Medical control of reproduction in the male dog with deslorelin subcutaneous implants

Slow-release subcutaneous implants containing GnRH agonist deslorelin were released into the European market in 2007. Since then, they are widely used per label by European veterinarians for the prevention of fertility in adult male dogs. Additionally, they are also used ‘off-label’ to postpone puberty, reduce unwanted behavior potentially linked to testosterone, eliminate clinical signs induced by benign prostatic hyperplasia, reduce the size of perianal adenomas, or reverse hair loss due to alopecia X in intact male dogs. After an initial ‘flare-up’ effect (short-duration increases in blood testosterone concentrations immediately after implantation) there is a perceptible decline in testosterone concentrations within a few weeks, due to pituitary downregulation. The dog becomes ‘medically castrated’ and infertile, with a reduction in testes size and spermatogenic arrest. Normal plasma testosterone concentrations are recovered in 18 months in 98% of dogs and reimplantations are possible for life. Preferably, reimplantation should occur prior to disappearance of previous implant action to avoid another ‘flare-up’ effect of reimplantation. After loss of implant function, it usually takes 1 - 2 months for complete sperm quality restoration before dog is potentially fertile again. ...

Male dog, fertility control, prostate, unwanted behavior, hair loss, deslorelin