Behavioural changes after treatment with GnRH implants in male dogs; the behavioural effects of a reversible chemical castration. In comparison: a literature review of the behavioural effects of surgical castration in male dogs.
Summary
The best known way of controlling or changing the behaviour of male dogs is through surgical castration. However, this method is not always very effective and above all irreversible. Therefore, a reversible alternative that results in behavioural changes comparable to the changes seen after surgical castration is desirable. GnRH-agonist implants can be this alternative. A lot of different agonists have been used in the past for the temporary castration of male animals for research purposes. Nowadays, the GnRH agonist used most in male dogs is deslorelin. The effect of chemical castration on the behaviour of male dogs is not very clear yet. It is interesting to know if this effect is comparable with the effect of surgical castration on the behaviour. A pilot study has been done to see if the results of chemical castration with deslorelin are promising. In this study 21 dogs were used. The owners of treated dogs received a questionnaire. The majority of dogs showed major behavioural changes after chemical castration with deslorelin implants. Depending on the specific behaviour, the effect of deslorelin on behaviour was however very diverse. Inter-male aggression did not apply or decreases, urine marking stayed the same or decreased. A complete reduction could be seen when regarding preputial infection and sexual behaviour like mounting people or other dogs. Some owners reported that their dog responded better to commands, were calmer and/or showed an increase in play behaviour. A reduction of testis circumference was seen in the majority of dogs. Because of these positive results a study has been started to determine the effect of a chemical castration on the behaviour of intact male dogs using the GnRH agonist deslorelin (4,7 mg/implant). Furthermore, it is important to determine if this effect is comparable with the effect of surgical castration on the behaviour of male dogs. For this study 44 dogs will be used, they will be divided in 2 groups of 22 dogs each: a chemical castration and a surgical castration group. The dogs will be subjected to a behavioural test and a GnRH challenge test before and after the chemical castration. The owners will receive a questionnaire about their dogs behaviour before and after the chemical castration. Furthermore, the owners will receive a follow-up questionnaire by phone on 4 different moments following the chemical castration (1, 3, 5 and 7 weeks). This is an ongoing study. The results of the telephonic follow-up questionnaire of 6 dogs are used in this paper to give a report of the initial results. The majority of these 6 dogs showed an increase in general agility and play behaviour after chemical castration. The effect on inter-male aggression was not very uniform, however, a decline seemed to be the tendency. A complete reduction was seen regarding preputial infection and sexual behaviour like mounting people or other dogs. Furthermore, the majority of dogs showed an increase in appetite. A reduction of testis circumference was observed by the owner in all of the dogs. Most changes started around the 3rd week after chemical castration. The results of the pilot study and the telephonic follow-up questionnaire are comparable. Furthermore, the effect of a chemical castration using deslorelin on the behaviour of male dogs seems to be comparable with the effect of a surgical castration when literature is compared with the results of this paper. The deslorelin implant could be considered a suitable and above all reversible alternative for surgical castration in male dogs.