Reproductive Conditions

By | 2011-12-04

Azoospermia with spermatogenic arrest

In azoospermia, the ejaculate appears normal but contains no spermatozoa. Azoospermia with spermatogenic arrest occurs in dogs that were previously fertile but have become azoospermic. It is believed to be the result of an autoimmune orchitis.

Congenital preputial stenosis

A congenital defect wherein there is an abnormally small preputial opening. This may interfere with normal urination and result in a failure to mate due to an inability to extrude the penis.

Cryptorchidism

Cryptorchidism is defined as a failure of one or both testes to descend into the scrotum. The undescended testis may be found in the inguinal canal or abdomen. Non-genetic factors may play a part, but the high incidence in some breeds of dog, and in families within those breeds, suggests a genetic influence. A sex-limited autosomal mode of inheritance has been suggested.

Dystocia

Dystocia can be defined as a difficulty or an inability in giving birth. It may result from a wide range of maternal or foetal factors. Brachycephalic breeds are predisposed due to a combination of a narrow maternal pelvis and a large foetal head and shoulders. Small nervous breeds may be predisposed due to a tendency to psychological inhibition and primary uterine inertia.

Hypospadias

Hypospadias results from incomplete fusion of the urethral folds during the formation of the male urethra such that the urethra opens abnormally on the underside of the penis, proximal to the glans penis. It may be seen with other congenital defects in intersex states.

Male pseudohermaphrodite syndrome

A pseudohermaphrodite is an individual in whom the chromosomal and gonadal sex agree, but the phenotypic sex is reversed. Therefore a male pseudohermaphrodite has a Y chromosome, testes (usually undescended) and female genitalia.

Penile hypoplasia

This is a rare congenital disorder that has been reported in the Cocker Spaniel, Collie, Dobermann and Great Dane. It may be seen as part of some intersex states.

Testicular neoplasia

See under Neoplastic conditions.

Urethral prolapse

See under Renal and Urinary conditions.

Vaginal hyperplasia

Vaginal hyperplasia is an exaggerated response of the vaginal mucosa to normal circulating oestrogen during proestrus or oestrus. Vaginal oedema and thickening occurs and may result in a degree of vaginal prolapse. Boxers and Mastiff breeds seem to be most commonly affected.

XO syndrome

XO syndrome occurs when there has been nondisjunction during development of the gametes (eggs or sperm) resulting in one gamete containing two sex chromosomes (e.g. an egg with two X chromosomes or a sperm with an X and a Y chromosome) and the other gamete containing no sex chromosomes. When the latter is fertilised with an X-containing gamete (egg or sperm) an XO zygote is the result. This individual is a phenotypic female who may be infertile or demonstrate prolonged proestrus.

XXX syndrome

XXX syndrome occurs when there has been non-disjunction during development of the gametes (eggs or sperm) resulting in one gamete containing two sex chromosomes (e.g. an egg with two X chromosomes or a sperm with an X and a Y chromosome) and the other gamete containing no sex chromosomes. When the XX egg is fertilised by an X-containing sperm, an XXX zygote is the result. This individual is a phenotypic female who may have underdeveloped genitalia and may fail to cycle.

XX sex reversal

Sex reversal refers to the situation where the chromosomal and phenotypic sex do not agree. In XX sex reversal a phenotypic male is chromosomally a female.