Neutering your rabbits is vital in helping your rabbits live a long and healthy life.
If you own a mixed sex pair of rabbits, they both need to be neutered in order to live together amicably. Even if your female is spayed, an un-castrated male will still try and mount her, this can trigger fighting and can lead to stress for both rabbits. On the other hand, if you leave your female un-spayed but neuter your male, she will have many false pregnancies, is very likely to become aggressive and is at a higher risk of developing uterine cancer.
There are many advantages of having your male rabbit neutered. Un-castrated males can breed, neutering prevents this. Un- castrated male rabbits often spray urine, just like tom cats, to mark their territory. This can include their possessions and their companions. Un-neutered males can also develop testicular and prostate cancer. Even though this risk is small, castration eliminates the chances completely. Neutering your male rabbit often makes litter training them a lot easier. Some un-neutered males are aggressive. After castration, testosterone levels will fall and this should dramatically reduce or eradicate this behaviour. Un-castrated male rabbits can realistically, not live with any other rabbits. In general, neutered males are much happier and relaxed pets.
There are many reasons why you should also have your female rabbit spayed. Unspayed females are at a very high risk of developing uterine cancer and pyometra, this is a disease of the uterus. Both conditions can be fatal. Some unspayed females are very aggressive and territorial. Many have repeated phantom pregnancies and some may growl, bite, scratch or lunge at their owners and companions. This is a particular risk in the warmer months. Keeping two unspayed females together, even if they are related can make their aggression issues even worse. Female rabbits are able to reproduce at around 4-6 months of age. Their pregnancies are very short, around 31 days, and there are several kits to each litter. Females are able to mate again immediately after they have given birth, so if the dad is still around the potential for a population explosion is obvious.