Chemical and Surgical Castration of Male Dogs: Behavioral Effects

Abstract

Chemical castration using GnRH agonists has proven to be an effective method of rendering dogs infertile as a reversible alternative to orchiectomy. However, little is known about the behavioral effects of chemical castration. In this study, the effects of surgical and chemical castration on aggression, sexual behavior, play behavior and fear/insecurity in male dogs were assessed. In order to do so, twenty-three dogs where chemically castrated using implants which slowly release the GnRH agonist Deslorelin (Suprelorin®), and 18 dogs were surgically castrated. Their behavior was assessed on the day of, but prior to treatment and 4-5 months after treatment by means of a behavior test and a questionnaire that was filled out by the dog-owners. No significant changes in fear/insecurity and aggression were seen after treatment using the behavior tests in both groups. However, many owners did observe a decrease in aggressive behavior towards other male dogs (suprelorin implant group: 43.5%, surgical castration group: 47.0%). Moreover, no significant differences could be found between groups concerning the individual results of the behavior test and the results of the perceptive questions concerning aggressive behavior and fear/insecurity. Play behavior increased significantly in the suprelorin group as well as the surgical castration group, both groups showed a similar increase (p=0.008 and p= 0.041 respectively). Additionally, the owners of the dogs in both groups observed a decrease of sexual behavior towards estrus bitches. However, significantly more owners of the surgical castration group noticed this decrease, compared to the owners of the suprelorin implant group (p=0.018). A decrease in sexual behavior was not observed during the behavior tests. Overall, this study shows that surgical and chemical castration in dogs induce similar effects with regard to aggression, fear/insecurity and play behavior. However, according to our study, a greater effect on sexual behavior can be expected following orchiectomy compared to the changes after chemical castration. Although this study provides some interesting information about the behavioral effects of surgical and chemical castration, more research is needed in order to make a clear statement about the degree in which surgical castration and chemical castration lead to similar results.