Effects of surgical sterilization on canine and feline health and on society.

Surgical sterilization of dogs and cats is a well-accepted measure for population control in some countries, but is considered unethical as an elective surgery in other countries. This is a review of what is known regarding positive and negative effects of gonadectomy surgery on individual animals and on societal management of unowned dog and cat populations.

The value of canine semen evaluation for practitioners.

Compared to human medicine, little is known in canine medicine regarding specific findings on semen evaluation and their correlation with fertility. Suggestions to optimize quality of semen evaluation in veterinary practice include creating standardized protocols for evaluation of all semen parameters and updating those protocols as needed; creating some form of quality control for the clinic laboratory; educating owners about our inability to predict with 100% accuracy whether dogs with poor semen quality never could impregnate a bitch or whether dogs with excellent semen quality always could impregnate a bitch; and generating protocols for further diagnostic work-up for those dogs with abnormal semen quality.

Effects of finasteride on size of the prostate gland and semen quality in dogs with benign prostatic hypertrophy.

OBJECTIVE: To determine the effect of the 5alpha-reductase inhibitor finasteride on prostatic diameter and volume, semen quality, and serum dihydrotestosterone (DHT) and testosterone concentrations in dogs with spontaneous benign prostatic hypertrophy (BPH). DESIGN: Double-blind placebo-controlled trial. ANIMALS: 9 dogs with BPH. PROCEDURE: Five dogs were treated with finasteride for 16 weeks (0.1 to 0.5 mg/kg [0.05 to 0.23 mg/lb] of body weight, PO, q 24 h); the other 4 received a placebo. Prostatic diameter, measured radiographically, prostatic volume, measured ultrasonographically, semen quality, and serum DHT and testosterone concentrations were evaluated before and during treatment. After receiving the placebo for 16 weeks, the 4 control dogs were treated with finasteride for 16 weeks, and evaluations were repeated. RESULTS: Finasteride significantly decreased prostatic diameter (mean percentage decrease, 20%), prostatic volume (mean percentage decrease, 43%), and serum DHT concentration (mean percentage decrease, 58%). Finasteride decreased semen volume but did not adversely effect semen quality or serum testosterone concentration. No adverse effects were reported by owners of dogs in the study. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that finasteride can be used to reduce prostatic size in dogs with BPH without adversely affecting semen quality or serum testosterone concentration.

Disorders of the canine penis.

Function and anatomy of the canine penis are reviewed. Functional abnormalities of the penis described include lack of erection and lack of ejaculation. Physical abnormalities of the penis also are described, including paraphimosis. Diagnosis and treatment options are described.

Early-age neutering of dogs and cats in the United States (a review).

Prepubertal gonadectomy, often referred to as early-age neutering, has increased in popularity in the United States. The procedure is often used at animal care and control facilities, where puppies and kittens are neutered as early as 7 weeks of age or before adoption. Although the anaesthetic and surgical procedures appear to be safe, studies continue to evaluate the long-term effects on health and behaviour. Early-age neutering is one technique that is used to combat pet overpopulation, a problem whereby millions of unwanted healthy dogs and cats are euthanased each year. Although neutering animals is helpful in controlling pet overpopulation, other factors must be considered. In addition, many animals are relinquished to shelters when they show inappropriate behaviours, because owners and veterinarians are unable to modify animal behaviour. This review discusses early-age neutering in the United States, and includes the review of scientific studies that have evaluated this procedure in puppies and kittens. Early-age neutering does not stunt growth in dogs or cats (a once-held belief), but may alter metabolic rates in cats. The anaesthetic and surgical procedures are apparently safe for young puppies and kittens; morbidity is lower and recovery is faster than in adult animals. To date, adverse side effects are apparently no greater in animals neutered at early ages (7 weeks) than in those neutered at the conventional age (7 months).

Prostatic disorders in the dog.

Common canine prostatic disorders include benign prostatic hypertrophy (BPH), prostatitis, prostatic cysts and prostatic adenocarcinoma. BPH is a spontaneous and age-related disorder of intact male dogs, which occurs in more than 80% male dogs over 5 years of age, and which is associated with clinical signs of sanguinous prostatic fluid, constipation and dysuria. BPH signs respond to castration or to finasteride treatment (0.1-0.5 mg/kg per os once daily), as finasteride inhibits conversion of testosterone to dihydrotestosterone, causing prostatic involution via apoptosis. BPH often occurs concurrently with prostatic infection, abscessation, cysts and neoplasia in the intact dog, and finasteride-induced prostatic involution may be beneficial in treatment of all of these conditions except neoplasia. Two studies suggest that risk of prostatic adenocarcinoma is increased in neutered, compared to intact male dogs. Although canine prostatic neoplasia, unlike human prostatic neoplasia, usually does not respond to androgen deprivation, recent reports of prostatic intraepithelial neoplasia (PIN) in a high percentage of older male dogs, with and without prostatic adenocarcinoma, suggests that PIN may be a precursor to adenocarcinoma in the dog as it is believed to be in man.

Early spay-neuter in the dog and cat.

Early spay-neuter refers to the surgical sterilization of 8- to 16-week-old animals. Anesthetic and surgical techniques for the dog and cat are described. Pros and cons of prepubertal gonadectomy are discussed, and the veterinary literature is reviewed.

The effects of stains and investigators on assessment of morphology of canine spermatozoa.

Percentage and types of morphological abnormalities found in canine spermatozoa were evaluated by three investigators using three stains (Giemsa-Wright stain [Diff-Quik], eosin Y/nigrosin [Hancock], and eosin B/nigrosin [Society for Theriogenology morphology stain] with conventional light microscopy, compared to phase contrast microscopy on unstained samples. The percentage of spermatozoa with abnormal heads, midpieces, and tails varied by technique and by investigator. Average percentages of morphologically normal spermatozoa were significantly higher in samples stained with Diff-Quik and samples examined by phase contrast microscopy than in samples stained with Hancock or Society for Theriogenology morphology stains. No effect of investigator on the percentage of morphologically normal spermatozoa was assessed. Results suggest that staining or preparation technique may alter the morphology of canine spermatozoa artifactually.