REPRODUCTIVE SYSTEM

True Hermaphroditism

Presence of both ovarian and testicular tissue with anomalies of the external genitalia due to a disorder of sexual development, gonadal sex determines sex phenotype, sexual behavior, and development of internal and external genitalia.

Pseudohermaphroditism

Gonads are of one sex but the external genitalia resemble the opposite sex, most common intersex condition.

Male Pseudohermaphroditism

Individual has testes but female-appearing external genitalia, testes are often abdominal or subcutaneous near the scrotum.

Freemartinism

Intersex condition in a female twin to a male caused by shared placental circulation and Anti-Müllerian Hormone, usually sterile (~92%), causes short blind-ending vagina, absent cervix, poorly developed ovaries, and variable masculinization of internal and external genitalia.

XXY Syndrome (Male)

XXY karyotype causing underdeveloped male reproductive organs with testicular, epididymal, and vas deferens hypoplasia, resulting in azoospermia and sterility.

XXY/Mosaic/Chimeric Male Tortoiseshell (Calico) Cat

Male calico/tortoiseshell cat with XXY, mosaicism, or chimerism, typically sterile.

Canine Transmissible Venereal Tumor (CTVT)

Contagious round cell tumor of dogs transmitted during coitus by implantation of viable neoplastic cells, primarily affects the external genitalia, may metastasize especially in stray, immunocompromised, or debilitated dogs, males commonly develop proximal penile masses and females commonly develop masses on the dorsal vaginal wall near the vestibulovaginal junction, lesions are large multinodular, reddish, friable, ulcerated, highly vascular, and bleed easily.

Cryptorchidism

Congenital failure of one or both testes to descend, bilateral cases are sterile, unilateral cases are usually fertile, retained testis still produces testosterone, increases risk of seminoma and interstitial (Leydig) cell tumor, treatment is cryptorchidectomy.

Testicular Hypoplasia

Congenital underdevelopment of the testes, may be associated with chromosomal abnormalities, reported in several domestic species and common in some camelid family lines, causing reduced fertility or sterility.

Anorchism

Congenital absence of one or both testes, unilateral cases reported in horses and camelids, camelids may also have ipsilateral kidney absence.

Segmental Aplasia of Mesonephric Duct Structures

Congenital partial or complete absence of epididymis, ductus deferens, ampullae, or seminal vesicles, described in bulls, bilateral epididymal hypoplasia occurs in azoospermic stallions and camelids, camelids may also have epididymal and rete testis cysts.

Persistent Penile Frenulum

Failure of the penile frenulum to rupture during maturation, affected species is the bull, causes downward curvature (skew penis), prevents full penile protrusion and mating.

Preputial Prolapse

Protrusion of the prepuce caused by a weak or absent preputial retractor muscle, prepuce protrudes from the sheath.

Congenital Short Penis

Congenitally short penis that prevents complete erection.

Short Retractor Penis Muscle

Congenital or injury-associated short retractor penis muscle, affected species is the bull, normal libido but penis only partially protrudes, ejaculatory thrust absent.

Hypospadias

Congenital urethral defect caused by failure or incomplete closure of the embryonic urethral groove, resulting in an abnormal urethral opening on the penis.

Ovarian Dysgenesis (Ovarian Hypoplasia)

Most common congenital ovarian abnormality, characterized by small underdeveloped ovaries with absent follicular activity, associated with XO (Turner syndrome), XXX, or XXY, causing infertility or sterility.

Periovarian (Paraovarian) Cysts

Cysts outside the ovary caused by persistent embryonic remnants of paramesonephric (Müllerian) or mesonephric (Wolffian) ducts or tubules, common incidental finding during OHE in dogs and cats.

Intraovarian Cysts

Cysts within the ovary including Graafian (Follicular) cysts, surface epithelial inclusion cysts, and rete ovarii (mesonephric tubular remnant) cysts, must be differentiated from ovarian cystic neoplasms.

Segmental Aplasia of the Paramesonephric (Müllerian) Ducts

Congenital aplasia or obstruction of the uterine tube, uterus, cervix, or vagina with normal ovaries, obstruction causes hydrosalpinx, hydrometra, mucometra, and colpometra.

Uterus Unicornis

Absence of one uterine horn due to segmental Müllerian duct aplasia, pregnancy is still possible.

Cervical Aplasia

Congenital absence of the cervix, rare.

Persistent (Imperforate) Hymen

Congenital failure of the hymen to perforate, most common anomaly, causes fluid accumulation, bulging hymen, and White Heifer Disease.

Double External Os (Double Cervical Opening)

Two external cervical openings sometimes separated by a tissue band due to failure of the Müllerian ducts to fuse, affected species is the cow, most conceive normally.

Uterus Didelphys

Complete double cervix, each cervical canal opens into its own uterine horn, usually an incidental congenital anomaly with minimal effect on fertility unless associated with other reproductive tract defects.

Vaginal Stricture/Vestibulovaginal Hypoplasia

Congenital narrowing or underdevelopment of the vagina or vestibule, affects mares, dogs, and camelids, causing difficulty breeding, difficulty during parturition, and vaginal discharge.

Vulvar Atresia/Hypoplasia (Atresia Vulvi)

Partial or complete fusion of the labia caused by an autosomal recessive inherited defect, affects camelids, interferes with breeding and urination.

Rectovaginal Constriction

Autosomal recessive connective tissue disorder causing stenosis of the anus or vestibulovaginal sphincter, may cause milk vein stenosis, udder edema, ischemic necrosis, difficult rectal palpation, and severe dystocia.

Uterine Prolapse

Protrusion of the uterus after parturition caused by a flaccid uterus, excessive straining, uterine inertia, prolonged dystocia, hypocalcemia, or estrogenic plants, affects cows, ewes, and sows, may involve the pregnant horn, cervix, vagina, bladder, or small intestine, causing vascular compression, congestion, and edema.

Mastitis

Inflammation of the mammary gland, often originating from galactophoritis, usually caused by bacterial infection with Staphylococcus aureus being most common, major disease of milk-producing animals especially dairy cattle, predisposing factors include high milk production, excessive milking machine vacuum, papillary lesions, fecal contamination, poor milking hygiene, and flies.

Galactophoritis

Inflammation of the lactiferous ducts due to infection or inflammation, often precedes mastitis.

Galactostasis

Milk retention due to failure of milk letdown caused by insufficient oxytocin release, produces engorged painful mammary glands without systemic illness.

Agalactia

Failure of milk production associated with CAEV in goats and Maedi-Visna in ewes, characterized by hard udders with no milk.

Galactorrhea

Inappropriate or precocious lactation caused by hormonal changes, occurs in bucks (billy goats) and bitches with pseudopregnancy.

Severe Necrotic Mastitis (Coliform Mastitis)

Severe necrotizing mastitis caused by coliform bacterial infection, affects cows, serum oozes through dead skin.

Necrotizing Mastitis (Coliform Mastitis)

Coliform mastitis in cows causing necrotic mammary tissue, sequestrum, edema, and a thin fibrous capsule.

Suppurative Mastitis

Bacterial mastitis in cows with purulent inflammation, lactiferous sinus and ducts are filled with viscous yellow pus.

Gangrenous Mastitis

Severe bacterial mastitis in cows with gangrene and hemorrhage, affected quarter is dark red, hemorrhagic, and has a well-demarcated hyperemic border.

Mammary Carcinoma

Malignant mammary epithelial neoplasia, highest incidence in the dog among domesticated species, locally infiltrative with a desmoplastic response.