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.

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.

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.

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.