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Multiple congenital abnormalities of the external genitalia consistent with XX sex reversal were detected in a juvenile llama. The llama had a typical female karyotype (74, XX) and did not have a Y chromosome, but a minute chromosome was detected. To determine whether a piece of Y chromosome containing the Sry gene might be located in a small translocation, DNA analysis by polymerase chain reaction was performed; the Sry gene was not detected. Histologic examination revealed ovarian tissue, whereas testicular tissue was not found. External genitalia were partially masculinized, indicating that the urogenital sinus, genital tubercle, and genital swellings had been exposed to androgens during development, although the dam had not received exogenous androgens. Testicular tissue in the ovaries may have been undetected or had regressed prior to birth, as has been reported in sex reversal in mice.

A 5-month-old llama was examined for evaluation of sexually ambiguous external genitalia. To determine the phenotypic, chromosomal, and gonadal sex of the llama, transrectal palpation and ultrasonography, contrast cystography, karyotype evaluation, laparoscopy, and necropsy were performed. A karyotype of 74,XX and finding of components of the müllerian duct system were suggestive of a female phenotype and chromosomal sex. On histologic evaluation, however, components of the wolffian duct system also were found, and the gonads were composed entirely of testicular tissue. The diagnosis was XX sex reversal, with a XX male phenotype.

XX True hermaphroditism was identified in a 5-month-old German Shorthaired Pointer with a large clitoris. The gonads were situated caudal to the kidneys at the cranial tips of the uterine horns, and were composed mainly of seminiferous tubules and interstitial cells and had ovarian follicles in the cortices. Each gonad had efferent tubules, a pampiniform plexus, fimbriae, and a uterine tube. The uterus was positioned normally in the abdomen and had no gross or histologic abnormalities. Giemsa-banded karyotypes revealed a normal female 78,XX chromosomal complement with no structural abnormalities.

Testicular feminization, caused by an inherited defect of the androgen receptor, was diagnosed in a domestic cat. Individuals affected with this syndrome are genetic males that have testes but fail to undergo masculinization because the internal and external genitalia cannot respond to androgens. The affected cat had the external appearance of a sexually normal female, but during surgery for ovariohysterectomy, only 2 abdominal gonads were found. Müllerian (uterus) or wolffian (epididymides) derivatives were not present. Only testicular tissue was found in histologic sections of the gonad. A normal male chromosome constitution (38,XY) was found in karyotypes prepared from lymphocyte cultures. High affinity binding of dihydrotestosterone was undetectable in fibroblasts cultured from genital skin of the affected cat, indicating that the cytosolic androgen receptor was nonfunctional. Pedigree analysis indicates that this is an X-linked disorder in cats, as it is in other mammals. Accurate diagnosis and genetic counseling are advocated to reduce the prevalence of the disorder.

Immediate and long-term outcomes of prostaglandin F2 alpha treatment for canine pyometra were studied in 10 bitches. Examination of pretreatment uterine biopsy specimens, taken for histopathologic diagnosis and classification of disease severity, revealed either type III or IV pyometra. Dinoprost tromethamine (0.25 or 0.5 mg/kg of body weight, SC) was given once daily for 3 days. Bitches were bred at the first posttreatment estrus and monitored for a minimum of one year. When pure cultures of Escherichia coli (n = 3) or Staphylococcus aureus (n = 1) were obtained from the vagina, these bacteria also were found in the uterus. Pretreatment WBC counts often did not reflect the severity of histopathologic findings in the uterus, but posttreatment WBC counts were useful in monitoring response to treatment. Four bitches produced a litter within one year of treatment. Four bitches (40%) had recurrence of pyometra within one year of treatment, and these same bitches had another recurrence after an additional prostaglandin treatment. Three additional bitches had a recurrence by 27 months after therapy, establishing a total recurrence rate of 77% (7/9). Results suggested that subclinical disease may persist after treatment, with clinical recurrence during diestrus. Despite the high recurrence rate, it was concluded that this treatment is a practical treatment for canine pyometra when reproduction is desired.

Blood samples were taken by jugular venipuncture from healthy kittens ranging in age from birth to 17 weeks. Complete blood cell counts, including RBC indices, provided data on reference blood values in kittens. Age-dependent RBC changes observed were decreases in PCV and hemoglobin (Hb) and mean cell Hb concentrations in neonatal kittens and a subsequent increase in PCV, Hb concentration, and RBC count in juvenile kittens. Leukocyte changes included an increasing WBC count from birth through the weanling period, increases in lymphocyte numbers in the neonatal and juvenile age groups, and increases in eosinophil numbers in the juvenile period.