Male (n=6/group) and female (n=6/group) kittens were gonadectomized at 7 weeks (prepuberally) or 7 months of age (postpuberally), or left intact. Lateral radiographic projections of the right forelimb were made from 4 months of age until the distal radial physis was closed, or 24 months of age. In males, distal radial physeal closure was delayed in both groups of gonadectomized animals, compared to intact males (p<0.01). In females, proximal radial physeal closure was significantly delayed in prepuberally gonadectomized animals (p=0.02), and distal radial physeal closure was significantly delayed in both groups of gonadectomized animals, compared to intact animals (p<0.01). Final radial length (females p<0.01, males p=0.01), and age and radial length at time of the growth plateau (p<0.01) were significantly increased in all gonadectomized animals. Age at gonadectomy had no effect on age and radial length at time of the growth plateau. No puberal growth spurt was observed in any of the cats.

Male (n = 6/group) and female (n = 6/group) kittens were gonadectomized at 7 weeks or 7 months of age, or left intact. At 22 months of age, complete penile extrusion was possible in all of the intact males, in 3/5 (60%) males castrated at 7 months of age, and in none of the males castrated at 7 weeks of age. Antegrade (voiding) cystourethrograms were performed at 22 months of age. Diameter of the preprostatic (p = 0.13) and penile (p>0.25) urethra of male cats did not vary by group. Diameter of the pre‐pelvic urethra of female cats gonadectomized at 7 weeks of age was significantly smaller than that of intact females (p = 0.02).

OBJECTIVE:To use indirect calorimetry to compare heat production between gonadectomized and sexually intact male and female cats.DESIGN:Male (n = 6) and female (n = 6) kittens were gonadectomized at 7 weeks or 7 months of age, or left sexually intact. Body heat production was measured by indirect calorimetry in all cats at 12, 18, and 24 months of age.ANIMALS:18 male and 18 female clinically normal domestic shorthair cats.PROCEDURE:Heat production was measured, using an open-circuit, respiratory, indirect calorimeter. All cats underwent calorimetry at 12, 18, and 24 months of age. The heat coefficient, a measure of resting metabolic rate, was calculated for each cat at each test; heat coefficient is defined as logarithm of heat (kcal/h) divided by logarithm of body weight (kg).RESULTS:Heat production did not vary with age in male or female cats. Heat coefficient was higher in sexually intact male and female cats than in gonadectomized male and female cats at 12, 18, and 24 months of age (12 months, females, P < 0.01, males, P = 0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months, females and males, P < 0.01).CONCLUSIONS:These data suggest that resting metabolic rate in cats decreases after gonadectomy.CLINICAL RELEVANCE:A decrease in metabolic rate is synonymous with a decrease in caloric requirements. Gonadectomized animals fed in a manner similar to sexually intact animals may be predisposed to obesity and its sequelae.

Vaginal cornification and/or serum progesterone concentration may be used as indicators of follicular and luteal function in the cat in diagnosis of estrus, induced or spontaneous ovulation, ovarian remnant syndrome, and prolonged gestation. Feline sperm may be collected by electroejaculation, ejaculation into an artificial vagina, cystocentesis of the male following ejaculation or by vaginal wash of the bred female. Normal feline seminal plasma contains high concentrations of alkaline phosphatase, and may contain more than 10 000 colony forming units (CFU) ml−1 bacteria, most of which are normal preputial flora. Serum testosterone concentration, often undetectable (less than 0.02 ng ml−1) in the normal male, increases 1 h after gonadotropin-releasing hormone (GnRH) or 4 h after human chorionic gonadotropin (hCG) administration in the tom. Presence of penile spines is an indicator of testicular tissue or testosterone administration. Gonadectomy performed at 7 weeks or 7 months of age in male and female cats is associated with increased length of long bones due to delayed physeal closure, decreased heat production, and increased risk of obesity, and not with decrease in urethral diameter. Normal penile extrusion was not possible in 66 male cats neutered at 7 weeks of age or 25 male cats neutered at 7 months of age, owing to persistence of the balanopreputial fold, which normally undergoes dissolution under the influence of androgens.

