Both castration in the male dog and spaying in the female are major operations which need a general anaesthetic. Your dog must be fasted overnight before the operation to reduce the risk of problems on the operating table. Castrating male dogs is a relatively straightforward operation and there is very little chance of anything going wrong. Spaying bitches is more difficult but it is one of the operations most frequently carried out by vets and any experienced vet will have done it many hundreds of times.

In the male the operation involves a single cut into the scrotum of the male dog to take out the testicles. Your dog should be ready to come home on the same day as surgery, as soon as the anaesthetic has worn off. If there are any complications, your vet might keep your dog overnight to keep an eye on them.