Can anyone help please?  My two year old male dobe was castrated a couple of weeks ago and has since become very much more aggressive towards other dogs (inc bitches).  It is a long story up to the point of the operation, and the reasons we had him castrated, but we had never seen any agression in the home towards the older bitch we have, and he has now laid into her several times.  Our vet says it is nothing to do with the op, but it must be related as it is a significant change that has happened since he was done.  Anyone else had similar experience, and does it pass in time? What can we do to manage this?

Hi Guest,

As this has only begun and he was only recently operated on it is possible that he was suffering paind and/or discomfort and therefore intending only to "see off" your older bitch.   If that is the case, I'd ensure they had very limited and only supervised contact for a few weeks to ensure he is fully recovered from any bruising etc.   If he keeps having access to her and attacking her, this behaviour could become entrenched so supervision is the order of the day IMO.

Castration for prevention of aggression problems is rarely successful in the mature dog as, again, his behaviour has become learned over a period and is no longer hormone driven - acquired behaviour has to be trained out - not cut off :o

Hopefully this helps and someone with frist hand experience of this problem will be along soon with more info.

Good luck, Teri ;)