A two-year-old domestic shorthair presented for estrous behavior four months after ovariohysterectomy. On exploratory laparotomy, ovarian remnant tissue and multiple intestinal diverticula were found. Histopathology identified the diverticula as pseudodiverticula.

Diabetes mellitus, characterised by persistent hyperglycaemia and glucosuria, was diagnosed in a six-week-old kitten. Pancreatic sections contained low numbers of atypically small islets and immunohistochemistry demonstrated pancreatic endocrine insufficiency with virtually no production of any islet hormones. There was no inflammatory infiltration of the islets, as seen in the form of diabetes mellitus characteristic of juvenile humans.

Reproductive performance in a feline research colony of 14 queens is reported. Average estrous length in 38 cycles was 5.8 +/- 3.3 days, with a range of two to 19 days. Estrous length in 23 bred cycles was not shorter (p greater than 0.05) than in 15 nonbred cycles, suggesting that induction of ovulation does not decrease estrous length. Pregnancy rate in 23 bred cycles was 73.9%. Gestation length averaged 66.9 +/- 2.9 days with a range of 62 to 71 days (n=15). Average parturition length was 16.1 +/- 14.3 hours (n=7), with a range of four to 42 hours. Litter size ranged from one to five kittens, with an average of 3.7 kittens per litter (n=15). Percent mortality by eight weeks of age was 29.1%, with 4.7% stillbirths.

Medical records of 15 dogs with vaginal septa, examined between April 1983 and December 1992, were reviewed. Overall prevalence of vaginal septation at the hospital during the study period was 0.03%. Thirteen breeds were represented; mean age at the time of initial examination was 2.4 years. Owners' original complaints included inability to breed naturally, dysuria, urinary incontinence, infertility, recurrent vaginitis, ambiguous external genitalia, and dystocia. One dog did not have clinical signs associated with the vaginal septum. In 11 of the 15 dogs, the septum could be palpated during digital vaginal examination. The septum could be seen in 6 of the 7 dogs in which vaginoscopy was performed. Twelve of the 15 dogs underwent positive-contrast vaginography; in all 12, the septum could be easily seen. Four of the 15 dogs underwent removal of the septum, with or without episiotomy, and 4 others were ovariohysterectomized. One dog was bred by means of artificial insemination and became pregnant. The remaining 6 dogs were lost to follow-up.

Retrograde ejaculation and hypothyroidism were diagnosed in a 19-mo-old Labrador retriever: The retrograde ejaculation was reversed following the administration of the sympathomimetic agent, pseudoephedrine hydrochloride, at a dose of 4 mg/kg per os given 1 and 3 h before semen collection. Antegrade ejaculation failed to occur after normalization of serum thyroid hormone levels by thyroxine supplementation. The pathophysiology of retrograde ejaculation is reviewed.

A 5-month-old male mixed-breed dog with two penises and a third, rudimentary rear limb which was attached by a hemipelvis was presented. One month after it was adopted from an animal shelter, the dog developed a gross hematuria and inappropriate urination. Several years later, the owners requested the dog be castrated. Ultrasonography reconfirmed the presence of two normal kidneys, a right and left bladder, and two prostate glands. Conclusions of the studies indicate that while the embryologic basis for development of these anomalies is not well understood, they need not be incompatible with life.

The termination of canine and feline pregnancies might substantially reduce pet overpopulation in the United States. As many as four million pregnancies could be annually terminated to prevent the births of millions of puppies and kittens destined to be surrendered or abandoned. While ovariohysterectomy can be performed safely in most pregnant dogs and cats, the development and utilization of non-surgical abortifacients has been slow. Abortifacients which are highly effiacious, safe, and reasonably priced continue to be sought.