has been reported that normal canine semen has less than or equal to 2000 WBC/uL, and less than or equal to 6 WBCs per high power field in a cyospin sample. Other inflammatory cells, such as macrophages, may be found also. Whenever inflammation is present, the sample should be cultured for aerobic bacteria and mycoplasma, and possibly also for anaerobic bacteria. Because some contamination from the prepuce and or urinary tract is likely, aerobic bacterial counts of 10,000 colony forming units/ml are considered clinically meaningful. Although samples with many inflammatory cells are most likely to have clinically meaningful bacterial growth, many dogs without inflammatory semen will too. Therefore, culture should be a routine part of the work-up, irrespective of the asence of inflammaroty cells in the semen. The canine spermatogenic cycle is about 62 days. Substantial change in semen quality is not likely to be evident in less time, unless the original cause of abnormal semen was iatrrogenic or because of "technical" difficulties during collection. Assuming that the cause of testicular damage is found and corrected, and that viable spermatogonia are still present, improvement or recovery is possible. For dogs that are otherwise healthy and normal, and that have testes of normal size and consistency, re-evaluation at 3, 6 and 12 months has been recommended. If there is no change in semen quality by 12 months, it is unlikely to ever occur. Examples of drugs adversely affecting reproduction: Cimetidine Hormones: Glucocorticoids, Estrogens, Androgens, Anabolic Steroids, Progestins Ketaconazole Spironolactone Anticholinergics Propanolol Digoxin CNS Drugs: Chlorpromazine, Barbituates, Diazepam Thiazide diuretics Factors deleterious to sperm: Water, Lubricants, Plastic, Latex, Cold, Heat, Urine. Canine semen parameters: Color: Normal: Opalescent Abnormal: Clear, yellow, red Volume: Normal: 2.5->80mls Total sperm in ejaculate: Normal: 300-2,000X10 6 Abnormal: <200X10 6 (oligozoospermia) % progressively motile sperm: Normal: >70% Abnormal: <50% (astenozoospermia) % morphologicaly normal: Normal: >80% Abnormal: <70% (teratozoospermia) PH Normal: 6.3-6.7 WBC per high power field (HPF) Normal: <6 Abnormal: >7-10 |